COSTILLA ENERGY INC
S-1, 1996-07-26
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<PAGE>
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 26, 1996
 
                                                   REGISTRATION NO. 333-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
                                    FORM S-1
 
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
 
                             COSTILLA ENERGY, INC.
             (Exact name of Registrant as specified in its charter)
 
<TABLE>
<S>                              <C>                             <C>
            DELAWARE                           1311                     75-2658940
 (State or other jurisdiction of   (Primary Standard Industrial      (I.R.S. Employer
 incorporation or organization)    Classification Code Number)     Identification No.)
</TABLE>
 
                            ------------------------
 
                         400 WEST ILLINOIS, SUITE 1000
                              MIDLAND, TEXAS 79701
                                 (915) 683-3092
              (Address, including zip code, and telephone number,
       including area code, of Registrant's principal executive offices)
 
                          MICHAEL J. GRELLA, PRESIDENT
                             COSTILLA ENERGY, INC.
                         400 WEST ILLINOIS, SUITE 1000
                              MIDLAND, TEXAS 79701
                                 (915) 683-3092
           (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)
                            ------------------------
 
                                   COPIES TO:
 
<TABLE>
<S>                                            <C>
             Richard T. McMillan                              R. Joel Swanson
      Cotton, Bledsoe, Tighe & Dawson,                     Baker & Botts, L.L.P.
         a Professional Corporation                            910 Louisiana
              500 West Illinois                            Houston, Texas 77002
                  Suite 300
            Midland, Texas 79701
</TABLE>
 
                            ------------------------
 
    APPROXIMATE  DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after this Registration Statement becomes effective.
 
    If any of the securities being registered on this Form are to be offered  on
a  delayed or continuous basis pursuant to  Rule 415 under the Securities Act of
1933, check the following box: / /
 
    If this Form  is filed  to register  additional securities  for an  offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and  list  the  Securities  Act registration  statement  number  of  the earlier
effective registration statement for the same offering.  / /
 
    If this Form  is a post-effective  amendment filed pursuant  to Rule  462(c)
under  the Securities Act, check  the following box and  list the Securities Act
registration statement number  of the earlier  effective registration  statement
for the same offering.  / /
 
    If  delivery of the Prospectus is expected  to be made pursuant to Rule 434,
please check the following box.  / /
 
                        CALCULATION OF REGISTRATION FEE
 
<TABLE>
<CAPTION>
                                                                         PROPOSED MAXIMUM
    TITLE OF EACH CLASS OF         AMOUNT TO BE     PROPOSED OFFERING   AGGREGATE OFFERING      AMOUNT OF
 SECURITIES TO BE REGISTERED        REGISTERED      PRICE PER NOTE(1)        PRICE(1)        REGISTRATION FEE
<S>                             <C>                 <C>                 <C>                 <C>
  % Senior Subordinated Notes
 due 2006                          $100,000,000           $1,000           $100,000,000          $34,483
</TABLE>
 
(1) Estimated solely for the purpose of calculating the registration fee.
                            ------------------------
 
    THE REGISTRANT HEREBY  AMENDS THIS  REGISTRATION STATEMENT ON  SUCH DATE  OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE  A  FURTHER  AMENDMENT  WHICH SPECIFICALLY  STATES  THAT  THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE  IN ACCORDANCE WITH SECTION 8(A)  OF
THE  SECURITIES ACT  OF 1933  OR UNTIL  THE REGISTRATION  STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION  8(A),
MAY DETERMINE.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
                             CROSS REFERENCE SHEET
                  (PURSUANT TO ITEM 501(B) OF REGULATION S-K)
 
<TABLE>
<CAPTION>
                    ITEM NUMBER AND HEADING                                 LOCATION OR CAPTION IN PROSPECTUS
- ----------------------------------------------------------------  -----------------------------------------------------
<C>        <S>                                                    <C>
       1.  Forepart of the Registration Statement and Outside
            Front Cover of Prospectus...........................  Outside Front Cover Page
       2.  Inside Front and Outside Back Cover Pages of
            Prospectus..........................................  Inside Front and Outside Back Cover Pages
       3.  Summary Information, Risk Factors and Ratio of
            Earnings to Fixed Charges                             Prospectus Summary; Risk Factors; The Company; Pro
                                                                   Forma Condensed Financial Statements; Selected
                                                                   Financial Information
       4.  Use of Proceeds......................................  Prospectus Summary; Use of Proceeds
       5.  Determination of Offering Price......................  Outside Front Cover Page; Underwriting
       6.  Dilution.............................................  *
       7.  Selling Security Holders.............................  *
       8.  Plan of Distribution.................................  Outside Front Cover Page; Underwriting
       9.  Description of Securities to Be Registered...........  Outside Front Cover Page; Prospectus Summary;
                                                                   Description of Notes
      10.  Interests of Named Experts and Counsel...............  *
      11.  Information with Respect to the Registrant...........  Prospectus Summary; Risk Factors; The Company;
                                                                   Capitalization; Pro Forma Condensed Financial
                                                                   Statements; Selected Financial Information;
                                                                   Management's Discussion and Analysis of Financial
                                                                   Condition and Results of Operations; Business and
                                                                   Properties; Management; Certain Transactions;
                                                                   Security Ownership of Certain Beneficial Owners and
                                                                   Management; Executive Compensation and Other
                                                                   Information; Description of Notes; Description of
                                                                   Other Indebtedness; Consolidated Financial
                                                                   Statements
      12.  Disclosure of Commission Position on Indemnification
            for Securities Act Liabilities......................  *
</TABLE>
 
- ------------------------
* Omitted because item is not applicable.
<PAGE>
INFORMATION   CONTAINED  HEREIN  IS  SUBJECT   TO  COMPLETION  OR  AMENDMENT.  A
REGISTRATION STATEMENT  RELATING TO  THESE SECURITIES  HAS BEEN  FILED WITH  THE
SECURITIES  AND EXCHANGE  COMMISSION. THESE SECURITIES  MAY NOT BE  SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR  TO THE TIME THE REGISTRATION STATEMENT  BECOMES
EFFECTIVE.  THIS  PROSPECTUS  SHALL  NOT  CONSTITUTE AN  OFFER  TO  SELL  OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE  SECURITIES
IN  ANY STATE IN WHICH SUCH OFFER,  SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.
<PAGE>
                   SUBJECT TO COMPLETION, DATED JULY 26, 1996
 
PRELIMINARY PROSPECTUS
 
                                  $100,000,000
 
                             COSTILLA ENERGY, INC.
 
                       % SENIOR SUBORDINATED NOTES DUE 2006
 
                               ------------------
 
    The   % Senior Subordinated Notes  due 2006 (the "Notes") are being  offered
(the  "Notes  Offering")  by  Costilla  Energy,  Inc.,  a  Delaware  corporation
("Costilla" or the "Company"). The net proceeds of the Notes Offering,  together
with  the net proceeds of the other  financing described herein, will be used by
the Company  to  refinance  existing  indebtedness,  to  pay  certain  costs  in
connection with the Corporate Reorganization (as defined herein) and for general
corporate purposes.
 
    The  Notes mature on         , 2006, unless previously redeemed. Interest on
the Notes is  payable semiannually on             , and            ,  commencing
        ,  1997. The Notes will  be redeemable at the  option of the Company, in
whole or in part, on or after         , 2001, at the redemption prices set forth
herein, plus  accrued and  unpaid  interest, if  any,  to the  redemption  date.
Notwithstanding the foregoing, at any time on or before         , 1999, Costilla
may  redeem up to  30% of the  original aggregate principal  amount of the Notes
with the net proceeds of an Equity Offering (as defined herein) at a  redemption
price  equal to    %  of the principal  amount thereof, plus  accrued and unpaid
interest thereon, if any, to the redemption  date. Upon a Change of Control  (as
defined herein), the Company will be required to make an offer to repurchase all
outstanding Notes at 101% of the aggregate principal amount thereof plus accrued
and  unpaid interest,  if any,  to the date  of repurchase.  See "Description of
Notes."
 
    Concurrently with  the  Notes Offering  the  Company is  offering  4,000,000
shares (4,600,000 shares if the underwriters' over-allotment option is exercised
in  full) of its Common Stock (the "Common Stock Offering" and together with the
Notes Offering, the  "Offerings") pursuant to  an underwritten public  offering.
The  Notes Offering and  the Common Stock  Offering are each  conditioned on the
consummation of the other.
 
    The Notes will be general unsecured obligations of the Company, subordinated
in right of payment to all  existing and future Senior Indebtedness (as  defined
herein)  of the Company, which will include borrowings under the Credit Facility
(as defined herein). As  of March 31,  1996, on a pro  forma basis after  giving
effect  to a recent acquisition, the Corporate Reorganization, the Offerings and
the application of the proceeds therefrom, as described under "Use of Proceeds",
the Company  would have  had  no Senior  Indebtedness.  No indebtedness  of  the
Company   is  expressly   subordinated  to   the  Notes.   The  Notes   will  be
unconditionally guaranteed,  jointly and  severally,  on a  senior  subordinated
basis  by  the Company's  material  subsidiaries (the  "Subsidiary Guarantors"),
provided that such  guarantees will terminate  under certain circumstances.  See
"Risk Factors," "Capitalization" and "Description of Notes."
 
    The Notes will be represented by a Global Certificate registered in the name
of the nominee of The Depository Trust Company, which will act as the Depositary
(the "Depositary"). Beneficial interests in the Global Certificate will be shown
on,  and transfer thereof  will be effected only  through, records maintained by
the Depositary  and  its participants.  Except  as described  herein,  Notes  in
definitive  form  will not  be  issued. See  "Description  of Notes--Book-Entry,
Delivery and Form."
 
    The Company does  not intend to  list the Notes  on any national  securities
exchange. See "Risk Factors--Absence of Public Market." Application will be made
to  list the Common Stock on The  Nasdaq Stock Market's National Market ("Nasdaq
National Market") under the symbol "COSE".
 
    SEE "RISK FACTORS" BEGINNING ON PAGE 11 FOR A DISCUSSION OF CERTAIN  FACTORS
THAT SHOULD BE CONSIDERED IN EVALUATING AN INVESTMENT IN THE NOTES.
 
                            ------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
    EXCHANGE  COMMISSION OR ANY  STATE SECURITIES COMMISSION  NOR HAS THE
       SECURITIES  AND  EXCHANGE  COMMISSION  OR  ANY  STATE   SECURITIES
       COMMISSION   PASSED  UPON  THE  ACCURACY  OR  ADEQUACY  OF  THE
          PROSPECTUS. ANY    REPRESENTATION  TO THE  CONTRARY IS  A
                               CRIMINAL OFFENSE.
<TABLE>
<S>                                                  <C>               <C>               <C>
- ---------------------------------------------------------------------------------------------------------
 
<CAPTION>
                                                         PRICE TO        UNDERWRITING      PROCEEDS TO
                                                        PUBLIC (1)      DISCOUNTS (2)     COMPANY (1)(3)
<S>                                                  <C>               <C>               <C>
- ---------------------------------------------------------------------------------------------------------
Per Note...........................................         %                 %                 %
Total..............................................    $100,000,000           $                 $
- ---------------------------------------------------------------------------------------------------------
</TABLE>
 
(1)  Plus accrued interest, if any, from         , 1996.
 
(2)  The  Company and  the Subsidiary  Guarantors have  agreed to  indemnify the
     Underwriters (as  defined herein)  against certain  liabilities,  including
     liabilities   under   the  Securities   Act  of   1933,  as   amended.  See
     "Underwriting."
 
(3)  Before deducting expenses payable by the Company, estimated at $        .
 
    The Notes are  being offered,  subject to  prior sale,  by the  Underwriters
when,  as and  if issued  to and  accepted by  the Underwriters,  and subject to
various prior conditions. The Underwriters reserve the right to withdraw, cancel
or modify such offer and  to reject orders in whole  or in part. It is  expected
that  delivery of the Global Certificate will be made on or about              ,
1996 in  book-entry  form through  the  facilities of  the  Depositary,  against
payment therefor.
 
NATIONSBANC CAPITAL MARKETS, INC.             PRUDENTIAL SECURITIES INCORPORATED
 
                 The date of this Prospectus is          , 1996
<PAGE>
                             COSTILLA ENERGY, INC.
                                GEOGRAPHIC FOCUS
 
       [GRAPHICS, AND FOR EDGAR A DESCRIPTION OF THE GRAPHICS, TO FOLLOW]
 
    IN  CONNECTION WITH THIS OFFERING, THE UNDERWRITERS MAY OVER-ALLOT OR EFFECT
TRANSACTIONS WHICH STABILIZE  OR MAINTAIN  THE MARKET PRICE  OF THE  NOTES AT  A
LEVEL  ABOVE  THAT  WHICH  MIGHT  OTHERWISE PREVAIL  IN  THE  OPEN  MARKET. SUCH
TRANSACTIONS  MAY  BE   EFFECTED  IN   THE  OPEN  MARKET   OR  OTHERWISE.   SUCH
STABILIZATION, IF COMMENCED, MAY BE DISCONTINUED AT ANY TIME.
 
                                       2
<PAGE>
                               PROSPECTUS SUMMARY
 
    THE  FOLLOWING  SUMMARY  IS  QUALIFIED  IN  ITS  ENTIRETY  BY  THE  DETAILED
INFORMATION, FINANCIAL STATEMENTS  AND OTHER  DATA APPEARING  ELSEWHERE IN  THIS
PROSPECTUS. THE PRO FORMA INFORMATION GIVES EFFECT TO THE CONVERSION OF COSTILLA
FROM A LIMITED LIABILITY COMPANY TO A CORPORATION, CERTAIN MATERIAL ACQUISITIONS
AND  THE OFFERINGS AND THE APPLICATION  OF THE ESTIMATED NET PROCEEDS THEREFROM.
SEE "-- SIGNIFICANT  ACQUISITIONS," "THE COMPANY  -- CORPORATE  REORGANIZATION,"
AND  "USE OF PROCEEDS." AS USED HEREIN, REFERENCES TO THE COMPANY OR TO COSTILLA
ARE TO COSTILLA ENERGY, INC.  AND ITS SUBSIDIARIES. UNLESS OTHERWISE  INDICATED,
THE  INFORMATION  IN THIS  PROSPECTUS  ASSUMES THE  UNDERWRITERS' OVER-ALLOTMENT
OPTION WITH RESPECT TO THE COMMON STOCK OFFERING WILL NOT BE EXERCISED.  CERTAIN
OIL AND GAS TERMS USED IN THIS PROSPECTUS ARE DEFINED IN THE "GLOSSARY" INCLUDED
HEREIN.  CERTAIN  TERMS USED  IN  CONNECTION WITH  THE  NOTES ARE  DEFINED UNDER
"DESCRIPTION OF NOTES -- CERTAIN DEFINITIONS."
 
                                  THE COMPANY
 
    Costilla is  an  independent  energy company  engaged  in  the  exploration,
acquisition  and development  of oil and  gas properties.  The Company's primary
operations are  in the  Permian Basin,  the Gulf  Coast and  the Rocky  Mountain
regions.  The  Company's  strategy  focuses  on  increasing  reserves  through a
targeted exploration program,  the exploitation of  its existing properties  and
selective  property acquisitions. In addition,  the Company recently acquired an
interest in  a  concession for  the  development  of mineral  interests  in  the
Republic  of Moldova, in Eastern Europe. The Company also has minor interests in
the domestic gas gathering and transmission business.
 
    The Company's  predecessor began  operating  in 1988  with the  strategy  of
acquiring and exploiting undervalued oil and gas properties, and at December 31,
1992  had net proved reserves  of 4.7 MMBOE. Since  January 1, 1993, the Company
has successfully closed seven  transactions for an  aggregate purchase price  of
approximately  $101  million.  As  of  March 31,  1996,  the  Company  had total
estimated net  proved reserves  of 16.5  Mmbbls of  oil and  112.9 Bcf  of  gas,
aggregating  35.3 MMBOE,  with a  PV-10 Value  of approximately  $179.5 million,
assuming the 1996 Acquisition (as defined below) had occurred at March 31, 1996.
The Company also has  a substantial undeveloped  acreage position consisting  of
205,908  gross (141,384 net) acres. The Company  has identified in excess of 200
drilling locations of which 82 are included in its proved reserves.
 
    Costilla  has  in-house  exploration   expertise  which  uses  3-D   seismic
technology  as  a  primary  tool  to  identify  drilling  opportunities  and has
experienced high rates of  success in each  of its first  two major 3-D  seismic
drilling  programs. Since 1994, the Company has  drilled 23 wells based on these
3-D surveys,  20  of  which  have been  productive.  The  Company  has  recently
completed  a third  3-D survey  in Pecos County,  Texas and  intends to commence
drilling on this acreage in  the second half of  1996. Moreover, the Company  is
currently  conducting two additional 3-D surveys. The Company currently plans to
drill 81 wells through 1997 based on its 3-D surveys.
 
    Since  1993,  Costilla  has   generated  significant  growth  in   reserves,
production  and EBITDA. The Company increased its estimated proved reserves from
6.0 MMBOE at December 31,  1993 to 35.3 MMBOE at  March 31, 1996 (pro forma  for
the  1996 Acquisition), representing a compound annual growth rate of 114%. This
reserve growth has been achieved at an average all-in finding cost of $3.49  per
BOE  over such period, a level which the Company believes is lower than industry
averages. Concurrently, the Company increased  its average net daily  production
from  827 BOE for the year  ended December 31, 1993 to  10,703 BOE for the three
months ended March 31, 1996 (pro forma for the 1996 Acquisition), representing a
compound annual growth rate of 195%. EBITDA increased at a 240% compound  annual
growth  rate from $1.8 million for 1993 to $20.8 million for 1995 (pro forma for
the 1995 Acquisition and the 1996 Acquisition).
 
                                       3
<PAGE>
                               BUSINESS STRATEGY
 
    The Company's strategy is to increase  its oil and gas reserves,  production
and  cash flow from operations through  a two-pronged approach which combines an
active exploration program  using 3-D seismic  and other technological  advances
with the acquisition and exploitation of producing properties. The Company seeks
to  reduce its operating and  commodity risks by holding  a diverse portfolio of
properties. The  Company also  seeks  to manage  the  elements of  its  business
strategy  through the operation of a  significant portion of its properties, the
use of  a disciplined  rate of  return  analysis and  the direct  marketing  and
hedging  of its oil and  gas production. The elements  of the Company's strategy
may be further described as follows:
 
- -   EXPLORATION  EFFORTS.     The  Company  uses   extensive  geological   and
    geophysical  analysis  to carefully  focus its  3-D seismic  surveys. This
    focus allows the Company to successfully direct the size and scope of  its
    exploration  program in order  to improve the  likelihood of success while
    managing overall exploration costs. The Company's exploration efforts  are
    concentrated  currently on known  producing regions. The  Company plans to
    drill 26 exploratory wells during the remainder of 1996 and 36 exploratory
    wells in 1997. Capital budgeted for exploration activities is $8.4 million
    for the last nine months of 1996 and $10.8 million for 1997.
 
- -   EXPLOITATION ACTIVITIES.    The  Company  is  actively  pursuing  numerous
    exploitation opportunities within its existing properties, including areas
    where  no proved reserves are  currently assigned. Exploitation activities
    currently in  progress  include  a carbon  dioxide  flood,  recompletions,
    workovers,  infill  and  horizontal  drilling  and  a  secondary  recovery
    project. The Company's capital budget for such activities is $8.9  million
    for the last nine months of 1996 and $9.2 million for 1997, which includes
    the  drilling of 17 development wells in  1996 and 13 development wells in
    1997.
 
- -   PROPERTY ACQUISITIONS.  The Company seeks to acquire producing  properties
    where  it has identified opportunities to increase production and reserves
    through both  exploitation and  exploration  activities. The  Company  has
    increased  the  value of  its  acquisitions by  aggressively  managing the
    operations of existing proved  properties and by successfully  identifying
    and  developing  previously  unproved reserves  on  acquired  acreage. The
    Company seeks to acquire reserves  which will fit its existing  portfolio,
    are  generally not  being actively  marketed and  where a  negotiated sale
    would be the method of  purchase. The Company does  not rely on major  oil
    company divestitures or property auctions.
 
- -   PROPERTY  DIVERSIFICATION.  The  Company holds a portfolio  of oil and gas
    properties located in  the Permian  Basin, the  Gulf Coast  and the  Rocky
    Mountain  regions. The Company believes  that by conducting its activities
    in distinct  regions  it is  able  to  reduce commodity  price  and  other
    operational risks. The Company's Moldovan interest is an extension of this
    strategy  and  can  be  characterized by  low  initial  costs, significant
    reserve potential  and the  availability  of technical  data that  may  be
    further developed by the Company.
 
- -   CONTROL  OF  OPERATIONS.   The  Company  prefers  to operate  and  own the
    majority working  interest  in its  properties.  This allows  the  Company
    greater  control over future development, drilling, completing and lifting
    costs and  marketing of  production.  At December  31, 1995,  the  Company
    operated  wells constituting  approximately 65%  of its  total PV-10 Value
    (pro forma for the 1996 Acquisition).
 
                                       4
<PAGE>
                            SIGNIFICANT ACQUISITIONS
 
    1995 ACQUISITION.  In  a $46.6 million acquisition  completed in June  1995,
the  Company acquired a group  of oil and gas  properties located in the Permian
Basin, Gulf Coast and  Rocky Mountain regions. At  the date of acquisition,  the
net  proved reserves included 6.9 Mmbbls of oil and 40.0 Bcf of gas, aggregating
13.6 MMBOE.  From the  date of  acquisition until  March 31,  1996, the  Company
produced  1.1  MMBOE from  the acquired  properties  and sold  a portion  of the
acquired properties for approximately $3.6 million.  At March 31, 1996, the  net
proved  reserves  of  the remaining  properties  were 13.4  MMBOE.  The acquired
properties also included 103,010 gross (93,786 net) undeveloped acres.
 
    1996 ACQUISITION.  In June 1996, the Company acquired a group of oil and gas
properties located primarily  in the Permian  Basin and Gulf  Coast regions  for
approximately  $42.5  million.  This acquisition  included  properties  with net
proved reserves at  March 31, 1996  of 5.0 Mmbbls  of oil and  33.5 Bcf of  gas,
aggregating  10.6  MMBOE. The  acquired  properties also  included  42,855 gross
(10,172 net) undeveloped acres and a pipeline located in Pennsylvania which  had
an allocated purchase price of $3.5 million.
 
                              DRILLING ACTIVITIES
 
    Exploration  efforts  since  January 1,  1996  include the  drilling  of two
successful wells located on the Company's Edwards/McElroy Ranch 3-D Prospect  in
the  Permian Basin. Production  from the initial  well averaged 344  BOE per day
from its May 11 completion to June 30, 1996, while the second well is  currently
being   completed.  These   successful  wells  confirm   the  Company's  seismic
interpretation of the  continuation of  a significant  trend. As  a result,  the
Company  has identified  75 additional  drilling locations,  three of  which are
included in the Company's  proved reserves. Through June  30, 1996, the  Company
had  drilled 11 total wells in the prospect,  10 of which have been completed as
producing wells.
 
    The Company has also  drilled three exploratory  wells in the  McGyver-Green
Acres  3-D Prospect since  January 1, 1996,  yielding two successful completions
and bringing the  total number  of wells  drilled in  that prospect  to 12.  The
average  daily  production  from the  11  producing  wells in  this  prospect is
approximately 83 BOE per well. The Company has identified 41 additional drilling
locations in the McGyver-Green Acres Prospect,  14 of which are included in  the
Company's proved reserves.
 
    The  Company has  also drilled and  completed five development  wells in the
Permian Basin and Gulf Coast regions since the beginning of 1996. Currently, the
Company's principal exploitation  activities include a  carbon dioxide flood  in
the  East Goldsmith  Unit, infill  drilling primarily  in the  Permian Basin and
horizontal drilling in the Susan Peak Field.
 
                                       5
<PAGE>
                                  THE OFFERING
 
<TABLE>
<S>                                           <C>
Securities Offered..........................  $100,000,000  aggregate  principal  amount  of
                                                      %  Senior Subordinated  Notes due 2006
                                              of the Company (the "Notes").
Maturity Date...............................  , 2006.
Interest Payment Dates......................  and         , commencing         , 1997.
Optional Redemption.........................  On or after           , 2001, the Company  may
                                              redeem  the Notes, in whole or in part, at the
                                              redemption  prices  set  forth  herein,   plus
                                              accrued  and unpaid  interest, if  any, to the
                                              date  of   redemption.   Notwithstanding   the
                                              foregoing,  at any time on or before         ,
                                              1999, the Company may redeem up to 30% of  the
                                              original  aggregate  principal  amount  of the
                                              Notes with  the  net  proceeds  of  an  Equity
                                              Offering  (as defined herein)  at a redemption
                                              price equal to     % of  the principal  amount
                                              thereof,  plus accrued and unpaid interest, if
                                              any, to the date of redemption, provided  that
                                              at   least  70%  of   the  original  aggregate
                                              principal   amount   of   the   Notes   remain
                                              outstanding immediately after such redemption.
                                              See   "Description   of   Notes   --  Optional
                                              Redemption."
Mandatory Redemption........................  None, except at maturity on         , 2006.
Ranking.....................................  The   Notes   will   be   general    unsecured
                                              obligations  of  the Company,  subordinated in
                                              right of payment  to all  existing and  future
                                              Senior Indebtedness of the Company, which will
                                              include  borrowings under the Credit Facility.
                                              At March 31, 1996, on a pro forma basis  after
                                              giving  effect  to the  1996  Acquisition, the
                                              Corporate Reorganization,  the  Offerings  and
                                              the application of the net proceeds therefrom,
                                              the  Company  would  have  had  no outstanding
                                              Senior Indebtedness. See "Description of Notes
                                              --   Subordination"    and   "--    Subsidiary
                                              Guarantees."
Guarantees..................................  The  Notes will  be unconditionally guaranteed
                                              on a senior subordinated basis by the existing
                                              and future  Subsidiary  Guarantors  under  the
                                              Subsidiary Guarantees (all as defined herein).
                                              The Subsidiary Guarantees will be subordinated
                                              in right of payment to all existing and future
                                              Senior    Indebtedness   of   the   Subsidiary
                                              Guarantors. Each of the Subsidiary  Guarantees
                                              will  be  a guarantee  of  payment and  not of
                                              collection.  See  "Description  of  Notes   --
                                              Subsidiary Guarantees."
</TABLE>
 
                                       6
<PAGE>
 
<TABLE>
<S>                                           <C>
Change of Control...........................  Upon  a Change of Control (as defined herein),
                                              the Company will be required to make an  offer
                                              to repurchase all outstanding Notes at 101% of
                                              the  principal amount thereof plus accrued and
                                              unpaid interest thereon, if  any, to the  date
                                              of  repurchase. See  "Description of  Notes --
                                              Repurchase at the Option of Holders --  Change
                                              of Control."
Covenants...................................  The Indenture pursuant to which the Notes will
                                              be  issued  (the  "Indenture")  will restrict,
                                              among other things,  the Company's ability  to
                                              incur  additional indebtedness,  pay dividends
                                              or make  certain  other  restricted  payments,
                                              incur   liens   to   secure   PARI   PASSU  or
                                              subordinated indebtedness, engage in any  sale
                                              and   leaseback  transaction,  sell  stock  of
                                              subsidiaries, apply net proceeds from  certain
                                              asset  sales,  merge or  consolidate  with any
                                              other person, sell,  assign, transfer,  lease,
                                              convey  or otherwise  dispose of substantially
                                              all of the assets  of the Company, enter  into
                                              certain transactions with affiliates, or incur
                                              indebtedness  that is subordinate  in right of
                                              payment to any Senior Indebtedness and  senior
                                              in right of payment to the Notes.
Common Stock Offering.......................  Concurrently  with  the  Notes  Offering,  the
                                              Company is offering 4,000,000 shares of Common
                                              Stock  to  the   public.  See  "Common   Stock
                                              Offering."  The closings of the Notes Offering
                                              and  the  Common   Stock  Offering  are   each
                                              conditioned   upon  the  consummation  of  the
                                              other.
Use of Proceeds.............................  The Company intends to use the net proceeds of
                                              the Notes  Offering,  together  with  the  net
                                              proceeds  of the Common  Stock Offering (i) to
                                              repay  existing  indebtedness,  (ii)  to   pay
                                              certain  costs incurred in connection with the
                                              Corporate Reorganization (as defined  herein),
                                              including    redeeming    certain   membership
                                              interests of  the  Company's  predecessor  and
                                              (iii) for general corporate purposes. See "Use
                                              of Proceeds."
</TABLE>
 
                                  RISK FACTORS
 
    See  "Risk  Factors" for  a  discussion of  certain  factors that  should be
considered in evaluating an investment in the Notes.
 
                                       7
<PAGE>
                         SUMMARY FINANCIAL INFORMATION
 
    The following  table sets  forth certain  summary historical  and pro  forma
financial data of the Company. The historical data should be read in conjunction
with  the  Consolidated  Financial  Statements and  the  notes  thereto included
elsewhere in this Prospectus. The Company acquired significant producing oil and
gas  properties  in  certain   of  the  periods   presented  which  affect   the
comparability  of the  historical financial and  operating data  for the periods
presented. The pro forma information should be read in conjunction with the  Pro
Forma  Condensed Financial  Statements and  notes thereto  included elsewhere in
this Prospectus. Neither the  historical results nor the  pro forma results  are
necessarily indicative of the Company's future operations or financial results.
 
<TABLE>
<CAPTION>
                                                                                             THREE MONTHS ENDED
                                                    YEAR ENDED DECEMBER 31,                       MARCH 31,
                                           ------------------------------------------  -------------------------------
                                                     HISTORICAL             PRO FORMA       HISTORICAL       PRO FORMA
                                           -------------------------------  ---------  --------------------  ---------
                                             1993       1994       1995      1995(1)     1995       1996      1996(1)
                                           ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                        (IN THOUSANDS, EXCEPT RATIOS AND PER SHARE DATA)
<S>                                        <C>        <C>        <C>        <C>        <C>        <C>        <C>
STATEMENT OF OPERATIONS DATA:
  Revenues...............................  $   4,397  $   7,836  $  21,816  $  52,637  $   2,180  $   8,951  $  14,038
  Expenses:
    Oil and gas production...............      1,688      2,351     10,355     26,937        896      3,659      6,283
    General and administrative...........        952      1,184      3,571      4,850        459      1,362      1,505
    Exploration and abandonment..........        218        793      1,650      2,761      1,007        228        475
    Depreciation, depletion and
     amortization........................        884      1,847      6,095     14,313        462      1,986      3,166
    Interest.............................        605      1,458      4,454     11,631        407      1,704      2,908
    Other................................         --         --          2          2         --         --
                                           ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Net income (loss) before income
   taxes.................................         50        203     (4,311)    (7,857)    (1,051)        12       (299)
  Pro forma earnings (loss) per common
   share.................................         --         --         --      (0.80)        --         --      (0.03)
  Pro forma weighted average common
   shares outstanding....................         --         --         --      9,861         --         --     10,000
STATEMENT OF CASH FLOWS DATA:
  Net cash provided by (used in):
    Operating activities.................  $     322  $   1,527  $   6,366         --  $  (1,827) $   2,276         --
    Investing activities.................     (6,731)   (12,146)   (62,467)        --     (1,389)    (5,132)        --
    Financing activities.................      6,315     10,618     58,830         --      3,272      3,000         --
OTHER FINANCIAL DATA:
  Capital expenditures...................  $   6,862  $  11,868  $  62,220         --  $   1,389  $   5,132         --
  EBITDA (2).............................      1,757      4,301      7,888  $  20,848        825      3,930  $   6,250
  EBITDA/Interest expense (3)............        2.9x       2.9x       1.8x       1.8x       2.0x       2.3x       2.1x
  Ratio of earnings to fixed charges
   (4)...................................        1.0        1.1         --         --         --        1.0         --
BALANCE SHEET DATA (AS OF PERIOD END):
  Working capital........................  $   1,612  $   1,081  $   2,496         --         --  $   2,104  $  15,955
  Total assets...........................     13,365     24,904     87,367         --         --     91,024    145,117
  Total debt.............................     12,006     23,591     71,494         --         --     74,494    100,000
  Redeemable members' capital............         --         --     11,320         --         --     11,678         --
  Members' capital.......................         51       (747)    (7,189)        --         --     (7,535)        --
  Pro forma stockholders' equity.........         --         --         --         --         --         --     35,843
  ACNTA (5)..............................                                                                      201,470
  Ratio of ACNTA to total debt...........         --         --         --         --         --         --        2.0x
</TABLE>
 
- ------------------------------
(1)  Assumes  that  the 1995  Acquisition, the  1996 Acquisition,  the Corporate
     Reorganization (as defined in "The Company-- Corporate Reorganization") and
     the Offerings and the application of proceeds therefrom had taken place  on
     March  31, 1996 for purposes  of the Balance Sheet  Data (to the extent not
     already reflected) and as of January  1, 1995 for purposes of Statement  of
     Operations Data and Other Financial Data.
 
(2)  EBITDA is presented because of its wide acceptance as a financial indicator
     as to a company's ability to service or incur debt. EBITDA (as used herein)
     is calculated by adding interest, income taxes, depreciation, depletion and
     amortization  and exploration and  abandonment costs to  net income (loss).
     EBITDA should not be considered as an alternative to earnings (loss) as  an
     indicator  of  the Company's  financial performance  or to  cash flow  as a
     measure of liquidity.
 
                                       8
<PAGE>
(3)  Calculated by  dividing  EBITDA  by interest.  Interest  includes  interest
     expense accrued and amortization of deferred financing costs.
 
(4)  For  purposes  of  calculating  the ratio  of  earnings  to  fixed charges,
     "earnings" are net income (loss) plus income taxes and fixed charges. Fixed
     charges are comprised of interest on indebtedness, amortization of deferred
     financing costs,  and that  portion  of operating  lease expense  which  is
     deemed   to  be  representative  of   an  interest  factor.  Earnings  were
     insufficient to cover fixed charges  by $4,311,000, and $1,051,000 for  the
     historical periods ended December 31, 1995 and March 31, 1995, respectively
     and  $7,857,000 and $299,000  for the pro forma  periods ended December 31,
     1995 and March 31, 1996, respectively.
 
(5)  ACNTA means Adjusted  Consolidated Net  Tangible Assets as  defined in  the
     Indenture. See "Description of Notes-- Certain Definitions."
 
                              SUMMARY RESERVE DATA
 
<TABLE>
<CAPTION>
                                                                 AS OF DECEMBER 31,           AS OF MARCH 31, 1996
                                                           -------------------------------  ------------------------
                                                             1993       1994       1995      ACTUAL    PRO FORMA(1)
                                                           ---------  ---------  ---------  ---------  -------------
<S>                                                        <C>        <C>        <C>        <C>        <C>
ESTIMATED PROVED RESERVES (2):
  Oil (MBbls)............................................      2,365      4,009     10,788     11,479        16,476
  Gas (Mmcf).............................................     21,619     27,512     78,152     79,420       112,920
  MBOE...................................................      5,968      8,594     23,813     24,716        35,297
  Percent of proved developed reserves...................       67.0%      62.3%      76.1%      73.9%         78.2%
  Present value of estimated future net cash flow, before
   income taxes, discounted at 10% (in thousands)........  $  26,377  $  36,779  $ 113,296  $ 129,091   $   179,527
  Reserve life index (in years) (3)......................       19.7       14.4       13.6         --            --
RESERVE REPLACEMENT DATA:
  Production replacement ratio (4).......................        513%       549%       969%        --            --
  All-in finding costs per BOE (5).......................  $    4.31  $    3.67  $    3.53  $    2.84   $      2.84
</TABLE>
 
- ------------------------------
(1)  Gives effect to  the 1995 Acquisition  and the 1996  Acquisition as if such
    transactions had occurred as of January 1, 1995.
 
(2) Estimates of net proved oil and gas reserves at March 31, 1996 are based  on
    reports  prepared by Williamson  Petroleum Consultants, Inc. ("Williamson"),
    independent petroleum engineers. The 1995 reserve estimates were prepared by
    the Company and such estimates of gross reserves with respect to certain  of
    the  Company's  producing properties  were subject  to  a limited  review by
    Williamson. Prior reserve estimates are based on information compiled by the
    Company. See "Risk Factors  -- Uncertainty of  Estimates of Proved  Reserves
    and  Future  Net  Revenues" and  "Business  and  Properties --  Oil  and Gas
    Reserves."
 
(3) Calculated by dividing year-end proved reserves by annual production for the
    most recent year.
 
(4) Calculated by dividing reserve  additions through acquisitions of  reserves,
    extensions  and discoveries and revisions during  the year by production for
    such year.
 
(5) The average  all-in finding costs  over the period  January 1, 1993  through
    March 31, 1996 (pro forma for the 1996 Acquisition) was $3.49 per BOE.
 
                                       9
<PAGE>
                             SUMMARY OPERATING DATA
 
<TABLE>
<CAPTION>
                                                             YEAR ENDED DECEMBER 31,
                                                  ----------------------------------------------
                                                                                                   THREE MONTHS ENDED MARCH
                                                            HISTORICAL             PRO FORMA(1)            31, 1996
                                                  -------------------------------  -------------  --------------------------
                                                    1993       1994       1995         1995        ACTUAL     PRO FORMA(1)
                                                  ---------  ---------  ---------  -------------  ---------  ---------------
<S>                                               <C>        <C>        <C>        <C>            <C>        <C>
PRODUCTION DATA:
  Oil (MBbls)...................................        158        330        950        2,085          338           502
  Gas (Mmcf)....................................        865      1,600      4,806       11,985        1,643         2,832
  MBOE..........................................        302        597      1,751        4,083          612           974
AVERAGE SALES PRICE PER UNIT:
  Oil (per Bbl).................................  $   16.93  $   15.25  $   15.53    $   15.75    $   17.32     $   17.37
  Gas (per Mcf).................................       1.82       1.63       1.45         1.59         1.81          1.88
COSTS PER BOE:
  Production costs, including severance taxes
   (2)..........................................  $    5.59  $    3.94  $    5.91    $    6.60    $    5.98     $    6.45
  Depreciation, depletion and amortization......       2.93       3.09       3.48         3.51         3.25          3.25
</TABLE>
 
- ------------------------------
(1)  Gives effect to  the 1995 Acquisition  and the 1996  Acquisition as if such
    transactions had occurred as of January 1, 1995.
 
(2) Production costs per BOE  in 1995 and for the  three months ended March  31,
    1996  were unusually high  as a result of  relatively high workover expenses
    with respect to properties  acquired in the 1995  Acquisition which did  not
    produce   related  production  improvements  until  subsequent  periods.  In
    addition, the Company expended approximately $1.6 million during 1995 in one
    field in  the Permian  Basin primarily  for plugging  wells to  comply  with
    applicable regulatory requirements.
 
                                       10
<PAGE>
                                  RISK FACTORS
 
    PRIOR  TO  MAKING  AN  INVESTMENT  DECISION,  PROSPECTIVE  INVESTORS  SHOULD
CONSIDER  FULLY,  TOGETHER  WITH  THE   OTHER  INFORMATION  CONTAINED  IN   THIS
PROSPECTUS, THE FOLLOWING FACTORS.
 
SIGNIFICANT LEVERAGE AND DEBT SERVICE
 
    As  of March 31, 1996,  as adjusted for the  1996 Acquisition, the Corporate
Reorganization, the Offerings and the application of the net proceeds therefrom,
the Company's total debt and stockholders' equity would have been $100.0 million
and $35.8 million, respectively. See "Capitalization." In addition, the  Company
may  currently  incur  additional  indebtedness under  its  Credit  Facility (as
defined under "Description  of Other Indebtedness").  Immediately following  the
consummation  of the Offerings, the Company anticipates that the Credit Facility
will afford it $50.0 million of  available borrowing capacity, none of which  is
expected to be outstanding on such date.
 
    The  Company's level of indebtedness will  have several important effects on
its future operations, including (i) a substantial portion of the Company's cash
flow from  operations  must be  dedicated  to the  payment  of interest  on  its
indebtedness  and  will  not be  available  for other  purposes,  (ii) covenants
contained in the  Credit Facility  and the  Indenture governing  the Notes  will
require  the Company to meet certain financial tests, and other restrictions may
limit its ability to  borrow additional funds  or to dispose  of assets and  may
affect  the Company's flexibility  in planning for, and  reacting to, changes in
its business, including possible acquisition activities and (iii) the  Company's
ability  to  obtain  additional financing  in  the future  for  working capital,
capital expenditures, acquisitions, general corporate purposes or other purposes
may be impaired. The Company's ability to meet its debt service obligations  and
to  reduce its  total indebtedness will  be dependent upon  the Company's future
performance, which  will  be  subject  to general  economic  conditions  and  to
financial,  business and other factors affecting  the operations of the Company,
many of which  are beyond its  control. Based upon  the current and  anticipated
level  of operations, the  Company believes that its  cash flow from operations,
together with amounts available under its Credit Facility and its other  sources
of  liquidity,  will be  adequate to  meet its  anticipated requirements  in the
foreseeable future for working capital, capital expenditures, interest  payments
and  scheduled principal payments. There can  be no assurance, however, that the
Company's business  will continue  to generate  cash flow  at or  above  current
levels.  If  the  Company  is  unable  to  generate  sufficient  cash  flow from
operations in the future to  service its debt, it  may be required to  refinance
all  or  a portion  of  its existing  debt, including  the  Notes, or  to obtain
additional financing. There can be no assurance that any such refinancing  would
be possible or that any additional financing could be obtained.
 
SUBORDINATION OF NOTES AND SUBSIDIARY GUARANTEES
 
    The Notes and Subsidiary Guarantees will be subordinated in right of payment
to  all existing  and future Senior  Indebtedness of the  Company, including all
indebtedness under the Credit Facility. As  of March 31, 1996, after giving  pro
forma effect to the 1996 Acquisition, the Corporate Reoganization, the Offerings
and the application of the net proceeds therefrom, the Company would have had no
Senior  Indebtedness outstanding and  anticipates that it will  have up to $50.0
million available  under  the Credit  Facility,  which, if  borrowed,  would  be
included  as Senior  Indebtedness. In  the event  of bankruptcy,  liquidation or
reorganization of the Company,  the assets of the  Company will be available  to
pay  obligations on the Notes only after  all Senior Indebtedness of the Company
has been paid in full,  and there may not be  sufficient funds remaining to  pay
amounts due on any or all of the Notes outstanding. See "Description of Notes --
Subordination."
 
SUBSIDIARY GUARANTEES MAY TERMINATE; FRAUDULENT CONVEYANCE CONSIDERATIONS
RELATING TO SUBSIDIARY GUARANTEES
 
    The  Company's obligations  under the Notes  will be guaranteed  on a senior
subordinated basis by  its subsidiaries, except  for subsidiaries through  which
its  Moldovan operations are conducted.  Various fraudulent conveyance laws have
been enacted for  the protection  of creditors  and may be  used by  a court  of
competent  jurisdiction to subordinate or avoid any Subsidiary Guarantee. To the
extent that a court were  to find that (x)  a Subsidiary Guarantee was  incurred
with the intent to hinder, delay or
 
                                       11
<PAGE>
defraud  any  present  or  future creditor  or  that  such  Subsidiary Guarantor
contemplated insolvency with  a design  to favor one  or more  creditors to  the
exclusion  in whole or in  part of others or (y)  a Subsidiary Guarantor did not
receive fair  consideration  or  reasonably equivalent  value  for  issuing  its
Subsidiary  Guarantee and, at the time  it issued the Subsidiary Guarantee, such
Subsidiary Guarantor (i) was  insolvent or rendered insolvent  by reason of  the
issuance  of the Subsidiary Guarantee, (ii) was  engaged or about to engage in a
business or  transaction  for which  the  remaining assets  of  such  Subsidiary
Guarantor  constituted unreasonably small capital or (iii) intended to incur, or
believed that it would incur, debts beyond its ability to pay such debts as they
matured, a court could avoid or subordinate the Subsidiary Guarantee in favor of
such Subsidiary  Guarantor's  other  creditors.  Among  other  things,  a  legal
challenge  of the  Subsidiary Guarantee issued  by such  Subsidiary Guarantor on
fraudulent conveyance grounds  may focus on  the benefits, if  any, realized  by
such  Subsidiary Guarantor  as a result  of the  issuance by the  Company of the
Notes. To  the extent  the  Subsidiary Guarantee  was  avoided as  a  fraudulent
conveyance  or held unenforceable for any other reason, the holders of the Notes
would cease to  have any claim  against such Subsidiary  Guarantor and would  be
creditors  solely of the Company and  any Subsidiary Guarantors whose Subsidiary
Guarantees were not avoided or held unenforceable. In such event, the claims  of
the  holders of the Notes against the  issuer of an invalid Subsidiary Guarantee
would be subject  to the  prior payment of  all liabilities  of such  Subsidiary
Guarantor. There can be no assurance that, after providing for all prior claims,
there  would be sufficient  assets to satisfy  the claims of  the holders of the
Notes relating to any avoided portions of any of the Subsidiary Guarantees.
 
    The measure of insolvency for purposes of the foregoing considerations  will
vary  depending upon the law applied in any such proceeding. Generally, however,
a Subsidiary Guarantor  may be  considered insolvent if  the sum  of its  debts,
including  contingent liabilities, was greater than the fair market value of all
of its assets  at a  fair valuation,  if the present  fair market  value of  its
assets  was less  than the  amount that  would be  required to  pay its probable
liability on  its  existing debts,  including  contingent liabilities,  as  they
become  absolute and mature, or  if it had insufficient  capital to carry on its
business.
 
    On the basis of historical  financial information, recent operating  history
as discussed in "Management's Discussion and Analysis of Financial Condition and
Results  of Operations"  and other  information currently  available to  it, the
Company  believes  that   the  Notes  and   the  Subsidiary  Guarantees   issued
concurrently  with  the issuance  of  the Notes  are  being incurred  for proper
purposes and  in  good faith  and  that,  after giving  effect  to  indebtedness
incurred  in  connection  with the  issuance  of  the Notes  and  the Subsidiary
Guarantees, the Company and  the Subsidiary Guarantors  would be solvent,  would
have sufficient capital for carrying on their respective businesses and would be
able  to pay their debts as such debts  become absolute and mature. There can be
no assurance, however, that a court passing on such issues would reach the  same
conclusions.  See "Management's  Discussion and Analysis  of Financial Condition
and Results of Operations -- Liquidity and Capital Resources."
 
POTENTIAL INABILITY TO FUND A CHANGE OF CONTROL OFFER
 
    The Indenture governing  the Notes provides  that upon the  occurrence of  a
Change  of Control, the Company is required to offer to repurchase any or all of
the outstanding Notes at a price equal to 101% of the aggregate principal amount
thereof, together  with accrued  and unpaid  interest, if  any, to  the date  of
purchase.  Generally, a "Change  of Control" includes any  person or group other
than Cadell S. Liedtke, Michael J.  Grella and Henry G. Musselman, the  Chairman
of   the  Board,  President  and  Executive   Vice  President  of  the  Company,
respectively, acquiring 50% or more of the voting securities of the Company, and
certain other events. If a Change of Control occurs, there is no assurance  that
the  Company will have available funds sufficient  to pay for the Notes tendered
for repurchase. See "Description of Notes -- Repurchase at the Option of Holders
- -- Change of Control."
 
    If an offer to repurchase  is required to be made  and the Company does  not
have  available funds  sufficient to pay  for Notes tendered  for repurchase, an
event of default would occur under the Indenture.
 
                                       12
<PAGE>
UNCERTAINTY OF ESTIMATES OF PROVED RESERVES AND FUTURE NET CASH FLOWS
 
    There are numerous uncertainties in estimating quantities of proved reserves
and in  projecting future  rates of  production and  the timing  of  development
expenditures,  including many  factors beyond  the control  of the  Company. The
reserve data set forth in this Prospectus are estimates only. Reserve  estimates
are imprecise and should be expected to change as additional information becomes
available.  Furthermore, estimates  of oil and  gas reserves,  of necessity, are
projections based on engineering data,  and there are uncertainties inherent  in
the  interpretation of such  data as well  as the projection  of future rates of
production and the timing of development expenditures. Reserve engineering is  a
subjective  process of estimating underground accumulations  of oil and gas that
cannot be  exactly measured,  and the  accuracy  of any  reserve estimate  is  a
function  of the  quality of  available data  and of  engineering and geological
interpretation  and  judgment.  Accordingly,   estimates  of  the   economically
recoverable  quantities of oil  and gas attributable to  any particular group of
properties, classifications  of such  reserves based  on risk  of recovery,  and
estimates  of the future net cash flows expected therefrom prepared by different
engineers or by the  same engineers at different  times may vary  substantially.
Moreover,  there can  be no  assurance that the  reserves set  forth herein will
ultimately be produced or that the proved undeveloped reserves will be developed
within the periods  anticipated. Variances from  the estimates contained  herein
could be material. In addition, the estimates of future net revenues from proved
reserves  of the Company  and the present  value thereof are  based upon certain
assumptions about production levels, prices and costs, which may not be correct.
The Company emphasizes with respect to such estimates that the discounted future
net cash flows  should not  be construed as  representative of  the fair  market
value  of the proved  oil and gas  properties belonging to  the Company, because
discounted future net cash flows are based upon projected cash flows that do not
provide for changes  in oil and  gas prices  or for escalation  of expenses  and
capital costs. The meaningfulness of such estimates is highly dependent upon the
accuracy  of  the assumptions  upon which  they were  based. Actual  results may
differ materially from  the results estimated.  Prospective purchasers of  Notes
are  cautioned not to place undue reliance  on the reserve data included in this
Prospectus.
 
ACQUISITION RISKS
 
    The Company's rapid growth  in recent years has  been largely the result  of
acquisitions  of  producing  properties.  The  Company  expects  to  continue to
evaluate and  pursue acquisition  opportunities  available on  terms  management
considers  favorable  to the  Company. The  successful acquisition  of producing
properties requires an assessment  of recoverable reserves,  future oil and  gas
prices, operating costs, potential environmental and other liabilities and other
factors  beyond the Company's control. Such an assessment is necessarily inexact
and its accuracy is inherently uncertain. In connection with such an assessment,
the Company  performs a  review of  the  subject properties  it believes  to  be
generally  consistent with industry practices. Such  a review, however, will not
reveal all existing or potential problems, nor will it permit a buyer to  become
sufficiently familiar with the properties fully to assess their deficiencies and
capabilities. Inspections may not be performed on every well, and structural and
environmental problems are not necessarily observable even when an inspection is
undertaken. The Company is generally not entitled to contractual indemnification
for  preclosing liabilities, including  environmental liabilities, and generally
acquires interests in the properties on an "as is" basis.
 
VOLATILITY OF OIL AND GAS PRICES
 
    The Company's financial results and,  therefore, its ability to service  its
debt,  including the Notes, are significantly affected by the price received for
the Company's oil and gas production. Historically, the markets for oil and  gas
have  been volatile and may continue to be volatile in the future. Prices of oil
and gas are  subject to  wide fluctuations  in response  to market  uncertainty,
changes  in supply and demand and a  variety of additional factors, all of which
are beyond  the control  of  the Company.  These  factors include  domestic  and
foreign  political conditions, the overall level of supply of and demand for oil
and gas, the price of  imported oil and gas,  weather conditions, the price  and
availability of alternative fuels and overall economic conditions. The Company's
future financial condition and
 
                                       13
<PAGE>
results  of operations will be dependent, in  part, upon the prices received for
the Company's  oil  and gas  production,  as well  as  the costs  of  acquiring,
finding,  developing and  producing reserves.  To reduce  its exposure  to price
risks in  the  sale  of  its  oil and  gas,  the  Company  enters  into  hedging
arrangements  from  time  to time.  Although  the Company  hedges  a significant
portion of its production, any substantial  or extended decline in the price  of
oil  and gas  would have  a material adverse  effect on  the Company's financial
condition and  results  of operations,  as  well as  reduce  the amount  of  the
Company's  oil and gas that could be produced economically. Moreover, if oil and
gas prices fall materially below their current levels, the availability of funds
and the Company's ability to repay outstanding amounts under its Credit Facility
and  the  Notes  could  be  materially  adversely  affected.  See  "Management's
Discussion and Analysis of Financial Condition and Results of Operations."
 
CONFLICTS OF INTEREST
 
    The Company has a continuing relationship with A&P Meter Sales and Services,
Inc.  ("A&P"), a corporation in which  Messrs. Liedtke, Grella and Musselman own
60.0% of the outstanding common stock. A&P owes the Company $437,000  (including
accrued  interest through December 31, 1995) pursuant to a promissory note under
which the Company is  not entitled to any  principal or interest payments  until
December  31,  2004. Currently,  A&P also  owes the  Company $247,000,  which is
represented  by   a  promissory   note  payable   upon  demand.   See   "Certain
Transactions."
 
    Under the Company's current credit arrangements, Messrs. Liedtke, Grella and
Musselman  are each  liable for  a portion of  the Company's  existing debt (see
"Description of Other  Indebtedness") pursuant to  limited guaranties.  However,
these  individuals will not be  liable for, or guarantee  amounts due under, the
Credit Facility or the indebtedness represented by the Notes.
 
DEPENDENCE ON KEY PERSONNEL
 
    The Company depends to  a large extent on  the services of Messrs.  Liedtke,
Grella and Musselman. The loss of the services of any of Messrs. Liedtke, Grella
or  Musselman could have a material  adverse effect on the Company's operations.
Pursuant  to  employment  agreements  which   are  to  be  effective  upon   the
consummation of the Offerings, Messrs. Liedtke, Grella and Musselman have agreed
not  to compete with the  Company for a one-year  period should they voluntarily
leave the  Company's employment  or should  their employment  be terminated  for
cause.  The Company believes that its success is also dependent upon its ability
to continue to employ and retain skilled technical personnel. See "Management."
 
CONTROL OF THE COMPANY
 
    If the Offerings are completed,  Messrs. Liedtke, Grella and Musselman  will
own  directly and indirectly, in the  aggregate, 49.2% of the outstanding Common
Stock (or 46.4% if the underwriters'  over-allotment option in the Common  Stock
Offering  is  exercised  in  full).  Accordingly,  Messrs.  Liedtke,  Grella and
Musselman may be  able to exercise  significant influence over  the election  of
directors of the Company and the control of the Company's management, operations
and   affairs.  See  "Security  Ownership   of  Certain  Beneficial  Owners  and
Management."
 
FOREIGN INVESTMENT
 
    The Company's investment in Moldova involves risks typically associated with
investments in  emerging  markets  such as  foreign  exchange  restrictions  and
currency  fluctuations, foreign taxation, changing political conditions, foreign
and  domestic  monetary  and   tax  policies,  expropriation,   nationalization,
nullification,  modification  or  renegotiation  of  contracts,  war  and  civil
disturbances and other risks that may limit or disrupt markets. In addition,  if
a  dispute arises in its Moldovan operations,  the Company may be subject to the
exclusive jurisdiction of foreign courts or may not be successful in  subjecting
foreign  persons to the jurisdiction of  the United States. The Company attempts
to conduct its business and financial affairs so as to protect against political
and economic risks  applicable to  operations in Moldova,  but there  can be  no
assurance the Company will be successful in so protecting itself.
 
                                       14
<PAGE>
DRILLING RISKS
 
    Drilling  involves numerous risks,  including the risk  that no commercially
productive oil or gas will be encountered. The cost of drilling, completing  and
operating  wells is often  uncertain, and drilling  operations may be curtailed,
delayed or cancelled as a result  of a variety of factors, including  unexpected
drilling   conditions,  pressure  or  irregularities  in  formations,  equipment
failures or accidents, adverse weather conditions and shortages or delays in the
delivery of  equipment. The  Company's  future drilling  activities may  not  be
successful and, if unsuccessful, such failure may have a material adverse effect
on the Company's future results of operations and financial condition.
 
OPERATING HAZARD AND UNINSURED RISKS
 
    The  Company's operations are  subject to hazards and  risks inherent in the
drilling for and production and transportation of oil and gas, including  fires,
natural  disasters, explosions, encountering formations with abnormal pressures,
blowouts, cratering, pipeline ruptures, and spills,  any of which can result  in
loss  of hydrocarbons, environmental pollution, personal injury or loss of life,
severe damage to and  destruction of properties of  the Company and others,  and
suspension of operations. Although the Company maintains insurance coverage that
it  considers to  be adequate  and customary  in the  industry, it  is not fully
insured against certain  of these risks,  either because such  insurance is  not
available  or because  of high  premium costs.  The occurrence  of a significant
event not fully covered by insurance could have a material adverse effect on the
Company's financial condition and results of operations.
 
COMPETITION
 
    The Company  encounters  substantial competition  in  acquiring  properties,
marketing  oil and  gas and  securing trained  personnel. Many  competitors have
substantially larger financial resources,  staffs and facilities. See  "Business
and Properties -- Competition and Markets."
 
GOVERNMENT LAWS AND REGULATIONS
 
    The  Company's operations are affected from  time to time in varying degrees
by political developments and federal, state and local laws and regulations.  In
particular,  oil and gas  production, operations and economics  are or have been
significantly affected by price controls, taxes  and other laws relating to  the
oil  and gas industry, by changes in  such laws and by changes in administrative
regulations. The Company cannot predict how existing laws and regulations may be
interpreted by enforcement  agencies or court  rulings, whether additional  laws
and  regulations will  be adopted, or  the effect  such changes may  have on its
business, financial  condition  or  results of  operations.  See  "Business  and
Properties -- Regulation."
 
ENVIRONMENTAL REGULATIONS
 
    The  Company's  operations are  subject to  complex and  constantly changing
environmental  laws  and  regulations  adopted  by  federal,  state  and   local
governmental  authorities. The Company  believes that compliance  with such laws
has had no  material adverse effect  upon the Company's  operations to date  and
that  the  cost of  such  compliance has  not  been material.  Nevertheless, the
discharge of oil, gas or other pollutants  into the air, soil or water may  give
rise to significant liabilities on the part of the Company to the government and
third  parties  and  may  require  the Company  to  incur  substantial  costs of
remediation. Moreover, the Company has agreed to indemnify sellers of  producing
properties   from  whom  the  Company  has  acquired  reserves  against  certain
liabilities for  environmental  claims  associated  with  the  properties  being
purchased by the Company, including, without limitation, in connection with both
the  1995 Acquisition and the  1996 Acquisition. No assurance  can be given that
existing  environmental  laws  or  regulations,  as  currently  interpreted   or
reinterpreted  in the future, or future laws or regulations, will not materially
adversely affect the Company's results of operations and financial condition  or
that  material indemnity claims will not  arise against the Company with respect
to  properties  acquired  by  the  Company.  See  "Business  and  Properties  --
Environmental Matters."
 
                                       15
<PAGE>
ABSENCE OF PUBLIC MARKET
 
    There  is no existing public  market for the Notes  and the Company does not
intend to  list the  Notes on  any national  securities exchange.  Although  the
Underwriters  have  advised the  Company that  they currently  intend to  make a
market in  the Notes,  the  Underwriters are  not obligated  to  do so  and  may
discontinue  such  market-making  at  any time.  Accordingly,  there  can  be no
assurance that  an active  market will  develop upon  completion of  this  Notes
Offering  or,  if developed,  that such  market will  be sustained.  The initial
offering price of the Notes will be determined through negotiations between  the
Company  and the Underwriters, and may bear  no relationship to the market price
of the Notes  after the Notes  Offering. Factors such  as quarterly or  cyclical
variations  in  the Company's  financial  condition and  results  of operations,
variations in interest rates, future announcements concerning the Company or its
competitors, government regulation,  general economic and  other conditions  and
developments  affecting the oil and gas industry could cause the market price of
the Notes to fluctuate substantially.
 
FORWARD-LOOKING STATEMENTS
 
    Certain  statements  contained   in  this   Prospectus,  including   without
limitation,   statements   containing  the   words   "believes,"  "anticipates,"
"intends," "expects," and words  of similar import, constitute  "forward-looking
statements"  within the meaning of the  Private Securities Litigation Reform Act
of 1995.  Such  forward-looking  statements involve  known  and  unknown  risks,
uncertainties  and other factors that may  cause the actual results, performance
or achievements of the Company or  industry to be materially different from  any
future  results,  performance  or  achievements  expressed  or  implied  by such
forward-looking statements.  Certain  of these  factors  are discussed  in  more
detail   elsewhere  in  this  Prospectus,  including  without  limitation  under
"Prospectus Summary," "Risk Factors,"  "Management's Discussion and Analysis  of
Financial  Condition and Results of  Operations," and "Business and Properties".
Given these  uncertainties, prospective  investors are  cautioned not  to  place
undue  reliance on  such forward-looking  statements. The  Company disclaims any
obligation to update any such factors or to publicly announce the result of  any
revisions  to any of the forward-looking  statements contained herein to reflect
future events or developments.
 
                                       16
<PAGE>
                                  THE COMPANY
 
GENERAL
 
    The Company  is  an  independent  energy company  that  is  engaged  in  the
acquisition,   exploration,  exploitation   and  development  of   oil  and  gas
properties. The Company's primary operations are in the Permian Basin, the  Gulf
Coast  and the Rocky Mountain regions. The Company recently acquired an interest
in a concession  for the  development of mineral  interests in  the Republic  of
Moldova, in Eastern Europe. The Company also has minor interests in the domestic
gas gathering and transmission business.
 
CORPORATE REORGANIZATION
 
    Costilla  was  incorporated  in Delaware  in  June 1996  to  consolidate and
continue the activities previously conducted by Costilla Energy, L.L.C., a Texas
limited liability company  (the "LLC"),  and its wholly  owned subsidiaries,  to
acquire  the assets  of CSL Management  Corporation ("CSL")  (which owns certain
office equipment  used by  the Company),  and  to acquire  the stock  of  Valley
Gathering  Company ("Valley"). Both CSL and Valley are owned by Messrs. Liedtke,
Grella and Musselman. See "Certain Transactions."
 
    Contemporaneously with the  closings of  the Offerings:  (1) the  redeemable
membership  interests of NationsBanc  Capital Corp. ("NBCC") in  the LLC will be
redeemed for  $15.4 million;  (2) the  LLC  will be  merged into  Costilla  (the
"Merger") and an aggregate of 6,000,000 shares of Common Stock will be issued to
the  four members of  the LLC; (3) Costilla  will acquire all  of the issued and
outstanding stock of Valley and the assets of CSL for $0.7 million; and (4) $4.3
million in distributions will be made to the members of the LLC, $3.5 million of
which, in the case of Messrs. Liedtke, Grella and Musselman, will be provided to
such persons  for certain  estimated income  tax effects  of the  Merger.  These
transactions  are  referred  to  throughout this  Prospectus  as  the "Corporate
Reorganization." As a result of the Corporate Reorganization, Costilla will have
four wholly  owned subsidiaries:  (i) Costilla  Petroleum Corporation,  a  Texas
corporation  ("CPC"), which operates properties owned by Costilla and owns minor
interests in the same properties;  (ii) Statewide Minerals Corporation, a  Texas
corporation ("Statewide"), which is engaged in the purchase of small royalty and
mineral interests; (iii) Valley, which owns several small gas gathering systems,
a  small  gas processing  plant,  certain salt  water  disposal systems  and gas
compressors;  and   (iv)  Costilla   Pipeline  Company,   a  Texas   corporation
("Pipeline") which owns a gas pipeline in Pennsylvania held for resale. CSL will
be  dissolved.  Costilla and  CPC  are the  sole  members of  two  Texas limited
liability  companies  through  which  the  Company's  Moldovan  operations   are
conducted.  Costilla also  owns a  45.0% interest  in a  Texas limited liability
company which owns  and operates  a gas  pipeline and  associated facilities  in
Louisiana.
 
    The  Company's executive  offices are  located at  400 West  Illinois, Suite
1000, Midland, Texas, 79701 and its telephone number is (915) 683-3092.
 
                             COMMON STOCK OFFERING
 
    Concurrently with this  Notes Offering,  the Company  is offering  4,000,000
shares of its Common Stock. The Notes Offering and the Common Stock Offering are
each conditioned upon the consummation of the other.
 
                                       17
<PAGE>
                                USE OF PROCEEDS
 
    The  net  proceeds of  the  Offerings are  estimated  to be  $151.8 million,
assuming an initial public offering price of  $15 per share in the Common  Stock
Offering ($160.2 million if the underwriters' over-allotment option with respect
to  the Common Stock Offering is  exercised). Approximately $125 million of such
proceeds, including all the net proceeds of the Notes Offering, will be used  to
repay  all of  the existing  senior indebtedness  of the  Company (the "Existing
Debt") incurred in connection  with the 1996 Acquisition,  and to refinance  its
previous  credit facility. The Existing Debt matures in June 1999. Approximately
$30 million of the Existing Debt currently bears interest at 14.0% per annum and
the balance currently bears interest at a rate selected by the Company equal  to
a  base rate  (generally the prime  rate established by  NationsBank, N.A.) plus
0.75% or LIBOR plus 3.0%. See "Description of Other Indebtedness." In  addition,
$20.4  million of the net proceeds will  be used to pay certain amounts incurred
in connection  with the  Corporate Reorganization,  including $15.4  million  to
redeem certain membership interests of NBCC in the LLC prior to the Merger, $0.7
million to acquire the stock of Valley and the assets of CSL and $4.3 million in
distributions  to the members of the LLC, $3.5  million of which, in the case of
Messrs. Liedtke, Grella  and Musselman,  will be  provided to  such persons  for
certain  estimated  federal  income  tax effects  of  the  Merger.  See "Certain
Transactions." The remaining estimated net proceeds of $6.4 million will be used
by the Company for general corporate purposes.
 
    The following is  a description  of sources and  uses of  proceeds from  the
Offerings,  assuming the underwriters' over-allotment  option in connection with
the Common Stock Offering is not exercised (in millions):
 
<TABLE>
<S>                                                                  <C>
Sources:
  Notes Offering...................................................  $   100.0
  Common Stock Offering............................................       60.0
                                                                     ---------
                                                                     $   160.0
                                                                     ---------
                                                                     ---------
Uses:
  Refinance Existing Debt..........................................  $   125.0
  Redeem membership interests......................................       15.4
  Distributions to individual members to pay estimated income tax
   liability of such members.......................................        3.5
  Pro rata distribution to remaining member........................        0.8
  Purchase of stock of Valley and assets of CSL....................        0.7
  Working capital..................................................        6.4
  Estimated fees, commissions, underwriting discounts and expenses
   related to the Offerings........................................        8.2
                                                                     ---------
                                                                     $   160.0
                                                                     ---------
                                                                     ---------
</TABLE>
 
                                       18
<PAGE>
                                 CAPITALIZATION
 
    The following table sets forth  the unaudited capitalization of the  Company
as  of March 31,  1996, on an historical  basis and on a  pro forma basis giving
effect to the 1996 Acquisition,  the Corporate Reorganization and the  Offerings
and  the application of the net proceeds  therefrom, as if such transactions had
been consummated as of  March 31, 1996, assuming  an initial offering price  for
the  Common Stock in the  Common Stock Offering of  $15 per share. The following
table should be read in  conjunction with the Consolidated Financial  Statements
of  the LLC, the unaudited Pro Forma Condensed Financial Statements, the related
notes, and  the  other  information  contained  elsewhere  in  this  Prospectus,
including  the information set forth in "Management's Discussion and Analysis of
Financial  Condition  and  Results  of  Operations."  For  further   information
regarding  the terms of the long-term debt reflected in the following table, see
"Description of Other  Indebtedness" and  Note 7  and Note  12 of  the Notes  to
Consolidated Financial Statements.
 
<TABLE>
<CAPTION>
                                                                                               MARCH 31, 1996
                                                                                           ----------------------
                                                                                           HISTORICAL  PRO FORMA
                                                                                           ---------  -----------
                                                                                               (IN THOUSANDS)
<S>                                                                                        <C>        <C>
Long-term debt:
  Existing debt..........................................................................  $  74,494  $        --
  Credit Facility........................................................................         --           --
     % Senior Subordinated Notes due 2006................................................         --      100,000
                                                                                           ---------  -----------
Total long-term debt.....................................................................     74,494      100,000
                                                                                           ---------  -----------
Redeemable members' capital..............................................................     11,678           --
                                                                                           ---------  -----------
Members' capital and stockholders' equity:
  Members' capital.......................................................................     (7,535)          --
  Preferred stock, $.10 par value (3,000,000 shares authorized; no shares issued or
   outstanding)..........................................................................         --           --
  Common Stock, $.10 par value (20,000,000 shares authorized; no shares outstanding
   actual, 10,000,000 shares outstanding pro forma)......................................         --        1,000
  Paid-in capital........................................................................         --       34,843
                                                                                           ---------  -----------
Total members' capital and stockholders' equity..........................................    ( 7,535)      35,843
                                                                                           ---------  -----------
Total capitalization.....................................................................  $  78,637  $   135,843
                                                                                           ---------  -----------
                                                                                           ---------  -----------
</TABLE>
 
                                       19
<PAGE>
                    PRO FORMA CONDENSED FINANCIAL STATEMENTS
 
    The  unaudited Pro Forma Condensed Financial  Statements of the Company have
been prepared to give effect to  the 1995 Acquisition and the 1996  Acquisition,
the  Corporate  Reorganization, and  the Offerings  and  the application  of the
estimated net proceeds  therefrom as  if such  transactions (to  the extent  not
already  reflected) had taken  place on March  31, 1996 for  purposes of the Pro
Forma Condensed Balance  Sheet and  as if the  transactions had  taken place  on
January  1,  1995  for  purposes  of  the  Pro  Forma  Condensed  Statements  of
Operations. The Pro Forma Condensed Financial Statements of the Company are  not
necessarily  indicative of  the results for  the periods presented  had the 1995
Acquisition and  the 1996  Acquisition, the  Corporate Reorganization,  and  the
Offerings  and the  application of  the estimated  net proceeds  therefrom taken
place on January  1, 1995. In  addition, future results  may vary  significantly
from  the results  reflected in the  accompanying Pro  Forma Condensed Financial
Statements because of normal production declines, changes in product prices, and
the success  of  future  exploration and  development  activities,  among  other
factors.  This information should  be read in  conjunction with the Consolidated
Financial Statements  of  Costilla  Energy, L.L.C.  and  subsidiaries,  and  the
Statements  of  Revenues  and  Direct Operating  Expenses  with  respect  to the
properties acquired  in  the 1995  Acquisition  and the  1996  Acquisition,  all
included elsewhere herein.
 
                                       20
<PAGE>
                             COSTILLA ENERGY, INC.
 
                 PRO FORMA CONDENSED BALANCE SHEET -- UNAUDITED
 
                                 MARCH 31, 1996
 
                                 (IN THOUSANDS)
<TABLE>
<CAPTION>
                                                                                                                 PRO FORMA
                                                                                    PRE OFFERING    PRO FORMA    COSTILLA
                                                          COSTILLA      PRO FORMA     COSTILLA      OFFERING      ENERGY,
                        ASSETS                             L.L.C.      ADJUSTMENTS     L.L.C.      ADJUSTMENTS     INC.
- ------------------------------------------------------  -------------  -----------  -------------  -----------  -----------
<S>                                                     <C>            <C>          <C>            <C>          <C>
Current assets:
  Cash and cash equivalents...........................    $   2,760     $    (700)(3)   $   2,060   $  (4,259)(4)  $  13,498
                                                                                                      151,800(5)
                                                                                                     (136,103)(6)
  Restricted cash.....................................          250                         250                        250
  Accounts receivable.................................        7,584                       7,584                      7,584
  Prepaid and other current assets....................          800                         800                        800
                                                        -------------               -------------               -----------
      Total current assets............................       11,394                      10,694                     22,132
Oil and gas properties, using the successful efforts
 method of accounting:
  Proved properties...................................       83,965        40,500(1)     124,465                   124,465
  Unproved properties.................................        3,580                       3,580                      3,580
  Accumulated depreciation, depletion and
   amortization.......................................      (11,281)                    (11,281)                   (11,281)
                                                        -------------               -------------               -----------
                                                             76,264                     116,764                    116,764
Other property and equipment, net.....................        1,024           700(3)       1,724                     1,724
Deferred charges (Note 2).............................        1,658         3,650(1)       3,650        3,813(5)      3,813
                                                                           (1,658)(2)                  (3,650)(6)
Note receivable -- affiliate..........................          684                         684                        684
                                                        -------------               -------------               -----------
                                                          $  91,024                   $ 133,516                  $ 145,117
                                                        -------------               -------------               -----------
                                                        -------------               -------------               -----------
 
<CAPTION>
 LIABILITIES, REDEEMABLE MEMBERS' CAPITAL AND EQUITY
- ------------------------------------------------------
<S>                                                     <C>            <C>          <C>            <C>          <C>
Current liabilities:
  Trade accounts payable..............................    $   6,190     $  (3,113)(1)   $   3,077                $   3,077
  Undistributed revenue...............................        1,026                       1,026                      1,026
  Other current liabilities...........................        2,074                       2,074                      2,074
                                                        -------------               -------------               -----------
      Total current liabilities.......................        9,290                       6,177                      6,177
 
Long-term debt, less current maturities...............       74,494        47,263(1)     121,757    $ 100,000(5)    100,000
                                                                                                     (121,757)(6)
Deferred income.......................................        3,097                       3,097                      3,097
                                                        -------------               -------------               -----------
      Total liabilities...............................       86,881                     131,031                    109,274
Redeemable members' capital...........................       11,678                      11,678       (11,678)(6)         --
Members' capital and capital of affiliates............       (7,535)       (1,658)(2)      (9,193)      9,193(4)         --
Stockholders' equity..................................           --                          --        (2,668)(6)     35,843
                                                                                                       (4,259)(4)
                                                                                                       (9,193)(4)
                                                                                                       55,613(5)
                                                                                                       (3,650)(6)
                                                        -------------               -------------               -----------
                                                          $  91,024                   $ 133,516                  $ 145,117
                                                        -------------               -------------               -----------
                                                        -------------               -------------               -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                       21
<PAGE>
                             COSTILLA ENERGY, INC.
 
            PRO FORMA CONDENSED STATEMENT OF OPERATIONS -- UNAUDITED
 
                          YEAR ENDED DECEMBER 31, 1995
 
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
<TABLE>
<CAPTION>
                                                                                                    PRE OFFERING     PRO FORMA
                                              COSTILLA        1995         1996        PRO FORMA      COSTILLA       OFFERING
                                               L.L.C.      ACQUISITION  ACQUISITION   ADJUSTMENTS      L.L.C.       ADJUSTMENTS
                                            -------------  -----------  -----------  -------------  -------------  -------------
<S>                                         <C>            <C>          <C>          <C>            <C>            <C>
Revenues..................................    $  21,816     $  10,930    $  19,891                    $  52,637
Expenses:
  Oil and gas production..................       10,355         5,473       11,409     $    (300)(3)      26,937
  General and administrative..............        3,571            --           --          (172)(3)       4,850
                                                                                           1,451(7)
  Exploration and abandonment.............        1,650           109        1,002                        2,761
  Depreciation, depletion and
   amortization...........................        6,095            --           --           100(3)      14,313
                                                                                           8,118(8)
  Interest................................        4,454                                    9,388(9)      13,842      $  (2,211)(10)
  Other...................................            2            --           --                            2
                                            -------------  -----------  -----------                 -------------
                                                 26,127         5,582       12,411                       62,705
                                            -------------  -----------  -----------                 -------------
Net income (loss) before federal income
 taxes....................................       (4,311)        5,348        7,480                      (10,068)
Provision for federal income taxes........            3            --           --                            3
                                            -------------  -----------  -----------                 -------------
Net income (loss).........................    $  (4,314)    $   5,348    $   7,480                    $ (10,071)
                                            -------------  -----------  -----------                 -------------
                                            -------------  -----------  -----------                 -------------
Net income (loss) per share...............
 
<CAPTION>
                                             PRO FORMA
                                             COSTILLA
                                              ENERGY,
                                               INC.
                                            -----------
<S>                                         <C>
Revenues..................................   $  52,637
Expenses:
  Oil and gas production..................      26,937
  General and administrative..............       4,850
 
  Exploration and abandonment.............       2,761
  Depreciation, depletion and
   amortization...........................      14,313
 
  Interest................................      11,631
  Other...................................           2
                                            -----------
                                                60,494
                                            -----------
Net income (loss) before federal income
 taxes....................................      (7,857)
Provision for federal income taxes........           3
                                            -----------
Net income (loss).........................   $  (7,860)
                                            -----------
                                            -----------
Net income (loss) per share...............   $   (0.80)
                                            -----------
                                            -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                       22
<PAGE>
                             COSTILLA ENERGY, INC.
 
            PRO FORMA CONDENSED STATEMENT OF OPERATIONS -- UNAUDITED
 
                       THREE MONTHS ENDED MARCH 31, 1996
 
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                                                       PRO FORMA
                                                                                        PRE OFFERING     PRO FORMA     COSTILLA
                                                               1996        PRO FORMA      COSTILLA       OFFERING       ENERGY,
                                           COSTILLA L.L.C.  ACQUISITION   ADJUSTMENTS      L.L.C.       ADJUSTMENTS      INC.
                                           ---------------  -----------  -------------  -------------  -------------  -----------
<S>                                        <C>              <C>          <C>            <C>            <C>            <C>
Revenues.................................     $   8,951      $   5,087                    $  14,038                    $  14,038
Expenses:
  Oil and gas production.................         3,659          2,699     $     (75)(3)       6,283                       6,283
  General and administrative.............         1,362             --           (43)(3)       1,505                       1,505
                                                                                 186 (7)
  Exploration and abandonment............           228            247                          475                          475
  Depreciation, depletion and
   amortization..........................         1,986             --            25(3)       3,166                        3,166
                                                                               1,155(8)
  Interest...............................         1,704             --         2,330(9)       4,034    $  (1,126)(10)      2,908
                                                -------     -----------                 -------------                 -----------
                                                  8,939          2,946                       15,463                       14,337
                                                -------     -----------                 -------------                 -----------
Net income (loss) before federal income
 taxes...................................            12          2,141                       (1,425)                        (299)
                                                -------     -----------                 -------------                 -----------
Net income (loss)........................     $      12      $   2,141                    $  (1,425)                   $    (299)
                                                -------     -----------                 -------------                 -----------
                                                -------     -----------                 -------------                 -----------
Net income (loss) per share..............                                                                              $   (0.03)
                                                                                                                      -----------
                                                                                                                      -----------
</TABLE>
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                       23
<PAGE>
                             COSTILLA ENERGY, INC.
          NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS
 
NOTE 1. -- BASIS OF PRESENTATION
    The  Pro  Forma  Condensed Financial  Statements  of the  Company  have been
prepared to give effect  to the 1995 Acquisition  and the 1996 Acquisition,  the
Corporate  Reorganization and the Offerings and the application of estimated net
proceeds therefrom, as if  such transactions had taken  place on March 31,  1996
for purposes of the Pro Forma Condensed Balance Sheet (with the exception of the
1995 Acquisition which was previously reflected in the balance sheet of Costilla
Energy,  L.L.C.), and as if each of  the transactions had taken place on January
1, 1995 for purposes  of the Pro Forma  Condensed Statements of Operations.  The
1995 Acquisition and 1996 Acquisition are accounted for by the purchase method.
 
        Costilla  L.L.C.  -- Represents  the  consolidated balance  sheet of
    Costilla Energy, L.L.C. and  subsidiaries as of March  31, 1996 and  the
    related  consolidated  statements  of  operations  for  the  year  ended
    December 31, 1995 and the three months ended March 31, 1996.
 
        1995 Acquisition  -- Represents  the revenues  and direct  operating
    expenses  of the  properties acquired  in the  1995 Acquisition  for the
    period from  January  1,  1995  to  June 12,  1995  (date  of  the  1995
    Acquisition).
 
        1996  Acquisition --  Represents the  revenues and  direct operating
    expenses of the properties acquired in the 1996 Acquisition for the year
    ended December 31, 1995 and the  three months ended March 31, 1996.  The
    1996 Acquisition was completed on June 14, 1996.
 
NOTE 2. -- PRO FORMA ENTRIES
 
    (1)  To record the issuance of  additional long-term debt under the Existing
Debt Facility (as defined under  "Description of Other Indebtedness") funded  on
June  14, 1996  (net of  amounts used to  repay indebtedness  under the previous
credit agreement),  and to  record the  use of  the net  proceeds for  the  1996
Acquisition,  to  pay  debt  issuance fees  associated  with  the  Existing Debt
approximating $3,650,000 (including amounts which  would be required to be  paid
in September 1996), and to reflect payment of certain trade accounts payable.
 
    (2)  To record  the write-off of  capitalized loan fees  associated with the
previous credit agreement.
 
    (3) To record the acquisition of Valley Gathering Company and CSL Management
Corporation from certain members  of Costilla Energy, L.L.C.  and to record  the
related  additional depreciation and amortization, and  reduction in oil and gas
production and general and administrative expenses.
 
    (4) To  reflect  the  Corporate Reorganization  including  the  transfer  of
members'  and affiliates'  capital to stockholders'  equity; and  to reflect the
distribution of cash to certain members. See "Use of Proceeds".
 
    (5) To  reflect the  issuance of  4,000,000  shares of  Common Stock  at  an
estimated  price of $15 per share for  estimated proceeds of $55,613,000, net of
estimated expenses of the  Common Stock Offering, and  issuance of the Notes  at
$100,000,000;  and  to  reflect payment  of  related debt  issuance  expenses of
$3,812,000.
 
    (6) To  record the  repayment of  the  Existing Debt  and the  write-off  of
related  debt issuance costs  and the repurchase  of redeemable members' capital
for approximately $14,346,000 from proceeds of the Offerings.
 
    (7) Estimated incremental general and administrative expenses necessary  due
to  estimated  public  reporting  costs  and  increased  personnel  required  to
administer the  properties  acquired in  the  1996 Acquisition  and  to  reflect
incremental  general  and administrative  expenses due  to the  1995 Acquisition
experienced subsequent to June 12, 1995.
 
                                       24
<PAGE>
                             COSTILLA ENERGY, INC.
    NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS (CONTINUED)
 
NOTE 2. -- PRO FORMA ENTRIES (CONTINUED)
    (8) To record  estimated incremental  depletion expense  for the  properties
acquired  in the  1995 Acquisition  from January 1,  1995 through  June 12, 1995
(date of  the 1995  Acquisition) and  for the  properties acquired  in the  1996
Acquisition from January 1, 1995 through March 31, 1996.
 
    (9)  To adjust  interest expense  to reflect  additional borrowings  for the
properties acquired in  the 1995 Acquisition  from January 1,  1995 to June  12,
1995  (date of the 1995 Acquisition) and for the properties acquired in the 1996
Acquisition for  the period  of January  1,  1995 through  March 31,  1996.  The
adjustment  also reflects  adjusted interest expense  due to  the Existing Debt.
Also included is the amortization of estimated debt issuance costs of $3,650,000
over a three-year period.
 
    (10) To adjust interest  expense to reflect issuance  of the Notes plus  the
amortization of estimated debt issuance costs over 10 years.
 
NOTE 3. -- INCOME TAXES
    Upon  consummation of the  Corporate Reorganization, the  Company intends to
account for income taxes pursuant  to the provisions of  SFAS 109. At March  31,
1996,  the pro forma tax basis of  the Company's assets and liabilities exceeded
the pro forma book  basis by approximately $6,400,000.  The pro forma  temporary
differences  are primarily related to  the differences in book  and tax basis of
oil and gas properties due to the expensing of intangible development costs  for
tax  purposes and other income tax differences arising from the tax treatment of
oil and gas producing activities.
 
NOTE 4. -- NET INCOME (LOSS) PER SHARE
    Net income (loss) per  share is calculated based  on the pro forma  weighted
average  shares  outstanding  during the  respective  periods.  Weighted average
shares reflect the  pro forma issuance  of 1,080,008 shares  of Common Stock  to
NBCC  on February  17, 1995 and  the pro  forma issuance of  4,919,992 shares of
Common Stock to the remaining holders prior to January 1, 1995. In addition, the
issuance of 4,000,000  shares in the  Common Stock Offering  is assumed to  have
taken place on January 1, 1995 and assumes that the underwriters' over-allotment
option is not exercised.
 
NOTE 5. -- SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION
    The  estimates of  proved oil  and gas  reserves, which  are located  in the
United States, were prepared by  the Company as of  December 31, 1993, 1994  and
1995, and Williamson as of March 31, 1996. Reserves were estimated in accordance
with  guidelines established by the Securities  and Exchange Commission and FASB
which require that  reserve estimates  be prepared under  existing economic  and
operating conditions with no provision for price and cost escalations, except by
contractual  arrangements.  The  Company  has presented  the  pro  forma reserve
estimates utilizing an oil price of $17.79 per Bbl and a gas price of $2.03  per
Mcf  as of December 31, 1995, and an oil price of $20.91 per Bbl and a gas price
of $2.02 per Mcf as of March 31, 1996. The pro forma reserve information assumes
that both the 1995 Acquisition and the 1996 Acquisition took place on January 1,
1995.
 
                                       25
<PAGE>
                             COSTILLA ENERGY, INC.
    NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS (CONTINUED)
 
NOTE 5. -- SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (CONTINUED)
OIL AND GAS PRODUCING ACTIVITIES
 
    Oil and gas reserve quantity estimates are subject to numerous uncertainties
inherent in  the  estimation  of  quantities  of  proved  reserves  and  in  the
projection  of  future  rates  of  production  and  the  timing  of  development
expenditures. The accuracy  of such estimates  is a function  of the quality  of
available  data and of  engineering and geological  interpretation and judgment.
Results of subsequent drilling, testing  and production may cause either  upward
or  downward revision of previous estimates.  Further, the volumes considered to
be commercially  recoverable  fluctuate with  changes  in prices  and  operating
costs.  The Company emphasizes  that reserve estimates  are inherently imprecise
and that estimates of new discoveries are more imprecise that those of currently
producing oil and gas properties.  Accordingly, these estimates are expected  to
change as additional information becomes available in the future.
 
<TABLE>
<CAPTION>
                                                                              OIL AND            GAS
                                                                        CONDENSATE (MBBLS)     (MMCF)
                                                                        -------------------  -----------
<S>                                                                     <C>                  <C>
Balance, January 1, 1995..............................................           17,990         115,281
  Revisions of previous estimates.....................................             (570)            425
  Extensions and discoveries..........................................              605           8,922
  Production..........................................................           (2,085)        (11,984)
                                                                                -------      -----------
Balance, December 31, 1995............................................           15,940         112,644
  Revisions of previous estimates.....................................              436           2,614
  Extensions and discoveries..........................................              592             296
  Production..........................................................             (492)         (2,634)
                                                                                -------      -----------
Balance, March 31, 1996...............................................           16,476         112,920
                                                                                -------      -----------
                                                                                -------      -----------
Proved Developed Reserves:
  December 31, 1995...................................................           13,235          87,345
  March 31, 1996......................................................           13,552          84,369
</TABLE>
 
STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS RELATING TO PROVED OIL
AND GAS RESERVES
 
    The  standardized measure of discounted future net cash flows is computed by
applying period-end prices of oil and  gas (with consideration of price  changes
only to the extent provided by contractual arrangements) to the estimated future
production  of proved oil  and gas reserves less  estimated future production of
proved oil and gas reserves less estimated future expenditures (based on period-
end costs) to be incurred in developing and producing the proved reserves,  less
estimated  future income tax expenses (based  on period-end statutory tax rates,
with consideration of  future tax rates  already legislated) to  be incurred  on
pretax  net cash flows less  tax basis of properties  and available credits, and
assuming continuation of existing economic conditions. The estimated future  net
cash  flows are  then discounted  using a rate  of 10%  per year  to reflect the
estimated timing of the future cash flows.
 
                                       26
<PAGE>
                             COSTILLA ENERGY, INC.
    NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS (CONTINUED)
 
NOTE 5. -- SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (CONTINUED)
    Discounted future  cash  flow  estimates  like those  shown  below  are  not
intended  to represent estimates  of the fair  value of oil  and gas properties.
Estimates of  fair value  should also  consider probable  reserves,  anticipated
future oil and gas prices, interest rates, changes in development and production
costs  and risks associated  with future production. Because  of these and other
considerations, any  estimate  of  fair  value  is  necessarily  subjective  and
imprecise.
 
<TABLE>
<CAPTION>
                                                                              DECEMBER 31,   MARCH 31,
                                                                                  1995          1996
                                                                              ------------  ------------
                                                                                    (IN THOUSANDS)
<S>                                                                           <C>           <C>
Future cash flows...........................................................   $  512,363   $    572,425
Future costs:
  Production................................................................     (239,388)      (253,347)
  Development...............................................................      (20,907)       (22,076)
                                                                              ------------  ------------
Future net cash flows.......................................................      252,068        297,002
10% annual discount for estimated timing of cash flows......................      (98,695)      (117,475)
                                                                              ------------  ------------
Discounted future net cash flows............................................      153,373        179,527
Future income taxes.........................................................      (12,739)       (22,302)
                                                                              ------------  ------------
Standardized measure of discounted net cash flows...........................   $  140,634   $    157,225
                                                                              ------------  ------------
                                                                              ------------  ------------
</TABLE>
 
Changes  in Standardized Measure of Discounted Future Net Cash Flows From Proved
Reserves:
 
<TABLE>
<CAPTION>
                                                                          YEAR ENDED     THREE MONTHS
                                                                         DECEMBER 31,  ENDED MARCH 31,
                                                                             1995            1996
                                                                         ------------  ----------------
                                                                                 (IN THOUSANDS)
<S>                                                                      <C>           <C>
Increase (decrease):
  Extensions and discoveries and improved recovery, net of future
   production and development costs....................................   $    9,598     $      6,002
  Accretion of discount................................................       14,147            3,516
  Net change in sales prices, net of production costs..................        2,992           20,807
  Changes in estimated future development costs........................       (1,651)            (238)
  Revisions of quantity estimates......................................       (2,392)           4,694
  Net change in income taxes...........................................        1,633           (9,563)
  Sales, net of production costs.......................................      (27,055)          (7,264)
  Changes of production rates (timing) and other.......................        1,893           (1,363)
                                                                         ------------  ----------------
    Net increase (decrease)............................................         (835)          16,591
Standardized measure of discounted future net cash flows:
  Beginning of period..................................................      141,469          140,634
                                                                         ------------  ----------------
  End of period........................................................   $  140,634     $    157,225
                                                                         ------------  ----------------
                                                                         ------------  ----------------
</TABLE>
 
                                       27
<PAGE>
                         SELECTED FINANCIAL INFORMATION
 
    The  following table sets forth selected  financial data of Costilla Energy,
L.L.C. See  "Management's Discussion  and Analysis  of Financial  Condition  and
Results of Operations." The historical information should be read in conjunction
with  the  Consolidated  Financial  Statements and  the  notes  thereto included
elsewhere in  this  Prospectus.  Costilla Energy,  L.L.C.  acquired  significant
producing  oil  and gas  properties in  certain of  the periods  presented which
affect the comparability of the historical financial and operating  information.
The  historical results are  not necessarily indicative  of the Company's future
operations or financial results.
 
<TABLE>
<CAPTION>
                                                                                                     THREE MONTHS ENDED
                                                            YEAR ENDED DECEMBER 31,                      MARCH 31,
                                             -----------------------------------------------------  --------------------
                                               1991       1992       1993       1994       1995       1995       1996
                                             ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                                    (IN THOUSANDS, EXCEPT RATIOS)
<S>                                          <C>        <C>        <C>        <C>        <C>        <C>        <C>
STATEMENT OF OPERATIONS DATA:
  Operating revenues.......................  $   1,623  $   2,364  $   4,231  $   7,637  $  21,693  $   2,177  $   8,833
  Total revenues...........................      2,134      2,887      4,397      7,836     21,816      2,180      8,951
  Expenses:
    Oil and gas production.................        769      1,340      1,688      2,351     10,355        896      3,659
    General and administrative.............        354        388        952      1,184      3,571        459      1,362
    Exploration and abandonment............        106          4        218        793      1,650      1,007        228
    Depreciation, depletion and
     amortization..........................        494        404        884      1,847      6,095        462      1,986
    Interest...............................        179        365        605      1,458      4,454        407      1,704
    Other..................................         --         --         --         --          2         --         --
                                             ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Net income (loss) before income taxes....        232        386         50        203     (4,311)    (1,051)        12
  Net income (loss)........................        234        368         73        163     (4,314)    (1,051)        12
STATEMENT OF CASH FLOWS DATA:
  Net cash provided by (used in):
    Operating activities...................  $     276  $     140  $     322  $   1,527  $   6,366  $  (1,827) $   2,276
    Investing activities...................     (2,659)    (1,432)    (6,731)   (12,146)   (62,467)    (1,389)    (5,132)
    Financing activities...................      2,440      1,450      6,315     10,618     58,830      3,272      3,000
OTHER FINANCIAL DATA:
  Capital expenditures.....................  $   3,092  $   3,720  $   6,862  $  11,868  $  62,220  $   1,389  $   5,132
  Distributions to members.................         --         --        456        961         55         55         --
  EBITDA (1)...............................      1,011      1,159      1,757      4,301      7,888        825      3,930
  EBITDA/Interest expense (2)..............        5.6x       3.2x       2.9x       2.9x       1.8x       2.0x       2.3x
  Ratio of earnings to fixed charges (3)...        1.3        1.5        1.0        1.1         --         --        1.0
BALANCE SHEET DATA (AS OF PERIOD END):
  Working capital..........................  $    (580) $     185  $   1,612  $   1,081  $   2,496         --  $   2,104
  Total assets.............................      4,602      6,675     13,365     24,904     87,367         --     91,024
  Total debt...............................      2,870      5,304     12,006     23,591     71,494         --     74,494
  Redeemable members' capital..............         --         --         --         --     11,320         --     11,678
  Members' capital.........................        504        434         51       (747)    (7,189)        --     (7,535)
</TABLE>
 
- ------------------------------
(1) EBITDA is presented because of its wide acceptance as a financial  indicator
    as  to a company's  ability to service  or incur debt.  EBITDA should not be
    considered as  an alternative  to earnings  (loss) as  an indicator  of  the
    Company's financial performance or to cash flow as a measure of liquidity.
 
(2)  Calculated  by  dividing  EBITDA by  interest.  Interest  includes interest
    expense accrued and amortization of deferred financing costs.
 
(3) For  purposes  of  calculating  the ratio  of  earnings  to  fixed  charges,
    "earnings"  are net income (loss) plus income taxes and fixed charges. Fixed
    charges are comprised of interest on indebtedness, amortization of  deferred
    financing costs, and that portion of operating lease expense which is deemed
    to  be representative of  an interest factor.  Earnings were insufficient to
    cover fixed charges by $4,311,000, and $1,051,000 for the historical periods
    ended December 31, 1995 and March 31, 1995, respectively.
 
                                       28
<PAGE>
          MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
                           AND RESULTS OF OPERATIONS
 
GENERAL
 
    Costilla  is  an  independent  energy company  engaged  in  the exploration,
acquisition and development of oil and gas properties. The Company's predecessor
began operating  in 1988  and through  mid-1995 had  grown primarily  through  a
series  of small acquisitions of oil and  gas properties and the exploitation of
those properties. In June 1995, Costilla consummated the 1995 Acquisition for  a
purchase  price  of approximately  $46.6  million, and  in  June 1996,  the 1996
Acquisition was consummated for a purchase price of approximately $42.5 million.
 
    To date, the Company has achieved its high rate of growth primarily  through
acquisitions.  This has impacted  its reported financial results  in a number of
ways. Properties sold by others  frequently have not received focused  attention
prior  to sale. After  acquisition, certain of  these properties are  in need of
maintenance,  workovers,   recompletions  and   other  remedial   activity   not
constituting  capital expenditures, which substantially increase lease operating
expenses. The increased production and revenue resulting from these expenditures
is predominately realized  in periods subsequent  to the period  of expense.  In
addition,  the rapid growth of the Company has required it to develop operating,
accounting and administrative personnel compatible with its increased size.  The
Company  believes it has  now achieved a  sufficient size to  expand its reserve
base without a corresponding increase in its general and administrative expense.
The Company also believes it now has a sufficient inventory of prospects and the
professional staff necessary to  follow a more  balanced program of  exploration
and exploitation activities to complement its acquisition efforts.
 
    Costilla's  strategy is to increase its oil and gas reserves, production and
cash flow  from operations  through  a two-pronged  approach which  combines  an
active  exploration  program with  the  acquisition and  exploitation  of proved
reserves. In  addition,  Costilla  continues  to  evaluate  the  acquisition  of
undeveloped   acreage  for  its  exploration   efforts.  Costilla  has  in-house
exploration expertise  using 3-D  seismic technology  to identify  new  drilling
opportunities as well as for the exploitation of acquired properties.
 
    Costilla  has  shown a  significant increase  in its  oil and  gas reserves,
production and  EBITDA, especially  due to  the 1995  Acquisition and  the  1996
Acquisition.  The following table sets forth  certain operating data of Costilla
for the periods presented:
 
<TABLE>
<CAPTION>
                                                                                        THREE MONTHS ENDED
                                                          YEAR ENDED DECEMBER 31,           MARCH 31,
                                                      -------------------------------  --------------------
                                                        1993       1994       1995       1995       1996
                                                      ---------  ---------  ---------  ---------  ---------
<S>                                                   <C>        <C>        <C>        <C>        <C>
OIL AND GAS PRODUCTION:
  Oil (MBbls).......................................        158        330        950         86        338
  Gas (Mmcf)........................................        865      1,600      4,806        477      1,643
  MBOE..............................................        302        597      1,751        166        612
AVERAGE SALES PRICES (1):
  Oil (per Bbl).....................................  $   16.93  $   15.25  $   15.53  $   17.82  $   17.32
  Gas (per Mcf).....................................       1.82       1.63       1.45       1.34       1.81
PRODUCTION COST (2):
  Per BOE (3).......................................  $    5.59  $    3.94  $    5.91  $    5.40  $    5.98
  Per dollar of sales...............................       0.40       0.31       0.48       0.41       0.41
DEPRECIATION, DEPLETION AND AMORTIZATION:
  Per BOE...........................................  $    2.93  $    3.09  $    3.48  $    2.78  $    3.25
  Per dollar of sales...............................       0.21       0.24       0.28       0.21       0.22
</TABLE>
 
- ------------------------
(1)  Before deduction of production taxes and net of hedging results.
 
(2)  Excludes depreciation, depletion and amortization. Production cost includes
     lease  operating  expenses  and  production   and  ad  valorem  taxes,   if
     applicable.
 
                                       29
<PAGE>
(3)  Production  costs per BOE in 1995 and  for the three months ended March 31,
     1996 were unusually high as a  result of relatively high workover  expenses
     with  respect to properties acquired in  the 1995 Acquisition which did not
     produce  related  production  improvement  until  subsequent  periods.   In
     addition,  the Company expended  approximately $1.6 million  during 1995 in
     one field in the Permian Basin primarily for plugging wells to comply  with
     applicable regulatory requirements.
 
    Costilla  uses the successful  efforts method of accounting  for its oil and
gas activities. Costs to acquire mineral interests in oil and gas properties, to
drill and equip exploratory wells that  result in proved reserves, and to  drill
and  equip development wells  are capitalized. Costs  to drill exploratory wells
that do  not result  in  proved reserves,  geological, geophysical  and  seismic
costs,  and costs  of carrying and  retaining unproved  properties are expensed.
Capitalized costs  of  producing  oil  and  gas  properties,  after  considering
estimated  dismantlement and abandonment costs and estimated salvage values, are
depreciated and depleted using the  unit-of-production method. Unproved oil  and
gas  properties that are individually  significant are periodically reviewed for
impairment of value,  and a  loss is  recognized at  the time  of impairment  by
providing an impairment allowance. Other unproved properties are amortized based
on the Company's experience of successful drilling and average holding period.
 
    The  Company utilizes option contracts to  hedge the effect of price changes
on a portion of  its future oil  and gas production.  Premiums paid and  amounts
receivable  under the option contracts are amortized  and accrued to oil and gas
sales, respectively. See "Business and Properties -- Risk Management."
 
    The Company's  predecessors  were  classified as  partnerships  for  federal
income tax purposes. Therefore, no income taxes were paid or provided for by the
Company  prior to the Offerings.  Future tax amounts, if  any, will be dependent
upon several factors,  including but  not limited  to the  Company's results  of
operations.
 
RESULTS OF OPERATIONS
 
  THREE  MONTHS ENDED MARCH  31, 1996 COMPARED  TO THREE MONTHS  ENDED MARCH 31,
1995
 
    The Company's total oil  and gas revenues for  the three months ended  March
31,  1996 were  $8,833,000, representing an  increase of  $6,656,000 (306%) over
revenues of $2,177,000  for the  comparable period  in 1995.  This increase  was
primarily  due  to  the  1995  Acquisition  which  accounted  for  approximately
$5,722,000 of the revenue increase.
 
    Oil and gas production was 612 MBOE in the 1996 period compared to 166  MBOE
in the 1995 period. Of the 446 MBOE increase, 380 MBOE was due to the properties
acquired  in the 1995  Acquisition. The remainder  of the increase  was due to a
combination of successful  drilling activities and  the enhancement of  existing
production.
 
    Interest  and other revenues  were $88,000 for the  three months ended March
31, 1996 compared to $3,000 for  the comparable period in 1995, representing  an
increase  of $85,000, which was  comprised of an increase  in interest income of
$21,000 in  1996 due  to increased  funds earning  interest and  $65,000 in  oil
marketing income. Also in the 1996 period, the Company realized gains of $30,000
on  the sale of various properties for  which there were no comparable sales for
the three months ended March 31, 1995.
 
    Oil and gas production costs in  the 1996 period were $3,659,000 ($5.98  per
BOE),  compared to $896,000 in the 1995  period ($5.40 per BOE), representing an
increase of $2,763,000 (308%), due principally to the 1995 Acquisition. On a per
BOE basis, production costs increased $0.58  due primarily to costs incurred  to
exploit  the properties acquired  in the 1995 Acquisition  which did not produce
related production improvement for the full period. In addition, the 1995 period
was negatively affected by operating costs incurred in connection with  plugging
and abandoning certain wells on properties acquired in late 1994.
 
                                       30
<PAGE>
    General and administrative expense for the three months ended March 31, 1996
was  $1,362,000, representing an increase of $903,000 (197%) from the comparable
period in 1995  of $459,000. The  increase is  primarily due to  an increase  in
personnel and related costs necessary to accommodate the increased activities of
the  Company  due  to the  1995  Acquisition  and in  anticipation  of  the 1996
Acquisition.
 
    Exploration and abandonment expense decreased to $228,000 in the 1996 period
compared to $1,007,000  in the 1995  period. The Company  did not incur  seismic
costs for the three months ended March 31, 1996, compared to $467,000 which were
incurred  for  the comparable  period  in 1995.  Dry  hole costs  decreased from
$540,000 to $228,000 for the comparable periods in 1995 and 1996, respectively.
 
    Depreciation, depletion and  amortization expense  for the  1996 period  was
$1,986,000 compared to $462,000 for the 1995 period, representing an increase of
$1,524,000  (330%). During 1996, depreciation, depletion and amortization on oil
and gas production was provided at an average rate of $3.25 per BOE compared  to
$2.78 per BOE for 1995. The increase was due primarily to the 1995 Acquisition.
 
    Interest expense was $1,704,000 in the 1996 period, compared to $407,000 for
the  comparable period in 1995. The  $1,297,000 (319%) increase was attributable
to increased  levels  of  debt  which  the Company  used  to  finance  the  1995
Acquisition.  The average  amounts of  applicable interest-bearing  debt for the
comparable  periods  in  1996  and   1995  were  $71,923,000  and   $19,820,000,
respectively.
 
  YEAR ENDED DECEMBER 31, 1995 COMPARED TO YEAR ENDED DECEMBER 31, 1994
 
    The  Company's  total  oil  and  gas  revenues  for  1995  were $21,693,000,
representing an increase of  $14,056,000 (184%) over  revenues of $7,637,000  in
1994.  This increase was  primarily due to the  1995 Acquisition which accounted
for approximately $12,032,000 of the revenue increase.
 
    Oil and gas production was 1,751 MBOE in  1995 and 597 MBOE in 1994. Of  the
1,154  MBOE increase, 1,099 MBOE was due  to the properties acquired in the 1995
Acquisition.
 
    Interest and other  revenues were $123,000  in 1995 compared  to $87,000  in
1994,  representing  an increase  of $36,000  (41%), which  was comprised  of an
increase in interest income  of $59,000 in  1995 due to  an increased amount  of
funds  earning  interest, partially  offset  by a  decrease  of other  income of
$23,000. In 1994, the Company realized a gain of $112,000 on the sale of various
properties for which there were no comparable gains in 1995.
 
    Oil and  gas production  costs in  1995 were  $10,355,000 ($5.91  per  BOE),
compared  to $2,351,000  in 1994  ($3.94 per  BOE), representing  an increase of
$8,004,000 (340%).  The major  portion  of the  increase  was due  to  increased
production  associated with the 1995  Acquisition. In addition, certain acquired
properties required remedial workovers and other activity immediately  following
acquisition  resulting  in  unusual operating  costs  of  approximately $600,000
during 1995. In  addition, $1,605,000  of operating costs  were incurred  during
1995  primarily  in connection  with plugging  and  abandoning certain  wells to
comply with applicable  regulatory requirements on  properties acquired in  late
1994.
 
    General  and administrative expense for 1995 was $3,571,000, representing an
increase of $2,387,000 (202%) from 1994  expense of $1,184,000. The increase  is
primarily  due  to  an increase  in  personnel  and related  costs  necessary to
accommodate the increased activities of the Company due to the 1995 Acquisition.
 
    Exploration and abandonment expense increased to $1,650,000 in 1995 compared
to $793,000 in 1994. The increase  of $857,000 (108%) was comprised  principally
of $790,000 of seismic costs.
 
    Depreciation,  depletion and  amortization expense  for 1995  was $6,095,000
compared to $1,847,000 for 1994, representing an increase of $4,248,000  (230%).
During  1995, depreciation, depletion and amortization on oil and gas production
was provided at an average rate of $3.48  per BOE compared to $3.09 per BOE  for
1994. The increase was due primarily to the 1995 Acquisition.
 
                                       31
<PAGE>
    Interest  expense was $4,454,000 in 1995 compared to $1,458,000 in 1994. The
$2,996,000 (205%) increase was  attributable to increased  levels of debt  which
the  Company  used  to finance  the  1995  Acquisition. The  average  amounts of
applicable  interest-bearing  debt  in  1995  and  1994  were  $49,972,000   and
$17,632,000, respectively.
 
  YEAR ENDED DECEMBER 31, 1994 COMPARED TO YEAR ENDED DECEMBER 31, 1993
 
    The  Company's  total  oil  and  gas  revenues  for  1994  were  $7,637,000,
representing an  increase of  $3,406,000 (81%)  over revenues  of $4,231,000  in
1993.  The  primary  reason  for  the  increase  in  revenues  was  due  to  two
acquisitions of properties in  1994, one of which  occurred in January 1994  and
the other in October 1994.
 
    Oil  and gas  production was  597 MBOE  in 1994  and 302  MBOE in  1993. The
increase in production of  295 MBOE was principally  due to properties  acquired
during 1994.
 
    Interest  and other  revenues were  $87,000 in  1994 compared  to $56,000 in
1993. The increase of $31,000 was comprised of an increase in interest income of
$26,000 in 1994,  due to  increased funds  earning interest,  and an  additional
$5,000 in other income.
 
    Oil  and  gas production  costs  in 1994  were  $2,351,000 ($3.94  per BOE),
compared to $1,688,000  in 1993  ($5.59 per  BOE), representing  an increase  of
$663,000.  The increase  in production  costs is  primarily attributable  to two
acquisitions in 1994.
 
    In 1994, general and administrative expense was $1,184,000, representing  an
increase of $232,000 (24%) from 1993 expense of $952,000. The increase is due to
an  increase in  personnel and costs  related primarily to  acquisitions made in
1994.
 
    Exploration and abandonment expense increased  to $793,000 in 1994  compared
to  $218,000 in 1993. The increase of $575,000  (264%) was due to an increase in
non-productive wells drilled in 1994 compared to 1993.
 
    Depreciation, depletion  and amortization  expense for  1994 was  $1,847,000
compared  to $884,000  for 1993,  representing an  increase of  $963,000 (109%),
primarily due to increased production. During 1994, depreciation, depletion  and
amortization  expense on oil and gas production  was provided at an average rate
of $3.09 per BOE  compared to $2.93 per  BOE for 1993. The  increase was due  to
increased   drilling  and   development,  and  the   acquisition  of  additional
properties.
 
    Interest expense was $1,458,000  in 1994 compared to  $605,000 in 1993.  The
$853,000 increase was attributable to increased debt levels related primarily to
the  Company's acquisition  of additional  oil and  gas properties  in 1994. The
average amount  of  applicable  interest-bearing  debt  in  1994  and  1993  was
$17,632,000 and $8,258,000, respectively.
 
LIQUIDITY AND CAPITAL RESOURCES
 
  CAPITAL SOURCES
 
    Funding for the Company's business activities has historically been provided
by  bank financings, cash  flow from operations,  private equity sales, property
divestitures  and  joint  ventures  with  industry  participants.  The   Company
completed a $10 million private equity placement in February 1995. Subsequently,
the  1995 Acquisition and the 1996 Acquisition were substantially funded by bank
financings. The Company plans to  finance its continuing operations and  execute
its  business strategy  with cash  flow from  operations, net  proceeds from the
Offerings and borrowings under the Credit Facility.
 
    The  Company  believes  that  cash   flow  from  operations  and   borrowing
availability  under  the  Credit  Facility will  be  sufficient  for anticipated
operating and  capital expenditure  requirements. However,  because future  cash
flows  and the availability  of financing are  subject to a  number of variables
beyond the  Company's control,  there can  be no  assurance that  the  Company's
capital  resources will  be sufficient to  maintain currently  planned levels of
capital expenditures.
 
                                       32
<PAGE>
    While the Company  regularly engages  in discussions  relating to  potential
acquisitions,  the Company has no present agreement, commitment or understanding
with respect to any such acquisition, other than the acquisition of  undeveloped
acreage  and royalty  and overriding royalty  interests in its  normal course of
business. Any future acquisition  may require additional  financing and will  be
dependent upon financing arrangements available at the time.
 
    The  Company  is in  discussion  with several  banks  to provide  the Credit
Facility following the closing of the Offerings. The Company anticipates that it
will have approximately $50.0 million available under the Credit Facility,  none
of which is expected to be outstanding immediately following the Offerings.
 
    Although  certain of  the Company's  costs and  expenses may  be affected by
inflation, inflationary costs have not had a significant effect on the Company's
results of operations.
 
  CAPITAL EXPENDITURES
 
    The Company requires capital primarily for the exploration, development  and
acquisition of oil and gas properties, the repayment of indebtedness and general
working capital needs.
 
    The  following  table  sets  forth  costs incurred  by  the  Company  in its
development,  exploration  and   acquisition  activities   during  the   periods
indicated. The table does not include the 1996 Acquisition which was consummated
in June 1996 for an approximate purchase price of $42.5 million.
 
<TABLE>
<CAPTION>
                                                                                          THREE MONTHS
                                                            YEARS ENDED DECEMBER 31,          ENDED
                                                         -------------------------------    MARCH 31,
                                                           1993       1994       1995         1996
                                                         ---------  ---------  ---------  -------------
                                                                       (IN THOUSANDS)
<S>                                                      <C>        <C>        <C>        <C>
Development costs......................................  $      --  $      --  $     158    $     232
Exploration costs......................................      2,017      2,167      5,627        1,822
Acquisition costs:
  Unproved properties..................................        829      1,232      1,742          677
  Proved properties....................................      4,665      9,649     52,470        2,246
                                                         ---------  ---------  ---------  -------------
                                                         $   7,511  $  13,048  $  59,997    $   4,977
                                                         ---------  ---------  ---------  -------------
                                                         ---------  ---------  ---------  -------------
</TABLE>
 
    The  Company anticipates that costs incurred  for 1996 will be approximately
$64.8 million, of which  approximately $42.5 million was  expended for the  1996
Acquisition,  and approximately  $5.0 million  was expended  for exploration and
development activities during the three months ended March 31, 1996.
 
                                       33
<PAGE>
                            BUSINESS AND PROPERTIES
 
GENERAL
 
    Costilla  is  an  independent  energy company  engaged  in  the exploration,
acquisition and development  of oil  and gas properties.  The Company's  primary
operations  are in  the Permian  Basin, the  Gulf Coast  and the  Rocky Mountain
regions. The Company's strategy focuses on increasing reserves through  targeted
exploration  programs, the exploitation of its existing properties and selective
property acquisitions. In addition, the Company recently acquired an interest in
a concession  for  the development  of  mineral  interests in  the  Republic  of
Moldova, in Eastern Europe. The Company also has minor interests in the domestic
gas gathering and transmission business.
 
    The  Company's  predecessor began  operating in  1988  with the  strategy of
acquiring and exploiting undervalued oil and gas properties, and at December 31,
1992 had net proved reserves  of 4.7 MMBOE. Since  January 1, 1993, the  Company
has  successfully closed seven  transactions for an  aggregate purchase price of
approximately $101  million.  As  of  March 31,  1996,  the  Company  had  total
estimated net proved reserves (as defined below) of 16.5 Mmbbls of oil and 112.9
Bcf  of gas, aggregating 35.3 MMBOE, with  a PV-10 Value of approximately $179.5
million, assuming the 1996 Acquisition (as defined below) had occurred at  March
31,  1996. The  Company also has  substantial undeveloped  acreage consisting of
205,908 gross (141,384  net) undeveloped  acres. The Company  has identified  in
excess  of  200  drilling locations  of  which  82 are  included  in  its proved
reserves.
 
    Costilla  has  in-house  exploration   expertise  which  uses  3-D   seismic
technology  as  a  primary  tool to  identify  drilling  opportunities,  and has
experienced high rates of  success in each  of its first  two major 3-D  seismic
drilling  programs. Since 1994, the Company has  drilled 23 wells based on these
3-D surveys,  20  of  which  have been  productive.  The  Company  has  recently
completed  a third  3-D survey  in Pecos County,  Texas and  intends to commence
drilling on this acreage in  the second half of  1996. Moreover, the Company  is
currently  conducting two additional 3-D surveys. The Company currently plans to
drill 81 wells through 1997 based on its 3-D surveys.
 
    Since  1993,  Costilla  has   generated  significant  growth  in   reserves,
production  and EBITDA. The Company increased its estimated proved reserves from
6.0 MMBOE at December 31,  1993 to 35.3 MMBOE at  March 31, 1996 (pro forma  for
the  1996 Acquisition), representing a compound annual growth rate of 114%. This
reserve growth has been achieved at an average all-in finding cost of $3.49  per
BOE  over such period, a level which the Company believes is lower than industry
averages. Concurrently, the Company increased  its average net daily  production
from  827 BOE for the year  ended December 31, 1993 to  10,703 BOE for the three
months ended March 31, 1996 (pro forma for the 1996 Acquisition), representing a
compound annual growth rate of 195%. EBITDA increased at a 240% compound  annual
growth  rate from $1.8 million for 1993 to $20.8 million for 1995 (pro forma for
the 1995 Acquisition and the 1996 Acquisition).
 
BUSINESS STRATEGY
 
    The Company's strategy is to increase  its oil and gas reserves,  production
and  cash flow from operations through  a two-pronged approach which combines an
active exploration program  using 3-D seismic  and other technological  advances
with the acquisition and exploitation of producing properties. The Company seeks
to  reduce its operating and  commodity risks by holding  a diverse portfolio of
properties. The  Company also  seeks  to manage  the  elements of  its  business
strategy  through the operation of a  significant portion of its properties, the
use of  a disciplined  rate of  return  analysis and  the direct  marketing  and
hedging  of its oil and  gas production. The elements  of the Company's strategy
may be further described as follows:
 
- -  EXPLORATION EFFORTS.  The Company  uses extensive geological and  geophysical
   analysis  to carefully focus  its 3-D seismic surveys.  This focus allows the
   Company to successfully direct the size and scope of its exploration  program
   in  order  to  improve  the  likelihood  of  success  while  managing overall
   exploration  costs.  The  Company's  exploration  efforts  are   concentrated
   currently on known
 
                                       34
<PAGE>
   producing regions. The Company plans to drill 26 exploratory wells during the
   remainder  of 1996  and 36  exploratory wells  in 1997.  Capital budgeted for
   exploration activities is $8.4 million for  the last nine months of 1996  and
   $10.8 million for 1997.
 
- -  EXPLOITATION   ACTIVITIES.    The  Company   is  actively  pursuing  numerous
   exploitation opportunities within  its existing  properties, including  areas
   where  no  proved reserves  are  currently assigned.  Exploitation activities
   currently  in  progress  include  a  carbon  dioxide  flood,   recompletions,
   workovers  and  infill  and  horizontal  drilling  and  a  secondary recovery
   project. The Company's capital budget for such activities is $8.9 million for
   the last nine months of  1996 and $9.2 million  for 1997, which includes  the
   drilling of 17 development wells in 1996 and 13 development wells in 1997.
 
- -  PROPERTY  ACQUISITIONS.   The Company  seeks to  acquire producing properties
   where it has  identified opportunities  to increase  production and  reserves
   through  both  exploitation  and  exploration  activities.  The  Company  has
   increased  the  value  of  its  acquisitions  by  aggressively  managing  the
   operations  of existing proved properties and by successfully identifying and
   developing previously  unproved reserves  on  acquired acreage.  The  Company
   seeks  to  acquire  reserves  which  will  fit  its  existing  portfolio, are
   generally not being actively  marketed and where a  negotiated sale would  be
   the  method  of purchase.  The Company  does  not rely  on major  oil company
   divestitures or property auctions.
 
- -  PROPERTY DIVERSIFICATION.   The  Company holds  a portfolio  of oil  and  gas
   properties  located  in  the Permian  Basin,  the  Gulf Coast  and  the Rocky
   Mountain regions. The Company believes  that by conducting its activities  in
   distinct  regions it is able to  reduce commodity price and other operational
   risks. The Company's Moldovan interest is  an extension of this strategy  and
   can  be characterized by low initial costs, significant reserve potential and
   the availability  of technical  data that  may be  further developed  by  the
   Company.
 
- -  CONTROL  OF OPERATIONS.  The Company prefers  to operate and own the majority
   working interest in its properties.  This allows the Company greater  control
   over future development, drilling, completing and lifting costs and marketing
   of  production. At December 31, 1995, the Company operated wells constituting
   approximately  65%  of  its  total  PV-10  Value  (pro  forma  for  the  1996
   Acquisition).
 
SIGNIFICANT ACQUISITIONS
 
    1995  ACQUISITION.  In  a $46.6 million acquisition  completed in June 1995,
the Company acquired a group  of oil and gas  properties located in the  Permian
Basin,  Gulf Coast and Rocky  Mountain regions. At the  date of acquisition, the
net proved reserves included 6.9 Mmbbls of oil and 40.0 Bcf of gas,  aggregating
13.6  MMBOE. From  the date  of acquisition  until March  31, 1996,  the Company
produced 1.1  MMBOE from  the acquired  properties  and sold  a portion  of  the
acquired  properties for approximately $3.6 million.  At March 31, 1996, the net
proved reserves  of  the remaining  properties  were 13.4  MMBOE.  The  acquired
properties also included 103,010 gross (93,786 net) undeveloped acres.
 
    1996 ACQUISITION.  In June 1996, the Company acquired a group of oil and gas
properties  located primarily  in the Permian  Basin and Gulf  Coast regions for
approximately $42.5  million.  This  acquisition included  properties  with  net
proved  reserves at March  31, 1996 of  5.0 Mmbbls of  oil and 33.5  Bcf of gas,
aggregating 10.6  MMBOE.  The acquired  properties  also included  42,855  gross
(10,172  net) undeveloped acres and a pipeline located in Pennsylvania which had
an allocated purchase price of $3.5 million.
 
                                       35
<PAGE>
PRINCIPAL PROPERTIES
 
    The following table  sets forth certain  information, as of  March 31,  1996
(pro forma for the 1996 Acquisition), which relates to the principal oil and gas
properties owned by the Company.
 
<TABLE>
<CAPTION>
                                                                                 PROVED RESERVES
                                                            ----------------------------------------------------------
                                                                                              TOTAL OIL    PERCENT OF
                                                              GROSS       OIL        GAS     EQUIVALENT    TOTAL OIL
AREA                                                          WELLS     (MBBLS)    (MMCF)      (MBOE)      EQUIVALENT
- ----------------------------------------------------------  ---------  ---------  ---------  -----------  ------------
<S>                                                         <C>        <C>        <C>        <C>          <C>
Permian Basin.............................................      1,890      9,200     55,200      18,400         52.1%
Gulf Coast................................................        968      2,054     38,440       8,461         24.0
Rocky Mountain............................................        236      4,526     12,886       6,674         18.9
Other.....................................................        428        696      6,394       1,762          5.0
                                                            ---------  ---------  ---------  -----------       -----
Total.....................................................      3,522     16,476    112,920      35,297        100.0%
                                                            ---------  ---------  ---------  -----------       -----
                                                            ---------  ---------  ---------  -----------       -----
</TABLE>
 
    PERMIAN  BASIN.  At March  31, 1996, 52.1% of  the Company's proved reserves
were concentrated in  the Permian  Basin, an approximately  70-county region  in
West  Texas and Southeast  New Mexico. The Company's  production comes from well
known fields such  as the  Spraberry Trend,  Sawyer Canyon,  Goldsmith Unit  and
Susan  Peak. The  majority of the  Company's producing intervals  in the Permian
Basin range from 4,500 feet to 9,500 feet in depth.
 
    The Company  has several  exploratory projects  in the  Permian Basin  based
primarily on 3-D seismic surveys. The most significant include:
 
    EDWARDS/MCELROY  RANCH PROSPECT, ECTOR AND  CRANE COUNTIES, TEXAS.  Costilla
has identified 75 drilling  locations on the Company's  9,849 gross (4,334  net)
acres  in  this prospect  based on  3-D seismic  data. The  Company successfully
completed the  Edwards 14-1  well in  the Strawn  formation in  May 1996,  which
initially  flowed at a rate  of 360 Bbls of  oil per day and  258 Mcf of gas per
day. At June 30, 1996, the well was flowing at a rate of 150 Bbls of oil and  85
Mcf  of gas  per day.  Six miles south  of the  Edwards 14-1  well, Costilla has
drilled the University 30-1  well, which has confirmed  the Strawn and  Wolfcamp
trends defined by the Company's extensive approximate 50-square mile 3-D seismic
project   undertaken  jointly  with  Texaco   Exploration  and  Producing,  Inc.
("Texaco"). This well  is currently  being completed. Two  additional wells  are
being  drilled on  seismic delineated  features similar  to the  initial Edwards
discovery. The Company plans to drill 25  wells in this trend through 1997.  The
Company's working interest in this prospect is approximately 44%.
 
    Costilla  and Texaco are also developing  a Queen Sand field identified from
the Edwards/McElroy Ranch seismic program.  The four wells drilled through  June
30,  1996 are producing an aggregate of approximately 80 Bbls of oil per day and
the Company is in  the process of completing  two additional wells. Drilling  of
six wells is anticipated through 1997, with the field ultimately being developed
on  a planned  waterflood pattern in  order to  maximize recovery of  the oil in
place.
 
    MCGYVER-GREEN ACRES  PROSPECT,  HOWARD  COUNTY,  TEXAS.    The  Company  has
identified  41 drilling locations in this  prospect based on information derived
from approximately 30 square miles of 3-D seismic data that the Company acquired
on the area in 1994.  The Talbot Fuller well was  the first well drilled by  the
Company on this prospect and was completed in the Canyon Lime formation at 8,200
feet  in August 1994. Since completion, the well has produced 62,000 Bbls of oil
and 207 Mmcf of gas, and averaged 77 Bbls of oil per day and 320 Mcf of gas  per
day  during June 1996.  Subsequent to the  first well, 11  additional wells have
been drilled on this prospect of  which ten are productive. The Company  intends
to  drill eight additional wells  during the balance of  1996 on its 9,148 gross
(6,587 net)  acres. The  Company's working  interest in  this prospect  averages
approximately 72%.
 
    The  following two 3-D programs currently being undertaken by the Company in
the Permian Basin are expected to provide additional drilling locations:
 
                                       36
<PAGE>
    WILSON RANCH 3-D PROJECT, PECOS COUNTY, TEXAS.  The Wilson Ranch is  located
in  northeastern Pecos County,  approximately 10 miles west  of the Yates field.
The Company recently completed an  approximate 17-square mile seismic survey  on
the  project. A second phase will be initiated in the first quarter of 1997. The
project presents several potential exploration targets, including the Queen, San
Andres, Wolfcamp, Devonian and Ellenberger  formations, found at depths  ranging
from  1,600 to 8,000 feet. The Company has  agreed to lease 3,750 gross acres on
this 50,000 acre ranch.  Upon acquiring the lease,  the Company intends to  sell
one-half  of its  approximate 75%  working interest.  The Company  believes that
there is significant additional potential in this area.
 
    DAVAN UNIT 3-D PROJECT,  STONEWALL COUNTY, TEXAS.   The Company has  another
3-D   seismic   project  under   way  with   Texaco   to  further   develop  the
Company-operated Davan Unit. The  project involves a  3-D seismic evaluation  of
approximately  3,200 gross acres adjacent to a Company-operated waterflood which
has produced in excess of three Mmbbls of oil.
 
    Two examples of the  Company's current exploitation  efforts in the  Permian
Basin include:
 
    EAST  GOLDSMITH  FIELD  QUEEN  DISCOVERY  AND  C02  PROJECT,  ECTOR  COUNTY,
TEXAS.  The Company owns 3,053 gross (2,073 net) acres in this field located  20
miles  northwest of Midland, Texas. Since  its discovery, the field has produced
in excess of 17 Mmbbls of oil  from seven formations. The most productive  zones
in  the East Goldsmith Field have been  the San Andres and Holt formations, both
of which have been subject to  secondary recovery by waterflooding. The  Company
has  been analyzing a  tertiary recovery project in  those formations using CO2,
and intends to initiate the project in the fourth quarter of 1996. The Company's
working interest in this project averages approximately 87%.
 
    SUSAN PEAK FIELD WORKOVER AND HORIZONTAL DRILLING PROGRAM, TOM GREEN COUNTY,
TEXAS.  The Company recently completed  the first horizontal well in this  field
located  south of San  Angelo, Texas, in  which it owns  a 100% working interest
until payout. Production from this well drilled in the Strawn formation was  110
Bbls  of oil per day and 240 Mcf of gas per day on June 30, 1996. Since February
1996, with  only two  workovers and  the new  horizontal well,  the Company  has
increased  Susan Peak production from  approximately 30 Bbls of  oil per day and
700 Mcf of gas per day  to a current rate of  approximately 200 Bbls of oil  per
day and 2,000 Mcf of gas per day. Two possible horizontal drilling locations and
additional  workover  candidates remain  on this  7,461  gross (3,730  net) acre
lease. The Company's working interest in this project ranges from 50% to 100%.
 
    GULF COAST.  At March 31, 1996, 24.0% of the Company's proved reserves  were
concentrated  in the Gulf Coast region.  The Company's production in this region
primarily comes from  known formations  such as  Frio, Yegua,  Austin Chalk  and
Wilcox.
 
    The  Company  plans  to use  its  expertise in  aggressively  developing 3-D
opportunities on the extensive acreage position it holds in the region. Examples
of such exploration projects in progress include:
 
    SEALY PROSPECT, AUSTIN COUNTY, TEXAS.  The Sealy Field, consisting of  3,534
gross  (1,767  net) acres,  was  acquired in  the  1995 Acquisition.  The Wilcox
formation in this field has produced over 66 Bcf of gas and there are subsurface
indications of  the presence  of several  fault blocks  that lie  untested.  The
Company's working interest in this prospect is 100%.
 
    SOUTHWEST  SPEAKS, LAVACA COUNTY, TEXAS.   This project, consisting of 5,078
gross (2,539 net) acres, was also acquired  in the 1995 Acquisition and is  held
by  several  shallow Company-operated  wells.  Multiple producing  horizons from
shallow depths to below 14,000 feet have produced over 199 Bcf of gas from  this
highly  faulted field. A recent well was completed in the Rainbow Wilcox sand on
acreage adjoining  Costilla's  lease. A  well,  in  which Costilla  holds  a  5%
interest  as a result of a farmout, has also been completed on Costilla's lease.
The Company's  plans include  a 3-D  survey in  the Speaks  area. The  Company's
working interest in this prospect is approximately 50%.
 
    BORCHERS  FIELD,  LAVACA COUNTY,  TEXAS.   This  field  was acquired  by the
Company in  the 1996  Acquisition. The  property  is on  trend with  the  Speaks
project and is also a highly faulted field
 
                                       37
<PAGE>
providing opportunity for further development. The Borchers field has produced a
total  of 17.5  Bcf of gas  from two Wilcox  sands. Costilla has  a 100% working
interest in this field consisting of 1,321 gross and net acres.
 
    Examples of exploitation activities in this region include:
 
    JOSEY RANCH LEASE,  HARRIS COUNTY,  TEXAS.   Two examples  of the  Company's
production  enhancement  of  Gulf  Coast  properties  were  undertaken  on  this
prospect. When the lease  was acquired in the  1995 Acquisition, production  had
nearly  ceased. Through  a series of  workovers, the Company  has improved daily
production, as of June 30, 1996, to 63 Bbls of oil per day and 73 Mcf of gas per
day. In addition, Costilla has  participated in a 13,000  foot test well on  the
Josey  Ranch lease to test the Wilcox formation. The well was completed in April
1996 and has consistently produced  in excess of 1,000 Mcf  of gas per day.  The
Josey  Ranch lease covers 1,661 gross (649 net) acres, and the Company's working
interest in this prospect is approximately 39%.
 
    PERSONVILLE, LIMESTONE COUNTY, TEXAS.  The Company has recently completed an
11,200 foot Cotton Valley well, with initial production rates of 1.1 Mmcf of gas
per day prior to stimulation. Costilla leases 412 gross (111 net) acres in  this
prospect,  and has identified two additional  drilling locations. The Company is
the operator of this prospect and its working interest is approximately 30%.
 
    AUSTIN CHALK, BRAZOS, BURLESON, FAYETTE  AND LEE COUNTIES, TEXAS.   Costilla
acquired  the majority of the working interest  in nine gross Austin Chalk wells
in the  1995 Acquisition  and an  additional 80  gross Austin  Chalk wells  were
included  in the 1996 Acquisition. The  Company intends to enhance production on
certain of these wells through stimulation and workover activities, and  analyze
further  development potential. Costilla has 30,414  gross (20,985 net) acres in
the  Austin  Chalk  area,  and  its  working  interest  in  this  area  averages
approximately 69%.
 
    ROCKY  MOUNTAIN.  At March 31, 1996,  18.9% of the Company's proved reserves
were concentrated in the  Rocky Mountain region,  which includes Montana,  North
Dakota, Wyoming, Colorado and Utah.
 
    RAYMOND  FIELD, SHERIDAN COUNTY, MONTANA.   Since its discovery in 1972, the
Raymond Field  has  produced  over  five  Mmbbls  of  oil  from  five  different
formations.  Daily production from the field has  increased from 180 Bbls of oil
per day since its acquisition in  June 1995 to 369 Bbls  of oil per day at  June
30, 1996 primarily as a result of the Company's improved operations. The Company
plans  a 3-D program on its  960 gross and net acres  in this field. The Company
owns a 100% working interest in this prospect.
 
    OUTLOOK FIELD, SHERIDAN COUNTY,  MONTANA.  The  Company undertook its  first
Rocky  Mountain 3-D seismic  survey in the  Outlook area to  further develop the
field. Three  drilling locations  were  identified from  the data.  The  Company
anticipates  commencing  an Outlook  test well  in September  1996 that  will be
drilled to 10,500 feet, a depth sufficient to test several different formations.
Costilla leases 5,168 gross (1,292 net) acres in the Outlook prospect, and  owns
an approximate 25% working interest in this prospect.
 
    NATURAL  BUTTES FIELD, UINTAH COUNTY, UTAH.  The Company owns a 100% working
interest in 1,280  gross and net  acres in this  prospect. Development by  prior
owners  was  on 640-acre  spacing  while offset  acreage  has been  developed on
80-acre spacing. Low  gas prices in  the area have  precluded the assignment  of
proved  resources to any  undeveloped acres. As gas  prices improve, the Company
plans to drill additional wells on the prospect.
 
    The Company owns an interest in  significant acreage positions in the  Rocky
Mountain  region which  are operated  by third  parties and  are the  subject of
active exploitation efforts. The most significant property is:
 
    CIRCLE RIDGE FIELD,  FREMONT COUNTY, WYOMING.   The Circle  Ridge Field,  in
which  the  Company has  an  approximate 18%  working  interest, is  operated by
Marathon Oil Company. This field is an approximate 1,100 acre waterflood located
in the Wind River Basin of Wyoming, approximately 30
 
                                       38
<PAGE>
miles north of  Riverton, Wyoming. There  are 97 active  producing wells and  10
active  injection wells in the field. Production originates from the Phosphoria,
Tensleep and Amsden formations  that are present at  depths ranging from 500  to
2,000  feet. Since January 1995,  45 projects have been  completed in the field.
These projects include recompletions, stimulation treatments and  reactivations,
which  have increased production from 1,469 Bbls  of oil per day in January 1995
to a rate of 1,876 Bbls  of oil per day for  May 1996. The operator has  several
other  projects scheduled  for the remainder  of 1996 and  is evaluating various
different methods of enhanced oil recovery for the field.
 
MARKETING ARRANGEMENTS
 
    The Company utilizes an active marketing program for a portion of its  crude
oil  production in order to enhance the net price it receives. The Company sells
its crude oil production from operated  properties in North Dakota, Montana  and
Wyoming,  at the  lease level  to an oil  transportation company  for the posted
price, plus an agreed upon bonus,  with a corresponding agreement to  repurchase
this production at its delivery point (typically, Cushing, Oklahoma) for a price
equal  to the then  posted price for  West Texas Intermediate  crude oil less an
agreed upon  deduction for  transportation and  quality differentials,  if  any,
between  the repurchased  crude oil and  West Texas Intermediate  crude oil. The
Company then employs  a broker to  resell its crude  oil to end  users (such  as
refineries)  on a  month-to-month basis.  The lease  level sales  and repurchase
contracts are  typically of  six  months duration.  With  respect to  its  other
operated  oil production  (primarily located  in Texas),  the Company  employs a
similar price enhancement strategy, although  the repurchase feature is  absent.
Instead,  the lease level  purchaser resells the  crude oil to  end users at the
delivery point  for the  account of  the Company.  The Company  markets its  gas
production  at the lease  level pursuant to  month-to-month contracts. No single
purchaser of  oil  or gas  accounted  for in  excess  of 10%  of  the  Company's
consolidated revenues for the year ended December 31, 1995.
 
RISK MANAGEMENT
 
    The  Company typically  employs a  strategy of  purchasing put  options on a
portion of its anticipated oil and gas production. This strategy is designed  to
protect  the  Company from  significant downward  movements in  commodity prices
while preserving the benefit  of rising prices. The  Company does not  establish
hedges  in  excess  of  its anticipated  production.  Upon  consummation  of the
Offerings, substantially  all of  the Company's  debt will  be fixed  rate.  The
Company's current position with regard to its commodity hedges is as follows:
 
    OIL  SALES.   The Company  has purchased "put  options" to  provide a "floor
price" for 3,000  Bbls of  oil per  day of its  oil production  for August  1996
through   December  1996.  These  put   options  currently  in  place  represent
approximately 57%  of the  Company's estimated  oil production  for August  1996
through  December 1996. The floor price the  Company has an agreement to receive
is $18.00 per Bbl, irrespective of the prices actually paid by purchasers of the
oil at the lease level.
 
    GAS SALES.  The Company has  purchased "put options" which provide a  "floor
price" for 900,000 Mmbtu's per month of its gas production through October 1996.
The  put options currently in place represent approximately 68% of the Company's
estimated gas production for  July 1996 through October  1996. The floor  prices
with  respect to such put options varies from $1.65 to $1.75 per Mmbtu depending
on the area in which the gas is produced.
 
                                       39
<PAGE>
OIL AND GAS RESERVES
 
    The Company's estimated total  proved and proved  developed reserves of  oil
and gas as of December 31, 1993, 1994 and 1995, and as of March 31, 1996 were as
follows:
 
<TABLE>
<CAPTION>
                                                       AS OF DECEMBER 31,
                               ------------------------------------------------------------------       PRO FORMA
                                                                                                        MARCH 31,
                                        1993                   1994                  1995                1996 (1)
                               ----------------------  --------------------  --------------------  --------------------
                                   OIL         GAS        OIL        GAS        OIL        GAS        OIL        GAS
                                 (MBBLS)     (MMCF)     (MBBLS)    (MMCF)     (MBBLS)    (MMCF)     (MBBLS)    (MMCF)
                               -----------  ---------  ---------  ---------  ---------  ---------  ---------  ---------
<S>                            <C>          <C>        <C>        <C>        <C>        <C>        <C>        <C>
Proved developed producing...       1,785      13,268      2,632     15,757      8,338     50,542     13,122     76,439
Proved developed non-
 producing...................           0           0          0        583        228      6,851        429      7,930
Proved undeveloped...........         580       8,351      1,377     11,172      2,222     20,759      2,925     28,551
                                    -----   ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Total proved...............       2,365      21,619      4,009     27,512     10,788     78,152     16,476    112,920
                                    -----   ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                    -----   ---------  ---------  ---------  ---------  ---------  ---------  ---------
</TABLE>
 
- ------------------------------
(1)  Assumes that the 1996 Acquisition had been consummated at March 31, 1996.
 
    The  following table sets forth the future net cash flows from the Company's
estimated proved reserves:
 
<TABLE>
<CAPTION>
                                                                            DECEMBER 31,              PRO FORMA
                                                                  ---------------------------------   MARCH 31,
                                                                    1993       1994        1995        1996(1)
                                                                  ---------  ---------  -----------  -----------
                                                                                  (IN THOUSANDS)
<S>                                                               <C>        <C>        <C>          <C>
Future net cash flows before income taxes.......................  $  47,213  $  68,596  $   188,337  $   297,002
Future net cash flows before income taxes, discounted at 10%....  $  26,377  $  36,779  $   113,296  $   179,527
</TABLE>
 
- ------------------------------
(1)  Assumes that the 1996 Acquisition had been consummated at March 31, 1996.
 
    The reserve estimates reflected above for 1993, 1994 and 1995 were  prepared
by  the Company. The Company's 1995 estimates  of gross reserves with respect to
certain of the Company's producing properties  were subject to a limited  review
by  Williamson.  The  pro forma  estimates  for  March 31,  1996,  including the
properties acquired in the 1996 Acquisition, were prepared by Williamson and are
part of reports on the Company's oil and gas properties prepared by  Williamson,
a summary of which is set forth herein as Appendix A.
 
    The  reserve  data  set forth  herein  present estimates  only.  In general,
estimates of economically recoverable oil and gas reserves and of the future net
revenues therefrom are based upon an number of variable factors and assumptions,
such as historical production from  the subject properties, the assumed  effects
of regulation by governmental agencies and assumptions concerning future oil and
gas  prices and future operating costs, all  of which may vary considerably from
actual  results.  All  such  estimates  are  to  some  degree  speculative,  and
classifications   of  reserves  are  only  attempts  to  define  the  degree  of
speculation  involved.  For  these   reasons,  estimates  of  the   economically
recoverable  oil  and  gas  reserves attributable  to  any  particular  group of
properties, classifications  of such  reserves  based on  risk of  recovery  and
estimates  of the future net revenues  expected therefrom, prepared by different
engineers or by the same engineers  at different times, may vary  substantially.
The Company therefore emphasizes that the actual production, revenues, severance
and  excise taxes,  development and operating  expenditures with  respect to its
reserves will  likely vary  from such  estimates, and  such variances  could  be
material.
 
    Estimates with respect to proved reserves that may be developed and produced
in  the future are often based upon  volumetric calculations and upon analogy to
similar types of reserves rather than actual production history. Estimates based
on these  methods  are  generally  less reliable  than  those  based  on  actual
production  history.  Subsequent  evaluation  of the  same  reserves  based upon
production history will result in variations,  which may be substantial, in  the
estimated reserves.
 
                                       40
<PAGE>
    In  accordance with applicable  requirements of the  Securities and Exchange
Commission, the estimated discounted future  net revenues from estimated  proved
reserves  are based on  prices and costs as  of the date  of the estimate unless
such prices or costs  are contractually determined at  such date. Actual  future
prices  and costs may be materially higher  or lower. Actual future net revenues
also will be affected  by factors such as  actual production, supply and  demand
for oil and natural gas, curtailments or increases in consumption by natural gas
purchasers,  changes in governmental  regulations or taxation  and the impact of
inflation on costs.
 
EXPLORATION AND DEVELOPMENT ACTIVITIES
 
    The Company  drilled, or  participated  in the  drilling of,  the  following
number of wells during the periods indicated. At March 31, 1996, the Company was
in  the process of drilling one gross (0.50  net) well and was in the process of
completing three gross (1.32 net) wells as producers which are not reflected  in
the following table.
<TABLE>
<CAPTION>
                                                              1993                    1994                    1995
                                                     ----------------------  ----------------------  ----------------------
                                                        GROSS        NET        GROSS        NET        GROSS        NET
                                                     -----------  ---------  -----------  ---------  -----------  ---------
<S>                                                  <C>          <C>        <C>          <C>        <C>          <C>
Exploratory:
  Productive.......................................           3        0.83           9        2.27          10        4.58
  Dry..............................................           2        1.06          10        3.73           6        2.57
                                                            ---         ---         ---         ---         ---         ---
    Total..........................................           5        1.89          19        6.00          16        7.15
                                                            ---         ---         ---         ---         ---         ---
                                                            ---         ---         ---         ---         ---         ---
Development:
  Productive.......................................          --          --          --          --           1        0.44
  Dry..............................................          --          --          --          --          --          --
                                                            ---         ---         ---         ---         ---         ---
    Total..........................................          --          --          --          --           1        0.44
                                                            ---         ---         ---         ---         ---         ---
                                                            ---         ---         ---         ---         ---         ---
Total:
  Productive.......................................           3        0.83           9        2.27          11        5.02
  Dry..............................................           2        1.06          10        3.73           6        2.57
                                                            ---         ---         ---         ---         ---         ---
    Total..........................................           5        1.89          19        6.00          17        7.59
                                                            ---         ---         ---         ---         ---         ---
                                                            ---         ---         ---         ---         ---         ---
 
<CAPTION>
 
                                                       THREE MONTHS ENDED
                                                         MARCH 31, 1996
                                                     ----------------------
                                                        GROSS        NET
                                                     -----------  ---------
<S>                                                  <C>          <C>
Exploratory:
  Productive.......................................           3        2.02
  Dry..............................................           1        0.72
                                                            ---         ---
    Total..........................................           4        2.74
                                                            ---         ---
                                                            ---         ---
Development:
  Productive.......................................           4        1.98
  Dry..............................................          --          --
                                                            ---         ---
    Total..........................................           4        1.98
                                                            ---         ---
                                                            ---         ---
Total:
  Productive.......................................           7        4.00
  Dry..............................................           1        0.72
                                                            ---         ---
    Total..........................................           8        4.72
                                                            ---         ---
                                                            ---         ---
</TABLE>
 
    The  Company  does  not  own  any drilling  rigs  and  all  of  its drilling
activities are  conducted by  independent  contractors under  standard  drilling
contracts.
 
PRODUCTIVE WELL SUMMARY
 
    The  following table  sets forth  the Company's  gross and  net interests in
productive oil and gas wells as of June 30, 1996. Productive wells are producing
wells and wells capable of production.
 
<TABLE>
<CAPTION>
                                                                                                      ACTUAL (1)
                                                                                                 --------------------
                                                                                                   GROSS       NET
                                                                                                 ---------  ---------
<S>                                                                                              <C>        <C>
Oil wells......................................................................................      2,245     678.54
Gas wells......................................................................................      1,277     231.11
                                                                                                 ---------  ---------
    Total......................................................................................      3,522     909.65
                                                                                                 ---------  ---------
                                                                                                 ---------  ---------
</TABLE>
 
- ------------------------------
(1)  Does  not  include  royalty  and  overriding  royalty  interests  owned  by
     Statewide  or the Company. See "-- Other Activities -- Minerals Acquisition
     Program." In addition, one well with  multiple completions is counted as  a
     single well.
 
                                       41
<PAGE>
ACREAGE
 
    The  following table sets forth  certain information regarding the Company's
developed and undeveloped  leasehold acreage as  of March 31,  1996. Acreage  in
which  the Company's interest is limited to royalty, overriding royalty, mineral
and similar interests (such as all acreage owned by Statewide) is excluded.
 
<TABLE>
<CAPTION>
                                                     DEVELOPED            UNDEVELOPED            TOTAL (1)
                                                --------------------  --------------------  --------------------
                                                  GROSS       NET       GROSS       NET       GROSS       NET
                                                ---------  ---------  ---------  ---------  ---------  ---------
<S>                                             <C>        <C>        <C>        <C>        <C>        <C>
Permian Basin.................................     27,049     23,489     52,903     42,250     79,951     65,742
Gulf Coast....................................     34,324     29,746     28,457     19,958     62,781     49,703
Rocky Mountain................................      8,967      8,676     47,510     40,799     56,477     49,453
Other.........................................     13,439     12,492     34,183     28,225     47,623     40,717
                                                ---------  ---------  ---------  ---------  ---------  ---------
    Total.....................................     83,779     74,403    163,053    131,212    246,832    205,615
                                                ---------  ---------  ---------  ---------  ---------  ---------
                                                ---------  ---------  ---------  ---------  ---------  ---------
</TABLE>
 
- ------------------------------
(1)  In the 1996 Acquisition, the  Company acquired an additional 292,146  gross
     (73,528  net)  developed acres  and 42,855  gross (10,172  net) undeveloped
     acres.
 
OTHER ACTIVITIES
 
    MOLDOVA CONCESSION  AGREEMENT.    In  July 1995,  the  Republic  of  Moldova
(located in Eastern Europe between Romania and the Ukraine) granted a Concession
Agreement  to Resource Development Company Limited, L.L.C. ("Redeco"), an entity
not affiliated with the Company. The Company has paid Redeco $90,000 and  agreed
to  bear the first  $2.0 million of  Concession expenses ($882,000  of which had
been expended through  March 31, 1996)  in return  for a 50.0%  interest in  the
Concession.  After the initial $2.0 million  expenditure, Redeco and the Company
are responsible for  bearing 50.0%  each of  future expenses.  The Company  will
serve  as operator  with respect  to all  activities undertaken  pursuant to the
Concession. The Concession Agreement covers  the entire country with respect  to
oil  and gas and other minerals and continues for various time periods depending
on the  nature of  the activity  conducted. In  connection with  two  previously
producing  but now abandoned fields, the Company's exclusive rights continue for
20 years. The Company's exclusive period to explore throughout the remainder  of
Moldova  expires in  2005, but the  Company will  maintain exclusive development
rights with respect to fields discovered for a period of 20 years from the  date
of  first  production  from  such  field. The  Company  has  no  fixed financial
commitments with respect to the Concession.
 
    MINERALS  ACQUISITION  PROGRAM.    Statewide,  a  Company  subsidiary,   was
organized  for the purpose  of acquiring overriding  royalty interests and other
types of non  cost-bearing mineral  interests underlying producing  oil and  gas
fields  primarily in Texas. The strategy of such acquisitions is to make blanket
offers to holders  of small interests.  From inception through  March 31,  1996,
Statewide   expended  approximately  $2.9  million  in  acquiring  interests  in
approximately 1,400 properties. Through March  31, 1996, Statewide had  received
revenues  from such interests aggregating approximately $1.2 million, as well as
proceeds from sales of such interests of approximately $150,000.
 
    GAS GATHERING AND  TRANSMISSION.   In 1996,  the Company  purchased a  45.0%
membership  interest (which reduces to 32.4%  when the Company and certain other
members recoup their original  investment) in Republic  Gas Partners, L.L.C.,  a
Texas  limited  liability  company  ("Republic"),  for  approximately  $800,000.
Republic owns  all of  the stock  of Mid  Louisiana Gas  Company, Mid  Louisiana
Marketing  Company and Mid Louisiana Gas Transmission Company (collectively, the
"Midla Companies").  The assets  of the  Midla Companies  include 409  miles  of
mainly  22-inch pipeline extending from the Monroe  field area south of the city
of  Baton  Rouge,  serving  various  Louisiana  and  Mississippi  municipal  and
industrial  customers along its  route. Mid Louisiana  Gas Company's pipeline is
subject  to  the  jurisdiction  of  the  Federal  Energy  Regulatory  Commission
("FERC").
 
    Valley,  a Company  subsidiary, owns a  small gas  gathering system, several
small gas plants,  11 salt water  disposal wells  located in each  of its  three
principal regions and compressors used in the
 
                                       42
<PAGE>
compression of gas located in the Gulf Coast region. For the year ended December
31,  1995,  Valley  had  revenues  of  $553,000  and  net  income  of  $264,000,
substantially all of which were related to transactions with Costilla.
 
    In the 1996 Acquisition, Pipeline, a Company subsidiary, acquired a 120-mile
gas transportation pipeline in southwestern Pennsylvania for an allocated  value
of $3.5 million. The Company regards this asset as non-strategic to its business
activities and is presently marketing the pipeline for sale.
 
COMPETITION AND MARKETS
 
    Competition  in all areas of the  Company's operations is intense. Major and
independent oil and gas  companies and oil and  gas syndicates actively bid  for
desirable  oil  and gas  properties,  as well  as  for the  equipment  and labor
required to  operate and  develop such  properties. A  number of  the  Company's
competitors   have   financial  resources   and  acquisition,   exploration  and
development budgets that are  substantially greater than  those of the  Company,
which  may  adversely  affect  the  Company's  ability  to  compete  with  these
companies. Many of  the Company's competitors  have been engaged  in the  energy
business  for a much longer time than the Company. Such companies may be able to
pay more for productive oil and gas properties and exploratory prospects and  to
define,  evaluate,  bid for  and  purchase a  greater  number of  properties and
prospects than the Company's financial or human resources permit. The  Company's
ability  to acquire additional properties and to discover reserves in the future
will be dependent on its ability to evaluate and select suitable properties  and
to consummate transactions in a highly competitive environment.
 
    The  market for  oil, gas  and natural gas  liquids produced  by the Company
depends on factors beyond its control, including domestic and foreign  political
conditions,  the overall level of supply of  and demand for oil, gas and natural
gas liquids, the price of imports of oil and gas, weather conditions, the  price
and  availability  of  alternative  fuels, the  proximity  and  capacity  of gas
pipelines and other transportation  facilities and overall economic  conditions.
The  oil and  gas industry  as a  whole also  competes with  other industries in
supplying the  energy  and  fuel  requirements  of  industrial,  commercial  and
individual consumers.
 
REGULATION
 
    The Company's oil and gas exploration, production and related operations are
subject  to extensive  rules and regulations  promulgated by  federal, state and
local agencies. Failure to comply with such rules and regulations can result  in
substantial  penalties.  The  regulatory  burden on  the  oil  and  gas industry
increases the Company's cost  of doing business  and affects its  profitability.
Because  such rules and regulations are frequently amended or reinterpreted, the
Company is unable to predict  the future cost or  impact of complying with  such
laws.
 
    The  State  of Texas  and  many other  states  require permits  for drilling
operations, drilling bonds  and reports concerning  operations and impose  other
requirements  relating to  the exploration and  production of oil  and gas. Such
states also  have  statutes  or  regulations  addressing  conservation  matters,
including  provisions for the unitization or  pooling of oil and gas properties,
the establishment of maximum rates of production from oil and gas wells and  the
regulation  of spacing, plugging and abandonment of such wells. The statutes and
regulations of  certain states  limit  the rate  at which  oil  and gas  can  be
produced from the Company's properties.
 
    FERC  regulates  interstate  natural gas  transportation  rates  and service
conditions, which affect the marketing of  gas produced by the Company, as  well
as  the revenues received by the Company for sales of such production. Since the
mid-1980s, the FERC  has issued a  series of orders,  culminating in Order  Nos.
636,  636-A  and  636-B  ("Order  636"),  that  have  significantly  altered the
marketing  and  transportation  of  gas.   Order  636  mandates  a   fundamental
restructuring of interstate pipeline sales and transportation service, including
the unbundling by interstate pipelines of the sales, transportation, storage and
other  components  of the  city-gate  sales services  such  pipelines previously
performed. One  of the  FERC's purposes  in issuing  the orders  is to  increase
competition within all phases of the gas industry. Order 636 and subsequent FERC
orders on rehearing have been appealed and are
 
                                       43
<PAGE>
pending judicial review. Because these orders may be modified as a result of the
appeals,  it is difficult  to predict the  ultimate impact of  the orders on the
Company and its gas  marketing efforts. Generally, Order  636 has eliminated  or
substantially  reduced the interstate pipelines' traditional role as wholesalers
of natural gas, and  has substantially increased  competition and volatility  in
natural gas markets. While significant regulatory uncertainty remains, Order 636
may  ultimately enhance the  Company's ability to market  and transport its gas,
although it may  also subject the  Company to greater  competition and the  more
restrictive  pipeline imbalance tolerances and  greater associated penalties for
violation of such tolerances.
 
    Sales of oil and natural  gas liquids by the  Company are not regulated  and
are made at market prices. The price the Company receives from the sale of these
products  is  affected  by the  cost  of  transporting the  products  to market.
Effective as of January  1, 1995, FERC  implemented regulations establishing  an
indexing  system for transportation  rates for oil  pipelines, which, generally,
would  index  such  rates  to  inflation,  subject  to  certain  conditions  and
limitations.  These regulations could increase the  cost of transporting oil and
natural gas liquids by pipeline,  although the most recent adjustment  generally
decreased rates. These regulations are subject to pending petitions for judicial
review.  The Company is not able to  predict with certainty what effect, if any,
these regulations  will  have  on  it,  but,  other  factors  being  equal,  the
regulations  may, over  time, tend  to increase  transportation costs  or reduce
wellhead prices for oil and natural gas liquids.
 
ENVIRONMENTAL MATTERS
 
    Operations of the Company  are subject to  numerous and constantly  changing
federal,  state  and  local  laws and  regulations  governing  the  discharge of
materials  into  the   environment  or  otherwise   relating  to   environmental
protection.  These laws and  regulations may require  the acquisition of certain
permits, restrict  or  prohibit  the  types,  quantities  and  concentration  of
substances that can be released into the environment in connection with drilling
and  production,  restrict or  prohibit  drilling activities  that  could impact
wetlands, endangered or threatened species or other protected natural  resources
and  impose substantial liabilities  for pollution resulting  from the Company's
operations. Such laws  and regulations  may substantially increase  the cost  of
exploring  for, developing or producing oil and gas and may prevent or delay the
commencement or continuation of a given project. In the opinion of the Company's
management, the Company  is in  substantial compliance  with current  applicable
environmental  laws and regulations,  and the cost of  compliance with such laws
and regulations has not been material and is not expected to be material  during
the  next fiscal year. Nevertheless, changes  in existing environmental laws and
regulations or in interpretations thereof could have a significant impact on the
operating costs of the Company, as well as the oil and gas industry in  general.
For  instance, legislation has been proposed in  Congress from time to time that
would reclassify certain oil  and gas production  wastes as "hazardous  wastes,"
which  reclassification would make exploration  and production wastes subject to
much  more  stringent  handling,  disposal  and  clean-up  requirements.   State
initiatives to further regulate the disposal of oil and gas wastes and naturally
occurring  radioactive materials are  also pending in  certain states, including
Texas, and these various initiatives could have a similar impact on the Company.
 
    The Comprehensive Environmental  Response, Compensation,  and Liability  Act
("CERCLA"), also known as the "Superfund" law, imposes liability, without regard
to  fault or the legality of the original conduct, on certain classes of persons
that are  considered  to  have  contributed  to  the  release  of  a  "hazardous
substance"  into the environment. These persons include the owner or operator of
the disposal site  or the  site where the  release occurred  and companies  that
disposed  or arranged for the disposal of  the hazardous substances found at the
site. Persons who are or were  responsible for releases of hazardous  substances
found  at  the site  and persons  who are  or were  responsible for  releases of
hazardous substances under CERCLA may be subject to joint and several  liability
for  the costs of cleaning  up the hazardous substances  that have been released
into the  environment  and for  damages  to natural  resources,  and it  is  not
uncommon  for neighboring landowners and other  third parties to file claims for
person injury and property damage  allegedly caused by the hazardous  substances
released  into  the environment.  The Company  is able  to control  directly the
operation of
 
                                       44
<PAGE>
only those wells with respect to which its acts as operator. Notwithstanding the
Company's lack of  control over  wells operated by  others, the  failure of  the
operator  to comply  with applicable  environmental regulations  may, in certain
circumstances, be  attributed  to  the  Company. The  Company  has  no  material
commitments  for  capital  expenditures to  comply  with  existing environmental
requirements.
 
EMPLOYEES
 
    At June  30, 1996,  the Company  had 109  full-time employees.  None of  the
Company's employees is subject to a collective bargaining agreement. The Company
considers its relations with its employees to be good.
 
LEGAL PROCEEDINGS
 
    The Company is a defendant or codefendant in minor lawsuits that have arisen
in  the ordinary  course of  business. While the  outcome of  the these lawsuits
cannot be predicted with certainty, management  does not expect any of these  to
have a material adverse effect on the Company's consolidated financial condition
or results of operations.
 
TITLE TO PROPERTIES
 
    The  Company  has  obtained  title  opinions  on  substantially  all  of its
producing properties  and  believes  that  it has  satisfactory  title  to  such
properties  in accordance with  standards generally accepted in  the oil and gas
industry. As is customary in  the oil and gas  industry, the Company performs  a
minimal  title investigation  before acquiring  undeveloped properties.  A title
opinion is obtained  prior to the  commencement of drilling  operations on  such
properties. The Company's properties are subject to customary royalty interests,
liens  incident  to  operating agreements,  liens  for current  taxes  and other
burdens which the Company believes do  not materially interfere with the use  of
or  affect the value of such properties.  Substantially all of the Company's oil
and gas  properties  are mortgaged  to  secure borrowings  under  the  Company's
Existing  Debt Facility and  will continue to be  mortgaged to secure borrowings
under  the  Credit  Facility.  See  "Management's  Discussion  and  Analysis  of
Financial  Conditions  and  Results  of  Operations  --  Liquidity  and  Capital
Resources," and "Description of Other Indebtedness."
 
OPERATIONAL HAZARDS AND INSURANCE
 
    The Company's operations are  subject to the hazards  and risks inherent  in
drilling  and production  and transportation  of oil  and gas,  including fires,
natural disasters, explosions, encountering formations with abnormal  pressures,
blowouts,  cratering, pipeline ruptures, and spills,  any of which can result in
loss of hydrocarbons, environmental pollution, personal injury or loss of  life,
severe  damage to and destruction  of properties of the  Company and others, and
suspension of operations. See "Risk Factors -- Drilling Risks" and "Risk Factors
- -- Operating Hazards and Uninsured Risks."
 
    The Company maintains insurance  of various types  to cover its  operations.
The  limits provided under its liability policies total $6 million. In addition,
the Company maintains operator's extra expense coverage which provides for care,
custody and control of  all material wells drilled  by the Company as  operator.
The  Company believes that its insurance is adequate and customary for companies
of a similar size  engaged in operations  similar to those  of the Company,  but
losses could occur for uninsurable or uninsured risks or in amounts in excess of
existing  insurance coverage.  The Company's  general policy  is to  only engage
drilling contractors who  provide substantial  insurance coverage  and name  the
Company  as an additional named insured. The occurrence of a significant adverse
event, the risks  of which  are not  fully covered  by insurance,  could have  a
material  adverse effect  on the  Company's financial  condition and  results of
operations. Moreover, no assurances can be  given that the Company will be  able
to maintain adequate insurance in the future at rates it considers reasonable.
 
                                       45
<PAGE>
                                   MANAGEMENT
 
    The  executive officers and directors of the Company following completion of
the Corporate Reorganization are  listed below, together  with a description  of
their experience and certain other information (ages provided are as of June 30,
1996).  Each of the directors serve for  a one year term. Executive officers are
appointed by the Board of Directors.
 
<TABLE>
<CAPTION>
NAME                             AGE       EMPLOYED SINCE                        POSITION WITH COMPANY
- ---------------------------      ---      -----------------  --------------------------------------------------------------
<S>                          <C>          <C>                <C>
Cadell S. Liedtke                    41            1988      Chairman of the Board, Chief Executive Officer and Director
Michael J. Grella                    47            1988      President, Chief Operating Officer and Director
Henry G. Musselman                   42            1992      Executive Vice President and Director
Jerry J. Langdon                     43             n/a      Director
W.D. Kennedy                         76             n/a      Director
Bobby W. Page                        53            1996      Senior Vice President, Treasurer and Chief Financial Officer
Clifford N. Hair, Jr.                49            1992      Vice President -- Land and Secretary
Roger J. Wetz                        47            1992      Vice President -- Exploration (Geology)
Roger A. Freidline                   46            1993      Vice President -- Exploration (Geophysics)
Brian K. Miller                      36            1992      Vice President -- Reservoir Engineering
Sal J. Pagano                        45            1995      Vice President -- Engineering and Operations
Keith Atwood                         42            1992      Vice President -- Field Operations
Celia A. Zinn                        48            1996      Controller
</TABLE>
 
    Cadell S. Liedtke entered the oil and gas business in Midland, Texas in 1977
as an independent landman generating oil and gas prospects in the Permian Basin.
He founded the  Company's predecessor  with Michael J.  Grella in  1988 and  has
served  as managing partner and/or chief  executive officer since that time. Mr.
Liedtke has served  on the  Board of  Directors of  Texas Commerce  Bank-Permian
Basin and has been appointed by Texas Governor George W. Bush to the Oil and Gas
Compact  Commission. Mr.  Liedtke is  a member  of the  All-American Wildcatters
Association, the Permian Basin Petroleum Association, the Permian Basin Landmans
Association and the Independent Producer's  Association of America. Mr.  Liedtke
graduated  from the University of Texas at Austin  in 1977 with a B.A. degree in
economics.
 
    Michael J. Grella has served as  Chief Operating Officer of the Company  and
its predecessor entities since their formation in 1988. He owned and operated an
independent  oil and gas  company and has  invested in the  oil and gas business
since 1982. Mr. Grella  is a member of  the Permian Basin Petroleum  Association
and  the Independent  Producer's Association of  America. Mr. Grella  has a B.S.
degree in computer science from the University of California.
 
    Henry G.  Musselman began  his oil  and gas  career in  1975 with  Musselman
Petroleum  and Land  Company where  he served as  Vice President  and a Director
until forming Musselman, Owen & King in 1982. For the 10 years until merging his
company into  Costilla's  predecessor  in  1992,  Mr.  Musselman  developed  and
acquired oil and gas properties throughout the Permian Basin. Mr. Musselman is a
member  and prior director of the Independent Producer's Association of America.
Mr. Musselman graduated from the  University of Texas at  Austin in 1975 with  a
B.B.A. degree.
 
    Jerry  J. Langdon has previously held positions with WP Corporation, Houston
Pipeline Company, Texas  Oil &  Gas Corporation  and W.  Wilson Corporation.  In
1980,  Mr. Langdon formed  Texas IntraMark Gas Company,  Inc., an intrastate gas
gathering company engaging in the business of constructing and operating natural
gas gathering, treating and processing  facilities. In 1984, Mr. Langdon  formed
Langdon  &  Associates,  a  natural  gas  consulting  group  advising  petroleum
resource-oriented companies, financial institutions and  law firms on a  variety
of technical, commercial and regulatory
 
                                       46
<PAGE>
issues. Mr. Langdon served as a member of the FERC from 1988 to June 1993. Since
leaving  the FERC, Mr.  Langdon formed Republic Gas  Corp. to acquire, construct
and operate intrastate natural gas pipeline, gathering, processing, treating and
marketing facilities. Mr.  Langdon is  the President  of both  Republic and  the
Midla  Companies. Mr. Langdon is  a 1975 graduate of  the University of Texas at
Austin with a B.S. degree.
 
    W. D. Kennedy  has been  continually involved in  the oil  and gas  business
since  1948. From  1953 until  1980, Mr.  Kennedy was  an executive  officer and
director of C&K Petroleum, Inc., and its predecessor. C&K Petroleum, Inc. was  a
publicly held corporation from 1971 until 1980, when the company was sold for in
excess  of $200 million. Mr.  Kennedy remains an active  investor in the oil and
gas business. Mr. Kennedy is a graduate of the University of Texas, and a member
of the All-American  Wildcatters Association,  a past president  of the  Permian
Basin  Petroleum Association, a  former director of  the Texas Mid-Continent Oil
and Gas Association, and an advisory director of Norwest Bank Texas, Midland.
 
    Bobby W. Page began his oil and gas career with MGF Oil Corporation in 1967,
where he remained until  1988, ultimately serving  as Executive Vice  President,
Chief  Financial Officer and a  member of the Board  of Directors. Following two
years as  a self-employed  financial  consultant, Mr.  Page joined  Alta  Energy
Corporation  in 1990 as Executive Vice  President, Treasurer and Chief Financial
Officer. From  July 1993  until joining  the Company,  Mr. Page  served as  Vice
President, Chief Financial Officer and Secretary of Marcum Natural Gas Services,
Inc.  Mr. Page graduated from the University of Oklahoma with a B.B.A. degree in
accounting in 1965.
 
    Clifford N. Hair, Jr. has served in district and division landman roles,  as
well  as a corporate officer with Texas Gas Exploration Corporation, Samedan Oil
Corporation, Henry Petroleum Corporation and Donald C. Slawson Oil Producer. For
the two  year period  prior to  joining the  Company in  1992, Mr.  Hair was  an
independent  landman involved  in drilling projects  in Texas  and Oklahoma. Mr.
Hair is a Certified Petroleum Landman's and a member of the American Association
of Petroleum  Landmen and  the  Petroleum Basin  Landman Association.  Mr.  Hair
graduated  with honors  from the  University of  Houston in  1971 with  a B.B.A.
degree in accounting.
 
    Roger J. Wetz began his oil and gas career with IMCO Services, a division of
Halliburton, Inc. in 1974. He held  a variety of geological positions with  Gulf
Energy  & Minerals Company, TXO Production Corporation and Terra Resources, Inc.
from 1976 to 1989. From 1989 until joining the Company in 1992, Mr. Wetz was  an
independent  geologist  generating  prospects  in the  Permian  Basin.  Mr. Wetz
graduated from St. Mary's University in 1973 with a B.S. degree in geology.
 
    Roger A.  Freidline began  his industry  career with  Union Oil  Company  of
California.  From 1976 until  1985, Mr. Freidline  served in various geophysical
capacities with Forest  Oil Corporation,  Gifford, Mitchell  and Wisenbaker  and
Heritage Resources, Inc. Mr. Freidline was an independent geophysicist from 1985
until  joining  the  Company, except  for  a  period of  employment  as district
geologist for Hondo  Oil & Gas  Company prior to  its sale. Mr.  Freidline is  a
Certified  Petroleum  Geologist,  and a  member  of the  Society  of Exploration
Geophysicists,  the  Permian  Basin  Geophysical  Society  and  the  West  Texas
Geological Society. He has co-authored papers which have appeared in Geology and
The  Bulletin of the Seismological Society  of America. Mr. Freidline received a
B.S. degree with  highest honors  from the New  Mexico Institute  of Mining  and
Technology  in  1972 and  a Masters  of  Science degree  in geophysics  from the
University of Utah in 1974.
 
    Brian K. Miller entered the oil  and gas business as an operations  engineer
for  ARCO Oil and  Gas Company. From 1984  to 1987, he  was a reservoir engineer
with First City  National Bank of  Midland, Texas,  and from 1987  to 1989,  Mr.
Miller  was an independent consulting engineer.  Prior to joining the Company in
1992, Mr. Miller  served as  an oil  and gas  analyst under  appointment to  the
Federal  Deposit Insurance Corporation. Mr. Miller is a member of the Society of
Petroleum Engineers. Mr. Miller  received a B.S. degree  with highest honors  in
petroleum  engineering from  the University  of Texas  at Austin  in 1982  and a
Master of Business Administration degree with honors in finance in 1984.
 
                                       47
<PAGE>
    Sal J. Pagano  began his oil  and gas career  with Amoco Production  Company
where  he  was employed  until  1978. From  1978  through 1989,  Mr.  Pagano was
employed by several  independent oil and  gas companies in  Midland, Texas in  a
variety  of petroleum  engineering capacities. Prior  to joining  the Company in
1995, Mr. Pagano was employed by Midland  Resources Company from 1989 as a  vice
president.  Mr. Pagano is  a registered petroleum  engineer and a  member of the
Society of Petroleum Engineers. Mr. Pagano graduated in 1973 from the University
of Missouri at Rolla with a B.S. degree in petroleum engineering.
 
    Keith Atwood began  his oil and  gas career with  Otis Engineering Corp.  in
1974.  Mr. Atwood worked as an independent  consultant from 1979 to 1983 when he
joined Musselman,  Owen &  King Operating  Co. to  manage field  operations.  He
served  in that capacity until joining the  Company in 1992. Mr. Atwood attended
Southwest Texas State University and the University of Texas.
 
    Celia A. Zinn joined the Company in  1996. From 1992 to 1996, she  practiced
public  accounting in Midland. Ms.  Zinn has 18 years  experience in the oil and
gas industry, including  12 years as  Controller for Clayton  W. Williams,  Jr.,
Inc.  from 1981  to 1992. Ms.  Zinn is  a certified public  accountant. Ms. Zinn
graduated from  the  University  of  Texas-Arlington in  1978  with  a  B.A.  in
mathematics.
 
                                       48
<PAGE>
                    SECURITY OWNERSHIP OF CERTAIN BENEFICIAL
                             OWNERS AND MANAGEMENT
 
    The  following  table sets  forth the  names  and addresses  of each  of the
Company's stockholders  who  beneficially own  more  than five  percent  of  the
Company's  Common  Stock,  the  number  of  shares  beneficially  owned  by such
shareholders and the percentage of the Common  Stock so owned at June 30,  1996,
assuming  in each case the Corporate Reorganization had been consummated at June
30, 1996.
 
<TABLE>
<CAPTION>
                                         AMOUNT AND NATURE OF
                                         BENEFICIAL OWNERSHIP    PERCENT OF
NAME AND ADDRESS OF BENEFICIAL OWNER             (1)                CLASS
- --------------------------------------  ----------------------  -------------
<S>                                     <C>                     <C>
Cadell S. Liedtke ....................          2,656,796             26.6%
400 W. Illinois
Midland, Texas 79701
Michael J. Grella ....................          1,558,161             15.6%
400 W. Illinois
Midland, Texas 79701
NationsBanc Capital Corp. ............          1,080,008             10.8%
100 North Tryon Street
Charlotte, North Carolina 28255
Henry G. Musselman ...................            705,035              7.0%
400 W. Illinois
Midland, Texas 79701
</TABLE>
 
- ------------------------------
(1)  Unless otherwise indicated, all persons own the listed shares of record.
 
    The following table sets forth information as of June 30, 1996 (assuming the
Corporate Reorganization had been consummated on such date) with respect to  the
shares  of Common Stock  beneficially owned by each  of the Company's Directors,
the Chief  Executive  Officer  and  the  three  other  most  highly  compensated
executive  officers for 1996 (whose annualized  compensation for such year based
on compensation levels following  the Offering is  expected to exceed  $100,000)
and  all Directors  and executive  officers as  a group  and the  percent of the
outstanding Common Stock owned by each.
 
<TABLE>
<CAPTION>
DIRECTORS AND NAMED                      AMOUNT AND NATURE OF    PERCENT OF
EXECUTIVE OFFICER                        BENEFICIAL OWNERSHIP     CLASS (1)
- --------------------------------------  ----------------------  -------------
<S>                                     <C>                     <C>
Cadell S. Liedtke.....................          2,656,796             26.6%
Michael J. Grella.....................          1,558,161             15.6%
Henry G. Musselman....................            705,035              7.0%
Bobby W. Page.........................             75,000(2)           0.7%
All Officers and Directors as a group
(13 persons)..........................          4,994,992(2)          49.6%
</TABLE>
 
- ------------------------------
(1)  For the sole purpose  of calculating these  percentages, the shares,  which
     the  named person has the  right to acquire within  60 days, by exercise of
     the options described  in these  footnotes, are  deemed outstanding  shares
     with  respect to that person's percentage ownership and with respect to the
     percentage ownership of all Officers and Directors as a group.
 
(2)  Includes 75,000 shares  issuable pursuant  to options  under the  Company's
     1996  Stock Option Plan which options  will be immediately exercisable upon
     closing of the Offerings  at a price equal  to the initial public  offering
     price of the Common Stock.
 
                                       49
<PAGE>
                  EXECUTIVE COMPENSATION AND OTHER INFORMATION
 
SUMMARY COMPENSATION TABLE
 
    The following table sets forth information for the Company's Chief Executive
Officer  and the  three other most  highly compensated  executive officers whose
annual compensation for the fiscal year ending December 31, 1996 is expected  to
exceed  $100,000.  Information  is  presented  for  1995,  and  for  1996  on an
annualized basis based on salaries to be effective following consummation of the
Offerings. Information for  1994 and  prior years  is not  comparable since  the
Company's  predecessor was a general partnership  in which the partners received
periodic partnership distributions in lieu of salary.
 
<TABLE>
<CAPTION>
                                                                                      LONG-TERM
                                                                                    COMPENSATION
                                                                                       AWARDS
                                                                                    -------------
                                                ANNUAL COMPENSATION                  SECURITIES
                                 -------------------------------------------------   UNDERLYING
                                                                    OTHER ANNUAL      OPTIONS/        ALL OTHER
NAME AND PRINCIPAL POSITION        YEAR     SALARY($)  BONUS($)   COMPENSATION($)    SARS(#)(2)    COMPENSATION($)
- -------------------------------  ---------  ---------  ---------  ----------------  -------------  ----------------
<S>                              <C>        <C>        <C>        <C>               <C>            <C>
Cadell S. Liedtke
  Chairman of the Board and           1995    185,700         --             --              --               --
   Chief Executive Officer            1996    300,000         --             --              --               --
Michael J. Grella
  President and Chief Operating       1995    261,750         --             --              --               --
   Officer                            1996    300,000         --             --              --               --
Henry G. Musselman
                                      1995    139,800         --             --              --               --
  Executive Vice President            1996    215,000         --             --              --               --
Bobby W. Page
  Senior Vice President,
   Treasurer and Chief                1995(1)        --        --            --              --               --
   Financial Officer                  1996    150,000         --             --          75,000               --
</TABLE>
 
- ------------------------------
(1)  Mr. Page joined the Company in June 1996.
 
(2)  The amount shown represents the number of shares subject to a stock  option
     to  be granted upon the closing of  the Offerings pursuant to the Company's
     1996 Stock Option  Plan described  under "--  Benefit Plans  -- 1996  Stock
     Option  Plan." The option will be granted  with an exercise price per share
     equal to the initial public offering price of the Common Stock and will  be
     granted for a 10-year term.
 
DIRECTORS' COMPENSATION
 
    Compensation  for non-employee directors (Messrs.  Langdon and Kennedy) will
consist of an annual retainer fee of  $10,000, plus a $1,000 fee for each  Board
meeting  attended and a $1,000  fee for attending a  committee meeting held on a
day other than the same day of  a Board meeting. In addition, outside  Directors
are  participants in the Company's Outside Directors Stock Option Plan described
under "--  Benefit  Plans --  Outside  Directors Stock  Option  Plan."  Employee
Directors  do not receive compensation  for serving on the  Board or the Board's
committees.
 
EMPLOYMENT AGREEMENTS
 
    Messrs.  Liedtke,  Grella  and   Musselman  have  entered  into   employment
agreements  (the "Founders Employment  Agreements") with the  Company which will
become effective upon the closing of the Offerings and replace certain  existing
agreements.  The  Founders  Employment  Agreements  are  each  for  three years,
commencing on the closing of the Offerings and each will automatically renew for
successive one-year periods thereafter  unless the employee  is notified to  the
contrary  thereafter.  The  Founders Employment  Agreements  provide  for salary
levels for  Messrs. Liedtke,  Grella  and Musselman  of $300,000,  $300,000  and
$215,000, respectively.
 
    Each  of Messrs. Liedtke, Grella and  Musselman would receive his salary for
the remaining  term  of the  applicable  Founders Employment  Agreement  if  the
Company were to terminate such person's
 
                                       50
<PAGE>
employment  other than  for cause. However,  if such person  were to voluntarily
leave his employment with  the Company, no further  payments would be  required.
Each  Founders Employment Agreement provides that  the covered employee will not
compete with the Company for a one year period following his voluntary cessation
of employment or termination of employment for cause. Competitive activities are
defined as engaging in the oil and gas business in any area in which the Company
is then active.
 
    Bobby W. Page has entered into an employment agreement (the "Page Employment
Agreement") with  the  Company effective  June  30, 1996.  The  Page  Employment
Agreement  is  for  a  period  of  three  years  from  June  30,  1996  and will
automatically renew for successive one-year  periods thereafter unless Mr.  Page
is  notified  to the  contrary  by the  Company.  The Page  Employment Agreement
provides a $25,000 bonus (which includes Mr. Page's cost of relocation), plus  a
base  salary of $150,000 until January 1,  1997; $175,000 until January 1, 1998;
and $185,000 thereafter. In addition, Mr. Page will receive options to  purchase
75,000  shares of  Common Stock, certain  insurance benefits  and other benefits
generally available  to the  Company's  employees. Mr.  Page would  receive  his
salary  for the remaining term  of the Page Employment  Agreement if the Company
were to terminate the Page Employment  Agreement other than for cause.  However,
if  Mr.  Page were  to voluntarily  leave  his employment  with the  Company, no
further payments would be required.
 
BENEFIT PLANS
 
    OUTSIDE DIRECTORS STOCK  OPTION PLAN.   The Outside  Directors Stock  Option
Plan  provides for the issuance of stock options to the outside directors of the
Company. A total  of          shares  of Common  Stock has  been authorized  and
reserved  for issuance under the plan, subject to adjustments to reflect changes
in the Company's capitalization resulting from stock splits, stock dividends and
similar events. Only outside directors are eligible to participate in the  plan.
Outside  directors  are those  directors of  the Company  who are  not executive
officers or regular salaried employees of the  Company as of the date an  option
is  granted. Under the plan, an option for        shares of Common Stock will be
granted to each person who qualifies as an outside director as of the  effective
date  of the  plan and  each year thereafter  that such  person is  elected as a
director of the  Company. The exercise  price of each  option granted under  the
plan  will be the fair market value  (as reported on the Nasdaq National Market)
of the Common Stock at the time the option is granted, and may be paid either in
cash or shares of Common Stock. Each option will be exercisable immediately, and
will expire ten years from the date  of grant. An option granted under the  plan
is not transferrable other than by will or the laws of descent and distribution.
In  the event a participant in the plan  ceases to be an outside director, other
than by reason of death  or change of control  of the Company, such  participant
may  exercise an outstanding option under the plan within ninety days after such
termination, to the extent the participant  was entitled to exercise the  option
on the date of termination. In the event of the death of a participant under the
plan,  such  participant's  option(s)  may  be  exercised  by  the  executors or
administrators of the optionee's estate or  by the legatees of such  participant
within  one year  after his death,  so long  as the term  of the  option has not
expired. The  Company does  not  receive any  consideration  upon the  grant  of
options  under the plan. The  options granted under the  plan are intended to be
non-qualifying options for  federal income tax  purposes. Because options  under
the  plan are  not generally  transferrable, do  not appear  to be  subject to a
substantial risk of forfeiture  and the exercise price  will be the fair  market
value  of the  common stock  on the  date of  grant, the  options should  not be
taxable to an optionee  until the optionee exercises  the option, at which  time
the optionee would recognize income on the difference between the exercise price
and  the fair market value of  the shares on the date  of exercise. The grant of
options under the plan should be treated as compensation paid by the Company for
purposes of  the  Company's federal  income  tax considerations.  The  Board  of
Directors  may amend the  plan without the  approval of the  stockholders of the
Company in  any respect  other  than the  following, which  require  stockholder
approval:  material increases in the number of shares which may be awarded under
the plan, material increases in the benefits accruing to participants under  the
plan,   material  modifications   of  the   requirements  for   eligibility  for
participation in the  plan, or  any other amendment  which requires  stockholder
approval  by law.  The Company  currently has  five directors,  two of  whom are
eligible to participate in the plan.
 
                                       51
<PAGE>
    1996 STOCK OPTION PLAN.   The 1996 Employee  Stock Option Plan provides  for
the  grant of qualified  stock options to  the employees of  the Company and its
subsidiaries, including officers  and directors  who are  salaried employees.  A
total  of         shares  of Common Stock  has been authorized  and reserved for
issuance under  the  plan, subject  to  adjustment  to reflect  changes  in  the
Company's  capitalization  resulting  from  stock  splits,  stock  dividends and
similar events. The plan is administered  by the Employee Plan Committee,  which
consists  of not  less than  two and not  more than  four directors  who are not
eligible to participate  in the plan.  The Committee has  the sole authority  to
interpret the plan, to determine the persons to whom options will be granted, to
determine the basis upon which the options will be granted, and to determine the
exercise  price, duration and other terms of the options to be granted under the
plan; provided that (a) the exercise price of each option granted under the plan
may not be less than the fair market  value of the Common Stock on the date  the
option  is granted (110% of fair market  value if the employee is the beneficial
owner of 10% or more of the Company's voting securities), (b) the exercise price
must be paid in cash or by surrendering previously owned shares of Common  Stock
upon  the exercise of the option, (c) the  term of the option may not exceed ten
years, and (d)  no option is  transferrable other than  by will or  the laws  of
descent  and distribution. Upon  termination of an  optionee's employment (other
than by  death  or  disability),  the  option may  be  exercised  prior  to  the
expiration  date of  the option or  within three  months after the  date of such
termination, whichever is earlier, but only  to the extent the optionee had  the
right  to exercise the option upon the date of such termination. In the event of
the death or  disability of an  optionee, the  option may be  exercised by  such
person,  his guardian, legatee  or personal representative at  any time prior to
the expiration date of the option, but  only to the extent the optionee had  the
right  to exercise the option as of the date of his death or disability. Options
may not be granted under the plan to any individual if the effect of such  grant
would permit that person to have the first opportunity to exercise such options,
in  any calendar year, for the purchase of shares having a fair market value (at
the time of grant of the option) in excess of $100,000. Neither the Company  nor
any  of  its subsidiaries  will receive  any consideration  for the  granting of
options under the plan. Options granted under the plan are intended to have  the
federal  income tax consequences of  a qualified stock option.  As a result, the
exercise of the option will not be a taxable event; the taxable event occurs  at
the  time the shares  of Common Stock  acquired upon exercise  of the option are
sold. If the optionee holds such shares for the later of two years from the date
the option was granted or one year from the date of exercise of the option,  the
difference  between the price paid for the  shares at exercise and the price for
which those shares  are sold will  be treated  as capital gains  income. If  the
optionee  does not hold the  shares for the required  holding period, the income
would be treated as ordinary income rather than capital gains income. The  grant
of  options under the  plan will be  treated as compensation  by the Company for
federal income tax purposes. The Board of Directors may amend the plan,  without
stockholder  approval,  in  any respect  other  than the  following,  which will
require stockholder approval: increasing  the total number  of shares for  which
options  may be  granted under  the plan,  changing the  minimum exercise price,
affecting outstanding options  or the unexercised  rights thereunder,  extending
the  option period,  or extending  the termination date  of the  plan. There are
currently approximately 100 persons  who are eligible  to participate under  the
plan.
 
                              CERTAIN TRANSACTIONS
 
    A&P  supplies meter  reading services which  measures gas  production to the
Company, as well as to unaffiliated oil  and gas companies. A&P is also  engaged
in  the sale  of gas meter  and regulating  equipment, and in  certain other oil
field related  businesses. For  the fiscal  year ended  December 31,  1995,  the
Company  accounted for approximately  27% of A&P's gross  revenues. From time to
time, the Company  has advanced funds  to A&P for  working capital needs.  These
advances have been consolidated into two promissory notes. One note was executed
December  31, 1994 in the original principal  amount of $370,000. The note bears
interest at a floating rate equal to the "prime rate" plus 1.0%. No principal or
interest payments are due until the maturity  of the note at December 31,  2004.
The note is secured by a second lien on A&P's accounts receivable, inventory and
equipment.  The second note is in the  original principal amount of $247,000 and
is dated May 22, 1996. The note bears interest at
 
                                       52
<PAGE>
6.0% per annum, is unsecured and is payable upon demand. During the fiscal  year
ended  December  31, 1995,  A&P  received $612,139  from  the Company  for meter
reading, meter repair,  calibration, flow  line installation  and other  related
services  provided to  the Company. The  Company believes that  the services and
charges therefor are comparable  to those the Company  could have obtained  from
unaffiliated third parties.
 
    During 1994 and 1995, the Company paid $2,458 and $440,884, respectively, to
Valley  for gas compression and salt water disposal charges. During 1995, Valley
paid the Company $109,399 for operating  costs of its salt water disposal  wells
and  gas  compressors.  Also during  1995,  the  Company paid  CSL  $592,920 for
management fees and lease payments on equipment.
 
    During a portion  of 1995, the  Company leased office  space from 511  Tex.,
L.C.,  in which Messrs. Liedtke, Grella and  Musselman are the sole members. The
amount of rental payments to 511 Tex, L.C. during 1995 was $67,896. The  Company
no longer leases office space from any affiliated party.
 
    The  Company  has  agreed that,  upon  the request  of  NBCC, on  up  to two
occasions, the  Company will  register  under the  Securities  Act of  1933,  as
amended (the "Securities Act"), and applicable state securities laws the sale of
the  Common Stock owned by NBCC. The  Company's obligation is subject to certain
limitations regarding the timing of registrations and certain other matters. The
Company is  also obligated  to offer  to NBCC  and Messrs.  Liedtke, Grella  and
Musselman  (collectively, the  "Affiliated Holders") the  opportunity to include
shares of the  Common Stock  owned by  them in  certain registration  statements
filed  by the  Company. In  addition, the  Company has  agreed to  indemnify the
Affiliated  Holders  and  their   respective  officers  and  directors   against
securities law liabilities arising in connection with such offerings, other than
liabilities  arising as a result of information  furnished to the Company by the
Affiliated Holders participating in the  registration. The Company is  obligated
to  pay  all  expenses  incident  to  such  registration,  except  underwriters'
discounts and commissions allocable to the sale of shares by Affiliated  Holders
and  any  professional  fees and  expenses  incurred by  the  Affiliated Holders
incident to such registration. The Affiliated Holders have agreed that they will
not sell any shares of Common Stock for a period of 180 days after the Offerings
without the consent of Prudential Securities Incorporated.
 
    Certain  of  the  transactions   comprising  the  Corporate   Reorganization
represent  transactions  between  the  Company,  or  its  predecessors,  and its
affiliates. Messrs. Liedtke,  Grella and Musselman,  the shareholders of  Valley
and  CSL will sell the stock of Valley and  the assets of CSL to the Company for
$0.7 million.  The  purchase price  is  based on  negotiations  between  Messrs.
Liedtke,  Grella and Musselman, on the one hand, and NBCC, considering the value
to the Company of the stock and assets being acquired. No third party  conducted
an appraisal of either Valley or CSL.
 
    In addition, Messrs. Liedtke, Grella and Musselman will receive an aggregate
distribution from the LLC of approximately $3.5 million which is estimated to be
the federal income tax liability (as well as the federal income tax liability on
such  distribution) which will be owed  by Messrs. Liedtke, Grella and Musselman
as a result of the Corporate Reorganization. However, the precise amount of such
liability will be dependent upon a number of factors which cannot be  determined
with  certainty until subsequent  to December 31,  1996. While the  amount to be
distributed has  been determined  in  good faith  by the  Company's  independent
accountants,  there can be no assurance that  the actual tax liability of any of
Messrs. Liedtke,  Grella or  Musselman will  not  be less  or greater  than  the
distributed  amounts.  If  the  distributed  amounts  exceed  the  ultimate  tax
liabilities, none of such persons  will reimburse the Company.  Correspondingly,
if  the tax liability exceeds the amount of such distributions, the Company will
not make  any further  distributions  to cover  such  short-fall. NBCC  is  also
receiving  a  distribution  of  $800,000  which  represents  its post-redemption
ownership percentage of  the distribution  made to Messrs.  Liedtke, Grella  and
Musselman.  However, NBCC  has no  tax or other  liability with  respect to such
distribution.
 
                                       53
<PAGE>
                              DESCRIPTION OF NOTES
 
GENERAL
 
    The Notes will be issued pursuant to an Indenture (the "Indenture")  between
the Company and State Street Bank and Trust Company, as trustee (the "Trustee").
A  copy of the Indenture in substantially the  form in which it will be executed
has been  filed  as an  Exhibit  to the  Registration  Statement of  which  this
Prospectus  is  a part.  The  terms of  the Notes  include  those stated  in the
Indenture and  those  made part  of  the Indenture  by  reference to  the  Trust
Indenture  Act of 1939,  as amended (the  "Trust Indenture Act").  The Notes are
subject to all such terms,  and Holders of Notes  are referred to the  Indenture
and  the Trust Indenture Act  for a statement thereof.  The following summary of
certain provisions  of the  Indenture does  not purport  to be  complete and  is
qualified  in  its  entirety  by  reference  to  the  Indenture,  including  the
definitions therein of certain terms used below and those terms that are made  a
part  of the Indenture by reference to  the Trust Indenture Act. The definitions
of certain terms used  in the following  summary are set  forth below under  the
caption "Certain Definitions."
 
    As of the date of the Indenture, Costilla Redeco Energy, L.L.C. and Costilla
Redeco  Operating,  L.L.C.,  through  which the  Company  conducts  its Moldovan
operations,  will   be  Unrestricted   Subsidiaries.  However,   under   certain
circumstances,  the Company will be able to designate additional Subsidiaries as
Unrestricted Subsidiaries.  If  so designated,  such  Subsidiaries will  not  be
subject to many of the restrictive covenants set forth in the Indenture. As used
herein,  "Subsidiary" refers  to any  Subsidiary of the  Company that  is not an
Unrestricted Subsidiary.
 
PRINCIPAL, MATURITY AND INTEREST
 
    The Notes will be unsecured  senior subordinated general obligations of  the
Company,  limited in aggregate principal amount  to $100 million and will mature
on                    ,  2006. Interest on the Notes will accrue at the rate  of
   %  per annum and will  be payable semiannually in  arrears on             and
          commencing on           1997, to Holders of record on the  immediately
preceding            and            . Interest on the Notes will accrue from the
most recent date to  which interest has  been paid or, if  no interest has  been
paid, from           , 1996. Interest will be computed on the basis of a 360-day
year comprised of twelve 30-day months. Principal, premium, if any, and interest
on  the Notes will be payable at the  office or agency of the Company maintained
for such purpose within the City and State of New York or, at the option of  the
Company,  payment of interest may be made by  check mailed to the Holders of the
Notes at their  respective addresses  set forth in  the register  of Holders  of
Notes;  PROVIDED that all payments with respect to Global Notes and Certificated
Securities the Holders  of which have  given wire transfer  instructions to  the
Company  will be required to  be made by wire  transfer of immediately available
funds to  the  accounts  specified  by  the  Holders  thereof.  Until  otherwise
designated by the Company, the Company's office or agency in New York will be in
the  office of the Trustee maintained for such purpose. The Notes will be issued
in denominations of $1,000 and integral multiples thereof.
 
SUBORDINATION
 
    The payment of principal of, premium, if any, and interest on the Notes will
be subordinated in right of payment, as set forth in the Indenture, to the prior
payment in full of Senior Indebtedness, which will include borrowings under  the
Credit  Facility, whether outstanding on the date of the Indenture or thereafter
incurred.
 
    Upon any  distribution to  creditors  of the  Company  in a  liquidation  or
dissolution  of  the Company  or  in a  bankruptcy,  reorganization, insolvency,
receivership or similar proceeding relating to  the Company or its property,  an
assignment  for  the benefit  of creditors  or any  marshaling of  the Company's
assets and liabilities, the holders of  Senior Indebtedness will be entitled  to
receive payment in full in cash of all Obligations due in respect of such Senior
Indebtedness  (including interest after the  commencement of any such proceeding
at the rate specified in the applicable Senior Indebtedness) before the  Holders
of  Notes will be entitled to receive any payment with respect to the Notes, and
until all Obligations with  respect to Senior Indebtedness  are paid in full  in
cash, any distribution to which
 
                                       54
<PAGE>
the  Holders of Notes would  be entitled shall be made  to the holders of Senior
Indebtedness (except  that Holders  of  Notes may  receive securities  that  are
subordinated at least to the same extent as the Notes are subordinated to Senior
Indebtedness  and any securities issued in  exchange for Senior Indebtedness and
Holders of Notes may  recover payments made from  the trust described under  the
caption "Legal Defeasance and Covenant Defeasance").
 
    The  Company also may not  make any payment upon or  in respect of the Notes
(except in such subordinated  securities or from the  trust described under  the
caption  "Legal Defeasance  and Covenant  Defeasance") if  (i) a  default in the
payment of the principal of, premium,  if any, or interest on Designated  Senior
Indebtedness  occurs and is continuing beyond  any applicable period of grace or
(ii) any  other default  occurs and  is continuing  with respect  to  Designated
Senior  Indebtedness  that  then  permits  holders  of  such  Designated  Senior
Indebtedness to accelerate  its maturity and  the Trustee receives  a notice  of
such   default  (a   "Payment  Blockage  Notice")   from  the   holders  or  the
representative of the holders of any Designated Senior Indebtedness. Payments on
the Notes may and shall  be resumed (a) in the  case of a payment default,  upon
the  date on  which such default  is cured or  waived and  (b) in the  case of a
nonpayment default, the earlier of the date on which such nonpayment default  is
cured  or waived  or 179  days after  the date  on which  the applicable Payment
Blockage Notice  is  received, unless  the  maturity of  any  Designated  Senior
Indebtedness  has been  accelerated. No  new period  of payment  blockage may be
commenced by a Payment  Blockage Notice unless and  until 360 days have  elapsed
since  the effectiveness  of the immediately  prior Payment  Blockage Notice. No
nonpayment default that existed or was continuing on the date of delivery of any
Payment Blockage Notice to  the Trustee shall  be, or be made,  the basis for  a
subsequent Payment Blockage Notice.
 
    The  Indenture will  further require  that the  Company promptly  notify the
Representatives of  holders of  Designated  Senior Indebtedness  and  Designated
Guarantor  Senior Indebtedness if payment of the Notes is accelerated because of
any Event of Default.
 
    As a result of the subordination provisions described above, in the event of
an insolvency, bankruptcy, reorganization or liquidation of the Company, or upon
the occurrence of a Change of Control  or an Asset Sale requiring repurchase  by
the  Company  of any  Notes, there  may  not be  sufficient assets  remaining to
satisfy the claims of  the Holders after satisfying  the claims of creditors  of
the  Company who are holders  of Senior Indebtedness and  claims of creditors of
the Company's Subsidiaries. See "Risk Factors -- Subordination of the Notes  and
Subsidiary  Guarantees." On a pro  forma basis, after giving  effect to the 1996
Acquisition, the Corporate Reorganization, the Offerings and the application  of
proceeds  therefrom,  no  Senior Indebtedness  of  the Company  would  have been
outstanding at March  31, 1996.  The Indenture  will limit,  subject to  certain
financial  tests,  the  amount  of  additional  Indebtedness,  including  Senior
Indebtedness, that  the Company  and its  Subsidiaries can  incur. See  "Certain
Covenants -- Incurrence of Indebtedness and Issuance of Preferred Stock."
 
SUBSIDIARY GUARANTEES
 
    The  Company's  payment  obligations under  the  Notes will  be  jointly and
severally guaranteed (the  "Subsidiary Guarantees")  by each  Subsidiary of  the
Company  (the "Subsidiary Guarantors").  So long as a  Person is an Unrestricted
Subsidiary, such Person will not be required to become a Subsidiary Guarantor or
execute  a  Subsidiary  Guarantee.   See  "Certain  Covenants  --   Unrestricted
Subsidiaries." The obligations of each Subsidiary Guarantor under its Subsidiary
Guarantee  will be  limited in  a manner intended  to result  in such Subsidiary
Guarantee not constituting a fraudulent conveyance under applicable law.
 
    The Indenture will provide that no Subsidiary Guarantor may consolidate with
or merge with or into (whether or not such Subsidiary Guarantor is the surviving
Person) another corporation,  Person or  entity whether or  not affiliated  with
such  Subsidiary Guarantor (other  than the consolidation or  merger of a Wholly
Owned Subsidiary of  the Company  with another  Wholly Owned  Subsidiary of  the
Company  or  into the  Company)  unless (i)  subject  to the  provisions  of the
following paragraph, the Person formed by or surviving any such consolidation or
merger (if other than such Subsidiary Guarantor) assumes all the obligations  of
such Subsidiary Guarantor pursuant to a supplemental
 
                                       55
<PAGE>
indenture  in form and  substance reasonably satisfactory  to the Trustee, under
the Notes and  the Indenture and  (ii) immediately after  giving effect to  such
transaction, (A) no Default or Event of Default would exist or be continuing and
(B)  other  than in  the case  of the  consolidation  or merger  of two  or more
Subsidiary Guarantors or of one or more Subsidiary Guarantors with the  Company,
the  Company  would  (A)  have  Consolidated  Net  Worth  immediately  after the
transaction equal to or greater than  the Consolidated Net Worth of the  Company
immediately  preceding the transactions; and (B) at the time of such transaction
and after  giving  effect thereto,  be  permitted to  incur  at least  $1.00  of
additional Indebtedness pursuant to the Consolidated Interest Coverage Ratio and
the Adjusted Consolidated Net Tangible Assets to Consolidated Indebtedness Ratio
tests set forth in the first paragraph of the covenant described below under the
caption  "Certain  Covenants  --  Incurrence  of  Indebtedness  and  Issuance of
Preferred Stock."
 
    The Indenture  will  provide that  (i)  in the  event  of a  sale  or  other
disposition  of all of the assets of any Subsidiary Guarantor, by way of merger,
consolidation or otherwise, or a sale or other disposition of all of the capital
stock of  any  Subsidiary Guarantor  or  (ii) in  the  event that  a  Subsidiary
Guarantor is properly designated as an Unrestricted Subsidiary, in each case, in
accordance  with the provisions of the Indenture, then such Subsidiary Guarantor
(in the  event  of a  sale  or  other disposition,  by  way of  such  a  merger,
consolidation  or  otherwise, of  all of  the capital  stock of  such Subsidiary
Guarantor  or  the  proper  designation  of  such  Subsidiary  Guarantor  as  an
Unrestricted  Subsidiary in accordance with the  provisions of the Indenture) or
the corporation  acquiring  the  property (in  the  event  of a  sale  or  other
disposition  of  all  or substantially  all  of  the assets  of  such Subsidiary
Guarantor),  will  be  released  and  relieved  of  any  obligations  under  its
Subsidiary  Guarantee;  provided that  the Net  Proceeds of  such sale  or other
disposition are  applied in  accordance with  the applicable  provisions of  the
Indenture. See "Certain Covenants -- Merger, Consolidation or Sale of Assets."
 
    The  obligations of each Subsidiary Guarantor under its Subsidiary Guarantee
are  subordinated  to  the  prior  payment  in  full  of  all  Guarantor  Senior
Indebtedness   of  such   Subsidiary  Guarantor  (including   its  guarantee  of
Indebtedness of the Company under the Credit Facility) to substantially the same
extent as the  Notes are  subordinated to Senior  Indebtedness. On  a pro  forma
basis,   after   giving  effect   to   the  1996   Acquisition,   the  Corporate
Reorganization, the  Offerings and  the application  of proceeds  therefrom,  no
Guarantor  Senior  Indebtedness of  the  Subsidiary Guarantors  would  have been
outstanding as of March 31, 1996.
 
OPTIONAL REDEMPTION
 
    The  Notes  will  not  be  redeemable  at  the  Company's  option  prior  to
          ,  2001. Thereafter,  the Notes will  be subject to  redemption at the
option of the Company, in whole or in part, upon not less than 30 nor more  than
60 days' notice, at the redemption prices (expressed as percentages of principal
amount)  set  forth below  plus accrued  and unpaid  interest to  the applicable
redemption date,  if  redeemed  during  the  twelve-month  period  beginning  on
          of the years indicated below:
 
<TABLE>
<CAPTION>
YEAR                                                                               PERCENTAGE
- ---------------------------------------------------------------------------------  -----------
<S>                                                                                <C>
2001.............................................................................            %
2002.............................................................................            %
2003.............................................................................            %
2004 and thereafter..............................................................     100.000%
</TABLE>
 
    Notwithstanding  the foregoing, at any time on  or before            , 1999,
the Company may (but shall not have the  obligation to) redeem up to 30% of  the
original aggregate principal amount of the Notes at a redemption price of      %
of the principal amount thereof, plus accrued and unpaid interest thereon to the
redemption  date,  with the  net  proceeds of  an  Equity Offering  made  by the
Company; PROVIDED that at least 70%  of the aggregate principal amount of  Notes
originally  issued remain outstanding  immediately after the  occurrence of such
redemption; and PROVIDED, FURTHER,  that such redemption  shall occur within  75
days of the date of the closing of such Equity Offering.
 
                                       56
<PAGE>
    If  less than all of the Notes are  to be redeemed at any time, selection of
Notes for redemption will be made by  the Trustee on a pro rata basis;  PROVIDED
that no Notes of $1,000 or less shall be redeemed in part. Notices of redemption
shall be mailed by first class mail at least 30 but not more than 60 days before
the  redemption date to  each Holder of  Notes to be  redeemed at its registered
address. If any Note is  to be redeemed in part  only, the notice of  redemption
that  relates  to such  Note shall  state  the portion  of the  principal amount
thereof to be redeemed. A new Note  in principal amount equal to the  unredeemed
portion  thereof  will  be  issued  in  the  name  of  the  Holder  thereof upon
cancellation of the original  Note. On and after  the redemption date,  interest
ceases to accrue on Notes or portions thereof called for redemption.
 
MANDATORY REDEMPTION
 
    The  Company is  not required to  make mandatory redemption  or sinking fund
payments with respect to the Notes.
 
REPURCHASE AT THE OPTION OF HOLDERS
 
  CHANGE OF CONTROL
 
    Upon the occurrence of a Change of  Control, each Holder of Notes will  have
the  right to require the Company to repurchase all or any part (equal to $1,000
or an integral multiple  thereof) of such Holder's  Notes pursuant to the  offer
described  below (the "Change of Control Offer") at an offer price in cash equal
to 101%  of the  aggregate  principal amount  thereof  plus accrued  and  unpaid
interest  thereon  (the  "Change of  Control  Purchase  Price") to  the  date of
purchase (the "Change of  Control Payment Date"). Within  30 days following  any
Change  of Control, the Company will mail a notice to each Holder describing the
transaction or transactions that constitute  the Change of Control and  offering
to  repurchase Notes  pursuant to the  procedures required by  the Indenture and
described in such notice. The Change of Control Payment Date shall be a business
day not less than 30 days nor more than 60 days after such notice is mailed. The
Company will comply with the requirements  of Rule 14e-1 under the Exchange  Act
and any other securities laws and regulations thereunder to the extent such laws
and regulations are applicable in connection with the repurchase of the Notes as
a result of a Change of Control.
 
    On  the Change  of Control  Payment Date,  the Company  will, to  the extent
lawful, (1) accept for payment all  Notes or portions thereof properly  tendered
pursuant  to the Change of  Control Offer, (2) deposit  with the Paying Agent an
amount equal to the Change of Control Purchase Price in respect of all Notes  or
portions  thereof so tendered  and (3) deliver  or cause to  be delivered to the
Trustee the Notes so accepted together with an Officers' Certificate stating the
aggregate principal amount of Notes or  portions thereof being purchased by  the
Company. The Paying Agent will promptly mail to each Holder of Notes so tendered
the  Change of  Control Payment  for such Notes,  and the  Trustee will promptly
authenticate and mail (or cause to be transferred by book entry) to each  Holder
a  new Note equal  in principal amount  to any unpurchased  portion of the Notes
surrendered, if any; PROVIDED  that each such  new Note will  be in a  principal
amount  of $1,000  or an integral  multiple thereof. The  Indenture will provide
that, prior to complying with the provisions of this covenant, but in any  event
within  30 days following a Change of Control, the Company will either repay all
outstanding Senior Indebtedness or obtain the requisite consents, if any,  under
all   agreements  governing  outstanding  Senior   Indebtedness  to  permit  the
repurchase of  Notes  required  by  this covenant.  The  Company  will  publicly
announce the results of the Change of Control Offer on or as soon as practicable
after the Change of Control Payment Date.
 
    Except as described above with respect to a Change of Control, the Indenture
does not contain provisions that permit the Holders of the Notes to require that
the  Company repurchase or  redeem the Notes in  the event of  a takeover by any
persons other than the Approved  Shareholders, or a recapitalization or  similar
restructuring.
 
    The  Credit Facility may provide that  certain change of control events with
respect to the Company would constitute a default thereunder. Any future  credit
agreements or other agreements
 
                                       57
<PAGE>
relating to Senior Indebtedness to which the Company becomes a party may contain
similar  restrictions and provisions. In the event a Change of Control occurs at
a time when the Company is  prohibited from purchasing Notes, the Company  could
seek  the consent of  its lenders to the  purchase of Notes  or could attempt to
repay or refinance the borrowings that contain such prohibition. If the  Company
does not obtain such a consent or repay such borrowings, the Company will remain
prohibited  from  purchasing  Notes.  In such  case,  the  Company's  failure to
purchase tendered Notes would constitute an Event of Default under the Indenture
which would, in turn,  constitute a default under  the Credit Facility. In  such
circumstances,  the  subordination  provisions  in  the  Indenture  would likely
restrict payments to the Holders of Notes.
 
  ASSET SALES
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  of its Subsidiaries to, engage in an  Asset Sale unless (i) the Company (or
such Subsidiary) receives consideration at the time of such Asset Sale at  least
equal to the fair market value, and in the case of a lease of assets under which
the Company or any of its Subsidiaries is the lessor, a lease providing for rent
and  other  conditions which  are  no less  favorable  to the  Company  (or such
Subsidiary) in any material respect  than the then prevailing market  conditions
(evidenced in each case by a resolution of the Board of Directors of such entity
set  forth in an Officers'  Certificate delivered to the  Trustee) of the assets
sold or otherwise disposed of, and (ii) at  least 85% (100% in the case of  such
lease  payments) of the  consideration therefor received by  the Company or such
Subsidiary is in the form of cash or Cash Equivalents or properties used in  the
Oil and Gas Business of the Company and its Subsidiaries.
 
    The  Company may apply Net Proceeds of an  Asset Sale, at its option, (a) to
permanently reduce Senior Indebtedness other than Senior Revolving Indebtedness,
(b) to permanently reduce Senior Revolving Indebtedness (and to  correspondingly
reduce  commitments with  respect thereto), or  (c) to invest  in properties and
assets that will  be used in  the Oil and  Gas Business of  the Company and  its
Subsidiaries.  Pending  the  final application  of  any such  Net  Proceeds, the
Company may temporarily reduce Senior Revolving Indebtedness or otherwise invest
such Net Proceeds in any manner that is not prohibited by the Indenture. Any Net
Proceeds from  Asset  Sales that  are  not applied  within  270 days  after  the
consummation  of  an  Asset Sale  as  provided  in the  first  sentence  of this
paragraph will be  deemed to  constitute "Excess Proceeds."  When the  aggregate
amount  of Excess Proceeds exceeds $5.0 million, the Company will be required to
make an offer to all  Holders of Notes (an "Asset  Sale Offer") to purchase  the
maximum  principal  amount of  Notes that  may  be purchased  out of  the Excess
Proceeds, at  a purchase  price  in cash  in  an amount  equal  to 100%  of  the
principal amount thereof plus accrued and unpaid interest thereon to the date of
purchase,  in accordance with the procedures set  forth in the Indenture. To the
extent that the aggregate unpaid amount  of Notes tendered pursuant to an  Asset
Sale  Offer is less than  the Excess Proceeds, the  Company may use such surplus
Excess Proceeds for general corporate  purposes. If the aggregate unpaid  amount
of  Notes surrendered by Holders thereof  exceeds the amount of Excess Proceeds,
the Trustee shall select  the Notes to  be purchased on a  pro rata basis.  Upon
completion  of such offer  to purchase, the  amount of Excess  Proceeds shall be
reset at zero.
 
CERTAIN COVENANTS
 
  OWNERSHIP OF CAPITAL STOCK
 
    The Indenture  will provide  that the  Company will  not permit  any  Person
(other  than the Company or  any Wholly Owned Subsidiary  of the Company) to own
any Capital Stock  of any  Subsidiary of  the Company  or any  lien or  security
interest  therein, and will  not permit any  Subsidiary of the  Company to issue
Capital Stock (except to the Company or to a Wholly Owned Subsidiary) or create,
incur, assume or suffer to exist any lien or security interest therein, in  each
case  except (a) directors' qualifying shares, (b) Capital Stock issued prior to
the time such Person becomes a Subsidiary of the Company, (c) if such Subsidiary
merges with and into another Subsidiary,  (d) if another Subsidiary merges  with
and into such Subsidiary, (e) if such Subsidiary ceases to be a Subsidiary (as a
result  of the sale of  100% of the shares of  such Subsidiary, the Net Proceeds
from which are applied in accordance
 
                                       58
<PAGE>
with "Repurchase at the Option of Holders -- Asset Sales") or (f) Capital  Stock
of a Subsidiary organized in a foreign jurisdiction required to be issued to, or
owned by, the government of such foreign jurisdiction or individual or corporate
citizens  of such foreign jurisdiction in  order for such Subsidiary to transact
business in such foreign jurisdiction.
 
  UNRESTRICTED SUBSIDIARIES
 
    The Board of Directors of the Company may designate any of its  Subsidiaries
as  an Unrestricted Subsidiary.  A Subsidiary may  only be so  designated if (i)
immediately after  giving effect  to such  designation no  Default or  Event  of
Default  exists, (ii)  the Company  would, at the  time of  such designation and
after giving pro forma effect thereto as if such designation had occurred at the
beginning of the applicable four-quarter period, have been permitted to incur at
least $1.00 of  additional Indebtedness  pursuant to  the Consolidated  Interest
Coverage Ratio and the Adjusted Consolidated Tangible Net Assets to Consolidated
Indebtedness  Ratio  tests set  forth  in the  first  paragraph of  the covenant
described under  the caption  "--  Incurrence of  Indebtedness and  Issuance  of
Preferred  Stock," and (iii) after  the date of the  Indenture and prior to such
designation, no  assets of  the Company  or  of any  Subsidiary of  the  Company
(including, without limitation, Capital Stock of any such Subsidiary) shall have
been  transferred, directly or indirectly, to any Unrestricted Subsidiary or any
of its Subsidiaries,  other than assets  transferred in the  ordinary course  of
business  and on terms that are no less favorable to the Company or the relevant
Subsidiary than those that would have been obtained in a comparable  transaction
by  the Company or  such Subsidiary with  an unrelated Person  and except to the
extent  permitted  under  the  caption   "--  Restricted  Payments."  Any   such
designation  by the Board of Directors of  the Company shall be evidenced to the
Trustee by filing with the Trustee a  certified copy of the Board Resolution  of
the  Company giving effect  to such designation and  an Officers' Certificate of
the Company  certifying  that  such  designation  complied  with  the  foregoing
conditions.
 
    Any  Subsidiary  of  the  Company  shall  continue  to  be  an  Unrestricted
Subsidiary  only  if  it  (a)  has  no  Indebtedness  other  than   Non-Recourse
Indebtedness;  (b) is a Person with respect to which neither the Company nor any
of its Subsidiaries has any direct  or indirect obligation (x) to subscribe  for
additional  Equity  Interests  or  (y) to  maintain  or  preserve  such Person's
financial condition or to cause such  Person to achieve any specified levels  of
operating  results;  and  (c)  has  not  guaranteed  or  otherwise  directly  or
indirectly provided credit support for any Indebtedness of the Company or any of
its Subsidiaries. If, at any time, any Unrestricted Subsidiary fails to meet the
foregoing requirements, such Unrestricted  Subsidiary shall thereafter cease  to
be  an Unrestricted Subsidiary for purposes  of the Indenture, such Unrestricted
Subsidiary shall execute and deliver a supplemental indenture pursuant to  which
such Person guarantees the payment of the Notes on the same terms and conditions
as   the  Subsidiary  Guarantees  and  any  Indebtedness  of  such  Unrestricted
Subsidiary shall be deemed to be incurred  by a Subsidiary of the Company as  of
such  date (and, if such Indebtedness is not permitted to be incurred as of such
date  under  the  covenant  described  under  the  caption  "--  Incurrence   of
Indebtedness  and Issuance of Preferred Stock,"  the Company shall be in default
of such covenant).
 
    The Board  of  Directors  of the  Company  may  at any  time  designate  any
Subsidiary,  if previously  designated as  an Unrestricted  Subsidiary, to  be a
Subsidiary; PROVIDED that such designation shall  be deemed to be an  incurrence
of  Indebtedness by a Subsidiary of  the Company of any outstanding Indebtedness
of such Subsidiary  and such  designation shall only  be permitted  if (i)  such
Indebtedness  is permitted  under the covenant  described under  the caption "--
Incurrence of Indebtedness and Issuance of Preferred Stock," (ii) no Default  or
Event of Default would be in existence following such designation and (iii) such
Subsidiary  shall execute and deliver a supplemental indenture pursuant to which
such Person guarantees the payment of the Notes on the same terms and conditions
as the Subsidiary Guarantees.
 
    As of the  date of the  Indenture, Costilla Redeco  Exploration, L.L.C.  and
Costilla  Redeco  Operating,  L.L.C.,  through which  the  Company  conducts its
Moldovan operations will be Unrestricted Subsidiaries.
 
                                       59
<PAGE>
  RESTRICTED PAYMENTS
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  of its  Subsidiaries to,  directly or  indirectly: (i)  declare or  pay any
dividend or make  any distribution on  account of  the Company's or  any of  its
Subsidiaries' Equity Interests, other than dividends or distributions payable in
Equity  Interests (other than Disqualified Stock) of the Company or dividends or
distributions payable  to the  Company or  any Wholly  Owned Subsidiary  of  the
Company;  (ii) purchase,  redeem or  otherwise acquire  or retire  for value any
Equity Interests of the Company or any Subsidiary or Unrestricted Subsidiary  or
other  Affiliate of the Company (other than Equity Interests of the Company, any
Subsidiary or Unrestricted Subsidiary  owned by any  Wholly Owned Subsidiary  of
the  Company); (iii) make any principal payment on, or purchase, redeem, defease
or otherwise acquire  or retire for  value any Indebtedness  of (x) the  Company
that  is PARI PASSU with or subordinated to  the Notes (other than the Notes) or
(y) any Subsidiary of  the Company that  is PARI PASSU  with or subordinated  to
such  Subsidiary's Subsidiary Guarantee (other than Indebtedness secured by such
Subsidiary Guarantee)  ("PARI PASSU  Indebtedness"), in  each case,  prior to  a
scheduled  mandatory sinking fund payment date or maturity date or (iv) make any
Restricted Investment (all such payments and other actions set forth in  clauses
(i) through (iv) above being collectively referred to as "Restricted Payments"),
unless, at the time of and after giving effect to such Restricted Payment:
 
        (a) no Default or Event of Default shall have occurred and be continuing
    or would occur as a consequence thereof;
 
        (b)  the Company would, at the time of such Restricted Payment and after
    giving pro forma effect thereto as if such Restricted Payment had been  made
    at  the beginning of the applicable four-quarter period, have been permitted
    to  incur  at  least  $1.00  of  additional  Indebtedness  pursuant  to  the
    Consolidated  Interest  Coverage  Ratio and  the  Adjusted  Consolidated Net
    Tangible Assets to Consolidated  Indebtedness Ratio tests  set forth in  the
    first  paragraph  of  the covenant  described  below under  the  caption "--
    Incurrence of Indebtedness and Issuance of Preferred Stock"; and
 
        (c) such Restricted Payment,  together with the  aggregate of all  other
    Restricted Payments made by the Company and its Subsidiaries on or after the
    date  of the Indenture  (excluding Restricted Payments  permitted by clauses
    (ii), (iii), (iv) and  (v) of the next  succeeding paragraph), is less  than
    the  sum of (i)  50% of the Consolidated  Net Income of  the Company and its
    Subsidiaries for  the  period (taken  as  one accounting  period)  from  the
    beginning  of  the first  fiscal quarter  commencing after  the date  of the
    Indenture to the end of the Company's most recently ended fiscal quarter for
    which internal  financial  statements are  available  at the  time  of  such
    Restricted Payment (or, if such Consolidated Net Income for such period is a
    deficit,  less 100% of  such deficit), plus  (ii) 100% of  the aggregate net
    cash proceeds  received  by the  Company  as capital  contributions  to  the
    Company  or from the issue or sale after the date of the Indenture of Equity
    Interests of the Company or of debt securities of the Company that have been
    converted into  such  Equity  Interests (other  than  Equity  Interests  (or
    convertible  debt  securities)  sold  to  a  Subsidiary  or  an Unrestricted
    Subsidiary of  the  Company  and  other  than  Disqualified  Stock  or  debt
    securities  that have been converted into Disqualified Stock) other than the
    Common Stock sold in the Common Stock Offering.
 
    The foregoing  clauses (b)  and  (c), however,  will  not prohibit  (i)  the
payment of any dividend within 60 days after the date of declaration thereof, if
at said date of declaration such payment would have complied with the provisions
of  the Indenture; (ii) the  payment of any dividend  on Equity Interests of the
Company (other  than Disqualified  Stock)  payable solely  in shares  of  Equity
Interests  of the Company (other than Disqualified Stock); (iii) any dividend or
other distribution payable from  a Subsidiary of the  Company to the Company  or
any  Wholly Owned  Subsidiary; (iv) the  making of any  Restricted Investment in
exchange for, or  out of  the proceeds  of, the  substantially concurrent  sale,
issuance  or exchange (other than to a Subsidiary or any Unrestricted Subsidiary
of the Company)  of Equity  Interests of  the Company  (other than  Disqualified
Stock);  PROVIDED, that  any net  cash proceeds that  are utilized  for any such
Restricted Investment  shall  be  excluded  from clause  (c)  of  the  preceding
 
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<PAGE>
paragraph;  (v) the redemption,  repurchase, retirement or  other acquisition of
any Equity Interests of the Company in exchange for, or out of the proceeds  of,
the  substantially  concurrent  sale,  issuance or  exchange  (other  than  to a
Subsidiary or  any  Unrestricted Subsidiary  of  the Company)  of  other  Equity
Interests  of the Company (other than any Disqualified Stock); PROVIDED that any
net cash  proceeds  that  are  utilized for  any  such  redemption,  repurchase,
retirement  or  other  acquisition shall  be  excluded  from clause  (c)  of the
preceding paragraph; and (vi) the  defeasance, redemption or repurchase of  PARI
PASSU  Indebtedness prior to a scheduled  mandatory sinking fund payment date or
maturity date thereof with the net cash proceeds from an incurrence of Permitted
Refinancing Indebtedness  or  the  substantially concurrent  sale,  issuance  or
exchange  (other  than to  a Subsidiary  or any  Unrestricted Subsidiary  of the
Company) of Equity Interests of the  Company (other than Disqualified Stock)  or
the  purchase, redemption or  acquisition of PARI PASSU  Indebtedness prior to a
scheduled mandatory sinking fund payment  date or maturity date thereof  through
the  issuance in exchange thereof of Equity Interests of the Company (other than
Disqualified Stock); PROVIDED, that any net cash proceeds that are utilized  for
any  such defeasance, redemption,  repurchase, purchase or  acquisition shall be
excluded from clause (c) of the preceding paragraph.
 
    The amount of all  Restricted Payments (other than  cash) shall be the  fair
market  value (evidenced by a resolution of  the Board of Directors set forth in
an Officers' Certificate delivered to the Trustee) on the date of the Restricted
Payment of  the asset(s)  proposed to  be  transferred by  the Company  or  such
Subsidiary,  as the case may  be, pursuant to the  Restricted Payment. Not later
than the date of making any Restricted Payment, the Company shall deliver to the
Trustee an Officers'  Certificate of  the Company stating  that such  Restricted
Payment  is permitted  and setting forth  the basis upon  which the calculations
required by the covenant  described under the  caption "-- Restricted  Payments"
were  computed,  which  calculations  may be  based  upon  the  Company's latest
available financial statements.
 
  INCURRENCE OF INDEBTEDNESS AND ISSUANCE OF PREFERRED STOCK
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  of  its  Subsidiaries to,  directly  or indirectly,  create,  incur, issue,
assume,  guarantee   or  otherwise   become  directly   or  indirectly   liable,
contingently   or  otherwise,  with  respect   to  (collectively,  "incur")  any
Indebtedness (including Acquired  Indebtedness) and  that the  Company will  not
issue  any Disqualified  Stock and  will not permit  any of  its Subsidiaries to
issue any shares  of preferred stock;  PROVIDED, HOWEVER, that  the Company  may
incur  Indebtedness (including Acquired Indebtedness)  and the Company may issue
shares of Disqualified Stock  if: (i) the  Consolidated Interest Coverage  Ratio
for  the  Company's most  recently  ended four  full  fiscal quarters  for which
internal financial statements  are available immediately  preceding the date  on
which  such additional  Indebtedness is incurred  or such  Disqualified Stock is
issued would have been at least,  during the period until the first  anniversary
of  the date of  the Indenture, 2.25  to 1, and,  thereafter, 2.5 to  1, in each
case, determined on a pro forma basis (including a pro forma application of  the
net proceeds therefrom), as if the additional Indebtedness had been incurred, or
the  Disqualified Stock had been issued, as the case may be, at the beginning of
such four-quarter period;  (ii) the  Adjusted Consolidated  Net Tangible  Assets
would  have been at least 150% of Consolidated Indebtedness, determined on a pro
forma basis (including a  pro forma application of  the net proceeds  therefrom)
and  (iii) no Default or Event of  Default shall have occurred and be continuing
or would occur  as a  consequence thereof; PROVIDED,  that no  Guarantee may  be
incurred  pursuant  to this  paragraph,  unless the  guaranteed  Indebtedness is
incurred by the Company or a Subsidiary pursuant to this paragraph.
 
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<PAGE>
    The foregoing provisions will not apply to:
 
        (i)  the  incurrence by  the Company  of  Indebtedness under  the Credit
    Facility (and the incurrence  by Subsidiaries of  Guarantees thereof) in  an
    aggregate  principal amount at any time  outstanding (with letters of credit
    being deemed  to have  a principal  amount equal  to the  maximum  potential
    liability  of the Company and its Subsidiaries thereunder) not to exceed $50
    million, less  the aggregate  amount  of all  Net  Proceeds of  Asset  Sales
    applied to permanently reduce the outstanding amount or the commitments with
    respect  to such Indebtedness pursuant to the covenant described above under
    the caption "-- Asset Sales";
 
        (ii) the incurrence by  the Company of  Indebtedness represented by  the
    Notes  and of its Subsidiaries of Indebtedness represented by the Subsidiary
    Guarantees;
 
       (iii) the  incurrence  by the  Company  or  any of  its  Subsidiaries  of
    Permitted  Refinancing Indebtedness in exchange for,  or the net proceeds of
    which are used to extend, refinance, renew, replace, defease or refund,  any
    Indebtedness described in the foregoing clause (ii);
 
       (iv)  the  incurrence  by  the  Company or  any  of  its  Subsidiaries of
    intercompany Indebtedness between or among the Company and any of its Wholly
    Owned Subsidiaries  or  between  or among  any  Wholly  Owned  Subsidiaries;
    PROVIDED  that, in the case of Indebtedness of the Company, such obligations
    shall be unsecured and subordinated  in case of an  event of default in  all
    respects  to the Company's obligations pursuant  to the Notes; and PROVIDED,
    however, that (i) any  subsequent issuance or  transfer of Equity  Interests
    that  results in any such  Indebtedness being held by  a Person other than a
    Wholly Owned Subsidiary  and (ii)  any sale or  other transfer  of any  such
    Indebtedness  to a Person that  is not either the  Company or a Wholly Owned
    Subsidiary shall be  deemed, in each  case, to constitute  an incurrence  of
    such Indebtedness by the Company or such Subsidiary, as the case may be;
 
        (v)  the  incurrence  by the  Company  of Hedging  Obligations  that are
    incurred for  the purpose  of  fixing or  hedging  interest rate  risk  with
    respect to any floating rate Indebtedness that is permitted by the Indenture
    to  be  incurred;  PROVIDED  that,  the  notional  amount  of  such  Hedging
    Obligations does  not exceed  the principal  amount of  the Indebtedness  to
    which such Hedging Obligations relate;
 
       (vi) the incurrence by the Company of Hedging Obligations under commodity
    hedging  and currency  exchange agreements;  PROVIDED that,  such agreements
    were entered into  in the  ordinary course of  business for  the purpose  of
    limiting risks that arise in the ordinary course of business; and
 
       (vii)  the incurrence by the Company and its Subsidiaries of Indebtedness
    (in  addition  to  Indebtedness  permitted  by  any  other  clause  of  this
    paragraph)  in an aggregate principal amount  at any time outstanding not to
    exceed $10.0 million.
 
  LIENS
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  of its  Subsidiaries to, directly  or indirectly, create,  incur, assume or
suffer to exist  any Lien (other  than Permitted  Liens but only  to the  extent
securing  obligations not constituting  Indebtedness) on any  of its assets, now
owned or  hereafter  acquired,  securing  any  Indebtedness  other  than  Senior
Indebtedness  unless the Notes  are secured equally and  ratably with such other
Indebtedness; PROVIDED  that, if  such Indebtedness  is by  its terms  expressly
subordinate  to  the  Notes,  the  Lien  securing  such  subordinate  or  junior
Indebtedness shall be subordinate and junior to the Lien securing the Notes with
the same relative  priority as  such subordinated or  junior Indebtedness  shall
have with respect to the Notes.
 
  DIVIDEND AND OTHER PAYMENT RESTRICTIONS AFFECTING SUBSIDIARIES
 
    The  Indenture will provide that  the Company will not,  and will not permit
any of its Subsidiaries to, directly or indirectly, create or otherwise cause or
suffer to  exist or  become  effective any  encumbrance  or restriction  on  the
ability   of  any  Subsidiary  to  (i)(a)   pay  dividends  or  make  any  other
 
                                       62
<PAGE>
distributions to the Company or any of its Subsidiaries on its Capital Stock  or
with  respect to  any other  interest or participation  in, or  measured by, its
profits, or  (b)  pay  any indebtedness  owed  to  the Company  or  any  of  its
Subsidiaries,  (ii)  make  loans  or  advances to  the  Company  or  any  of its
Subsidiaries or (iii) transfer any of its properties or assets to the Company or
any of its  Subsidiaries, (iv) transfer  any of  its property or  assets to  the
Company or any of its Subsidiaries, (v) grant liens or security interests on the
assets  in favor  of the Holders  of Notes, or  (vi) guarantee the  Notes or any
renewals or refinancings thereof, except  for such encumbrances or  restrictions
existing under or by reason of (A) the Credit Facility, the Indenture, the Notes
or any other agreement in existence on the date of the Indenture, (B) applicable
law,  (C) any instrument  governing Acquired Indebtedness of  Capital Stock of a
Person acquired by the Company  or any of its Subsidiaries  as in effect at  the
time  of such acquisition  (except to the extent  such Acquired Indebtedness was
incurred in  connection with  or in  contemplation of  such acquisition),  which
encumbrance or restriction is not applicable to any Person, or the properties or
assets  of any Person, other  than the Person, or the  property or assets of the
Person, so acquired, PROVIDED that the Consolidated EBITDA of such Person is not
taken into account in determining whether such acquisition was permitted by  the
terms of the Indenture, or (D) Permitted Refinancing Indebtedness, PROVIDED that
the   restrictions  contained   in  the  agreements   governing  such  Permitted
Refinancing Indebtedness are  no more  restrictive than those  contained in  the
agreements governing the Indebtedness being refinanced.
 
  LIMITATION ON LAYERING INDEBTEDNESS
 
    The  Indenture will provide that the  Company will not incur, create, issue,
assume, guarantee  or  otherwise become  liable  for any  Indebtedness  that  is
subordinate  or junior in right of payment to any Senior Indebtedness and senior
in any respect in right of payment to the Notes.
 
  MERGER, CONSOLIDATION OR SALE OF ASSETS
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  Subsidiary to,  in a single  transaction or series  of related transactions
consolidate or merge with or into (other  than the consolidation or merger of  a
Wholly  Owned Subsidiary of the Company  with another Wholly Owned Subsidiary of
the Company or into the Company) (whether or not the Company or such  Subsidiary
is  the  surviving  corporation),  or  directly  and/or  indirectly  through its
Subsidiaries sell, assign, transfer, lease,  convey or otherwise dispose of  all
or  substantially all of its properties  or assets (determined on a consolidated
basis for the  Company and its  Subsidiaries taken as  a whole) in  one or  more
related transactions to, another corporation, Person or entity unless (i) either
(a)  the Company, in  the case of  a transaction involving  the Company, or such
Subsidiary, in  the  case  of  a transaction  involving  a  Subsidiary,  is  the
surviving corporation or (b) in the case of a transaction involving the Company,
the entity or the Person formed by or surviving any such consolidation or merger
(if  other than the Company) or to which such sale, assignment, transfer, lease,
conveyance or other disposition shall have been made is a corporation  organized
or  existing  under the  laws of  the United  States, any  state thereof  or the
District of Columbia and  assumes all the obligations  of the Company under  the
Notes  and  the  Indenture  pursuant  to  a  supplemental  indenture  in  a form
reasonably satisfactory to the Trustee; (ii) immediately after such  transaction
no  Default or Event of Default exists; and  (iii) the Company or, if other than
the Company, the entity or Person formed by or surviving any such  consolidation
or  merger, or  to which such  sale, assignment, transfer,  lease, conveyance or
other disposition shall  have been  made (A)  will have  Consolidated Net  Worth
immediately  after the transaction equal to or greater than the Consolidated Net
Worth of the Company immediately preceding the transaction and (B) will, at  the
time  of such transaction and  after giving pro forma  effect thereto as if such
transaction had occurred at the beginning of the applicable four-quarter period,
be permitted to incur at least $1.00 of additional Indebtedness pursuant to  the
Consolidated  Interest Coverage Ratio and the Adjusted Consolidated Net Tangible
Assets to Consolidated Indebtedness Ratio tests set forth in the first paragraph
of the covenant described above under the caption "-- Incurrence of Indebtedness
and Issuance of Preferred Stock."
 
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<PAGE>
  TRANSACTIONS WITH AFFILIATES
 
    The Indenture will provide  that the Company will  not, and will not  permit
any  of  its Subsidiaries  to, after  the  date of  the Indenture,  sell, lease,
transfer or otherwise dispose of any of its properties or assets to, or make any
payment to, or purchase any property or assets from, or enter into or suffer  to
exist  any transaction or  series of transactions, or  make any agreement, loan,
advance or guarantee with,  or for the  benefit of, any  Affiliate (each of  the
foregoing,   an   "Affiliate   Transaction"),   other   than   Exempt  Affiliate
Transactions, unless (i) such Affiliate Transaction is on terms that are no less
favorable to the Company or the relevant Subsidiary (as reasonably determined by
the  Company)  than  those  that  would  have  been  obtained  in  a  comparable
transaction  by the Company or such Subsidiary with an unrelated Person and (ii)
the  Company  delivers  to  the  Trustee  (a)  with  respect  to  any  Affiliate
Transaction  entered into  after the date  of the  Indenture involving aggregate
consideration in excess of $1.0 million, a resolution of the Board of  Directors
set forth in an Officers' Certificate certifying that such Affiliate Transaction
complies  with clause  (i) above  and that  such Affiliate  Transaction has been
approved by a majority  of the disinterested members  of the Board of  Directors
and   (b)  with  respect  to   any  Affiliate  Transaction  involving  aggregate
consideration in excess of $5.0  million, an opinion as  to the fairness to  the
Company  or such Subsidiary of such Affiliate Transaction from a financial point
of view issued by an investment banking firm of national standing.
 
  SALE AND LEASEBACK
 
    The Company will not, and will not permit any of its Subsidiaries to,  enter
into  any  Sale  and  Leaseback  Transaction  unless  (a)  the  Company  or  its
Subsidiaries entering  into  such  Sale and  Leaseback  Transaction  could  have
incurred  the  Indebtedness  relating  to such  Sale  and  Leaseback Transaction
pursuant to the "-- Incurrence of Indebtedness and Issuance of Preferred  Stock"
and  "-- Liens" covenants  and (b) the  Net Proceeds of  such Sale and Leaseback
Transaction are at  least equal to  the fair  market value of  such property  as
determined by the Board of Directors of the Company.
 
  REPORTS
 
    The  Indenture will provide that,  whether or not required  by the rules and
regulations of the Commission, so long as any Notes are outstanding, the Company
will furnish to the Holders of Notes, and file with the Trustee, within 15  days
after  it is, or would have been, required  to file such with the Commission (i)
all quarterly and annual financial information  that is or would be required  to
be  contained in  a filing  with the Commission  on Forms  10-Q and  10-K if the
Company is  or were  required  to file  such  Forms, including  a  "Management's
Discussion  and Analysis of Financial Condition  and Results of Operations" and,
with respect to the annual information  only, a report thereon by the  Company's
certified independent accountants and (ii) all current reports that are or would
be  required to be  filed with the Commission  on Form 8-K if  the Company is or
were required to file such reports. In addition, whether or not required by  the
rules  and regulations of  the Commission, the  Company will file  a copy of all
such information and reports with the Commission for public availability (unless
the Commission  will  not  accept  such a  filing)  and  make  such  information
available to securities analysts and prospective investors upon written request.
 
  EVENTS OF DEFAULT AND REMEDIES
 
    The  Indenture will provide that each  of the following constitutes an Event
of Default: (i) default for 30 days in  the payment when due of interest on  the
Notes  (whether  or  not  prohibited  by  the  subordination  provisions  of the
Indenture); (ii) default in payment when  due (upon redemption or otherwise)  of
the  principal of or premium, if any, on the Notes (whether or not prohibited by
the subordination provisions of the Indenture); (iii) failure by the Company  to
comply with the provisions described under the captions "Repurchase at Option of
Holders -- Change of Control," "Repurchase at Option of Holders -- Asset Sales,"
"--  Ownership of  Capital Stock," "--  Restricted Payments,"  "-- Incurrence of
Indebtedness and Issuance of  Preferred Stock" or  "-- Merger, Consolidation  or
Sale  of Assets"; (iv)  failure by the Company  or any of  its Subsidiary for 60
days after notice by  the Trustee or  Holders of at least  25% of the  aggregate
principal amount of the Notes outstanding to comply with
 
                                       64
<PAGE>
any of its other agreements in the Indenture or the Notes; (v) default under any
mortgage,  indenture or instrument under  which there may be  issued or by which
there may be  secured or evidenced  any Indebtedness for  money borrowed by  the
Company or any of its Subsidiaries (or the payment of which is guaranteed by the
Company  or any of its Subsidiaries)  whether such Indebtedness or Guarantee now
exists, or is  created after the  date of  the Indenture, which  default (a)  is
caused  by a  failure to  pay principal of  such Indebtedness  at final maturity
thereof (a  "Payment  Default") or  (b)  results  in the  acceleration  of  such
Indebtedness  prior to  its express  maturity and,  in each  case, the principal
amount of any such Indebtedness, together with the principal amount of any other
such Indebtedness under which there has  been a Payment Default or the  maturity
of  which has been so accelerated, aggregates  $10 million or more; (vi) failure
by the Company  or any of  its Subsidiaries  to pay final  judgments (not  fully
covered  by insurance) aggregating in excess  of $1 million, which judgments are
not paid, discharged or stayed for a period of 60 days; (vii) certain events  of
bankruptcy  or insolvency with respect to the Company or any of its Subsidiaries
or any Unrestricted Subsidiary; and (viii) any Subsidiary Guarantor attempts  to
revoke  its  Subsidiary  Guarantee or  contest  its validity  or  any Subsidiary
Guarantee shall not be in full force and effect.
 
    If any Event of Default occurs and is continuing, the Trustee or the Holders
of at least 25% in  principal amount of the  then outstanding Notes may  declare
all  the Notes to be due and payable immediately. Notwithstanding the foregoing,
in the case of an Event of Default arising from certain events of bankruptcy  or
insolvency  with respect  to the Company  or any Subsidiary  or any Unrestricted
Subsidiary, all outstanding Notes  will become due  and payable without  further
action  or notice.  Holders of the  Notes may  not enforce the  Indenture or the
Notes except  as provided  in  the Indenture.  Subject to  certain  limitations,
Holders  of a  majority in  principal amount of  the then  outstanding Notes may
direct the Trustee in its exercise of any trust or power. The Indenture provides
that if a Default occurs and  is continuing, generally the Trustee must,  within
90 days after the occurrence of such default, give to the Holders notice of such
Default.  The  Trustee may  withhold from  Holders  of the  Notes notice  of any
continuing Default or  Event of Default  (except a Default  or Event of  Default
relating  to the  payment of principal  or premium,  if any, or  interest) if it
determines that withholding notice is in their interest.
 
    The Holders of a  majority in aggregate principal  amount of the Notes  then
outstanding  by notice to the Trustee may on behalf of the Holders of all of the
Notes waive any existing Default or Event of Default and its consequences  under
the  Indenture except a continuing Default or Event of Default in the payment of
interest or  premium on,  or the  principal of,  the Notes  or in  respect of  a
provision  that cannot be  amended or waived  without the consent  of the Holder
affected. See "Amendment, Supplement and Waiver."
 
    The Company  is required  to deliver  to the  Trustee annually  a  statement
regarding  compliance  with  the Indenture,  and  the Company  is  required upon
becoming aware of any Default or Event  of Default, to deliver to the Trustee  a
statement specifying such Default or Event of Default.
 
NO PERSONAL LIABILITY OF DIRECTORS, OFFICERS, EMPLOYEES AND STOCKHOLDERS
 
    No  director, officer, employee, incorporator  or stockholder of the Company
or any Subsidiary, as such, shall have any liability for any obligations of  the
Company  under the  Notes or  the Indenture  or the  Subsidiary Guarantors under
their Subsidiary Guarantees  or for any  claim based  on, in respect  of, or  by
reason of, such obligations or their creation. Each Holder of Notes by accepting
a  Note waives and releases all such  liability. The waiver and release are part
of the consideration for issuance of the Notes. Such waiver may not be effective
to waive liabilities under the federal securities laws and it is the view of the
Commission that such waiver is against public policy.
 
LEGAL DEFEASANCE AND COVENANT DEFEASANCE
 
    The Company may, at  its option and at  any time, elect to  have all of  its
obligations   discharged  with   respect  to   the  outstanding   Notes  ("Legal
Defeasance") except  for (i)  the  rights of  Holders  of outstanding  Notes  to
receive  payments in respect of the principal  of, premium, if any, and interest
on such Notes when such payments are due from the trust referred to below,  (ii)
the Company's obligations
 
                                       65
<PAGE>
with  respect to the  Notes concerning issuing  temporary Notes, registration of
Notes, mutilated, destroyed,  lost or  stolen Notes  and the  maintenance of  an
office  or agency  for payment  and money for  security payments  held in trust,
(iii) the rights, powers, trusts, duties and immunities of the Trustee, and  the
Company's  obligations  in connection  therewith and  (iv) the  Legal Defeasance
provisions of the Indenture. In addition, the Company may, at its option and  at
any  time, elect to have the obligations of the Company released with respect to
certain covenants that  are described in  the Indenture ("Covenant  Defeasance")
and thereafter any omission to comply with such obligations shall not constitute
a  Default or Event of Default with respect  to the Notes. In the event Covenant
Defeasance  occurs,  certain  events  (not  including  nonpayment,   bankruptcy,
receivership,  rehabilitation and insolvency events)  described under "Events of
Default" will  no longer  constitute an  Event of  Default with  respect to  the
Notes.
 
    In order to exercise either Legal Defeasance or Covenant Defeasance, (i) the
Company  must irrevocably deposit with the Trustee, in trust, for the benefit of
the Holders of Notes, cash  in U.S. dollars, noncallable Government  Securities,
or  a combination thereof, in such amounts as will be sufficient, in the opinion
of a nationally recognized  firm of independent public  accountants, to pay  the
principal  of, premium,  if any,  and interest on  the outstanding  Notes on the
stated maturity or on the  applicable redemption date, as  the case may be,  and
the  Company must specify whether the Notes are being defeased to maturity or to
a particular redemption date; (ii) in the case of Legal Defeasance, the  Company
shall  have delivered to the Trustee an  opinion of counsel in the United States
reasonably acceptable  to  the  Trustee  confirming that  (A)  the  Company  has
received  from, or there has  been published by, the  Internal Revenue Service a
ruling or (B) since the  date of the Indenture, there  has been a change in  the
applicable  federal income tax law, in either case to the effect that, and based
thereon such  opinion  of  counsel  shall  confirm  that,  the  Holders  of  the
outstanding Notes will not recognize income, gain or loss for federal income tax
purposes  as a result  of such Legal  Defeasance and will  be subject to federal
income tax on  the same amounts,  in the same  manner and at  the same times  as
would have been the case if such Legal Defeasance had not occurred; (iii) in the
case  of Covenant Defeasance, the Company shall have delivered to the Trustee an
opinion of counsel  in the United  States reasonably acceptable  to the  Trustee
confirming  that the Holders of the outstanding Notes will not recognize income,
gain or  loss for  federal income  tax purposes  as a  result of  such  Covenant
Defeasance and will be subject to federal income tax on the same amounts, in the
same  manner and at the same times as  would have been the case if such Covenant
Defeasance had not  occurred; (iv)  no Default or  Event of  Default shall  have
occurred  and be continuing on the date of such deposit (other than a Default or
Event of Default resulting  from the borrowing  of funds to  be applied to  such
deposit)  or insofar as  Events of Default from  bankruptcy or insolvency events
are concerned, at any time in the period ending on the 123rd day after the  date
of  deposit; (v) such Legal Defeasance or Covenant Defeasance will not result in
a breach or violation of, or  constitute a default under any material  agreement
or  instrument (other  than the Indenture)  to which  the Company or  any of its
Subsidiaries is a party or  by which the Company or  any of its Subsidiaries  is
bound;  (vi) the  Company must deliver  to the Trustee  an Officers' Certificate
stating that  the  deposit was  not  made by  the  Company with  the  intent  of
preferring  the Holders of  Notes over other  creditors of the  Company with the
intent of defeating, hindering, delaying or defrauding creditors of the  Company
or  others;  and (vii)  the Company  must  deliver to  the Trustee  an Officers'
Certificate and  an  opinion  of  counsel,  each  stating  that  all  conditions
precedent  relating to the Legal Defeasance or the Covenant Defeasance have been
complied with.
 
TRANSFER AND EXCHANGE
 
    A Holder may transfer  or exchange Notes in  accordance with the  Indenture.
The  Company, the Registrar  and the Trustee  may require a  Holder, among other
things, to furnish appropriate  endorsements and transfer  documents as well  as
certifications, legal opinions and other information and the Company may require
a  Holder  to  pay any  taxes  and fees  required  by  law or  permitted  by the
 
                                       66
<PAGE>
Indenture. The Company is not required to transfer or exchange any Note selected
for redemption. Also, the  Company is not required  to transfer or exchange  any
Note for a period of 15 days before a selection of Notes to be redeemed.
 
    The  registered Holder of a Note will be  treated as the owner of it for all
purposes.
 
AMENDMENT, SUPPLEMENT AND WAIVER
 
    Except as provided in the next  two succeeding paragraphs, the Indenture  or
the  Notes may be amended or supplemented with  the consent of the Holders of at
least a majority in  principal amount of the  Notes then outstanding  (including
consents  obtained  in connection  with  a tender  offer  or exchange  offer for
Notes), and  any  existing default  or  compliance  with any  provision  of  the
Indenture  or the  Notes may  be waived  with the  consent of  the Holders  of a
majority in principal amount of  the then outstanding Notes (including  consents
obtained in connection with a tender offer or exchange offer for Notes).
 
    Without  the consent of each Holder affected, an amendment or waiver may not
(with respect  to any  Notes held  by a  nonconsenting Holder):  (i) reduce  the
principal amount of Notes whose Holders must consent to an amendment, supplement
or waiver, (ii) reduce the principal of or change the fixed maturity of any Note
or  alter the provisions with respect to the redemption of the Notes (other than
provisions  relating  to  the  covenants  described  above  under  the   caption
"Repurchase  at the Option of Holders"), (iii)  reduce the rate of or change the
time for payment  of interest  on any  Note, (iv) waive  a Default  or Event  of
Default  in the payment of  principal of or premium, if  any, or interest on the
Notes (except a rescission  of acceleration of  the Notes by  the Holders of  at
least  a majority in aggregate principal amount of the Notes and a waiver of the
payment default that resulted from such acceleration), (v) make any Note payable
in money  other than  that stated  in the  Notes, (vi)  make any  change in  the
provisions  of the Indenture relating to waivers  of past Defaults or the rights
of Holders of Notes to receive payments  of principal of or premium, if any,  or
interest on the Notes, (vii) waive a redemption payment with respect to any Note
(other than a payment required by one of the covenants described above under the
caption  "Repurchase at the Option of Holders") or (viii) make any change in the
foregoing amendment and waiver provisions.
 
    Notwithstanding the foregoing, without the  consent of any Holder of  Notes,
the  Company and the Trustee may amend  or supplement the Indenture or the Notes
to cure any ambiguity,  defect or inconsistency,  to provide for  uncertificated
Notes  in addition  to or  in place  of certificated  Notes, to  provide for the
assumption of the Company's  obligations to Holders  of Notes in  the case of  a
merger  or consolidation, to  make any change that  would provide any additional
rights or benefits to the Holders of Notes or that does not adversely affect the
legal rights  under  the  Indenture  of  any such  Holder,  or  to  comply  with
requirements  of the Commission in order to effect or maintain the qualification
of the Indenture under the Trust Indenture Act.
 
CONCERNING THE TRUSTEE
 
    The State  Street Bank  and Trust  Company  will be  the Trustee  under  the
Indenture.  The  Trustee's current  address is  Corporate Trust  Department, Two
International Place, 4th Floor, Boston, Massachusetts 02110.
 
    The Holders of a majority in principal amount of the then outstanding  Notes
will  have the  right to  direct the  time, method  and place  of conducting any
proceeding for  exercising  any remedy  available  to the  Trustee,  subject  to
certain  exceptions. The  Indenture provides  that in  case an  Event of Default
shall occur (which shall  not be cured),  the Trustee will  be required, in  the
exercise of its power, to use the degree of care of a prudent man in the conduct
of  his own affairs.  Subject to such  provisions, the Trustee  will be under no
obligation to exercise any of  its rights or powers  under the Indenture at  the
request  of any Holder  of Notes, unless  such Holder shall  have offered to the
Trustee security and indemnity satisfactory to it against any loss, liability or
expense.
 
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<PAGE>
ADDITIONAL INFORMATION
 
    Anyone who  receives this  Prospectus may  obtain a  copy of  the  Indenture
without  charge by  writing to  Costilla Energy,  Inc., 400  West Illinois, 10th
Floor, Midland, Texas 79701, Attention: Chief Financial Officer.
 
BOOK-ENTRY, DELIVERY AND FORM
 
    The Notes to be  sold as set  forth herein will initially  be issued in  the
form  of one Global Note (the "Global  Note"). The Global Note will be deposited
on the date of the closing of the sale of the Notes offered hereby (the "Closing
Date") with  the Trustee  as custodian  for The  Depository Trust  Company  (the
"Depositary")  and  registered in  the name  of Cede  & Co.,  as nominee  of the
Depositary (such nominee being referred to herein as the "Global Note Holder").
 
    The Depositary is a limited-purpose trust  company that was created to  hold
securities for its participating organizations (collectively, the "Participants"
or  the  "Depositary's  Participants")  and  to  facilitate  the  clearance  and
settlement of  transactions  in  such securities  between  Participants  through
electronic  book-entry changes in accounts of its Participants. The Depositary's
Participants   include   securities   brokers   and   dealers   (including   the
Underwriters),  banks  and trust  companies,  clearing corporations  and certain
other organizations.  Access to  the Depositary's  system is  also available  to
other   entities   such  as   banks,  brokers,   dealers  and   trust  companies
(collectively,  the  "Indirect  Participants"  or  the  "Depositary's   Indirect
Participants")  that clear through  or maintain a  custodial relationship with a
Participant, either directly or indirectly. Persons who are not Participants may
beneficially own securities held by or on behalf of the Depositary only  through
the Depositary's Participants or the Depositary's Indirect Participants.
 
    The   Company  expects  that  pursuant  to  procedures  established  by  the
Depositary (i) upon deposit of the  Global Note, the Depositary will credit  the
accounts  of Participants  designated by the  Underwriters with  portions of the
principal amount of the Global Note  and (ii) beneficial ownership of the  Notes
evidenced  by  the  Global Note  will  be shown  on,  and the  transfer  of such
ownership will be effected  only through, records  maintained by the  Depositary
(with   respect  to  the  interests   of  the  Depositary's  Participants),  the
Depositary's  Participants   and   the   Depositary's   Indirect   Participants.
Prospective  purchasers are  advised that the  laws of some  states require that
certain persons take  physical delivery  in definitive form  of securities  that
they  own. Consequently, the  ability to transfer Notes  evidenced by the Global
Note will be limited to such extent.
 
    So long as  the Global Note  Holder is  the registered owner  of the  Global
Note,  the Global Note Holder will be  considered the sole owner or Holder under
the Indenture of any  Notes evidenced by the  Global Note. Beneficial owners  of
Notes  evidenced by the Global Note will not be considered the owners or Holders
thereof under  the Indenture  for any  purpose, including  with respect  to  the
giving  of any directions, instructions or  approvals to the Trustee thereunder.
Except as provided below, owners of beneficial interests in the Global Note will
not be entitled to have Notes registered in their names and will not receive  or
be  entitled to receive  physical delivery of Notes  in definitive form. Neither
the Company nor the  Trustee will have any  responsibility or liability for  any
aspect  of  the records  of the  Depositary or  for maintaining,  supervising or
reviewing any records of the Depositary relating to the Notes.
 
    Payments in respect of  the principal of, premium,  if any, and interest  on
any  Notes registered in  the name of  the Global Note  Holder on the applicable
record date will be payable by the Company to or at the direction of the  Global
Note  Holder in its capacity as the registered Holder under the Indenture. Under
the terms of the Indenture, the Company and the Trustee may treat the persons in
whose names the Notes, including the  Global Note, are registered as the  owners
thereof  for the purpose  of receiving such  payments. Consequently, neither the
Company nor the Trustee has or will have any responsibility or liability for the
payment of such  amounts to beneficial  owners of Notes.  The Company  believes,
however, that it is currently the policy of the Depositary to immediately credit
the  accounts  of  the  relevant Participants  with  such  payments,  in amounts
proportionate to  their  respective  holdings of  beneficial  interests  in  the
relevant    security   as   shown   on    the   records   of   the   Depositary.
 
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<PAGE>
Payments  by  the  Depositary's  Participants  and  the  Depositary's   Indirect
Participants  to the  beneficial owners  of Notes  will be  governed by standing
instructions and  customary  practice and  will  be the  responsibility  of  the
Depositary's Participants or the Depositary's Indirect Participants.
 
    As  long as  the Notes  are represented by  a Global  Note, the Depositary's
nominee will be the holder  of the Notes and therefore  will be the only  entity
that  can exercise  a right  to repayment  or repurchase  of the  Notes. See "--
Repurchase  at   the   Option   of   Holders   --   Change   of   Control"   and
"--  Asset Sales." Notice  by the Depositary's  Participants or the Depositary's
Indirect Participants or by owners of beneficial interests in a Global Note held
through such Participants or Indirect Participants of the exercise of the option
to elect repayment of beneficial interests in Notes represented by a Global Note
must be transmitted  to the Depositary  in accordance with  its procedures on  a
form required by the Depositary and provided to Participants. In order to ensure
that  the Depositary's  nominee will timely  exercise a right  to repayment with
respect to a particular  Note, the beneficial owner  of such Note must  instruct
the  broker or other Participant or  Indirect Participant through which it holds
an interest in such Note  to notify the Depositary of  its desire to exercise  a
right   to  repayment.  Different   firms  have  cut-off   times  for  accepting
instructions from their customers and, accordingly, each beneficial owner should
consult the broker or other Participant or Indirect Participant through which it
holds an interest in a Note in order to ascertain the cut-off time by which such
an instruction must be given in order  for timely notice to be delivered to  the
Depositary.  The Company will not be liable for any delay in delivery of notices
of the exercise of the option to elect repayment.
 
    The Company will issue Notes in  definitive form in exchange for the  Global
Note  if, and  only if, either  (1) the Depositary  is at any  time unwilling or
unable to continue as depositary and a successor depositary is not appointed  by
the  Company within  90 days,  or (2) an  Event of  Default has  occurred and is
continuing and the Notes registrar has received a request from the Depositary to
issue Notes in definitive form in lieu of  all or a portion of the Global  Note.
In either instance, an owner of a beneficial interest in the Global Note will be
entitled  to have  Notes equal in  principal amount to  such beneficial interest
registered in its name and will be  entitled to physical delivery of such  Notes
in  definitive  form. Notes  so  issued in  definitive  form will  be  issued in
denominations of $1,000  and integral multiples  thereof and will  be issued  in
registered form only, without coupons.
 
  CERTIFICATED NOTES
 
    If  the Company notifies  the Trustee in  writing that the  Depositary is no
longer willing or  able to  act as  a depositary and  the Company  is unable  to
locate  a qualified successor within 90 days  then, upon surrender by the Global
Note Holder of its Global Note, Notes in the form of registered definitive Notes
will be issued to  each person that  the Global Note  Holder and the  Depositary
identify as being the beneficial owner of the related Notes.
 
    Neither  the Company  nor the Trustee  will be  liable for any  delay by the
Global Note Holder  or the Depositary  in identifying the  beneficial owners  of
Notes  and the  Company and the  Trustee may  conclusively rely on,  and will be
protected in  relying  on, instructions  from  the  Global Note  Holder  or  the
Depositary for all purposes.
 
  SAME-DAY SETTLEMENT AND PAYMENT
 
    The Indenture will require that payments in respect of the Notes represented
by  the Global Note (including  principal, premium, if any,  interest be made by
wire transfer of immediately  available funds to the  accounts specified by  the
Global  Note Holder. With  respect to Certificated Notes,  the Company will make
all payments  of  principal, premium,  if  any,  interest by  wire  transfer  of
immediately available funds to the accounts specified by the Holders thereof or,
if  no  such account  is specified,  by mailing  a check  to each  such Holder's
registered address.  Secondary  trading in  long-term  notes and  debentures  of
corporate  issuers is generally settled in  clearinghouse or next-day funds. The
Company expects that secondary  trading in the Certificated  Notes will also  be
settled in immediately available funds.
 
                                       69
<PAGE>
GOVERNING LAW
 
    The  Indenture, the Notes and the Subsidiary Guarantees will be governed by,
and construed in accordance with, the laws of the State of New York.
 
CERTAIN DEFINITIONS
 
    Set forth below are certain defined  terms used in the Indenture.  Reference
is made to the Indenture for a full disclosure of all such terms, as well as any
other capitalized terms used herein for which no definition is provided.
 
    "ACQUIRED  INDEBTEDNESS" means with respect to any specified Person, (i) any
Indebtedness of  any other  Person existing  at the  time such  other Person  is
merged with or into or becomes a Subsidiary of such specified Person, including,
without   limitation,   Indebtedness  incurred   in   connection  with,   or  in
contemplation of,  such  other  Person  merging  with  or  into  or  becoming  a
Subsidiary  of such  specified Person, and  (ii) Indebtedness secured  by a Lien
encumbering any asset acquired by such specified Person.
 
    "ADJUSTED CONSOLIDATED  NET  TANGIBLE  ASSETS"  means, as  of  the  date  of
determination,  without duplication,  (a) the sum  of (i)  discounted future net
revenue from proved  oil and gas  reserves of the  Company and its  Subsidiaries
calculated  in accordance with Commission guidelines before any state or federal
income taxes, as estimated  in a reserve  report prepared as of  the end of  the
Company's  most recently completed fiscal year, which reserve report is prepared
or audited by independent petroleum engineers,  as increased by, as of the  date
of  determination, the discounted future net revenue of (A) estimated proved oil
and gas  reserves  of the  Company  and  its Subsidiaries  attributable  to  any
acquisition  consummated since the date of such year-end reserve report, and (B)
estimated oil and gas reserves of the Company and its Subsidiary attributable to
extensions, discoveries and other additions and upward revisions of estimates of
proved oil  and  gas reserves  due  to exploration,  development,  exploitation,
production  or other activities conducted or  otherwise occurring since the date
of such year-end reserve report which would, in the case of determinations  made
pursuant  to clauses (A) and (B), in accordance with standard industry practice,
result in such  additions or revisions,  in each case  calculated in  accordance
with  Commission  guidelines (utilizing  the  prices utilized  in  such year-end
reserve report),  and  decreased  by,  as of  the  date  of  determination,  the
discounted  future net revenue of  (C) estimated proved oil  and gas reserves of
the Company and its Subsidiaries produced or disposed of since the date of  such
year-end reserve report and (D) reductions in the estimated oil and gas reserves
of  the Company  and its  Subsidiaries since the  date of  such year-end reserve
report attributable to  downward revisions of  estimates of proved  oil and  gas
reserves  due  to exploration,  development,  exploitation, production  or other
activities conducted  or otherwise  occurring since  the date  of such  year-end
reserve  report  which would,  in the  case of  determinations made  pursuant to
clauses (C) and (D),  in accordance with standard  industry practice, result  in
such revisions, in each case calculated in accordance with Commission guidelines
(utilizing  the prices utilized in such year-end reserve report); provided that,
in the case of each of the  determinations made pursuant to clauses (A)  through
(D),  such  increases  and decreases  shall  be  as estimated  by  the Company's
engineers, except  that  if as  a  result of  such  acquisitions,  dispositions,
discoveries,  extensions or  revisions, there  is a  Material Change  that is an
increase, then such increases and decreases in the discounted future net revenue
shall be  confirmed in  writing  by independent  petroleum engineers,  (ii)  the
capitalized costs that are attributable to oil and gas properties of the Company
and  its Subsidiaries to  which no proved  oil and gas  reserves are attributed,
based on the Company's books and records as  of a date no earlier than the  date
of  the Company's latest annual or quarterly financial statements, (iii) the net
working capital (which shall be calculated as all current assets of the  Company
and  its  Subsidiaries minus  all  current liabilities  of  the Company  and its
Subsidiaries, except current liabilities included  in Indebtedness on a date  no
earlier  than the  date of  the Company's  latest annual  or quarterly financial
statements) and (iv) the greater of (I) the net book value of the other tangible
assets of the Company and its Subsidiaries on a date no earlier than the date of
the Company's  latest annual  or  quarterly financial  statements and  (II)  the
appraised  value,  as estimated  by  independent appraisers,  of  other tangible
assets of the Company and its Subsidiaries as of a date no earlier than the date
of the Company's latest audited
 
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financial statements,  MINUS (b)  the sum  of (i)  minority interests  of  third
parties  to the extent included in  the calculation of the immediately preceding
clause (a), (ii) the positive remainder, if any, obtained by subtracting (I) gas
balancing underpayments of  the Company  and its Subsidiaries  reflected in  the
Company's  latest audited financial statements and not otherwise included in the
calculation of the immediately preceding clause (a) from (II) any gas  balancing
liabilities  of  the Company  and its  Subsidiaries  reflected in  the Company's
latest  audited  financial  statements  and   not  otherwise  included  in   the
calculation  of the immediately  preceding clause (a),  and (iii) the discounted
future  net  revenue,  calculated  in  accordance  with  Commission   guidelines
(utilizing  the same prices utilized in  the Company's year-end reserve report),
attributable to oil and gas reserves of the Company and its Subsidiaries subject
to participation interests, overriding royalty  interests or other interests  of
third parties, pursuant to participation, partnership, vendor financing or other
agreements  then in effect, other than  pursuant to Production Payments, or that
otherwise are required to be delivered to third parties, other than pursuant  to
Production Payments.
 
    "ADJUSTED  CONSOLIDATED  NET  TANGIBLE ASSETS  TO  CONSOLIDATED INDEBTEDNESS
RATIO" means,  at any  time, the  ratio of  Adjusted Consolidated  Net  Tangible
Assets at such time to Consolidated Indebtedness at such time.
 
    "AFFILIATE"  of any specified Person means  (i) any other Person directly or
indirectly controlling  or controlled  by  or under  direct or  indirect  common
control with such specified Person or (ii) any other Person who is a director or
executive  officer of (a) such  specified Person or (b)  any Person described in
the preceding clause (i). For purposes of this definition, "control" (including,
with correlative meanings, the terms  "controlling," "controlled by" and  "under
common  control  with"), as  used with  respect  to any  Person, shall  mean the
possession, directly  or  indirectly,  of  the power  to  direct  or  cause  the
direction  of the  management or  policies of  such Person,  whether through the
ownership of  voting  securities,  by  agreement  or  otherwise;  PROVIDED  that
beneficial ownership of 10% or more of any class, or any series of any class, of
equity  securities of  a Person, whether  or not  voting, shall be  deemed to be
control.
 
    "ASSET SALE" means with respect to  any Person, the sale, lease,  conveyance
or  other  disposition, that  does  not constitute  a  Restricted Payment  or an
Investment, by such Person of any of its assets (including, without  limitation,
by  way  of a  Sale  and Leaseback  and including  the  issuance, sale  or other
transfer of any Equity Interests in any Subsidiary or the sale or other transfer
of any Equity  Interests in any  Unrestricted Subsidiary of  such Person)  other
than  to the  Company (including  the receipt of  proceeds of  insurance paid on
account of the loss of or damage to any asset and awards of compensation for any
asset taken by condemnation, eminent domain or similar proceeding, and including
the receipt of proceeds  of business interruption insurance),  in each case,  in
one  or a  series of  related transactions;  PROVIDED that,  notwithstanding the
foregoing, the  term  "Asset Sale"  shall  not  include: (a)  the  sale,  lease,
conveyance,  disposition or  other transfer of  all or substantially  all of the
assets of the Company, as permitted  pursuant to the covenant entitled  "Merger,
Consolidation or Sale of Assets," (b) the sale or lease of hydrocarbons or other
mineral  interests in the ordinary  course of business and  customary in the Oil
and Gas Business, (c) any  Production Payment, (d) a  transfer of assets by  the
Company  to  a Wholly  Owned  Subsidiary of  the Company  or  by a  Wholly Owned
Subsidiary of the Company to the  Company or to another Wholly Owned  Subsidiary
of the Company, (e) an issuance of Equity Interests by a Wholly Owned Subsidiary
of  the Company  to the  Company or  to another  Wholly Owned  Subsidiary of the
Company, (e) sale or other disposition of  cash or Cash Equivalents, or (f)  any
lease,  abandonment, disposition, relinquishment or farm  out of any oil and gas
property that are customary in nature and scope in the Oil and Gas Business  and
are  entered into  in the  ordinary course of  the Oil  and Gas  Business of the
Company and its Subsidiaries.
 
    "BENEFICIARY", when used with respect  to any individual, means the  spouse,
lineal descendants, parents and siblings of any such individual, the estates and
the  legal representatives of any  such individual and any  of the foregoing and
the trustee of any bona fide trust of  which any such individual and any of  the
foregoing are the sole beneficiaries or grantors.
 
                                       71
<PAGE>
    "CAPITAL  LEASE OBLIGATION" means, at the  time any determination thereof is
to be made, the amount of the liability in respect of a capital lease that would
at such time be required to be capitalized on a balance sheet in accordance with
GAAP.
 
    "CAPITAL STOCK" means (i) in the case of a corporation, capital stock,  (ii)
in the case of an association or business entity, any and all shares, interests,
participations,  rights  or other  equivalents  (however designated)  of capital
stock, (iii) in the case of partnership, partnership interests (whether  general
or  limited) and  (iv) any  other interest  or participation  that confers  on a
Person the  right  to  receive  a  share  of  the  profits  and  losses  of,  or
distributions of assets of, the issuing Person.
 
    "CASH  EQUIVALENT"  means  (a)  securities  issued  or  directly  and  fully
guaranteed or  insured  by  the  United  States of  America  or  any  agency  or
instrumentality  thereof (provided that the full  faith and credit of the United
States is pledged  in support thereof)  having maturities not  more than  twelve
months  from the  date of acquisition,  (b) U.S. dollar  denominated (or foreign
currency fully hedged) time deposits,  certificates of deposit, Eurodollar  time
deposits  or Eurodollar certificates  of deposit of  (i) any domestic commercial
bank of recognized standing having capital and surplus in excess of $500 million
or (ii) any bank whose short-term commercial  paper rating from S&P is at  least
A-1  or the equivalent thereof or from Moody's is at least P-1 or the equivalent
thereof (any such bank being an "Approved Lender"), in each case with maturities
of not more than twelve months from the date of acquisition, and (c)  commercial
paper  issued by any Approved  Lender (or by the  parent company thereof) or any
variable rate notes issued by, or guaranteed by, any domestic corporation  rated
A-1  (or the  equivalent thereof)  or better  by S&P  or P-1  (or the equivalent
thereof) or better by Moody's and maturing  within twelve months of the date  of
acquisition.
 
    "CHANGE OF CONTROL" means such time as any of the following events occur:
 
        (i)  any "person" or "group"  (as such terms are  used in Sections 13(d)
    and 14(d) of  the Exchange Act),  other than Cadell  S. Liedtke, Michael  J.
    Grella and Henry G. Musselman and any of their respective Beneficiaries (the
    "Approved Shareholders), is or becomes the "beneficial owner" (as defined in
    Rule 13d-3 under the Exchange Act), directly or indirectly, of more than 50%
    of the total Voting Stock of the Company;
 
        (ii)  the Company  is merged with  or into or  consolidated with another
    Person and, immediately after giving effect to the merger or  consolidation,
    (A)  less than 50% of the total voting power of the outstanding Voting Stock
    of the surviving or  resulting Person is  then "beneficially owned"  (within
    the  meaning of Rule 13d-3  under the Exchange Act)  in the aggregate by the
    stockholders  of  the   Company  immediately   prior  to   such  merger   or
    consolidation,  and  (B)  any "person"  or  "group" (as  defined  in Section
    13(d)(3)  or  14(d)(2)  of  the  Exchange  Act)  other  than  the   Approved
    Stockholders  has  become  the  direct or  indirect  "beneficial  owner" (as
    defined in Rule 13d-3 under the Exchange Act) of more than 50% of the  total
    voting power of the Voting Stock of the surviving or resulting Person;
 
        (iii)  the Company,  either individually or  in conjunction  with one or
    more Subsidiaries, sells, assigns,  conveys, transfers, leases or  otherwise
    disposes  of, or the  Subsidiaries sell, assign,  convey, transfer, lease or
    otherwise dispose of,  all or  substantially all  of the  properties of  the
    Company and the Subsidiaries, taken as a whole (either in one transaction or
    a   series  of  related  transactions),   including  Capital  Stock  of  the
    Subsidiaries, to  any Person  (other  than the  Company  or a  Wholly  Owned
    Subsidiary);
 
        (iv)  during  any consecutive  two-year period,  individuals who  at the
    beginning of such period constituted the  Board of Directors of the  Company
    (together  with any new directors whose  election by such Board of Directors
    or whose nomination  for election  by the  stockholders of  the Company  was
    approved  by a vote of a majority of  the directors then still in office who
    were either directors at the beginning  of such period or whose election  or
    nomination  for election was previously so approved) cease for any reason to
    constitute a  majority of  the Board  of Directors  of the  Company then  in
    office; or
 
                                       72
<PAGE>
        (v) the liquidation or dissolution of the Company.
 
    "CONSOLIDATED  EBITDA" means, with respect to any Person for any period, the
sum of, without duplication, (i) the Consolidated Net Income of such Person  and
its  Subsidiaries  for such  period, plus  (ii)  to the  extent deducted  in the
computation of such Consolidated Net  Income, the Consolidated Interest  Expense
for  such period, plus (iii)  to the extent deducted  in the computation of such
Consolidated Net Income,  amortization of  deferred financing  charges for  such
period, plus (iv) provision for taxes based on income or profits for such period
(to  the extent such  income or profits were  included in computing Consolidated
Net Income for such period), plus (v) to the extent deducted in the  computation
of  such Consolidated  Net Income,  consolidated depreciation,  amortization and
other noncash  charges  of such  Person  and  its Subsidiaries  required  to  be
reflected  as expenses on the books and records of such Person, plus (vi) to the
extent deducted in the computation of such Consolidated Net Income, consolidated
exploration and abandonment  expenses of  such Person and  its Subsidiaries  for
such  periods,  minus  (vii) cash  payments  with respect  to  any nonrecurring,
noncash charges  previously added  back pursuant  to clause  (v), and  excluding
(viii)   the  impact  of  foreign  currency  translations.  Notwithstanding  the
foregoing, the provision for taxes  based on the income  or profits of, and  the
depreciation  and amortization and other noncash charges of, and the exploration
and abandonment  expenses  of,  a Subsidiary  of  a  Person shall  be  added  to
Consolidated  Net Income to compute Consolidated  EBITDA only to the extent (and
in the same proportion) that the Net  Income of such Subsidiary was included  in
calculating   the  Consolidated  Net  Income  of  such  Person  and  only  if  a
corresponding amount  would be  permitted at  the date  of determination  to  be
dividended to such Person by such Subsidiary without prior approval (unless such
approval  has  been obtained),  pursuant to  the  terms of  its charter  and all
agreements,  instruments,  judgments,  decrees,  orders,  statutes,  rules   and
governmental regulations applicable to that Subsidiary or its stockholders.
 
    "CONSOLIDATED  INDEBTEDNESS" means, with respect to any Person for any time,
the Indebtedness of such Person and its Subsidiaries at such time as  determined
on a consolidated basis in accordance with GAAP.
 
    "CONSOLIDATED  INTEREST COVERAGE RATIO" means with respect to any Person for
any period,  the  ratio  of (i)  Consolidated  EBITDA  of such  Person  and  its
Subsidiaries  for  such period  to (ii)  Consolidated  Interest Expense  of such
Person and its Subsidiaries for  such period. In the  event that the Company  or
any  of its  Subsidiaries incurs, assumes,  Guarantees or repays  or redeems any
Indebtedness (other  than  revolving credit  borrowings)  or issues  or  redeems
preferred  stock subsequent  to the  commencement of  the four-quarter reference
period for which the  Consolidated Interest Coverage  Ratio is being  calculated
but  on or prior to the date on which the event for which the calculation of the
Consolidated Interest Coverage Ratio is made (the "Calculation Date"), then  the
Consolidated Interest Coverage Ratio shall be calculated giving pro forma effect
to   such  incurrence,   assumption,  Guarantee,  repayment   or  redemption  of
Indebtedness, or such issuance or redemption of preferred stock, as if the  same
had  occurred at the beginning of  the applicable four-quarter reference period.
For purposes of making the computation referred to above, (i) acquisitions  that
have  been made  by the  Company or any  of its  Subsidiaries, including through
mergers or  consolidations and  including  any related  financing  transactions,
during  the four-quarter reference period or subsequent to such reference period
and on or prior to the Calculation Date shall be deemed to have occurred on  the
first day of the four-quarter reference period, and (ii) the Consolidated EBITDA
attributable  to discontinued operations, as determined in accordance with GAAP,
and operations or businesses disposed of prior to the Calculation Date, shall be
excluded,  and  (iii)   the  Consolidated  Interest   Expense  attributable   to
discontinued  operations, as determined in  accordance with GAAP, and operations
or businesses disposed of prior to the Calculation Date, shall be excluded,  but
only  to  the  extent that  the  obligations  giving rise  to  such Consolidated
Interest Expense will not be  obligations of the referent  Person or any of  its
Subsidiaries following the Calculation Date.
 
    "CONSOLIDATED  INTEREST EXPENSE" means,  with respect to  any Person for any
period, the sum, without duplication,  of (i) the consolidated interest  expense
of  such  Person  and  its  Subsidiaries  for  such  period  including,  without
limitation,  amortization   of  original   issue  discount,   noncash   interest
 
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payments,  the  interest  component  of any  deferred  payment  obligations, the
interest component of  all payments associated  with Capital Lease  Obligations,
commissions,  discounts and other fees and charges incurred in respect of letter
of credit or bankers' acceptance financings, and net payments (if any)  pursuant
to Hedging Obligations, but excluding amortization of deferred financing charges
for  such period, and (ii) the consolidated  interest expense of such Person and
its Subsidiaries that was capitalized during such period, and (iii) any interest
expense on Indebtedness of another Person  that is Guaranteed by such Person  or
one  of its Subsidiaries or secured by a Lien on assets of such Person or one of
its Subsidiaries (whether  or not such  Guarantee or Lien  is called upon),  and
(iv)  the  product  of (a)  all  cash  dividend payments  (and  noncash dividend
payments in  the case  of  a Person  that  is a  Subsidiary)  on any  series  of
preferred  stock of such Person  payable to a party other  than the Company or a
Wholly Owned Subsidiary, times (b) a fraction, the numerator of which is one and
the denominator of which is one  minus the then current combined federal,  state
and  local  statutory tax  rate of  such Person,  expressed as  a decimal,  on a
consolidated basis and in accordance with GAAP.
 
    "CONSOLIDATED NET INCOME" means, with respect to any Person for any  period,
the  aggregate of the  Net Income of  such Person and  its Subsidiaries for such
period, on a consolidated  basis, determined in  accordance with GAAP;  provided
that (i) the Net Income (but not loss) of any Person that is not a Subsidiary or
that  is accounted for by the equity method of accounting shall be included only
to the extent of the  amount of dividends or distributions  paid in cash to  the
referent Person or a Wholly Owned Subsidiary thereof, (ii) the Net Income of any
Subsidiary  shall be excluded to  the extent that the  declaration or payment of
dividends or similar distributions by that Subsidiary of that Net Income is  not
at  the date of determination permitted  without any prior governmental approval
(unless such  approval  has  been  obtained)  or,  directly  or  indirectly,  by
operation  of the terms  of its charter or  any agreement, instrument, judgment,
decree, order,  statute,  rule or  governmental  regulation applicable  to  that
Subsidiary or its stockholders, (iii) the Net Income of any Person acquired in a
pooling  of  interests transaction  for any  period  prior to  the date  of such
acquisition shall  be  excluded, (iv)  the  cumulative  effect of  a  change  in
accounting  principles  shall be  excluded and  (v)  the Net  Income of,  or any
dividends or  other  distributions from,  any  Unrestricted Subsidiary,  to  the
extent  otherwise included, shall be excluded  unless distributed in cash to the
Company or one of its Subsidiaries.
 
    "CONSOLIDATED NET WORTH" means, with respect  to any Person as of any  date,
the  consolidated  stockholders'  equity  of such  Person  and  its consolidated
Subsidiaries as of such  date less (w) the  amount of such stockholders'  equity
attributable  to Disqualified Stock, (x) all write-ups subsequent to the date of
the Indenture  in  the book  value  of  any asset  owned  by such  Person  or  a
consolidated   Subsidiary  of  such  Person   (other  than  purchase  accounting
adjustments made, in connection with any acquisition of any entity that  becomes
a  consolidated Subsidiary of such Person after the date of the Indenture to the
book value of the assets of such entity), (y) all investments as of such date in
unconsolidated Subsidiaries and in Persons that are not Subsidiaries (except, in
each case, Permitted  Investments), and  (z) all unamortized  debt discount  and
expense  and unamortized deferred charges as of  such date, all of the foregoing
determined in accordance with GAAP.
 
    "CREDIT FACILITY" means a credit facility that may be entered into among the
Company  and  the  lenders  parties   thereto,  including  any  related   notes,
guarantees,   collateral  documents,  instruments  and  agreements  executed  in
connection therewith, and in each case as amended, modified, renewed,  refunded,
replaced, restated or refinanced from time to time.
 
    "DEFAULT"  means any event that is or with the passage of time or the giving
of notice or both would be an Event of Default.
 
    "DESIGNATED GUARANTOR SENIOR INDEBTEDNESS" means  (i) so long as the  Senior
Bank  Indebtedness is  outstanding, any  Subsidiary Guarantor's  Indebtedness in
respect of the Senior Bank Indebtedness and (ii) thereafter, any other Guarantor
Senior Indebtedness permitted under the Indenture the principal amount of  which
is  $15.0  million  or more  and  that has  been  designated by  the  Company as
"Designated Guarantor Senior Indebtedness."
 
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<PAGE>
    "DESIGNATED SENIOR  INDEBTEDNESS"  means (i)  so  long as  the  Senior  Bank
Indebtedness  is outstanding, the Senior  Bank Indebtedness and (ii) thereafter,
any other Senior Indebtedness permitted under the Indenture the principal amount
of which is $15.0 million or more and that has been designated by the Company as
"Designated Senior Indebtedness"; provided  that for purposes  of clause (i)  of
the  first sentence  of the third  paragraph under  the caption "Subordination,"
"Designated Senior Indebtedness" shall also  mean any other Senior  Indebtedness
permitted  under the Indenture the principal amount of which is $15.0 million or
more.
 
    "DISQUALIFIED STOCK" means (a) with respect to any Person, Capital Stock  of
such Person that, by its terms (or by the terms of any security into which it is
convertible or for which it is exchangeable), or upon the happening of any event
(unless  any redemption or repurchase of  such Capital Stock upon the occurrence
of such event  is required  by any such  terms, but  only to the  extent that  a
payment in respect thereof would be permitted under the covenant set forth under
the  caption  "Restricted  Payments"),  matures  or  is  mandatorily redeemable,
pursuant to a  sinking fund  obligation or otherwise,  or is  redeemable at  the
option of the Holder thereof, in whole or in part, on or prior to the date which
is one year after the date on which the Notes mature and (b) with respect to any
Subsidiary  of  such Person  (including with  respect to  any Subsidiary  of the
Company), any Capital  Stock other  than any  common stock  with no  preference,
privileges, or redemption or repayment provisions.
 
    "DOLLAR-DENOMINATED  PRODUCTION  PAYMENTS" mean  dollar  denominated payment
obligations of the  Company or any  of its  Subsidiaries that are  or, upon  the
occurrence of a contingent event, would be recorded as liabilities in accordance
with  GAAP, together with all undertakings and obligations of the Company or any
of its Subsidiaries in connection therewith, which obligations will be deemed to
constitute Indebtedness for borrowed money for purposes of the Indenture.
 
    "EQUITY INTERESTS" means Capital  Stock and all  warrants, options or  other
rights  to  acquire  Capital Stock  (but  excluding  any debt  security  that is
convertible into, or exchangeable for, Capital Stock), whether outstanding prior
to, on or after the date of the Indenture.
 
    "EQUITY OFFERING" means an offer and sale of Qualified Stock of the  Company
to a Person other than an Affiliate of the Company.
 
    "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended.
 
    "EXEMPT  AFFILIATE TRANSACTIONS" means (a) transactions between or among the
Company and/or  its  Wholly  Owned  Subsidiaries, (b)  advances  not  to  exceed
$1,000,000  at any time outstanding to officers of the Company or any Subsidiary
of the Company in the ordinary course of business to provide for the payment  of
reasonable  expenses  incurred  by  such persons  in  the  performance  of their
responsibilities to the  Company or such  Subsidiary or in  connection with  any
relocation,  (c) fees and compensation paid  to and indemnity provided on behalf
of directors, officers  or employees  of the Company  or any  Subsidiary of  the
Company in the ordinary course of business, (d) any employment agreement that is
in  effect on the date  of the Indenture in the  ordinary course of business and
any such agreement entered into by the Company or a Subsidiary after the date of
the Indenture  in  the  ordinary course  of  business  of the  Company  or  such
Subsidiary and (e) payments and transactions under the Indebtedness of A&P Meter
Service  and Supply, Inc. ("A&P") to the  Company outstanding on the date of the
Indenture and the performance of and payment for services provided by A&P to the
Company and its Subsidiaries in the ordinary course of business consistent  with
past practice. See "Certain Transactions."
 
    "GAAP"  means  generally accepted  accounting  principles set  forth  in the
opinions and pronouncements of the  Accounting Principles Board of the  American
Institute  of Certified Public Accountants  and statements and pronouncements of
the Financial Accounting  Standards Board or  in such other  statements by  such
other  entity as have been  approved by a significant  segment of the accounting
profession, which are in effect on the date of the Indenture.
 
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<PAGE>
    "GUARANTEE" means  a  guarantee (other  than  by endorsement  of  negotiable
instruments  for  collection  in the  ordinary  course of  business),  direct or
indirect, in any manner  (including, without limitation,  letters of credit  and
reimbursement  agreements  in  respect  thereof),  of all  or  any  part  of any
Indebtedness.
 
    "GUARANTOR  SENIOR  INDEBTEDNESS"   means  (i)  all   Guarantees  or   other
Indebtedness   of  a  Subsidiary  Guarantor  in   respect  of  the  Senior  Bank
Indebtedness and  (ii) any  other indebtedness  permitted to  be incurred  by  a
Subsidiary  Guarantor under the  terms of this  Indenture, unless the instrument
under which  such  Indebtedness  is  incurred  expressly  provides  that  it  is
subordinated  in  right  of  payment to  any  Indebtedness  for  money borrowed.
Notwithstanding anything  to the  contrary in  the foregoing,  Guarantor  Senior
Indebtedness  will not  include (w) any  liability for federal,  state, local or
other taxes owed or owing by a  Subsidiary Guarantor, (x) any Indebtedness of  a
Subsidiary   Guarantor  to  any  of  the  Company's  Subsidiaries,  Unrestricted
Subsidiaries or other Affiliates, (y) any trade payables or (z) any Indebtedness
that is incurred in violation of this Indenture.
 
    "HEDGING OBLIGATIONS" means, with respect to any Person, the obligations  of
such  Person  under  (i)  interest  rate  swap  agreements,  interest  rate  cap
agreements and  interest rate  collar agreements  and (ii)  other agreements  or
arrangements  designed  to  protect  such  Person  against  fluctuations  in (a)
interest rates, (b) the value of foreign currencies and (c) Oil and Gas Purchase
and Sales Contracts.
 
    "INDEBTEDNESS" means, with respect to  any Person, without duplication,  (a)
all  liabilities of such Person for borrowed  money or for the deferred purchase
price of property or  services (excluding any trade  accounts payable and  other
accrued  current liabilities incurred  in the ordinary  course of business), and
all liabilities  of such  Person  incurred in  connection  with any  letters  of
credit,  bankers'  acceptances  or  other  similar  credit  transactions  or any
agreement to purchase, redeem, exchange, convert or otherwise acquire for  value
any  Capital Stock of such Person, or any warrants, rights or options to acquire
such Capital Stock outstanding on the  date of the Indenture or thereafter,  if,
and  to the  extent, any  of the foregoing  would appear  as a  liability upon a
balance sheet  of  such  Person  prepared  in  accordance  with  GAAP,  (b)  all
obligations  of  such  Person evidenced  by  bonds, notes,  debentures  or other
similar instruments, if, and to the extent, any of the foregoing would appear as
a liability upon  a balance  sheet of such  Person prepared  in accordance  with
GAAP,  (c)  all  Indebtedness  of  such  Person  created  or  arising  under any
conditional sale or  other title  retention agreement with  respect to  property
acquired by such Person (even if the rights and remedies of the seller or lender
under such agreement in the event of default are limited to repossession or sale
of  such property), but excluding trade accounts payable arising in the ordinary
course of business, (d)  all Capitalized Lease Obligations  of such Person,  (e)
all  Indebtedness referred to in the preceding  clauses of other Persons and all
dividends of other Persons, the payment of which is secured by (or for which the
holder of such Indebtedness  has an existing  right to be  secured by) any  Lien
upon  property  (including, without  limitation,  accounts and  contract rights)
owned by such Person, even though such  Person has not assumed or become  liable
for the payment of such Indebtedness (the amount of such obligation being deemed
to  be the lesser of  the value of such  property or asset or  the amount of the
obligation so  secured) (f)  all Production  Payments of  such Person,  (g)  all
guarantees  by such Person  of Indebtedness referred to  in this definition, (h)
all Disqualified Stock of such Person valued at the greater of its voluntary  or
involuntary  maximum fixed repurchase  price plus accrued  dividends and (i) all
obligations of such Person under or  in respect to currency exchange  contracts,
oil  or  natural gas  price hedging  arrangements  and Hedging  Obligations. For
purposes hereof,  the "maximum  fixed repurchase  price" of  Disqualified  Stock
which  does not have a fixed repurchase  price shall be calculated in accordance
with the  terms  of  such  Disqualified Stock  as  if  Disqualified  Stock  were
purchased  on any date on which Indebtedness  shall be required to be determined
pursuant to the Indenture, and if such price is based upon, or measured by,  the
fair  market value of such  Disqualified Stock, such fair  market value shall be
determined in  good faith  by  the board  of directors  of  the issuer  of  such
Disqualified Stock; provided, however, that if such Disqualified Stock is not at
the  date of determination permitted or  required to be repurchase, the "maximum
fixed repurchase price" shall be the book value of such Disqualified Stock.
 
                                       76
<PAGE>
    "INVESTMENTS" means, with  respect to  any Person, all  investments by  such
Person in other Persons (including Affiliates) in the form of direct or indirect
loans  (including guarantees of Indebtedness  or other obligations), advances or
capital contributions (excluding advances to officers and employees of the  type
specified  in clause  (b) of the  definition of  Exempt Affiliate Transactions),
purchases or  other  acquisitions  for  consideration  of  Indebtedness,  Equity
Interests  or  other  securities  and  all other  items  that  are  or  would be
classified as investments on  a balance sheet prepared  in accordance with  GAAP
and  the acquisition, by purchase  or otherwise, of all  or substantially all of
the business or assets of any other Person.
 
    "LIEN" means, with respect to any asset, any mortgage, lien, pledge, charge,
security interest or encumbrance of any  kind in respect of such asset,  whether
or  not filed, recorded  or otherwise perfected  under applicable law (including
any conditional sale or other title retention agreement, any lease in the nature
thereof, any option or other  agreement to sell or  give a security interest  in
and any filing of or agreement to give any financing statement under the Uniform
Commercial Code (or equivalent statutes) of any jurisdiction).
 
    "MATERIAL  CHANGE"  means an  increase or  decrease (excluding  changes that
result solely from changes in prices) of  more than 10% during a fiscal  quarter
in  the discounted future net cash flows from proved oil and gas reserves of the
Company and its Subsidiaries calculated in accordance with clause (a)(i) of  the
definition of Adjusted Consolidated Net Tangible Assets; PROVIDED, however, that
the  following will be excluded from the calculation of Material Change: (i) any
acquisition during the quarter of oil and gas reserves that have been  estimated
by  independent petroleum engineers and on which  a report or reports exists and
(ii) any disposition  of properties existing  at the beginning  of such  quarter
that have been disposed of pursuant to the provisions of the Indenture described
under the caption "Redemption of the Option of the Holders."
 
    "NET  INCOME" means, with  respect to any  Person, the net  income (loss) of
such Person, determined  in accordance  with GAAP  and before  any reduction  in
respect  of preferred stock dividends, excluding, however, (i) any gain (but not
loss), together  with any  related provision  for taxes  on such  gain (but  not
loss),  realized  in  connection with  (a)  any Asset  Sale  (including, without
limitation, dispositions pursuant to Sale and Leaseback transactions) or (b) the
disposition of any securities  by such Person  or any of  its Subsidiary or  the
extinguishment of any Indebtedness of such Person or any of its Subsidiary, (ii)
any extraordinary or nonrecurring gain (but not loss), together with any related
provision  for taxes on such extraordinary  or nonrecurring gain (but not loss),
and (iii) any gain (but not loss) from currency exchange transactions not in the
ordinary course of business consistent with past practice.
 
    "NET PROCEEDS" means the aggregate cash proceeds received by the Company  or
any  of  its  Subsidiaries in  respect  of  any Asset  Sale  (including, without
limitation, any cash received upon the sale or other disposition of any  noncash
consideration  received in any Asset Sale), net  of the direct costs relating to
such Asset Sale (including, without limitation, legal, accounting and investment
banking fees, and sales commissions) and  any relocation expenses incurred as  a
result  thereof, taxes paid or payable as  a result thereof, and any reserve for
adjustment in respect of the sale price  of such asset or assets established  in
accordance with GAAP.
 
    "NON-RECOURSE  INDEBTEDNESS" means Indebtedness (i)  as to which neither the
Company nor any  of its  Subsidiaries (a) provides  credit support  of any  kind
(including  any  undertaking,  agreement  or  instrument  that  would constitute
Indebtedness),  (b)  is  directly  or  indirectly  liable  (as  a  guarantor  or
otherwise),  or (c) constitutes the lender; and  (ii) no default with respect to
which  (including  any  rights  that  the  holders  thereof  may  have  to  take
enforcement  action  against  an  Unrestricted  Subsidiary)  would  permit (upon
notice, lapse of  time or  both) any  holder of  any other  Indebtedness of  the
Company  or  any  of  its  Subsidiaries  to  declare  a  default  on  such other
Indebtedness or cause the payment thereof to be accelerated or payable prior  to
its stated maturity.
 
    "OBLIGATIONS"    means   any    principal,   interest,    penalties,   fees,
indemnifications, reimbursements, damages  and other  liabilities payable  under
the documentation governing any Indebtedness.
 
                                       77
<PAGE>
    "OIL  AND  GAS BUSINESS"  means  the business  of  the exploration  for, and
development,  acquisition,  and  production   of  hydrocarbons,  together   with
activities   ancillary  thereto  (including   with  limitation,  the  gathering,
processing, treatment,  marketing and  transportation  of such  production)  and
other related energy and natural resources businesses.
 
    "OIL  AND GAS PURCHASE AND SALE CONTRACT"  means with respect to any Person,
any oil  and  gas  agreements  and  other  agreements  or  arrangements  or  any
combination  thereof  entered into  by  such Person  in  the ordinary  course of
business and that is designed to provide protection against oil and natural  gas
price fluctuations.
 
    "PERMITTED INVESTMENTS" means (a) any Investments by the Subsidiaries of the
Company in the Company; (b) any Investments in Cash Equivalents; (c) Investments
made as a result of the receipt of noncash consideration from an Asset Sale that
was  made pursuant to and in compliance  with the covenant described above under
the  caption  "Repurchase  at  the  Option  of  Holders  --  Asset  Sales";  (d)
Investments  outstanding as  of the  date of  the Indenture;  (e) Investments in
Wholly Owned Subsidiaries engaged in the Oil and Gas Business and Investments in
any Person that, as a  result of such Investment  (or a series of  substantially
contemporaneous  Investments  made pursuant  to a  single  plan) (x)  such other
Person becomes a Wholly Owned Subsidiary engaged in the Oil and Gas Business  or
(y)  such other Person that is engaged in  the Oil and Gas Business is merged or
consolidated with or into, or transfers  or conveys all or substantially all  of
its  assets  to  the Company  or  a  Wholly Owned  Subsidiary  in  a transaction
permitted under  the  Indenture;  (f) entry  into  operating  agreements,  joint
ventures,  partnership agreements, working interests, royalty interests, mineral
leases, processing  agreements, farm-out  agreements,  contracts for  the  sale,
transportation  or  exchange of  oil  and natural  gas,  unitization agreements,
pooling arrangements, area  of mutual  interest agreements or  other similar  or
customary  agreements, transactions, properties,  interests or arrangements, and
Investments and expenditures  in connection  therewith or  pursuant thereto,  in
each  case  made or  entered into  in the  ordinary  course of  the Oil  and Gas
Business, excluding, however,  Investments in corporations;  (g) entry into  any
hedging  arrangements  in the  ordinary course  of business  for the  purpose of
protecting the Company's or  any Subsidiaries's production against  fluctuations
in oil or natural gas prices; (h) shares of money mutual or similar funds having
assets in excess of $500,000,000, and (i) Investments in an aggregate amount not
to exceed $5,000,000 at any one time outstanding.
 
    "PERMITTED  LIENS" means (a)  liens for taxes,  assessments and governmental
charges not then due or the validity  of which is being contested in good  faith
by  appropriate proceedings,  promptly instituted and  diligently conducted, and
for which adequate  reserves have  been established  to the  extent required  by
GAAP;  (b)  mechanics', workmen's,  materialman's,  operator's or  similar liens
arising in  the ordinary  course  of business;  (c)  easements, rights  of  way,
restrictions  and other similar encumbrances incurred  in the ordinary course of
business or  minor  imperfections in  title  that do  not  impair the  value  of
property for its intended use; (d) liens on, or related to, properties to secure
all  or  part  of the  costs  incurred in  the  ordinary course  of  business of
exploration, drilling,  development  or  operation  thereof;  (e)  judgment  and
attachment  liens not giving rise to an Event  of Default or liens created by or
existing from  any  litigation or  legal  proceeding that  are  currently  being
contested  in  good faith  by appropriate  proceedings, promptly  instituted and
diligently conducted, and  for which  adequate reserves  have been  made to  the
extent  required by GAAP; (f)  liens on deposits made  in the ordinary course of
business; (g) liens  in favor of  collecting or  payor banks having  a right  of
selloff,  revocation, refund or chargeback with  respect to money or instruments
of the Company or any Subsidiary on deposit with or in possession of such  bank;
(h)  liens on pipeline  or pipeline facilities  which arise out  of operation of
law; (i) liens on deposits to secure public or statutory obligations or in  lieu
of  surety or appeal bonds entered into  in the ordinary course of business; (j)
liens reserved  in oil  and gas  leases for  bonus or  rental payments  and  for
compliance  with  the  terms  of  such  leases;  and  (k)  liens  arising  under
partnership agreements, oil and gas leases, farmout agreements, division orders,
contracts for the sale, purchase, exchange, transportation or processing of oil,
gas or other hydrocarbons, unitization and pooling declarations and  agreements,
development agreements, operating agreements, area of mutual interest agreements
and other agreements that are customary in the Oil and Gas Business.
 
                                       78
<PAGE>
    "PERMITTED  REFINANCING INDEBTEDNESS" means any  Indebtedness of the Company
or any of its Subsidiaries issued in exchange for, or the net proceeds of  which
are  used  to  extend,  refinance,  renew,  replace,  defease  or  refund  other
Indebtedness of the Company or any  of its Subsidiaries; PROVIDED that: (i)  the
principal  amount of such Permitted Refinancing Indebtedness does not exceed the
principal or  accrued  amount  of  the  Indebtedness  so  extended,  refinanced,
renewed,  replaced,  defeased  or  refunded;  (ii)  such  Permitted  Refinancing
Indebtedness has a Weighted Average Life  to Maturity and a final maturity  date
equal  to  or greater  than  the Weighted  Average  Life to  Maturity  and final
maturity date,  respectively, of  the Indebtedness  being extended,  refinanced,
renewed,  replaced,  defeased  or  refunded;  (iii)  if  the  Indebtedness being
extended, refinanced, renewed, replaced, defeased or refunded is subordinated in
right of  payment to  the Notes  or the  Subsidiary Guarantees,  such  Permitted
Refinancing Indebtedness has a final maturity date later than the final maturity
date of, and is subordinated in right of payment to the Notes and the Subsidiary
Guarantees  on terms at least  as favorable to the Holders  of the Note as those
contained in  the  documentation  governing  the  Indebtedness  being  extended,
refinanced,  renewed, replaced, defeased or refunded; and (iv) such Indebtedness
is incurred either by the Company or by the Subsidiary who is the obligor on the
Indebtedness  being  extended,  refinanced,   renewed,  replaced,  defeased   or
refunded.
 
    "PRODUCTION  PAYMENTS"  means,  collectively,  Dollar-Denominated Production
Payments and Volumetric Production Payments.
 
    "QUALIFIED STOCK" means, for any Person,  any and all Capital Stock of  such
Person, other than Disqualified Stock.
 
    "RESTRICTED   INVESTMENT"  means  an  Investment   other  than  a  Permitted
Investment.
 
    "SENIOR BANK  INDEBTEDNESS" means  the  Indebtedness outstanding  under  the
Credit Facility.
 
    "SENIOR  INDEBTEDNESS" means (i)  the Senior Bank  Indebtedness and (ii) any
other Indebtedness permitted to  be incurred by the  Company under the terms  of
the  Indenture, unless the instrument under  which such Indebtedness is incurred
expressly  provides  that  it  is  subordinated  in  right  of  payment  to  any
Indebtedness for money borrowed. Notwithstanding anything to the contrary in the
foregoing,  Senior Indebtedness will not include  (w) any liability for federal,
state, local or other taxes owed or  owing by the Company, (x) any  Indebtedness
of  the Company to  any of its Subsidiaries,  Unrestricted Subsidiaries or other
Affiliates, (y) any trade payables, or (z) any Indebtedness that is incurred  in
violation of the Indenture.
 
    "SENIOR  REVOLVING  INDEBTEDNESS"  means  revolving  credit  borrowings  and
letters of credit  under the Credit  Facility and/or any  successor facility  or
facilities.
 
    "SUBSIDIARY"  means,  with  respect  to  any  Person,  (i)  any corporation,
association or other business entity of which more than 50% of the total  voting
power  of shares of Capital Stock entitled  (without regard to the occurrence of
any contingency) to  vote in  the election  of directors,  managers or  trustees
thereof  is at  the time  owned or controlled,  directly or  indirectly, by such
Person or one or more of the other Subsidiaries of that Person (or a combination
thereof) and (ii) any partnership (a)  the sole general partner or the  managing
general  partner of which is  such Person or a Subsidiary  of such Person or (b)
the only  general  partners  of  which  are  such  Person  or  of  one  or  more
Subsidiaries  of such Person  (or any combination  thereof). Notwithstanding the
foregoing, an Unrestricted Subsidiary shall not  be a Subsidiary of the  Company
for any purposes of the Indenture.
 
    "UNRESTRICTED  SUBSIDIARY" means any Subsidiary,  if designated by the Board
of Directors of the  Company as an Unrestricted  Subsidiary pursuant to a  Board
Resolution  and  permitted to  be so  designated  pursuant to  the terms  of the
Indenture.
 
    "VOLUMETRIC  PRODUCTION  PAYMENTS"   means  volumetric  production   payment
obligations  of the  Company or any  of its  Subsidiaries that are  or, upon the
occurrence of  a contingent  event, would  be recorded  as deferred  revenue  in
accordance  with GAAP,  together with  all undertakings  and obligations  of the
Company or any of its Subsidiaries in connection therewith, which will be deemed
to constitute debt for borrowed money for purpose of the Indenture.
 
    "VOTING STOCK" of a corporation means  all classes of Capital Stock of  such
corporation  then outstanding and  normally entitled to vote  in the election of
directors.
 
                                       79
<PAGE>
    "WEIGHTED AVERAGE LIFE TO MATURITY" means, when applied to any  Indebtedness
at any date, the number of years obtained by dividing (i) the sum of the product
obtained  by  multiplying (a)  the amount  of  each then  remaining installment,
sinking fund, serial maturity or other required payments of principal, including
payments at  final maturity,  in respect  thereof, by  (b) the  number of  years
(calculated  to the nearest one-twelfth) that  will elapse between such date and
the making of  such payment, by  (ii) the then  outstanding principal amount  of
such Indebtedness.
 
    "WHOLLY  OWNED SUBSIDIARY" of  any Person means a  Subsidiary of such Person
(i) all of the outstanding Capital  Stock or other ownership interests of  which
(other  than directors  qualifying shares)  shall at the  time be  owned by such
Person or  by one  or more  Wholly Owned  Subsidiaries of  such Person  or  (ii)
organized  in a foreign jurisdiction and is  required by the applicable laws and
regulations of such foreign jurisdiction to be partially owned by the government
of such foreign jurisdiction or individual or corporate citizens of such foreign
jurisdiction in order for such Subsidiary  to transact business in such  foreign
jurisdiction, provided that such Person or one or more Wholly Owned Subsidiaries
of  such Person, owns the remaining Capital  Stock or ownership interest in such
Subsidiary and, by contract or  otherwise, controls the management and  business
of  such  Subsidiary and  derives  the economic  benefits  of ownership  of such
Subsidiary to substantially the same extent as if such Subsidiary were a  wholly
owned  Subsidiary.  Unrestricted  Subsidiaries  shall  not  be  included  in the
definition of Wholly Owned Subsidiary for any purposes of the Indenture.
 
                                       80
<PAGE>
                       DESCRIPTION OF OTHER INDEBTEDNESS
 
EXISTING DEBT FACILITY
 
    In  June 1996,  the Company entered  into a credit  agreement (the "Existing
Debt Facility")  provided by  NationsBridge, L.L.C.  and NationsBank,  N.A.  and
consisting  of a $95.0  million revolving credit  loan (the "Existing Revolver")
and a $30.0  million term  loan (the "Existing  Term Loan").  The Existing  Debt
Facility  provided funds to consummate the 1996 Acquisition and to refinance the
Company's prior senior bank facility.  Prudential Securities Group Inc.  ("PGI")
has purchased an interest in the Existing Debt Facility.
 
    The Existing Revolver and the Existing Term Loan each matures June 10, 1999.
No  periodic principal reductions are required with respect to the Existing Term
Loan; however, quarterly principal reductions in the amount of $3.0 million  are
required  with respect to the Existing  Revolver, commencing January 1, 1997. In
addition, the Existing  Debt Facility requires  that the net  proceeds from  the
Notes  Offering be applied to reduce  the amounts outstanding under the Existing
Revolver and the  Existing Term  Loan, and  100% of  the net  proceeds from  the
Common  Stock  Offering  are  required  to be  utilized  to  reduce  the amounts
outstanding under the Existing Term Loan and Existing Revolver.
 
    Interest accrues on  the Existing Term  Loan initially at  14.0% per  annum,
increasing  by 0.5% per annum  at the end of  each successive three month period
(commencing September 10, 1996) up to a maximum of 16.5% per annum. Interest may
be paid in cash  or "in kind"  by delivery of additional  notes having the  same
terms as the notes issued pursuant to the Existing Term Loan. Interest under the
Existing  Revolver accrues, at the option of  the Company, at a margin in excess
of either NationsBank, N.A. "LIBOR" rate, up to a maximum of 5.0% per annum,  or
NationsBank, N.A. fluctuating "prime rate" up to a maximum of 2.75% per annum.
 
    The  Existing Debt Facility is  secured by a pledge  of substantially all of
the Company's  assets,  guaranties by  the  Company's subsidiaries  and  limited
guaranties  by  Messrs. Liedtke,  Grella  and Musselman  proportionate  to their
membership interests in the LLC.
 
CREDIT FACILITY
 
    The Company is negotiating with several banks to provide the Credit Facility
which  will  be  consummated  concurrently  with  the  Offerings.  The   Company
anticipates  that the Credit Facility will provide a revolving facility based on
the borrowing base of its oil and gas assets. Based on its negotiations to date,
the Company anticipates having approximately $50.0 million available pursuant to
the Credit  Facility,  none  of which  is  expected  to be  outstanding  at  its
inception.  The  Credit  Facility is  expected  to  be secured  by  a  pledge of
substantially all of the Company's assets.
 
                          DESCRIPTION OF CAPITAL STOCK
 
    The authorized capital stock of the Company consists of 20,000,000 shares of
Common Stock, par value $0.10 per share ("Common Stock") and 3,000,000 shares of
preferred stock,  par  value  $0.10  per share  ("Preferred  Stock").  Upon  the
completion  of the  Offerings and the  Corporate Reorganization,  the issued and
outstanding capital stock of  the Company will consist  of 10,000,000 shares  of
Common Stock (or 10,600,000 shares if the underwriters' over-allotment option is
exercised in full).
 
    The  following description of certain matters  relating to the capital stock
of the Company  is summary in  nature and is  qualified in its  entirety by  the
provisions  of the Company's Certificate of  Incorporation and Bylaws, copies of
which have been filed  as exhibits to the  Registration Statement of which  this
Prospectus is a part.
 
COMMON STOCK
 
    The  holders  of Common  Stock are  entitled to  one vote  per share  on all
matters submitted to a  vote of stockholders of  the Company. In addition,  such
holders  are  entitled to  receive ratably  such  dividends, if  any, as  may be
declared from  time to  time by  the Board  of Directors  out of  funds  legally
 
                                       81
<PAGE>
available  therefor,  subject  to  the payment  of  preferential  dividends with
respect to any Preferred Stock that from time to time may be outstanding. In the
event of the dissolution, liquidation or winding-up of the Company, the  holders
of  Common Stock  are entitled  to share ratably  in all  assets remaining after
payment of all liabilities of the Company and subject to the prior  distribution
rights  of the holders  of any Preferred  Stock that may  be outstanding at that
time. The  holders of  Common Stock  do  not have  cumulative voting  rights  or
preemptive  rights. All shares of Common Stock outstanding and to be outstanding
after the Common Stock Offering will be fully paid and nonassessable.
 
PREFERRED STOCK
 
    The Board  of Directors  has  the authority  to  issue 3,000,000  shares  of
Preferred  Stock, in  one or  more series, and  to fix  the rights, preferences,
qualifications, privileges,  limitations or  restrictions  of each  such  series
without  any further vote or action  by the stockholders, including the dividend
rights, dividend rate,  conversion rights,  voting rights,  terms of  redemption
(including  sinking fund  provisions), redemption  price or  prices, liquidation
preferences and the number of shares constituting any series or the designations
of such series.  No shares of  Preferred Stock  have ever been  issued, and  the
Company  has no present plans to issue any Preferred Stock. In certain instances
the Indenture limits the  ability of the Company  to issue Preferred Stock.  See
"Description  of Notes  -- Certain Covenants  -- Incurrence  of Indebtedness and
Issuance of Preferred Stock."
 
                                       82
<PAGE>
                                  UNDERWRITING
 
    Upon the terms and subject to  the conditions of the Underwriting  Agreement
(the  "Underwriting Agreement") among the Company, the Subsidiary Guarantors and
NationsBanc Capital Markets, Inc.,  and Prudential Securities Incorporated  (the
"Underwriters"),  the Underwriters  severally have  agreed to  purchase from the
Company and the  Company has agreed  to sell to  the Underwriters severally  the
principal  amount of  Notes set  forth opposite  the names  of such Underwriters
below:
 
<TABLE>
<CAPTION>
                                                                                                     PRINCIPAL
UNDERWRITER                                                                                            AMOUNT
- ------------------------------------------------------------------------------------------------  ----------------
<S>                                                                                               <C>
NationsBanc Capital Markets, Inc................................................................  $
Prudential Securities Incorporated..............................................................
                                                                                                  ----------------
    Total.......................................................................................  $    100,000,000
                                                                                                  ----------------
                                                                                                  ----------------
</TABLE>
 
    In the Underwriting Agreement, the several Underwriters have agreed, subject
to certain conditions, to purchase all of  the Notes, if any are purchased.  The
Underwriting  Agreement  provides  that,  in  the  event  of  a  default  by  an
Underwriter,   in   certain   circumstances,   the   purchase   commitments   of
non-defaulting  Underwriters may be increased  or the Underwriting Agreement may
be terminated.
 
    The Company has been advised by the Underwriters that they propose to  offer
the  Notes to the public initially  at the price set forth  on the cover page of
this Prospectus, to certain securities dealers (who may include Underwriters) at
such price less a concession not  in excess of     % of the amount per Note  and
that  the Underwriters and such dealers may  reallow a discount not in excess of
   % of the amount per Note to other dealers, including the Underwriters.  After
the  closing of the  public offering, the public  offering price, the concession
and the discount to other dealers may be changed by the Underwriters.
 
    There is no currently  existing trading market for  the Notes, and  although
the  Underwriters have advised the Company that  they currently intend to make a
market in the Notes, they are not obligated to do so and any such market  making
may  be discontinued at any time, without  notice, in the sole discretion of the
Underwriters. Accordingly, there can  be no assurance as  to the development  or
liquidity of any market that may develop for the Notes.
 
    The  Company  and the  Subsidiary Guarantors  have  agreed to  indemnify the
Underwriters  against  certain  liabilities,  including  liabilities  under  the
Securities  Act of 1933, as amended (the  "Securities Act"), or to contribute to
payments the Underwriters may be required to make in respect thereof.
 
    NationsBanc Capital Markets, Inc. is an affiliate of NationsBank, N.A., NBCC
and NationsBridge,  L.L.C.  NationsBridge,  L.L.C.  and  NationsBank,  N.A.  are
lenders  under the  Existing Credit  Facility. PGI  is also  a lender  under the
Existing   Credit   Facility.   See   "Description   of   Other   Indebtedness."
NationsBridge,  L.L.C., NationsBank, N.A. and  PGI will receive their respective
proportionate shares of  the repayment by  the Company of  borrowings under  the
Existing  Debt  Facility  from the  net  proceeds of  the  Offerings. Prudential
Securities Incorporated  is  also acting  as  an underwriter  in  the  Company's
concurrent   Common  Stock  Offering   for  which  it   will  receive  customary
underwriting discounts and commissions. In addition, the Underwriters and  their
respective  affiliates  provide or  have  provided banking,  advisory  and other
financial services for the Company in the ordinary course of business for  which
they have received customary compensation.
 
    NBCC  is a stockholder  of the Company and  will receive approximately $15.4
million of the  proceeds of  the Offerings  in redemption  of a  portion of  the
membership  interests owned by  it in the Corporate  Reorganization. See "Use of
Proceeds," "The Company -- Corporate Reorganization" and "Security Ownership  of
Certain  Beneficial Owners and  Management." As a result  of such ownership, The
National Association of Securities Dealers, Inc. ("NASD") may view this offering
as a participation by NationsBanc Capital Markets, Inc. in the distribution in a
public offering of  the securities of  an affiliate and  this Notes Offering  is
being   made  pursuant   to  the   provisions  of   Rule  2720   of  the  NASD's
 
                                       83
<PAGE>
Conduct Rules. In accordance with Rule 2720, Prudential Securities  Incorporated
is  acting as a qualified  independent underwriter in the  Notes Offering and is
assuming the responsibilities of  acting as such in  pricing the Notes  Offering
and conducting due diligence.
 
                                 LEGAL MATTERS
 
    Certain  legal matters related to the  Notes offered hereby are being passed
upon for  the  Company  by  Cotton, Bledsoe,  Tighe  &  Dawson,  a  Professional
Corporation,  Midland,  Texas.  Certain  matters will  be  passed  upon  for the
Underwriters by Baker & Botts, L.L.P., Houston, Texas.
 
                                    EXPERTS
 
    The  consolidated  financial  statements  of  Costilla  Energy,  L.L.C.  and
subsidiaries as of December 31, 1995 and for the year then ended, the statements
of  revenues and direct operating expenses of the 1996 Acquisition for the years
ended December  31, 1993,  1994 and  1995, and  the statements  of revenues  and
direct  operating expenses of the 1995  Acquisition for the years ended December
31, 1993 and 1994, and the period ended June 12, 1995, have been included herein
and in  the registration  statement in  reliance upon  the report  of KPMG  Peat
Marwick  LLP,  independent  certified  public  accountants,  appearing elsewhere
herein, and  upon  the authority  of  said firm  as  experts in  accounting  and
auditing.
 
    The  consolidated  financial  statements  of  Costilla  Energy,  L.L.C.  and
subsidiaries as of December 31, 1994, and for the years ended December 31,  1993
and  1994,  have  been included  herein  and  in the  registration  statement in
reliance upon  the report  of Elms,  Faris &  Co., P.C.,  independent  certified
public  accountants, appearing elsewhere herein, and  upon the authority of said
firm as experts in accounting and auditing.
 
    In September 1995, the Company changed its principal accountants from  Elms,
Faris  & Co., P.C. to KPMG  Peat Marwick LLP. The reports  of Elms, Faris & Co.,
P.C. on the Company's financial statements for the year ended December 31,  1994
did  not  contain an  adverse opinion  or a  disclaimer of  opinion, nor  was it
qualified or modified in  any way as to  uncertainty, audit scope or  accounting
principles.  Moreover, there were no disagreements  with Elms, Faris & Co., P.C.
on any  matter  of  accounting  principles  or  practices,  financial  statement
disclosure, or auditing scope or procedure.
 
    Certain   information  appearing  in  this  Prospectus  regarding  estimated
quantities of oil and  gas reserves and the  discounted present value of  future
pre-tax cash flows therefrom attributable to the Company's properties and to the
properties  included in  the 1996  Acquisition is  based upon  estimates of such
reserves and present values prepared  by Williamson Petroleum Consultants,  Inc.
All  of  such information  has  been so  included  herein in  reliance  upon the
authority of such firm as  experts in such matters. Set  forth as Appendix A  is
Williamson's  Summary Reserve Report dated July 23, 1996 with respect to the oil
and gas interests of the Company and with respect to properties acquired in  the
1996 Acquisition.
 
                             AVAILABLE INFORMATION
 
    Upon  completion  of  the Offerings,  the  Company  will be  subject  to the
informational requirements of the  Securities Exchange Act  of 1934, as  amended
(the  "Exchange Act"),  and, in accordance  therewith, will  file reports, proxy
statements and other  information with  the Securities  and Exchange  Commission
(the  "Commission"). Such reports, proxy  statements and other information filed
by the Company  with the  Commission can be  inspected at  the Public  Reference
Section of the Commission at Room 1024, Judiciary Plaza, 450 Fifth Street, N.W.,
Washington,  D.C. 20549, and the Regional  Offices of the Commission at Citicorp
Center, 500 West Madison Street, Suite 1400, Chicago, Illinois 60661-2511, and 7
World Trade Center, New York, New York  10048. Copies of such material can  also
be  obtained from the Public  Reference Section of the  Commission at Room 1024,
Judiciary Plaza, 450
 
                                       84
<PAGE>
Fifth Street, N.W., Washington, D.C. 20549, at prescribed rates. The  Commission
maintains  a  World Wide  Web site  on the  Internet at  HTTP:\\WWW.SEC.GOV that
contains  reports,  proxy  and  information  statements  and  other  information
regarding registrants that file electronically with the Commission.
 
    The  Company has filed with the  Commission a Registration Statement on Form
S-1 under the  Securities Act  with respect to  the Notes  offered hereby.  This
Prospectus,  which constitutes  a part of  the Registration  Statement, does not
contain all of the information set forth in the Registration Statement,  certain
items  of  which are  contained  in exhibits  to  the Registration  Statement as
permitted  by  the  rules  and  regulations  of  the  Commission.  For   further
information  with respect to the Company and the Notes offered hereby, reference
is made to the Registration Statement, including the exhibits thereto, which may
be inspected without charge at the public reference facilities maintained by the
Commission at 450 Fifth Street, N.W., Washington, D.C. 20549 and at the Regional
Offices of  the  Commission,  and copies  of  which  may be  obtained  from  the
Commission  at prescribed rates.  Statements made in  this Prospectus concerning
the contents of any  document referred to herein  are not necessarily  complete.
With  respect to each such  document filed with the  Commission as an exhibit to
the Registration Statement, reference is made to the exhibit for a more complete
description of the matter involved, and each such statement made herein shall be
deemed qualified by such reference.
 
                                       85
<PAGE>
                                    GLOSSARY
 
    The terms defined in this section are used throughout this Prospectus.
 
    ALL-IN FINDING COSTS.  The  amount of total capital expenditures,  including
acquisition  costs,  and  exploration  and abandonment  costs  for  oil  and gas
activities divided by  the amount of  proved reserves (expressed  in BOE)  added
during  the specified period (including the effect on proved reserves of reserve
revisions).
 
    BBL.  One stock tank barrel, or  42 U.S. gallons liquid volume, used  herein
in reference to crude oil or other liquid hydrocarbons.
 
    BCF.  One billion cubic feet.
 
    BOE.   Equivalent barrels of  oil. In reference to  natural gas, natural gas
equivalents are determined using the ratio of six Mcf of natural gas to one  Bbl
of crude oil, condensate or natural gas liquids.
 
    BTU.   One British thermal unit. The  quantity of heat required to raise the
temperature of one pound of water one degree Fahrenheit.
 
    DEVELOPED ACREAGE.  The number of acres which are allocated or assignable to
producing wells or wells capable of production.
 
    DEVELOPMENT WELL.  A well  drilled within the proved area  of an oil or  gas
reservoir to the depth of a stratigraphic horizon known to be productive.
 
    DRY  WELL.  A well found  to be incapable of producing  either oil or gas in
sufficient quantifies to justify completion of an oil or gas well.
 
    EBITDA.    Calculated  by  adding  interest,  income  taxes,   depreciation,
depletion  and amortization and exploration and  abandonment costs to net income
(loss).
 
    EXPLORATORY WELL.   A well  drilled to  find and produce  oil or  gas in  an
unproved  area,  to find  a  new reservoir  in a  field  previously found  to be
productive of oil or gas in another reservoir, or to extend a known reservoir.
 
    GROSS ACRES OR GROSS WELLS.  The total  acres or wells, as the case may  be,
in which a working interest is owned.
 
    MBBL.  One thousand barrels of crude oil or other liquid hydrocarbons.
 
    MBOE.  One thousand barrels of oil equivalent.
 
    MMBOE.  One million barrels of oil equivalent.
 
    MMBBLS.  One million barrels of crude oil or other liquid hydrocarbons.
 
    MMBTU.  One million Btu's.
 
    MCF.  One thousand cubic feet.
 
    MMCF.  One million cubic feet.
 
    NET  ACRES OR NET WELLS.  The  sum of the fractional working interests owned
in gross acres or gross wells.
 
    PRESENT VALUE OF ESTIMATED FUTURE NET REVENUES OR PV-10 VALUE.  The  present
value  of estimated future  net revenues is  an estimate of  future net revenues
from a property at  its acquisition date, at  a specified date, after  deducting
production  and ad valorem  taxes, future capital  costs and operating expenses,
but before deducting  federal income taxes.  The future net  revenues have  been
discounted  at an  annual rate  of 10% to  determine their  "present value." The
present value is shown to indicate the
 
                                       86
<PAGE>
effect of time on the  value of the revenue stream  and should not construed  as
being  the fair market value  of the properties. Estimates  have been made using
constant oil and natural gas prices and operating costs at the specified date.
 
    PRODUCTIVE WELL.  A  well that is  producing oil or gas  that is capable  of
production.
 
    PROVED  DEVELOPED RESERVES.   Reserves that can be  expected to be recovered
through existing wells with existing equipment and operating methods.
 
    PROVED RESERVES.   The estimated quantities  of crude oil,  natural gas  and
natural  gas  liquids which  geological  and engineering  data  demonstrate with
reasonable certainty to  be recoverable  in future years  from known  reservoirs
under existing economic and operating conditions.
 
    PROVED  UNDEVELOPED RESERVES.   Reserves that  are expected  to be recovered
from new wells on undrilled acreage,  or from existing wells where a  relatively
major expenditure is required for recompletion.
 
    ROYALTY  INTEREST.   An interest  in an oil  and gas  property entitling the
owner to a share of oil and gas production free of costs of production.
 
    3-D SEISMIC.    Advanced technology  method  of detecting  accumulations  of
hydrocarbons  identified by the collection and  measurement of the intensity and
timing of sound waves  transmitted into the  earth as they  reflect back to  the
surface.
 
    UNDEVELOPED  ACREAGE.  Lease acreage on which wells have not been drilled or
completed to a point that would  permit the production of commercial  quantities
of oil and gas regardless of whether such acreage contains proved reserves.
 
    WORKING INTEREST.  The operating interest which gives the owner the right to
drill,  produce and conduct operating activities on  the property and a share of
production.
 
                                       87
<PAGE>
                         INDEX TO FINANCIAL STATEMENTS
 
<TABLE>
<S>                                                                                    <C>
Financial Statements of Costilla Energy, L.L.C.:
  Independent Auditors' Reports......................................................        F-2
  Consolidated Balance Sheets as of December 31, 1994 and 1995, and March 31, 1996
   (unaudited).......................................................................        F-4
  Consolidated Statements of Operations for the Years Ended December 31, 1993, 1994,
   and 1995, and the Three Months ended March 31, 1995 and 1996 (unaudited)..........        F-5
  Consolidated Statements of Members' Capital for the Years Ended December 31, 1993,
   1994, and 1995, and the Three Months ended March 31, 1996 (unaudited).............        F-6
  Consolidated Statements of Cash Flows for the Years Ended December 31, 1993, 1994,
   and 1995, and the Three Months ended March 31, 1995 and 1996 (unaudited)..........        F-7
  Notes to Consolidated Financial Statements.........................................        F-8
 
Financial Statements of the 1995 Acquisition:
  Independent Auditors' Report.......................................................       F-21
  Statements of Revenues and Direct Operating Expenses for the Years Ended December
   31, 1993 and 1994 and the period ended June 12, 1995..............................       F-22
  Notes to the Statements of Revenues and Direct Operating Expenses..................       F-23
 
Financial Statements of the 1996 Acquisition:
  Independent Auditors' Report.......................................................       F-26
  Statements of Revenues and Direct Operating Expenses for the Years Ended December
   31, 1993, 1994 and 1995, and the periods ended March 31, 1995 and 1996
   (unaudited).......................................................................       F-27
  Notes to the Statements of Revenues and Direct Operating Expenses..................       F-28
</TABLE>
 
                                      F-1
<PAGE>
                          INDEPENDENT AUDITORS' REPORT
 
The Members
Costilla Energy, L.L.C. (a Texas limited liability company):
 
    We  have  audited the  accompanying consolidated  balance sheet  of Costilla
Energy, L.L.C.  (a  Texas limited  liability  company) and  subsidiaries  as  of
December  31,  1995,  and  the  related  consolidated  statement  of operations,
members' capital, and  cash flows for  the year then  ended. These  consolidated
financial  statements are  the responsibility  of the  Company's management. Our
responsibility is to express an opinion  on these financial statements based  on
our audit.
 
    We  conducted  our  audit  in accordance  with  generally  accepted auditing
standards. Those standards require that we plan and perform the audit to  obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also  includes
assessing  the  accounting principles  used  and significant  estimates  made by
management, as well as evaluating the overall financial statement  presentation.
We believe that our audit provides a reasonable basis for our opinion.
 
    In  our  opinion, the  consolidated financial  statements referred  to above
present fairly, in  all material  respects, the financial  position of  Costilla
Energy,  L.L.C. and  subsidiaries as  of December 31,  1995, and  the results of
their operations and  their cash flows  for the year  then ended, in  conformity
with generally accepted accounting principles.
 
                                                           KPMG PEAT MARWICK LLP
 
Midland, Texas
April 16, 1996 (except  with respect to matters  discussed in the last paragraph
               of Note 7 and Note 12, as to which the date is May 28, 1996.)
 
                                      F-2
<PAGE>
                          INDEPENDENT AUDITORS' REPORT
 
The Members
Costilla Energy, L.L.C.:
 
    We have  audited the  accompanying consolidated  balance sheet  of  Costilla
Energy,  L.L.C.  (a  Texas  limited  liability  company)  and  subsidiaries (the
combination of  CSL  Partners,  Costilla  Petroleum  Corporation  and  Statewide
Minerals, L.C.) as of December 31, 1994, and the related consolidated statements
of operations, members' capital, and cash flows for the years ended December 31,
1993 and 1994. These consolidated financial statements are the responsibility of
the  Company's management. Our responsibility is  to express an opinion on these
financial statements based on our audits.
 
    We conducted  our  audits in  accordance  with generally  accepted  auditing
standards. Those standards require that we plan and perform the audits to obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also  includes
assessing  the  accounting principles  used  and significant  estimates  made by
management, as well as evaluating the overall financial statement  presentation.
We believe that our audits provides a reasonable basis for our opinion.
 
    In  our  opinion, the  consolidated financial  statements referred  to above
present fairly, in all material respects, the consolidated financial position of
Costilla Energy,  L.L.C. and  subsidiaries  as of  December  31, 1994,  and  the
results  of their operations and  their cash flows for  the years ended December
31, 1993 and 1994, in conformity with generally accepted accounting principles.
 
                                          ELMS, FARIS & CO., P.C.
 
Midland, Texas
March 31, 1995
 
                                      F-3
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
                          CONSOLIDATED BALANCE SHEETS
                                 (IN THOUSANDS)
 
                                     ASSETS
<TABLE>
<CAPTION>
                                                                                              DECEMBER 31,
                                                                                            ----------------   MARCH 31,
                                                                                             1994     1995       1996
                                                                                            -------  -------  -----------
                                                                                                              (UNAUDITED)
<S>                                                                                         <C>      <C>      <C>
Current assets:
  Cash and cash equivalents...............................................................  $   137  $ 2,616    $ 2,760
  Restricted cash.........................................................................       --      250        250
  Accounts receivable:
    Trade, net............................................................................    1,042    3,154      2,401
    Affiliates............................................................................       --      507        994
    Oil and gas sales.....................................................................    1,715    3,915      4,189
  Prepaid and other current assets........................................................      223      439        800
                                                                                            -------  -------  -----------
        Total current assets..............................................................    3,117   10,881     11,394
                                                                                            -------  -------  -----------
Property, plant and equipment, at cost:
  Oil and gas properties, using the successful efforts method of accounting:
    Proved properties.....................................................................   22,794   79,897     83,965
    Unproved properties...................................................................    2,060    2,903      3,580
  Accumulated depletion, depreciation and amortization....................................   (3,562)  (9,413)   (11,281)
                                                                                            -------  -------  -----------
                                                                                             21,292   73,387     76,264
                                                                                            -------  -------  -----------
Other property and equipment, net.........................................................       76      679      1,024
Deferred charges (Note 2).................................................................       29    1,736      1,658
Note receivable -- affiliate..............................................................      390      684        684
                                                                                            -------  -------  -----------
                                                                                            $24,904  $87,367    $91,024
                                                                                            -------  -------  -----------
                                                                                            -------  -------  -----------
 
<CAPTION>
 
                              LIABILITIES, REDEEMABLE MEMBERS' CAPITAL AND MEMBERS' CAPITAL
<S>                                                                                         <C>      <C>      <C>
Current liabilities:
  Current maturities of long-term debt....................................................  $    22  $    --    $    --
  Trade accounts payable..................................................................    1,712    5,467      6,190
  Undistributed revenue...................................................................      110    1,227      1,026
  Other current liabilities...............................................................      192    1,691      2,074
                                                                                            -------  -------  -----------
        Total current liabilities.........................................................    2,036    8,385      9,290
                                                                                            -------  -------  -----------
Long-term debt, less current maturities (Note 7)..........................................   23,591   71,494     74,494
Deferred income (Note 2)..................................................................       24    3,319      3,097
Other noncurrent liabilities..............................................................       --       38         --
                                                                                            -------  -------  -----------
        Total liabilities.................................................................   25,651   83,236     86,881
                                                                                            -------  -------  -----------
Redeemable members' capital (Note 10).....................................................       --   11,320     11,678
                                                                                            -------  -------  -----------
Members' capital (Note 10)................................................................     (747)  (7,189)    (7,535)
Commitments and contingencies (Note 8)....................................................       --       --         --
                                                                                            -------  -------  -----------
                                                                                            $24,904  $87,367    $91,024
                                                                                            -------  -------  -----------
                                                                                            -------  -------  -----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-4
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
                     CONSOLIDATED STATEMENTS OF OPERATIONS
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                                THREE MONTHS ENDED
                                                                 YEARS ENDED DECEMBER 31,           MARCH 31,
                                                              -------------------------------  --------------------
                                                                1993       1994       1995       1995       1996
                                                              ---------  ---------  ---------  ---------  ---------
                                                                                                   (UNAUDITED)
<S>                                                           <C>        <C>        <C>        <C>        <C>
Revenues:
  Oil and gas sales.........................................  $   4,231  $   7,637  $  21,693  $   2,177  $   8,833
  Interest and other........................................         56         87        123          3         88
  Gain on sale of assets....................................        110        112         --         --         30
                                                              ---------  ---------  ---------  ---------  ---------
                                                                  4,397      7,836     21,816      2,180      8,951
                                                              ---------  ---------  ---------  ---------  ---------
Expenses:
  Oil and gas production....................................      1,688      2,351     10,355        896      3,659
  General and administrative................................        952      1,184      3,571        459      1,362
  Exploration and abandonments..............................        218        793      1,650      1,007        228
  Depreciation, depletion and amortization..................        884      1,847      6,095        462      1,986
  Interest..................................................        605      1,458      4,454        407      1,704
  Other.....................................................         --         --          2         --         --
                                                              ---------  ---------  ---------  ---------  ---------
                                                                  4,347      7,633     26,127      3,231      8,939
                                                              ---------  ---------  ---------  ---------  ---------
    Net income (loss) before federal income taxes...........  $      50  $     203  $  (4,311) $  (1,051)        12
Provision for federal income taxes
  Current...................................................        (25)         8          3         --         --
  Deferred..................................................          2         32         --         --         --
                                                              ---------  ---------  ---------  ---------  ---------
    Net income (loss).......................................  $      73  $     163  $  (4,314) $  (1,051) $      12
                                                              ---------  ---------  ---------  ---------  ---------
                                                              ---------  ---------  ---------  ---------  ---------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-5
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
                  CONSOLIDATED STATEMENTS OF MEMBERS' CAPITAL
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                                          MEMBERS'
                                                                                                           CAPITAL
                                                                                                         -----------
<S>                                                                                                      <C>
Balance at January 1, 1993.............................................................................   $     433
  Net income...........................................................................................          73
  Contributions........................................................................................           1
  Withdrawals..........................................................................................        (456)
                                                                                                         -----------
Balance at December 31, 1993...........................................................................          51
  Net income...........................................................................................         163
  Withdrawals..........................................................................................        (961)
                                                                                                         -----------
Balance at December 31, 1994...........................................................................        (747)
  Issuance costs (Note 10).............................................................................        (753)
  Net loss.............................................................................................      (4,314)
  Withdrawals..........................................................................................         (55)
  Preferred return on redeemable members' capital......................................................      (1,320)
                                                                                                         -----------
Balance at December 31, 1995...........................................................................      (7,189)
  Net income (unaudited)...............................................................................          12
  Preferred return on redeemable members' capital (unaudited)..........................................        (358)
                                                                                                         -----------
Balance at March 31, 1996 (unaudited)..................................................................   $  (7,535)
                                                                                                         -----------
                                                                                                         -----------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-6
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                                               THREE MONTHS ENDED
                                                                               YEARS ENDED DECEMBER 31,            MARCH 31,
                                                                           ---------------------------------  --------------------
                                                                             1993        1994        1995       1995       1996
                                                                           ---------  ----------  ----------  ---------  ---------
                                                                                                                  (UNAUDITED)
<S>                                                                        <C>        <C>         <C>         <C>        <C>
Cash flows from operating activities:
  Net income (loss)......................................................  $      73  $      163  $   (4,314) $  (1,051) $      12
  Adjustments to reconcile net income (loss) to net cash provided by
   operating activities:
    Depreciation and amortization........................................        884       1,847       5,958        462      1,986
    Amortization of deferred charges.....................................         --          --         137         --         78
    Other noncash........................................................        (21)         35         (75)       (67)       (47)
    Gain on sale of oil and gas properties...............................       (110)       (112)         --         --        (30)
    Change in operating assets and liabilities:
      Increase in accounts receivable....................................       (837)     (1,535)     (4,818)    (1,562)        (7)
      Decrease (increase) in other assets................................         20         301        (216)      (146)      (361)
      Increase in accounts payable.......................................        262         723       4,863        537        522
      Increase in other liabilities......................................         59         102       1,537         --        345
      Increase (decrease) in deferred income.............................         (8)          3       3,294         --       (222)
                                                                           ---------  ----------  ----------  ---------  ---------
        Total adjustments................................................        249       1,364      10,680       (776)     2,264
                                                                           ---------  ----------  ----------  ---------  ---------
        Net cash provided by (used in) operating activities..............        322       1,527       6,366     (1,827)     2,276
                                                                           ---------  ----------  ----------  ---------  ---------
Cash flows from investing activities:
  Capital expenditures for oil and gas properties........................     (6,634)    (11,819)    (61,500)    (1,342)    (4,749)
  Proceeds from sale of oil and gas properties...........................        131         112          --         --         --
  Additions to other property and equipment..............................       (228)        (49)       (720)       (47)      (383)
  Advances on affiliate notes receivable.................................         --        (390)       (247)        --         --
                                                                           ---------  ----------  ----------  ---------  ---------
        Net cash used in investing activities............................     (6,731)    (12,146)    (62,467)    (1,389)    (5,132)
                                                                           ---------  ----------  ----------  ---------  ---------
Cash flows from financing activities:
  Borrowings under long-term debt........................................      6,770      11,579      62,704      1,960      3,000
  Payments of long-term debt.............................................         --          --     (11,232)    (7,880)        --
  Deferred loan and financing costs......................................         --          --      (2,587)      (753)        --
  Proceeds from redeemable members' capital..............................         --          --      10,000     10,000         --
  Contributions..........................................................          1          --          --         --         --
  Withdrawals............................................................       (456)       (961)        (55)       (55)        --
                                                                           ---------  ----------  ----------  ---------  ---------
        Net cash provided by financing activities........................      6,315      10,618      58,830      3,272      3,000
                                                                           ---------  ----------  ----------  ---------  ---------
Net increase (decrease) in cash and cash equivalents.....................        (94)         (1)      2,729         56        144
Cash and cash equivalents, beginning of period...........................        232         138         137        137      2,866
                                                                           ---------  ----------  ----------  ---------  ---------
Cash and cash equivalents, end of period.................................  $     138  $      137  $    2,866  $     193  $   3,010
                                                                           ---------  ----------  ----------  ---------  ---------
                                                                           ---------  ----------  ----------  ---------  ---------
</TABLE>
 
          See accompanying notes to consolidated financial statements.
 
                                      F-7
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(1) ORGANIZATION AND NATURE OF OPERATIONS
    Costilla  Energy, L.L.C. (the "Company"), a Texas limited liability company,
was formed on  February 14,  1995, as  the successor  to CSL  Partners, a  Texas
general  partnership, which was organized on January 11, 1989. The Company is an
unincorporated association of  several individuals  and a  corporation and  will
cease  to exist thirty (30)  years from the date  of formation. Its members have
limited personal liability for the Company's obligations and debts. The  Company
is classified as a partnership for federal income tax purposes.
 
    The  Company  is an  oil  and gas  exploration  and production  concern with
properties located  principally  in  West  Texas, South  Texas,  and  the  Rocky
Mountain regions of the United States.
 
(2) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
    PRINCIPLES OF CONSOLIDATION
 
    As  of December 31, 1995, the  consolidated financial statements include the
accounts of  the  Company and  its  wholly-owned subsidiaries.  All  significant
accounts  and transactions  between the Company  and its  subsidiaries have been
eliminated. At  December 31,  1993 and  1994, the  financial statements  of  the
Company  and its affiliates were combined. Significant intercompany transactions
were eliminated.
 
    USE OF ESTIMATES
 
    Preparation  of  the  accompanying  consolidated  financial  statements   in
conformity  with generally accepted accounting principles requires management to
make estimates and assumptions  that affect the reported  amounts of assets  and
liabilities  and disclosure of contingent assets  and liabilities at the date of
the financial  statements and  the  reported amounts  of revenues  and  expenses
during the reporting period. Actual results could differ from those estimates.
 
    CASH AND CASH EQUIVALENTS
 
    For  purposes of  the statements  of cash  flows, cash  and cash equivalents
include cash on hand and depository accounts held by banks.
 
    CONCENTRATIONS OF CREDIT RISK
 
    Financial instruments that potentially expose the Company to  concentrations
of   credit  risk  consist  primarily  of  unsecured  accounts  receivable  from
unaffiliated working interest owners and crude oil and natural gas purchasers.
 
    HEDGING
 
    Premiums  paid  for  commodity  option  contracts  and  interest  rate  swap
agreements   are  amortized  to   oil  and  gas   sales  and  interest  expense,
respectively, over  the  terms  of  the  agreements.  Unamortized  premiums  are
included  in other assets in the  consolidated balance sheet. Amounts receivable
under the  commodity option  contracts  and interest  rate swap  agreements  are
accrued as an increase in oil and gas sales and a reduction of interest expense,
respectively, for the applicable periods.
 
    OIL AND GAS PROPERTIES
 
    The Company uses the successful efforts method of accounting for oil and gas
producing  activities.  Costs  to  acquire  mineral  interests  in  oil  and gas
properties, to drill and equip exploratory wells that find proved reserves,  and
to drill and equip development wells are capitalized. Costs to drill exploratory
wells  that do not  find proved reserves, geological  and geophysical costs, and
costs of carrying and retaining unproved properties are expensed.
 
    Unproved oil  and  gas  properties that  are  individually  significant  are
periodically  assessed for impairment of value, and  a loss is recognized at the
time of impairment by providing an impairment
 
                                      F-8
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(2) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
allowance. Other  unproved  properties  are amortized  based  on  the  Company's
experience  of successful drilling and average holding period. Capitalized costs
of producing oil and gas  properties, after considering estimated  dismantlement
and abandonment costs and estimated salvage values, are depreciated and depleted
by  the  unit-of-production method.  Support  equipment and  other  property and
equipment are depreciated over their estimated useful lives.
 
    On sale or retirement of a complete unit of a proved property, the cost  and
related  accumulated  depreciation, depletion,  and amortization  are eliminated
from the property  accounts, and the  resultant gain or  loss is recognized.  On
retirement  or sale of a partial unit of proved property, the cost is charged to
accumulated depreciation, depletion, and amortization  with a resulting gain  or
loss recognized in income.
 
    On  sale of  an entire  interest in  an unproved  property for  cash or cash
equivalent, gain or loss  on the sale is  recognized, taking into  consideration
the  amount  of  any  recorded  impairment if  the  property  had  been assessed
individually. If a partial interest in an unproved property is sold, the  amount
received is treated as a reduction of the cost of the interest retained.
 
    IMPAIRMENT OF LONG-LIVED ASSETS
 
    As  of January 1, 1995,  the Company adopted the  provisions of Statement of
Financial Accounting  Standards No.  121  -- ACCOUNTING  FOR THE  IMPAIRMENT  OF
LONG-LIVED  ASSETS  AND FOR  LONG-LIVED ASSETS  TO BE  DISPOSED OF  ("FAS 121").
Consequently, the Company  reviews its long-lived  assets to be  held and  used,
including  oil and  gas properties  accounted for  under the  successful efforts
method of  accounting,  whenever  events  or  circumstances  indicate  that  the
carrying  value of those  assets may not  be recoverable. An  impairment loss is
indicated if the sum of the expected future cash flows is less than the carrying
amount of the assets. In this circumstance, the Company recognizes an impairment
loss for the amount by which the  carrying amount of the asset exceeds the  fair
value of the asset.
 
    DEFERRED CHARGES
 
    The  Company capitalized certain costs incurred in connection with obtaining
the Credit Agreement and  the related revolver  and term notes  (see Note 7  for
definitions  and descriptions of each). These costs are being amortized over the
lives of the notes.
 
    DEFERRED INCOME
 
    In November 1995, the Company entered  into gas sales agreements whereby  it
committed  to delivery  of a  total of  2,379,000 Mmbtu,  from December  1, 1995
through December 1, 1996, for a total fixed price of $3,429,610. Income from the
agreements is recognized in the period of delivery.
 
    REVENUE RECOGNITION
 
    The Company uses the production method of accounting for crude oil revenues.
To the extent  that crude oil  is produced but  not sold, the  oil in tanks,  if
material,  is recorded as  inventory in the  accompanying consolidated financial
statements.
 
    The Company uses  the sales method  of accounting for  natural gas  revenues
adjusted  for  over and  under produced  amounts  associated with  gas balancing
arrangements. Under this method, revenues are recognized based on actual volumes
of gas sold to purchasers.
 
    Deferred income  associated  with gas  balancing  is accounted  for  on  the
entitlements  method  and represents  amounts received  for  gas sold  under gas
balancing agreements in excess of the Company's
 
                                      F-9
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(2) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
interest in properties covered by such  agreements. The Company had $157,785  of
deferred income associated with gas balancing at December 31, 1995. There was no
significant deferred income at December 31, 1994.
 
    ENVIRONMENTAL
 
    The  Company is subject to extensive  Federal, state and local environmental
laws and regulations. These  laws, which are  constantly changing, regulate  the
discharge  of  materials into  the environment  and may  require the  Company to
remove or  mitigate the  environmental effects  of the  disposal or  release  of
petroleum  or chemical  substances at various  sites. Environmental expenditures
are  expensed  or  capitalized  depending  on  their  future  economic  benefit.
Expenditures  that relate to an existing condition caused by past operations and
that have no future economic benefits are expensed. Liabilities for expenditures
of a  noncapital  nature are  recorded  when environmental  assessment  and/  or
remediation is probable, and the costs can be reasonably estimated.
 
    RECLASSIFICATIONS
 
    Certain  reclassifications have  been made  to the  1993 and  1994 financial
statements to conform to the 1995 presentation.
 
    INTERIM FINANCIAL STATEMENTS
 
    The interim financial information  as of March 31,  1996, and for the  three
months  ended March 31, 1995 and 1996,  is unaudited. However, in the opinion of
management,  these  interim  financial  statements  include  all  the  necessary
adjustments  to fairly present the  results of the interim  periods and all such
adjustments are of a normal  recurring nature. The interim financial  statements
should  be read  in conjunction  with the  audited financial  statements for the
years ended December 31, 1993, 1994 and 1995.
 
(3) ACQUISITION OF OIL AND GAS PROPERTIES
    On June 12, 1995, the Company  completed the acquisition of certain oil  and
gas  properties and  related assets from  Parker & Parsley  Development L.P. and
Parker &  Parsley  Producing  L.P.  for  $46,621,371.  The  Company  funded  the
acquisition  under the  Credit Agreement described  in Note (7).  Certain of the
acquired properties,  which  were located  outside  of the  Company's  areas  of
strategic focus, were sold in 1995. No gain or loss was recorded on these sales.
 
(4) IMPAIRMENT OF LONG-LIVED ASSETS
    The  Company  adopted FAS  121  effective as  of  January 1,  1995.  FAS 121
requires that long-lived assets  held and used by  an entity, including oil  and
gas  properties accounted for under the successful efforts method of accounting,
be reviewed for impairment whenever events or changes in circumstances  indicate
that  the carrying amount of an asset  may not be recoverable. Long-lived assets
to be disposed of  are to be accounted  for at the lower  of carrying amount  or
fair  value less cost to sell when management has committed to a plan to dispose
of  the  assets.  All  companies,  including  successful  efforts  oil  and  gas
companies,  are  required to  adopt  FAS 121  for  fiscal years  beginning after
December 15, 1995.
 
    In order  to  determine whether  an  impairment had  occurred,  the  Company
estimated  the expected  future cash  flows of  its oil  and gas  properties and
compared such  future cash  flows to  the carrying  amount of  the oil  and  gas
properties  to determine if  the carrying amount was  recoverable. Based on this
process, no writedown in the carrying amount of the Company's proved  properties
was necessary at December 31, 1995.
 
                                      F-10
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(5) DERIVATIVE FINANCIAL INSTRUMENTS
    The Company utilizes derivative financial instruments to manage well-defined
interest rate and commodity price risks. The Company is exposed to credit losses
in  the event of nonperformance by the  counterparties to its interest rate swap
agreements and its commodity hedges. The Company anticipates, however, that such
counterparties will  be  able  to  fully satisfy  their  obligations  under  the
contracts.  The Company does not obtain  collateral or other security to support
financial instruments subject to credit risk but monitors the credit standing of
the counterparties.
 
    COMMODITY HEDGES.  The Company utilizes option contracts to hedge the effect
of price changes  on future  oil and gas  production. The  following table  sets
forth the future volumes hedged by year and the weighted-average strike price of
the option contracts at December 31, 1995:
 
<TABLE>
<CAPTION>
                                                           OIL          GAS
                                                         VOLUME       VOLUME         STRIKE PRICE
                                                         (BBLS)       (MMBTU)        PER BBL/MMBTU
                                                       -----------  -----------  ---------------------
<S>                                                    <C>          <C>          <C>
Oil:
  1996...............................................    1,830,000           --   $16.00 - $20.38(a)
  1997...............................................      912,500           --   $16.00 - $20.65(a)
Gas:
  1996...............................................           --    1,500,000        $1.65(b)
  1997...............................................           --    1,350,000        $1.65(b)
</TABLE>
 
- ------------------------
(a) Represents  the  weighted-average  price  of  collars  established  with the
    purchase of put option contracts and the sale of call option contracts.
 
(b) Represents the strike price on purchased put option contracts.
 
    INTEREST RATE  SWAP AGREEMENTS.   The  Company utilizes  interest rate  swap
agreements  to reduce  the potential  impact of  increases in  interest rates on
floating-rate, long-term debt. At December 31, 1995, the Company was a party  to
two  interest rate swap agreements, providing  the Company with a fixed interest
rate for the terms of the agreements. The following table sets forth the  terms,
fixed  rates, and notional amounts of the agreements in place as of December 31,
1995:
 
<TABLE>
<CAPTION>
                                        NOTIONAL
                                        PRINCIPAL                 FIXED
                TERM                     AMOUNT               INTEREST RATE
- ------------------------------------  -------------  -------------------------------
<S>                                   <C>            <C>
Jan. 25, 1996 to Jan. 25, 1999         $24 million      ranging from 7.5% to 8.5%
May 24, 1995 to May 27, 1997           $60 million                5.99%
</TABLE>
 
                                      F-11
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(6) FAIR VALUE OF FINANCIAL INSTRUMENTS
    The following table presents the carrying amounts and estimated fair  values
of  the  Company's financial  instruments at  December 31,  1994 and  1995. FASB
Statement No.  107,  DISCLOSURES  ABOUT FAIR  VALUE  OF  FINANCIAL  INSTRUMENTS,
defines  the fair  value of a  financial instrument  as the amount  at which the
instrument could be exchanged in a current transaction between willing parties.
 
<TABLE>
<CAPTION>
                                                                             1994                  1995
                                                                     --------------------  --------------------
                                                                     CARRYING     FAIR     CARRYING     FAIR
                                                                      AMOUNT      VALUE     AMOUNT      VALUE
                                                                     ---------  ---------  ---------  ---------
<S>                                                                  <C>        <C>        <C>        <C>
                                                                                  ($ IN THOUSANDS)
Financial assets:
  Cash, cash equivalents and restricted cash.......................  $     137  $     137  $   2,866  $   2,866
  Receivables (trade)..............................................      1,042      1,042      3,154      3,154
  Receivables (oil and gas sales)..................................      1,715      1,715      3,915      3,915
  Commodity option contracts.......................................         --         --        165        555
  Interest rate swap and option agreements.........................        203         --        146     (2,970)
  Notes receivable -- affiliate....................................        390        390        684        684
Financial liabilities:
  Payables (trade).................................................      1,712      1,712      5,467      5,467
  Deferred income..................................................         --         --      3,319      2,950
  Long-term debt...................................................     23,613     23,613     71,494     71,494
</TABLE>
 
    The carrying amounts  shown in the  table are included  in the statement  of
financial position under the indicated captions.
 
    The  following methods and assumptions were  used to estimate the fair value
of each class of financial instruments:
 
    CASH,  TRADE  RECEIVABLES,  AND  TRADE  PAYABLES:    The  carrying   amounts
approximate fair value because of the short maturity of those instruments.
 
    OTHER  CURRENT ASSETS:  The amounts  reported relate to the commodity option
contracts and interest rate  swap agreements described in  Note 5. The  carrying
amount comprises the unamortized premiums paid for the contracts. The fair value
is  estimated using option  pricing models and  essentially values the potential
for the  contracts and  agreements  to become  in-the-money through  changes  in
commodity prices and interest rates during the remaining terms.
 
    NOTES RECEIVABLE-AFFILIATE:  The amounts reported relate to notes receivable
from  an affiliated company. The carrying amount approximates fair value because
the rate given  to the affiliate  company is not  materially different from  the
affiliate company's bank debt.
 
    DEFERRED INCOME:  The amounts reported relate to the gas purchase agreements
described  in Note 2. The carrying amount represents the payments received under
the agreements for  which subsequent  delivery is  required. The  fair value  is
estimated  based upon the  commodity price at  December 31, 1995,  for a similar
agreement.
 
    LONG-TERM DEBT:  The fair value of the Company's long-term debt is estimated
by discounting expected cash flows at the rates currently offered to the Company
for debt of the same remaining maturities, as advised by the Company's bankers.
 
                                      F-12
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(7) LONG-TERM DEBT
    Long-term debt consists of the following (in thousands):
 
<TABLE>
<CAPTION>
                                                                             DECEMBER 31,
                                                                         --------------------
                                                                           1994       1995
                                                                         ---------  ---------
<S>                                                                      <C>        <C>
Revolver note..........................................................  $      --  $  59,824
Term notes.............................................................         --     11,670
Note payable to bank...................................................     23,591         --
Note payable to member.................................................         22         --
                                                                         ---------  ---------
                                                                            23,613     71,494
    Less current maturities............................................         22         --
                                                                         ---------  ---------
                                                                         $  23,591  $  71,494
                                                                         ---------  ---------
                                                                         ---------  ---------
</TABLE>
 
    At December  31, 1995,  the  Company and  certain  of its  subsidiaries  are
parties  to a  Credit Agreement  with a  syndicate of  banks (the  "Banks"). The
Credit Agreement provides for an aggregate $185 million senior secured revolving
line of credit  ("Revolver Notes")  and an aggregate  of $15  million in  senior
secured  term notes ("Term Notes"). All notes are secured with the assets of the
Company and  are guaranteed  by the  Company's subsidiaries  and, to  a  limited
extent, its individual members.
 
    The  Revolver Notes  and Term  Notes are  subject to  an aggregate borrowing
base, as determined by the Banks or their agents in their sole discretion and is
redetermined at least bi-annually  as of January 15  and July 15, utilizing  oil
and  gas reserve information as  of the immediately preceding  period end. As of
January 15, 1996, the borrowing base was $71,670,000.
 
    All outstanding balances under  the Credit Agreement  may be designated,  at
the  Company's option, as  either "Base Rate Portions"  or "Fixed Rate Portions"
(both as  defined in  the Credit  Agreement), provided  that no  more than  five
Eurodollar  Tranches may be outstanding  at any time. The  Base Rate Portions of
the Revolver Notes bear interest at  the fluctuating Base Rate, plus a  Revolver
Base  Rate Spread  ranging from 0.25%  to 0.75%, depending  upon the outstanding
principal balances of the Term Notes. The  Base Rate Portions of the Term  Notes
bear  interest at the fluctuating Base Rate  plus 0.75%. The Fixed Rate Portions
of the Revolver Notes bear interest at the Eurodollar Rate for a fixed period of
time elected by  the Company,  plus a Revolver  Fixed Rate  Spread ranging  from
2.25%  to 3.00%,  depending on  the outstanding  principal balances  of the Term
Notes. The Fixed Rate Portions of the Term Notes bear interest at the Eurodollar
Rate for a fixed period of time elected by the Company, plus a Fixed Rate Spread
of 3.00%. As of December 31, 1995, the Company had elected a fixed rate of 8.82%
for the Revolver Notes and had elected  fixed rates ranging from 8.82% to  8.94%
for  $14,000,000  of  the  outstanding  Term Notes  at  December  31,  1995. The
remaining balances  of  the  Term  Notes  bear interest  at  the  Base  Rate  of
NationsBank Prime plus 1.50% at December 31, 1995.
 
    The  outstanding principal balance of the  Revolver Notes is due and payable
in sixty  (60) monthly  installments beginning  August 1,  1996, and  continuing
regularly  thereafter until July  1, 2001. The  outstanding principal balance of
the Term Notes is due and payable  in two (2) installments, each of which  shall
be  equal to one-half of  the unpaid principal balance of  each note, on July 1,
1996, and January 1, 1997.
 
    The Credit Agreement requires the Company to hedge not less than 60% of  the
Company's  total  sales  volume,  through December  31,  1997,  from  its proved
developed producing oil and gas  reserves, with a floor  price of not less  than
$16 per Bbl of oil or $1.50 per Mcf of gas.
 
                                      F-13
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(7) LONG-TERM DEBT (CONTINUED)
    Additionally,  the Credit  Agreement contains  various restrictive covenants
and compliance requirements,  which include: (a)  restrictions on dividends  and
the  incurrence of additional indebtedness; (b)  restrictions as to merger, sale
or transfer of  assets; (c) limiting  total lease payments  and total  aggregate
executive  compensation to  $750,000 and  $500,000, respectively,  in any fiscal
year; and (d) compliance with certain financial ratios.
 
    The  Company  was   in  violation  of   certain  covenants  and   compliance
requirements  as of  December 31,  1995. Subsequent  to December  31, 1995, such
violations were waived by the Banks.
 
    Maturities of  long-term debt  at  December 31,  1995,  are as  follows  (in
thousands):
 
<TABLE>
<S>                                                         <C>
1996......................................................  $  10,820
1997......................................................     17,800
1998......................................................     11,965
1999......................................................     11,965
2000......................................................     11,965
Thereafter................................................      6,979
</TABLE>
 
    The  Company paid  interest on  long-term debt  of $546,147,  $1,356,604 and
$4,453,684 in 1993, 1994 and 1995, respectively.
 
    As described in Note 12,  on June 10, 1996, the  Company entered into a  new
loan agreement, proceeds of which were used to repay the existing notes.
 
(8) COMMITMENTS AND CONTINGENCIES
 
    LEASES
 
    The Company leases equipment and office facilities under operating leases on
which  rental expense for the years ended  December 31, 1993, 1994 and 1995, was
$110,023, $197,533 and $311,221, respectively. Future minimum lease  commitments
under  noncancellable operating leases at December  31, 1995, are as follows (in
thousands):
 
<TABLE>
<S>                                                          <C>
1996.......................................................  $     257
1997.......................................................        272
1998.......................................................        268
1999.......................................................        195
2000.......................................................        188
Thereafter.................................................      1,190
</TABLE>
 
    SEVERANCE AGREEMENTS
 
    On February 17, 1995,  the Company entered  into employment agreements  with
each  of the officers which  are effective from the  above date through February
17, 2000, or  until terminated by  the officer  or the Company.  In addition  to
providing  a  base salary  and nominal  yearly increases  for each  officer, the
employment agreements provide  for severance  payments upon  termination of  any
such officer's employment or a significant reduction in that officer's duties or
responsibilities.
 
    In  the event  of such a  termination, the  Company is obligated  to pay the
officer an  amount  equal  to the  present  value  (discounted at  10%)  of  the
officer's  salary  which would  have been  paid through  February 17,  2000. The
current annual  base salaries  for the  officers covered  under such  employment
agreements total approximately $500,000.
 
    EXPLORATION AND DEVELOPMENT
 
    On July 6, 1995, the Company, entered into an agreement with an unaffiliated
third  party which  had previously  obtained a  concession from  the Republic of
Moldova whereby the Company committed to  develop several oil and gas fields  in
the   Republic   of   Moldova,   commencing   in   1995,   and   embark   on   a
 
                                      F-14
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(8) COMMITMENTS AND CONTINGENCIES (CONTINUED)
multi-year 400 kilometer seismic survey, beginning in 1996, in exchange for  the
exclusive  right  to develop  and explore  for oil  and gas  in the  Republic of
Moldova. Through  December  31,  1995,  the Company  has  incurred  $214,178  in
connection with these activities.
 
    LETTERS OF CREDIT
 
    As  a result of certain bonding and trade creditor requirements, the Company
has caused  irrevocable  letters of  credit  to be  issued  by a  bank  totaling
$106,000. As of December 31, 1995, no amounts had been drawn on these letters of
credit.
 
(9) 401(K) PLAN
    The  Company has established a qualified  cash or deferred arrangement under
IRS code section 401(k)  covering substantially all  employees. Under the  plan,
the  employees have  an option  to make elective  contributions of  a portion of
their eligible compensation, not to exceed specified annual limitations, to  the
plan  and the  Company has  an option  to match  a percentage  of the employee's
contribution. The Company has made  matching contributions to the plan  totaling
$16,950, $8,921 and $22,531 in 1993, 1994 and 1995, respectively.
 
(10) REDEEMABLE MEMBERS' CAPITAL AND MEMBERS' CAPITAL
    During  1995,  NationsBank  Capital  Corporation  ("NBCC")  contributed  $10
million in exchange for  a 30% ownership interest  in the Company including  the
preferential return described below. The Company incurred $751,737 in legal fees
and  broker's commissions in connection with this transaction and recorded these
costs as direct charges to members' capital in 1995.
 
    Redeemable members' capital is subject to  a preferential return of 15%  per
annum  and  is redeemable  at any  time at  the Company's  option, subject  to a
redemption premium as described below, or at NBCC's option on February 17,  2003
or  at an earlier date  upon occurrence of certain  events including a change in
control, certain changes in  management, a change in  the Company's status as  a
limited liability company for tax purposes, or violation of any of various other
restrictive  provisions contained in the  Regulations of Costilla Energy, L.L.C.
(the "Regulations").  The 15%  preferred return  is treated  as a  reduction  of
members'  capital. The redemption price to be paid by the Company shall be equal
to the  initial  amount  received  for  the  preferred  units  plus  a  premium,
determined in the year the units are purchased, as follows:
 
<TABLE>
<CAPTION>
      YEAR AFTER            PREMIUM
   FEBRUARY 17, 1995      PERCENTAGE
- -----------------------  -------------
<S>                      <C>
               1                  10%
               2                  10%
               3                   8%
               4                   6%
               5                   4%
               6                   2%
               7                   0%
               8                   0%
</TABLE>
 
    NBCC's 30% members' interest may be repurchased by the Company to the extent
the Company has exercised its right to redeem all or a portion of the redeemable
members'  capital or  the Company  may be  required to  purchase NBCC's members'
capital upon the occurrence of certain events similar
 
                                      F-15
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(10) REDEEMABLE MEMBERS' CAPITAL AND MEMBERS' CAPITAL (CONTINUED)
to  those  events  requiring  redemption  of  the  redeemable  members'  capital
described  above, but not  on any specified  date in the  future. The redemption
price the Company  would pay is  determined by  the year in  which the  members'
capital is repurchased, as follows:
 
<TABLE>
<CAPTION>
                                                                       AGGREGATE
BEFORE FEBRUARY 17                                                  REDEMPTION PRICE
- ------------------------------------------------------------------  ----------------
<S>                                                                 <C>
1996..............................................................   $            1
1997..............................................................        1,500,000
1998..............................................................        3,000,000
1999..............................................................        4,500,000
2000..............................................................        5,500,000
</TABLE>
 
    At  December 31, 1995,  the Company was in  violation of various restrictive
provisions of the Regulations. Subsequent to December 31, 1995, NBCC waived such
violations.
 
(11) RELATED PARTY TRANSACTIONS
    Certain members  and officers  of  the Company  own  interests in  and  hold
positions  with  A&P  Meter Service  and  Supply, Inc.  ("A&P"),  CSL Management
Corporation ("CSL"),  511 Tex  L.C.  ("511 Tex")  and Valley  Gathering  Company
("Valley").
 
    Advances  from the Company to A&P have been consolidated into two promissory
notes. The first note, which was  originally executed December 31, 1994,  totals
$390,000,  including accrued interest of $20,000  at December 31, 1995. The note
bears interest  at a  floating rate  equal to  the "prime  rate" plus  1.0%.  No
principal  or  interest payments  are  due until  the  maturity of  the  note at
December 31,  2004. The  note is  secured by  a second  lien on  A&P's  accounts
receivable,  inventory  and  equipment. The  second  note  is in  the  amount of
$294,000, including accrued interest of $47,000, and is dated May 22, 1996.  The
note  bears interest at 6.0% per annum, is unsecured and is payable upon demand.
During 1995, the Company paid $612,139 to A&P for goods and services provided.
 
    During 1993,  1994  and  1995,  the  Company  paid  $312,623,  $549,620  and
$592,920,  respectively,  to  CSL  for management  fees  and  lease  payments on
equipment.
 
    During 1995, the Company paid $67,896 to 511 Tex for office rent.
 
    During 1994 and 1995, the Company paid $2,458 and $440,884, respectively, to
Valley for gas compression and salt water disposal charges. During 1995,  Valley
paid  the Company $109,399 for operating costs  of its salt water disposal wells
and gas compressors.
 
(12) SUBSEQUENT EVENTS
    On March 8, 1996,  the Company executed a  Purchase and Sale Agreement  with
Parker  and Parsley Petroleum Company to  acquire certain oil and gas properties
for an  estimated adjusted  purchase  price of  approximately $40  million.  The
properties are located primarily in south and west Texas. The acquisition closed
on June 14, 1996.
 
    In  connection  with the  foregoing,  the Company  entered  into a  new loan
agreement with  NationsBridge  L.L.C., an  affiliate  of the  Company's  current
lender,  to provide financing of  up to $125 million  in advances (the "Loans"),
subject to certain terms and conditions. Proceeds of the Loans were used to fund
the Acquisition, to  refinance substantially  all of  the Company's  outstanding
indebtedness, and for other general corporate purposes.
 
    Advances  under the Loans were to be made  in two portions, Tranche A was up
to $95,000,000  and  Tranche  B  was  $30,000,000.  Tranche  A  initially  bears
interest,  at the Company's option, at  the applicable prime rate ("Prime") plus
0.75% or LIBOR plus 3.0%. Each margin  above Prime and LIBOR increases by  0.50%
at  the  end  of  each  successive  three-month  period,  up  to  a  maximum  of
 
                                      F-16
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(12) SUBSEQUENT EVENTS (CONTINUED)
2.75% and 5.0%  for Prime  and LIBOR,  respectively. Tranche  B initially  bears
interest  at 14.00% per  annum, increasing 0.50%  at the end  of each successive
three-month period, up to a maximum of 16.5%.
 
    Tranche A loans are subject to  a borrowing base determination. The  initial
borrowing  base is $95,000,000 which is  automatically reduced by $3,000,000 per
quarter beginning  January  1, 1997.  The  borrowing  base is  also  subject  to
periodic  redetermination by NationsBridge L.L.C.  based on its determination of
the collateral value of the Company's oil and gas properties. Final maturity  of
loans made under Tranches A and B is June 10, 1999.
 
    The  Loans are  secured by  first priority  liens, assignments  and security
interests in all oil and gas properties, pipelines and gathering systems of  the
Company  and stock  of the Company's  subsidiaries. Additionally,  the Loans are
subject to various restrictive covenants and compliance requirements,  including
but  not  limited  to  (a)  restrictions  on  dividends  and  the  incurrence of
additional indebtedness, (b) minimum limitations on the Company's current  ratio
and  tangible net  worth, (c) limitations  on payments for  leases and executive
compensation, (d) maximum  limitations on general  and administrative  expenses,
capital  expenditures and the Company's ratio of debt to adjusted cash flow, and
(e) a requirement to pay to the lender all net oil and gas revenues (as  defined
and as adjusted for capital expenditures) on a quarterly basis.
 
    The Company paid the lender's fees and expenses in connection with obtaining
the  Loans.  The fees  were  approximately $2,625,000  and  will increase  by an
additional $625,000 if the Tranche B  Loans remain outstanding for more than  90
days.  In addition, if the Tranche B amounts  are not repaid within one year, an
additional amount of $4,800,000 will accrue.
 
(13) OIL AND GAS EXPENDITURES
    The following  table  reflects  costs  incurred  in  oil  and  gas  property
acquisition, exploration and development activities:
 
<TABLE>
<CAPTION>
                                                                     YEARS ENDED DECEMBER 31,       THREE MONTHS
                                                                  -------------------------------  ENDED MARCH 31,
                                                                    1993       1994       1995          1996
                                                                  ---------  ---------  ---------  ---------------
<S>                                                               <C>        <C>        <C>        <C>
                                                                          (IN THOUSANDS)
Property acquisition costs:
  Proved........................................................  $   4,665  $   9,649  $  52,470     $   2,246
  Unproved......................................................        829      1,232      1,742           677
Exploration.....................................................      2,017      2,167      5,627         1,822
Development.....................................................         --         --        158           232
                                                                  ---------  ---------  ---------       -------
                                                                  $   7,511  $  13,048  $  59,997     $   4,977
                                                                  ---------  ---------  ---------       -------
                                                                  ---------  ---------  ---------       -------
</TABLE>
 
(14) SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (UNAUDITED)
    The  estimates of proved oil and gas reserves, which are located principally
in the United States, were prepared by the Company as of December 31, 1993, 1994
and 1995, and Williamson  Petroleum Consultants as of  March 31, 1996.  Reserves
were  estimated in  accordance with guidelines  established by the  SEC and FASB
which require that  reserve estimates  be prepared under  existing economic  and
operating conditions with no provision for price and cost escalations, except by
contractual  arrangements.  The  Company  has  presented  the  reserve estimates
utilizing an oil price of $17.79 per Bbl and a gas price of $2.03 per Mcf as  of
December  31, 1995, and an oil price of $20.71  per Bbl and a gas price of $2.00
per Mcf as of March 31, 1996.
 
                                      F-17
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                         NOTES TO FINANCIAL STATEMENTS
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(14) SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (UNAUDITED)
 
    OIL AND GAS PRODUCING ACTIVITIES
 
    Oil and gas reserve quantity estimates are subject to numerous uncertainties
inherent  in  the  estimation  of  quantities  of  proved  reserves  and  in the
projection  of  future  rates  of  production  and  the  timing  of  development
expenditures.  The accuracy of  such estimates is  a function of  the quality of
available data and  of engineering and  geological interpretation and  judgment.
Results  of subsequent drilling, testing and  production may cause either upward
or downward revision of previous  estimates. Further, the volumes considered  to
be  commercially  recoverable fluctuate  with  changes in  prices  and operating
costs. The Company  emphasizes that reserve  estimates are inherently  imprecise
and that estimates of new discoveries are more imprecise than those of currently
producing  oil and gas properties. Accordingly,  these estimates are expected to
change as additional information becomes available in the future.
 
<TABLE>
<CAPTION>
                                                                                 OIL AND CONDENSATE       GAS
                                                                                       (MBBLS)          (MMCF)
                                                                                 -------------------  -----------
<S>                                                                              <C>                  <C>
Total Proved Reserves:
Balance, January 1, 1993.......................................................           1,985           16,418
  Revisions of previous estimates..............................................              57            1,160
  Extensions and discoveries...................................................             380              591
  Production...................................................................            (158)            (865)
  Purchases of minerals-in-place...............................................             101            4,315
                                                                                        -------       -----------
Balance, December 31, 1993.....................................................           2,365           21,619
  Revisions of previous estimates..............................................            (460)          (5,424)
  Extensions and discoveries...................................................             761            1,520
  Production...................................................................            (330)          (1,600)
  Purchases of minerals-in-place...............................................           1,673           11,397
                                                                                        -------       -----------
Balance, December 31, 1994.....................................................           4,009           27,512
  Revisions of previous estimates..............................................            (570)             425
  Extensions and discoveries...................................................             605            8,922
  Production...................................................................            (950)          (4,806)
  Purchases of minerals-in-place...............................................           7,694           46,099
                                                                                        -------       -----------
Balance, December 31, 1995.....................................................          10,788           78,152
  Revisions of previous estimates..............................................             437            2,615
  Extensions and discoveries...................................................             592              296
  Production...................................................................            (338)          (1,643)
  Purchases of minerals-in-place...............................................              --               --
                                                                                        -------       -----------
Balance, March 31, 1996........................................................          11,479           79,420
                                                                                        -------       -----------
                                                                                        -------       -----------
Proved Developed Reserves:
  January 1, 1993..............................................................           1,488           10,055
  December 31, 1993............................................................           1,785           13,268
  December 31, 1994............................................................           2,632           16,340
  December 31, 1995............................................................           8,566           57,393
  March 31, 1996...............................................................           9,037           55,408
</TABLE>
 
                                      F-18
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                         NOTES TO FINANCIAL STATEMENTS
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(14) SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (UNAUDITED) (CONTINUED)
 
    STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS RELATING TO PROVED
OIL AND GAS RESERVES
 
    The standardized measure of discounted future net cash flows is computed  by
applying  year-end prices  of oil and  gas (with consideration  of price changes
only to the extent provided by contractual arrangements) to the estimated future
production of proved oil  and gas reserves,  less estimated future  expenditures
(based  on year-end costs) to be incurred in developing and producing the proved
reserves, less estimated future income tax expenses (based on year-end statutory
tax rates, with  consideration of  future tax  rates already  legislated) to  be
incurred  on  pretax  net cash  flows,  less  tax basis  of  the  properties and
available credits, and  assuming continuation of  existing economic  conditions.
The  estimated future net cash flows are then discounted using a rate of 10% per
year to reflect the estimated timing of the future cash flows.
 
    Discounted future  cash  flow  estimates  like those  shown  below  are  not
intended  to represent estimates  of the fair  value of oil  and gas properties.
Estimates of  fair value  should also  consider probable  reserves,  anticipated
future oil and gas prices, interest rates, changes in development and production
costs  and risks associated  with future production. Because  of these and other
considerations, any  estimate  of  fair  value  is  necessarily  subjective  and
imprecise.
 
<TABLE>
<CAPTION>
                                                                                                   THREE MONTHS
                                                                 YEARS ENDED DECEMBER 31,         ENDED MARCH 31,
                                                           -------------------------------------  ---------------
                                                              1993        1994          1995           1996
                                                           ----------  -----------  ------------  ---------------
                                                                               (IN THOUSANDS)
<S>                                                        <C>         <C>          <C>           <C>
Future cash flows........................................  $   83,510  $   122,098  $    350,653   $     396,919
Future costs:
  Production.............................................     (31,811)     (46,345)     (145,510)       (162,146)
  Development............................................      (4,486)      (7,157)      (16,806)        (17,975)
                                                           ----------  -----------  ------------  ---------------
Future net cash flows....................................      47,213       68,596       188,337         216,798
10% annual discount for estimated timing of cash flows...     (20,836)     (31,817)      (75,041)        (87,707)
                                                           ----------  -----------  ------------  ---------------
Standardized measure of discounted net cash flows........  $   26,377  $    36,779  $    113,296   $     129,091
                                                           ----------  -----------  ------------  ---------------
                                                           ----------  -----------  ------------  ---------------
</TABLE>
 
                                      F-19
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                         NOTES TO FINANCIAL STATEMENTS
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(14) SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (UNAUDITED) (CONTINUED)
 
    CHANGES IN STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS FROM
PROVED RESERVES
 
<TABLE>
<CAPTION>
                                                                                                  THREE MONTHS
                                                                  YEARS ENDED DECEMBER 31,       ENDED MARCH 31,
                                                              ---------------------------------  ---------------
                                                                1993       1994        1995           1996
                                                              ---------  ---------  -----------  ---------------
                                                                                (IN THOUSANDS)
<S>                                                           <C>        <C>        <C>          <C>
Increase (decrease):
  Purchase of minerals-in-place.............................  $   3,732  $  15,231  $    77,343    $        --
  Extensions and discoveries and improved recovery, net of
   future production and development costs..................      2,707      4,072        9,799          6,002
  Accretion of discount.....................................      2,056      2,638        3,678          2,832
  Net change in sales prices, net of production costs.......       (209)       503       (3,422)         9,229
  Changes in estimated future development costs.............        (16)       940       (2,419)          (235)
  Revisions of quantity estimates...........................      1,203     (7,248)      (2,855)         4,839
  Sales, net of production costs............................     (2,543)    (5,286)     (11,338)        (5,174)
  Changes of production rates (timing) and other............     (1,114)      (448)       5,731         (1,698)
                                                              ---------  ---------  -----------  ---------------
    Net increase............................................      5,816     10,402       76,517         15,795
Standardized measure of discounted future net cash flows:
    Beginning of period.....................................     20,561     26,377       36,779        113,296
                                                              ---------  ---------  -----------  ---------------
    End of period...........................................  $  26,377  $  36,779  $   113,296    $   129,091
                                                              ---------  ---------  -----------  ---------------
                                                              ---------  ---------  -----------  ---------------
</TABLE>
 
    The  1995  future cash  flows shown  above  include amounts  attributable to
proved undeveloped  reserves requiring  approximately  $15.0 million  of  future
development costs. If these reserves are not developed, the standardized measure
of  discounted future net  cash flows for  1995 shown above  would be reduced by
approximately $22.4 million.
 
                                      F-20
<PAGE>
                          INDEPENDENT AUDITORS' REPORT
 
The Members
Costilla Energy, L.L.C.:
 
    We have audited the accompanying statements of revenues and direct operating
expenses of the 1995 Acquisition (see Note  1) for the years ended December  31,
1993  and 1994,  and the period  ended June  12, 1995. These  statements are the
responsibility of the Company's management. Our responsibility is to express  an
opinion on these statements based on our audits.
 
    We  conducted  our audits  in  accordance with  generally  accepted auditing
standards. Those standards require that we plan and perform the audit to  obtain
reasonable  assurance  about  whether  the  statements  of  revenues  and direct
operating  expenses  are  free  of  material  misstatement.  An  audit  includes
examining,  on a test basis, evidence  supporting the amounts and disclosures in
the financial  statements.  An  audit also  includes  assessing  the  accounting
principles  used  and  significant  estimates made  by  management,  as  well as
evaluating the  overall  statement  presentation. We  believe  that  our  audits
provide a reasonable basis for our opinion.
 
    The  accompanying statements of revenues  and direct operating expenses were
prepared for the  purpose of  complying with the  rules and  regulations of  the
Securities  and  Exchange Commission  (for inclusion  in  Forms S-1  of Costilla
Energy, Inc. as  described in  Note 1)  and are not  intended to  be a  complete
presentation of the 1995 Acquisition interests' revenue and expenses.
 
    In  our opinion,  the statements of  revenues and  direct operating expenses
referred to above  present fairly, in  all material respects,  the revenues  and
direct  operating expenses of the 1995  Acquisition for the years ended December
31, 1993  and 1994,  and the  period ended  June 12,  1995, in  conformity  with
generally accepted accounting principles.
 
                                          KPMG PEAT MARWICK LLP
 
Midland, Texas
July 4, 1996
 
                                      F-21
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                                1995 ACQUISITION
 
              STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                YEARS ENDED
                                                                                DECEMBER 31,
                                                                            --------------------   PERIOD ENDED
                                                                              1993       1994     JUNE 12, 1995
                                                                            ---------  ---------  --------------
<S>                                                                         <C>        <C>        <C>
Revenues:
  Oil and condensate......................................................  $  18,542  $  16,217    $    7,572
  Natural gas.............................................................     13,780     11,407         3,358
                                                                            ---------  ---------  --------------
                                                                               32,322     27,624        10,930
Direct operating expenses:
  Lease operating.........................................................     13,376     11,220         4,550
  Workovers and dry hole costs............................................        462        470           109
  Production taxes........................................................      2,070      2,023           923
                                                                            ---------  ---------  --------------
                                                                               15,908     13,713         5,582
                                                                            ---------  ---------  --------------
Revenues in excess of direct operating expenses...........................  $  16,414  $  13,911    $    5,348
                                                                            ---------  ---------  --------------
                                                                            ---------  ---------  --------------
</TABLE>
 
                See the accompanying notes to these statements.
 
                                      F-22
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                                1995 ACQUISITION
 
       NOTES TO THE STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES
 
(1) BASIS OF PRESENTATION
    On June 12, 1995, Costilla Energy, L.L.C. and Costilla Petroleum Corporation
(collectively,  the "Company") acquired  from Parker &  Parsley Development L.P.
and Parker & Parsley Producing  L.P. (collectively, "Parker & Parsley")  certain
oil   and  gas  properties   (the  "1995  Acquisition")   for  $46,621,371.  The
accompanying statements of revenues and  direct operating expenses for the  1995
Acquisition  do not include general and administrative expenses, interest income
or expense, a  provision for  depreciation, depletion and  amortization, or  any
provision  for income taxes since historical expenses of this nature incurred by
Parker & Parsley are not necessarily indicative  of the costs to be incurred  by
the Company.
 
    Historical  financial information reflecting  financial position, results of
operations, and cash flows  of the 1995 Acquisition,  are not presented  because
the  purchase price was assigned to the oil and gas property interests acquired.
Other assets acquired  and liabilities assumed  were not material.  Accordingly,
the  historical statements of revenues and direct operating expenses of the 1995
Acquisition are presented  in lieu  of the financial  statements required  under
Rule 3-05 of Securities and Exchange Commission Regulation S-X.
 
    Revenues  in the  accompanying statements  of revenues  and direct operating
expenses are  recognized on  the  sales method.  Direct operating  expenses  are
recognized on the accrual method.
 
(2) SUPPLEMENTARY FINANCIAL INFORMATION FOR OIL AND GAS PRODUCING ACTIVITIES
(UNAUDITED)
 
    ESTIMATED QUANTITIES OF PROVED OIL AND GAS RESERVES
 
    Reserve  information presented  below for the  1995 Acquisition  is based on
Company prepared reserve estimates, using prices and costs in effect at December
31, 1993  and 1994,  and the  period ended  June 12,  1995. Changes  in  reserve
estimates  were derived  by adjusting the  period-end quantities  and values for
actual production using historical prices and costs.
 
    Proved reserves are estimated quantities of crude oil and natural gas  which
geological  and  engineering data  demonstrate with  reasonable certainty  to be
recoverable in future years  from known reservoirs  under existing economic  and
operating  conditions. Proved developed reserves are those which are expected to
be recovered  through  existing  wells with  existing  equipment  and  operating
methods.  Oil  and  gas  reserve  quantity  estimates  are  subject  to numerous
uncertainties inherent in the estimation of quantities of proved reserves and in
the projection  of future  rates of  production and  the timing  of  development
expenditures.  The accuracy of  such estimates is  a function of  the quality of
available data and  of engineering and  geological interpretation and  judgment.
Results  of subsequent drilling, testing and  production may cause either upward
or downward revision of previous  estimates. Further, the volumes considered  to
be  commercially  recoverable fluctuate  with  changes in  prices  and operating
costs. The Company  emphasizes that reserve  estimates are inherently  imprecise
and that estimates of new discoveries are more imprecise than those of currently
producing  oil  and gas  properties.  Accordingly, these  reserve  estimates are
expected to change as additional information becomes available in the future.
 
                                      F-23
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                                1995 ACQUISITION
 
 NOTES TO THE STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES (CONTINUED)
 
(2) SUPPLEMENTARY FINANCIAL INFORMATION FOR OIL AND GAS PRODUCING ACTIVITIES
(UNAUDITED)
    (CONTINUED)
    Below are  the  net  estimated  quantities of  proved  reserves  and  proved
developed reserves for the 1995 Acquisition.
 
<TABLE>
<CAPTION>
                                                                     OIL (MBBLS)  GAS (MMCF)
                                                                     -----------  -----------
<S>                                                                  <C>          <C>
Proved reserves at December 31, 1992...............................       9,880       60,199
Production.........................................................      (1,204)      (6,914)
                                                                     -----------  -----------
Proved reserves at December 31, 1993...............................       8,676       53,285
Production.........................................................      (1,142)      (6,778)
                                                                     -----------  -----------
Proved reserves at December 31, 1994...............................       7,534       46,507
Production.........................................................        (479)      (2,405)
                                                                     -----------  -----------
Proved reserves at June 12, 1995...................................       7,055       44,102
                                                                     -----------  -----------
                                                                     -----------  -----------
Proved developed reserves at June 12, 1995.........................       6,707       38,151
                                                                     -----------  -----------
                                                                     -----------  -----------
</TABLE>
 
    STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS OF PROVED OIL AND
GAS RESERVES
 
    The  Company has estimated the standardized measure of discounted future net
cash flows  and changes  therein relating  to  proved oil  and gas  reserves  in
accordance  with the standards established by the Financial Accounting Standards
Board through  its Statement  No. 69.  The estimates  of future  cash flows  and
future production and development costs are based on period-end sales prices for
oil  and  gas, estimated  future production  of  proved reserves,  and estimated
future production and  development costs  of proved reserves,  based on  current
costs  and economic  conditions. The  estimated future  net cash  flows are then
discounted at a rate of 10%.
 
    Discounted future net  cash flow estimates  like those shown  below are  not
intended  to  represent  estimates of  the  fair  market value  of  oil  and gas
properties. Estimates  of  fair  market  value  should  also  consider  probable
reserves,  anticipated future  oil and  gas prices,  interest rates,  changes in
development and production  costs and risks  associated with future  production.
Because  of these and other considerations, any estimate of fair market value is
necessarily subjective and imprecise.
 
    The following are the Company's estimated standardized measure of discounted
future net cash flows from proved reserves attributable to the 1995  Acquisition
(in thousands):
 
<TABLE>
<CAPTION>
                                                                       DECEMBER 31,
                                                                 ------------------------
                                                                    1993         1994      JUNE 12, 1995
                                                                 -----------  -----------  -------------
<S>                                                              <C>          <C>          <C>
Future:
  Cash inflows.................................................  $   222,698  $   188,828   $   191,758
  Production costs.............................................     (111,619)     (97,988)      (93,268)
  Development costs............................................       (4,797)      (4,797)       (4,797)
                                                                 -----------  -----------  -------------
    Net cash flows before income taxes.........................      106,282       86,043        93,693
10% annual discount for estimated timing of cash flows.........      (37,518)     (30,373)      (33,074)
                                                                 -----------  -----------  -------------
Standardized measure of discounted future net cash flows before
 income taxes..................................................  $    68,764  $    55,670   $    60,619
                                                                 -----------  -----------  -------------
                                                                 -----------  -----------  -------------
</TABLE>
 
                                      F-24
<PAGE>
                            COSTILLA ENERGY, L.L.C.
 
                                1995 ACQUISITION
 
 NOTES TO THE STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES (CONTINUED)
 
(2) SUPPLEMENTARY FINANCIAL INFORMATION FOR OIL AND GAS PRODUCING ACTIVITIES
(UNAUDITED)
    (CONTINUED)
    The  following are  the sources  of changes  in the  standardized measure of
discounted net cash flows (in thousands):
 
<TABLE>
<CAPTION>
                                                                   YEAR ENDED DECEMBER
                                                                           31,
                                                                  ----------------------  PERIOD ENDED
                                                                     1993        1994     JUNE 12, 1995
                                                                  ----------  ----------  -------------
<S>                                                               <C>         <C>         <C>
Standardized measure, beginning of period.......................  $   96,022  $   68,764   $    55,670
Sales, net of production costs..................................     (16,414)    (13,911)       (5,348)
Net change in prices............................................     (15,892)     (3,910)        8,032
Accretion of discount...........................................       9,602       6,876         2,517
Other...........................................................      (4,554)     (2,149)         (252)
                                                                  ----------  ----------  -------------
Standardized measure, end of period.............................  $   68,764  $   55,670   $    60,619
                                                                  ----------  ----------  -------------
                                                                  ----------  ----------  -------------
</TABLE>
 
                                      F-25
<PAGE>
                          INDEPENDENT AUDITORS' REPORT
 
The Members
Costilla Energy, L.L.C.:
 
    We have audited the accompanying statements of revenues and direct operating
expenses  of the 1996 Acquisition (see Note  1) for the years ended December 31,
1993, 1994 and 1995.  These statements are the  responsibility of the  Company's
management.  Our responsibility  is to  express an  opinion on  these statements
based on our audits.
 
    We conducted  our  audits in  accordance  with generally  accepted  auditing
standards.  Those standards require that we plan and perform the audit to obtain
reasonable assurance  about  whether  the  statements  of  revenues  and  direct
operating  expenses  are  free  of  material  misstatement.  An  audit  includes
examining, on a test basis, evidence  supporting the amounts and disclosures  in
the  financial  statements.  An  audit also  includes  assessing  the accounting
principles used  and  significant  estimates  made by  management,  as  well  as
evaluating  the  overall  statement  presentation. We  believe  that  our audits
provide a reasonable basis for our opinion.
 
    The accompanying statements of revenues  and direct operating expenses  were
prepared  for the  purpose of  complying with the  rules and  regulations of the
Securities and  Exchange Commission  (for  inclusion in  Forms S-1  of  Costilla
Energy,  Inc. as  described in  Note 1) and  are not  intended to  be a complete
presentation of the 1996 Acquisition interests' revenues and expenses.
 
    In our opinion,  the statements  of revenues and  direct operating  expenses
referred  to above  present fairly, in  all material respects,  the revenues and
direct operating expenses of the 1996  Acquisition for the years ended  December
31,  1993,  1994  and 1995,  in  conformity with  generally  accepted accounting
principles.
 
                                          KPMG PEAT MARWICK LLP
 
Midland, Texas
July 4, 1996
 
                                      F-26
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                                1996 ACQUISITION
              STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES
 
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                              (UNAUDITED)
                                                                   YEARS ENDED            THREE-MONTH PERIODS
                                                                  DECEMBER 31,              ENDED MARCH 31,
                                                         -------------------------------  --------------------
                                                           1993       1994       1995       1995       1996
                                                         ---------  ---------  ---------  ---------  ---------
<S>                                                      <C>        <C>        <C>        <C>        <C>
Revenues:
  Oil and condensate...................................  $  11,467  $  10,170  $  10,564  $   2,659  $   2,799
  Natural gas..........................................     11,294     10,105      8,645      2,031      1,967
  Gas plant............................................         57         57        126         26         23
  Transportation.......................................         39        379        556        139        298
                                                         ---------  ---------  ---------  ---------  ---------
                                                            22,857     20,711     19,891      4,855      5,087
 
Direct operating expenses:
  Lease operating......................................     10,977      9,053      9,232      1,921      2,179
  Workovers and dry hole costs.........................        675        869      1,002        219        247
  Production taxes.....................................      1,166      1,089        992        246        250
  Gas plant............................................        131        350        598        216        148
  Transportation.......................................         10        394        587        147        122
                                                         ---------  ---------  ---------  ---------  ---------
                                                            12,959     11,755     12,411      2,749      2,946
                                                         ---------  ---------  ---------  ---------  ---------
Revenues in excess of direct operating expenses........  $   9,898  $   8,956  $   7,480  $   2,106  $   2,141
                                                         ---------  ---------  ---------  ---------  ---------
                                                         ---------  ---------  ---------  ---------  ---------
</TABLE>
 
                See the accompanying notes to these statements.
 
                                      F-27
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                                1996 ACQUISITION
       NOTES TO THE STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES
 
(1) BASIS OF PRESENTATION
    On June 14, 1996, Costilla Energy, L.L.C. and Costilla Petroleum Corporation
(collectively, the "Company") acquired from  Parker & Parsley Development  L.P.,
Parker  &  Parsley  Producing  L.P.  and Parker  &  Parsley  Gas  Processing Co.
(collectively, "Parker &  Parsley") certain  oil and gas  properties (the  "1996
Acquisition")  for approximately  $42.5 million. The  accompanying statements of
revenues and direct operating expenses for  the 1996 Acquisition do not  include
general and administrative expenses, interest income or expense, a provision for
depreciation,  depletion  and amortization,  or any  provision for  income taxes
since historical expenses of  this nature incurred by  Parker & Parsley are  not
necessarily indicative of the costs to be incurred by the Company.
 
    Historical  financial information reflecting  financial position, results of
operations, and cash flows  of the 1996 Acquisition,  are not presented  because
the  purchase price was assigned to the oil and gas property interests acquired.
Other assets acquired  and liabilities assumed  were not material.  Accordingly,
the  historical statements of revenues and direct operating expenses of the 1996
Acquisition are presented  in lieu  of the financial  statements required  under
Rule 3-05 of Securities and Exchange Commission Regulation S-X.
 
    Revenues  in the  accompanying statements  of revenues  and direct operating
expenses are  recognized on  the  sales method.  Direct operating  expenses  are
recognized on the accrual method.
 
    INTERIM STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES
 
    The  interim financial information for the three months ended March 31, 1995
and 1996,  is unaudited.  However, in  the opinion  of management,  the  interim
statements  of revenues and direct operating  expenses include all the necessary
adjustments to fairly present  the results of the  interim periods and all  such
adjustments are of a normal recurring nature. The interim statements of revenues
and  direct operating  expenses should be  read in conjunction  with the audited
statements of  revenues  and  direct  operating expenses  for  the  years  ended
December 31, 1993, 1994 and 1995.
 
(2) SUPPLEMENTARY FINANCIAL INFORMATION FOR OIL AND GAS PRODUCING ACTIVITIES
(UNAUDITED)
 
    ESTIMATED QUANTITIES OF PROVED OIL AND GAS RESERVES
 
    Reserve  information presented below  for the 1996  Acquisition, as of March
31, 1996,  is  based  on  reserve estimates  prepared  by  Williamson  Petroleum
Consultants,  using prices and costs in effect  at that date. Changes in reserve
estimates were  derived  by adjusting  such  quantities and  values  for  actual
production using historical prices and costs.
 
    Proved  reserves are estimated quantities of crude oil and natural gas which
geological and  engineering data  demonstrate with  reasonable certainty  to  be
recoverable  in future years  from known reservoirs  under existing economic and
operating conditions. Proved developed reserves are those which are expected  to
be  recovered  through  existing  wells with  existing  equipment  and operating
methods. Oil  and  gas  reserve  quantity  estimates  are  subject  to  numerous
uncertainties inherent in the estimation of quantities of proved reserves and in
the  projection  of future  rates of  production and  the timing  of development
expenditures. The accuracy  of such estimates  is a function  of the quality  of
available  data and of  engineering and geological  interpretation and judgment.
Results of subsequent drilling, testing  and production may cause either  upward
or  downward revision of previous estimates.  Further, the volumes considered to
be commercially  recoverable  fluctuate with  changes  in prices  and  operating
costs.  The Company emphasizes  that reserve estimates  are inherently imprecise
and that estimates of new discoveries are more imprecise than those of currently
producing oil  and  gas properties.  Accordingly,  these reserve  estimates  are
expected to change as additional information becomes available in the future.
 
                                      F-28
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                                1996 ACQUISITION
 NOTES TO THE STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES (CONTINUED)
 
(2) SUPPLEMENTARY FINANCIAL INFORMATION FOR OIL AND GAS PRODUCING ACTIVITIES
(UNAUDITED) (CONTINUED)
    Below  are  the  net  estimated quantities  of  proved  reserves  and proved
developed reserves for the 1996 Acquisition.
 
<TABLE>
<CAPTION>
                                                                                          OIL (MBBLS)  GAS (MMCF)
                                                                                          -----------  -----------
<S>                                                                                       <C>          <C>
Proved reserves at December 31, 1992....................................................       7,211       49,963
Production..............................................................................        (718)      (5,481)
                                                                                               -----   -----------
Proved reserves at December 31, 1993....................................................       6,493       44,482
Production..............................................................................        (685)      (5,217)
                                                                                               -----   -----------
Proved reserves at December 31, 1994....................................................       5,808       39,265
Production..............................................................................        (656)      (4,773)
                                                                                               -----   -----------
Proved reserves at December 31, 1995....................................................       5,152       34,492
Production..............................................................................        (154)        (991)
                                                                                               -----   -----------
Proved reserves at March 31, 1996.......................................................       4,998       33,501
                                                                                               -----   -----------
                                                                                               -----   -----------
Proved developed reserves at March 31, 1996.............................................       4,515       28,961
                                                                                               -----   -----------
                                                                                               -----   -----------
</TABLE>
 
STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS OF PROVED OIL AND GAS
RESERVES
 
    The Company has estimated the standardized measure of discounted future  net
cash  flows  and changes  therein relating  to  proved oil  and gas  reserves in
accordance with the standards established by the Financial Accounting  Standards
Board  through its  Statement No.  69. The  estimates of  future cash  flows and
future production and development costs are  based on year-end sales prices  for
oil  and  gas, estimated  future production  of  proved reserves,  and estimated
future production and  development costs  of proved reserves,  based on  current
costs  and economic  conditions. The  estimated future  net cash  flows are then
discounted at a rate of 10%.
 
    Discounted future net  cash flow estimates  like those shown  below are  not
intended  to  represent  estimates of  the  fair  market value  of  oil  and gas
properties. Estimates  of  fair  market  value  should  also  consider  probable
reserves,  anticipated future  oil and  gas prices,  interest rates,  changes in
development and production  costs and risks  associated with future  production.
Because  of these and other considerations, any estimate of fair market value is
necessarily subjective and imprecise.
 
    The following are the Company's estimated standardized measure of discounted
future net cash flows from proved reserves attributable to the 1996  Acquisition
(in thousands):
 
<TABLE>
<CAPTION>
                                                                           DECEMBER 31,
                                                              ---------------------------------------   MARCH 31,
                                                                  1993          1994         1995         1996
                                                              ------------  ------------  -----------  -----------
<S>                                                           <C>           <C>           <C>          <C>
Future:
  Cash inflows..............................................  $    181,010  $    156,222  $   165,862  $   175,507
  Production costs..........................................      (116,115)     (105,104)     (93,878)     (91,202)
  Development costs.........................................        (4,101)       (4,101)      (4,101)      (4,101)
                                                              ------------  ------------  -----------  -----------
    Net cash flows before income taxes......................        60,794        47,017       67,883       80,204
10% annual discount for estimated timing of cash flows......       (22,564)      (17,451)     (25,195)     (29,768)
                                                              ------------  ------------  -----------  -----------
Standardized measure of discounted future net cash flows
 before income taxes........................................  $     38,230  $     29,566  $    42,688  $    50,436
                                                              ------------  ------------  -----------  -----------
                                                              ------------  ------------  -----------  -----------
</TABLE>
 
                                      F-29
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                                1996 ACQUISITION
 NOTES TO THE STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES (CONTINUED)
 
(2) SUPPLEMENTARY FINANCIAL INFORMATION FOR OIL AND GAS PRODUCING ACTIVITIES
(UNAUDITED) (CONTINUED)
    The  following are  the sources  of changes  in the  standardized measure of
discounted net cash flows (in thousands):
 
<TABLE>
<CAPTION>
                                                                                                   THREE-MONTH
                                                                      YEAR ENDED DECEMBER 31,      PERIOD ENDED
                                                                  -------------------------------   MARCH 31,
                                                                    1993       1994       1995         1996
                                                                  ---------  ---------  ---------  ------------
<S>                                                               <C>        <C>        <C>        <C>
Standardized measure, beginning of year.........................  $  56,372  $  38,230  $  29,566   $   42,688
Sales, net of production costs..................................     (9,943)    (9,264)    (7,983)      (2,090)
Net change in prices............................................    (11,890)    (2,838)    18,141        9,277
Accretion of discount...........................................      5,637      3,823      2,957        1,067
Other...........................................................     (1,946)      (385)         7         (506)
                                                                  ---------  ---------  ---------  ------------
Standardized measure, end of year...............................  $  38,230  $  29,566  $  42,688   $   50,436
                                                                  ---------  ---------  ---------  ------------
                                                                  ---------  ---------  ---------  ------------
</TABLE>
 
                                      F-30
<PAGE>
                                                                      APPENDIX A
 
                                 July 23, 1996
 
Costilla Energy, Inc.
400 West Illinois, Suite 1000
Midland, Texas 79701
 
Attention  Mr. Michael J. Grella
 
Gentlemen:
 
Subject:    Summary  Letter  (for Inclusion  in a  Prospectus Included  in a
            Registration Statement for  Costilla Energy, Inc.  on Form  S-1)
            Combining   Specific   Data   from   Two   Williamson  Petroleum
            Consultants, Inc. Evaluations (1)  to the Interests of  Costilla
            Petroleum  Corporation  in  Various Properties  and  (2)  to the
            Interests of Parker  & Parsley  Petroleum USA,  Inc. in  Various
            Properties Included in Their First Quarter 1996 Sales Package
            Effective April 1, 1996
            Williamson Project 6.8393
 
    In  accordance  with your  request,  Williamson Petroleum  Consultants, Inc.
(Williamson) has prepared  a summary letter  for inclusion in  a prospectus  for
Costilla  Energy, Inc. (Costilla). The filing of this Prospectus gives effect to
the conversion of Costilla Energy, L.L.C. to Costilla Energy, Inc. This  summary
letter  includes specific  data from two  evaluations the subjects  of which are
described in  Item I.  All values  and  discussion of  proved reserves  and  net
revenues,  data  utilized, assumptions,  and qualifications  are taken  from and
include by reference data from these two evaluations.
 
    Interests in this summary letter represent the April 1, 1996 effective  date
consolidation of the ownership interests of Costilla and the ownership interests
of  Parker & Parsley in various properties  included in their first quarter 1996
sales package  which Costilla  acquired on  June  14, 1996  but which  was  made
effective  as  of  January  1,  1996. The  Costilla  interests  include  all the
interests of  Costilla  Energy, L.L.C.  and  all its  wholly-owned  subsidiaries
including Costilla Petroleum Corporation.
 
I.  THE TWO SUBJECT EVALUATIONS
 
    This  summary  letter  combines  certain proved  oil  and  gas  reserves and
revenues from the following two Williamson evaluations:
 
    (1) Evaluation  of  Oil  and  Gas Reserves  to  the  Interests  of  Costilla
       Petroleum  Corporation in  Various Properties,  Effective April  1, 1996,
       Utilizing Nonescalated Economics,  for Disclosure to  the Securities  and
       Exchange Commission, Williamson Project 6.8393, transmitted July 18, 1996
       (the Costilla report)
 
    (2)  Evaluation of Oil and Gas Reserves to the Interests of Parker & Parsley
       Petroleum USA, Inc. in Various Properties Included in Their First Quarter
       1996 Sales  Package,  Effective  April 1,  1996,  Utilizing  Nonescalated
       Economics,  for  Disclosure to  the  Securities and  Exchange Commission,
       Williamson Project  6.8393, transmitted  July 18,  1996 (the  Acquisition
       report)
 
II.  ESTIMATED SEC RESERVES AND FUTURE NET REVENUES
 
    Projections  of  the  reserves  that are  attributable  to  the consolidated
interests in this summary letter were based on economic parameters and operating
conditions considered applicable  as of April  1, 1996 and  are pursuant to  the
requirements of the Securities and Exchange Commission (SEC).
 
    In  accordance with  instructions from  Costilla, Williamson  utilized lease
operating expenses for the Costilla-operated  properties in the Costilla  report
that excluded COPAS overhead and internal
 
                                      A-1
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 2
indirect  overhead  which are  billed to  outside  working interest  owners. The
exclusion of these costs for the operated properties results in the  calculation
of  a lower  economic limit  and causes  the economic  lifetime to  be extended.
Williamson has  not  quantified the  incremental  reserves resulting  from  this
procedure. COPAS overhead was excluded from the lease operating expenses for the
Parker & Parsley-operated properties in the Acquisition report.
 
    The present values of the estimated future net revenues from proved reserves
were  calculated  using a  discount  rate of  10.00  percent per  year  and were
computed in accordance  with the  financial reporting requirements  of the  SEC.
Following  is a summary of the results of the two evaluations effective April 1,
1996:
 
<TABLE>
<CAPTION>
                                                 PROVED           PROVED
                                               DEVELOPED         DEVELOPED           PROVED           TOTAL
                                               PRODUCING       NONPRODUCING       UNDEVELOPED         PROVED
                                             --------------  -----------------  ----------------  --------------
<S>                                          <C>             <C>                <C>               <C>
Net Reserves to the Evaluated Interests:
  Oil/Condensate, BBL......................      13,122,088          429,450          2,924,589       16,476,127
  Gas, MCF.................................      76,439,217        7,929,591         28,551,497      112,920,305
Future Net Revenue, $:
  Undiscounted.............................     212,071,507       18,097,949         66,832,632      297,002,088
  Discounted Per Annum at 10.00 Percent....     135,185,097        9,530,285         34,811,523      179,526,905
</TABLE>
 
- ------------------------
Note: The values presented in this table are taken from evaluations described in
      Item I and include by reference all data, qualifications, and  assumptions
      from  these  evaluations. Realization  of  these values  is  contingent on
      achieving successful results from the various schedules and assumptions in
      these evaluations.  The available  engineering data  and the  completeness
      and/or  quality of data utilized in evaluating the properties are detailed
      in the specific evaluation. Review of any additionally available data  may
      necessitate  revision to these interpretations  and assumptions and impact
      these values.
 
III.  DEFINITIONS OF SEC RESERVES (1)
 
    The estimated  reserves presented  in  this summary  letter are  net  proved
reserves,  including proved developed  producing, proved developed nonproducing,
and proved  undeveloped  reserves, and  were  computed in  accordance  with  the
financial  reporting requirements of the SEC. In preparing these evaluations, no
attempt has been made to quantify the element of uncertainty associated with any
category. Reserves were assigned to each category as warranted. The  definitions
of  oil and gas reserves pursuant to the requirements of the Securities Exchange
Act are:
 
PROVED RESERVES (2)
 
    Proved reserves are the estimated quantities of crude oil, natural gas,  and
natural  gas  liquids which  geological  and engineering  data  demonstrate with
reasonable certainty to  be recoverable  in future years  from known  reservoirs
under the economic criteria employed and existing operating
 
- ------------------------
(1)  For  evaluations prepared  for disclosure  to  the Securities  and Exchange
    Commission, see SEC ACCOUNTING RULES. Commerce Clearing House, Inc.  October
    1981, Paragraph 290, Regulation 210.4-10, p. 329.
 
(2) Any variations to these definitions will be clearly stated in the report.
 
                                      A-2
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 3
conditions,  i.e., prices and costs as of  the date the estimate is made. Prices
and  costs  include  consideration  of  changes  provided  only  by  contractual
arrangements but not on escalations based upon an estimate of future conditions.
 
A.   Reservoirs are considered proved  if economic producibility is supported by
    either actual  production  or  conclusive  formation test.  The  area  of  a
    reservoir considered proved includes:
 
    1.    that portion  delineated  by drilling  and  defined by  gas-oil and/or
       oil-water contacts, if any; and
 
    2.  the  immediately adjoining portions  not yet drilled,  but which can  be
       reasonably  judged as economically  productive on the  basis of available
       geological and engineering data. In  the absence of information on  fluid
       contacts, the lowest known structural occurrence of hydrocarbons controls
       the lower proved limit of the reservoir.
 
B.   Reserves which can be produced economically through application of improved
    recovery techniques (such as fluid  injection) are included in the  "proved"
    classification  when successful testing by a pilot project, or the operation
    of  an  installed  program  in  the  reservoir,  provides  support  for  the
    engineering analysis on which the project or program was based.
 
C.  Estimates of proved reserves do not include the following:
 
    1.   oil that may  become available from known  reservoirs but is classified
       separately as "indicated additional reserves;"
 
    2.  crude oil, natural gas, and  natural gas liquids, the recovery of  which
       is  subject to  reasonable doubt  because of  uncertainty as  to geology,
       reservoir characteristics, or economic factors;
 
    3.  crude  oil, natural  gas, and  natural gas  liquids, that  may occur  in
       undrilled prospects; and
 
    4.   crude oil, natural gas, and  natural gas liquids, that may be recovered
       from oil shales, coal (3), gilsonite and other such sources.
 
PROVED DEVELOPED RESERVES (4)
 
    Proved developed reserves are reserves that can be expected to be  recovered
through existing wells with existing equipment and operating methods. Additional
oil  and gas expected to be obtained  through the application of fluid injection
or other improved recovery techniques  for supplementing the natural forces  and
mechanisms of primary recovery should be included as "proved developed reserves"
only  after testing by  a pilot project  or after the  operation of an installed
program has confirmed through production  response that increased recovery  will
be achieved.
 
PROVED UNDEVELOPED RESERVES
 
    Proved  undeveloped reserves are reserves that  are expected to be recovered
from new wells on undrilled acreage,  or from existing wells where a  relatively
major  expenditure is required  for recompletion. Reserves  on undrilled acreage
shall   be   limited   to    those   drilling   units   offsetting    productive
 
- ------------------------
(3) According to Staff Accounting Bulletin 85, excluding certain coalbed methane
    gas.
 
(4)  Williamson Petroleum Consultants, Inc.  separates proved developed reserves
    into proved developed producing and proved developed nonproducing  reserves.
    This  is  to identify  proved developed  producing reserves  as those  to be
    recovered from  actively  producing  wells;  proved  developed  nonproducing
    reserves  as those  to be  recovered from  wells or  intervals within wells,
    which  are  completed  but  shut   in  waiting  on  equipment  or   pipeline
    connections,  or wells where a relatively  minor expenditure is required for
    recompletion to another zone.
 
                                      A-3
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 4
units that are reasonably  certain of production  when drilled. Proved  reserves
for  other undrilled units can be claimed only where it can be demonstrated with
certainty that there is  continuity of production  from the existing  productive
formation.  Under  no  circumstances  should  estimates  for  proved undeveloped
reserves be  attributable to  any  acreage for  which  an application  of  fluid
injection  or  other improved  recovery technique  is contemplated,  unless such
techniques have been proved  effective by actual  tests in the  area and in  the
same reservoir.
 
IV.  DISCUSSION OF SEC RESERVES
 
A.  THE COSTILLA REPORT
 
    A  total of 1,014  properties in 294  fields were evaluated  in the Costilla
    report. Nineteen individual properties had  values greater than 1.0  percent
    of the total future net revenue discounted at 10.00 percent per annum (DFNR)
    and  in aggregate represent 34.5 percent of the DFNR in the Costilla report.
    The most valued property, the T.B. Pruett  Gas Unit No. 3, Soda Lake  field,
    Ward  County, Texas, had a  value equal to 4.5 percent  of the total DFNR in
    the Costilla report. The top  eight major-value fields are Talbot  (Canyon),
    Howard  County, Texas; Spraberry (Trend Area), Various Counties, Texas; Soda
    Lake (Fusselman), Ward  County, Texas;  South Buffalo  Ridge, Crane  County,
    Texas;  Wattenberg,  Weld County,  Colorado;  East Goldsmith,  Ector County,
    Texas; Raymond,  Sheridan County,  Montana; and  South West  Speaks,  Lavaca
    County,  Texas. These fields contain ten of  the 19 top value properties and
    represent, in aggregate,  41.0 percent  of the  total DFNR  in the  Costilla
    report. The remaining 286 fields represent 59.0 percent with no field having
    more  than 2.9 percent of  the DFNR in the  Costilla report. A more detailed
    property review is included in the Costilla report.
 
    Area oil prices were provided by Costilla  to be used at the effective  date
    with  the written assurance that the use  of these area prices is reasonable
    on an aggregate basis  and would not materially  affect the income from  any
    major-value  property. These  area prices  were calculated  by adjusting the
    West Texas Intermediate oil April 1, 1996 posted price of $20.75 per barrel.
    The oil  price adjustments  for  each area  are the  calculated  differences
    between  the actual price received during 1995 and the posted price for West
    Texas Intermediate oil during  that same period.  After the effective  date,
    prices  were held constant  for the life  of the properties.  No attempt has
    been made to account for oil  price fluctuations which have occurred in  the
    market subsequent to the effective date of this report.
 
    Gas prices were provided by Costilla to be used at the effective date. These
    prices  were based on the April 1996 spot price of $1.75 per million British
    thermal units  (MMBTU) at  the Waha,  Texas receipt  point. This  price  was
    adjusted  with  an  area  price  adjustment  which  was  calculated  as  the
    difference between the actual price received during 1995 and the stop price.
    The resultant price was further adjusted for the BTU content of the gas  for
    each  well. If the BTU  content was unknown, it was  assumed to be one MMBTU
    per MCF of gas. After the effective date, prices were held constant for  the
    life  of the properties unless Costilla indicated that changes were provided
    for by contract. All gas prices were applied to projected wellhead volumes.
 
    It should  be  emphasized  that with  the  current  economic  uncertainties,
    fluctuation in market conditions could significantly change the economics of
    the properties included in this report.
 
    Operating expenses were provided by Costilla and represented, when possible,
    the  latest available 12-month  average of all  recurring expenses excluding
    COPAS and internal indirect overhead costs which are billable to the working
    interest owners.  These expenses  included,  but were  not limited  to,  all
    direct  operating expenses, field  overhead costs, and  any ad valorem taxes
    not
 
                                      A-4
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 5
    deducted separately. Expenses  for workovers, well  stimulations, and  other
    maintenance were not included in the operating expenses unless such work was
    expected   on  a  recurring  basis.  Judgments  for  the  exclusion  of  the
    nonrecurring expenses were made by Costilla. In accordance with instructions
    from Costilla, Williamson has excluded COPAS overhead and internal  indirect
    overhead  which are billed  to the outside working  interest owners from the
    operating expenses for Costilla-operated properties. The exclusion of  these
    costs for operated properties results in the calculation of a lower economic
    limit  and causes the  economic lifetime to be  extended. Williamson has not
    calculated the reserves that have been added as a result of this  procedure.
    For  new and  developing properties  where data  were unavailable, operating
    expenses were estimated by Costilla. Operating costs were held constant  for
    the life of the properties.
 
    State  production  taxes  have  been  deducted  at  the  published  rates as
    appropriate. For  operated  properties,  average  county  ad  valorem  taxes
    provided  by Costilla were  deducted for those  properties located in states
    for which the  data were  available. Any  ad valorem  taxes for  nonoperated
    properties  or for properties in other states were assumed to be included in
    the operating expenses.
 
    All capital  costs for  drilling and  completion of  wells and  nonrecurring
    workover  or operating costs  have been deducted  as applicable. These costs
    were provided  by Costilla.  No adjustments  were made  to account  for  the
    potential effect of inflation on these costs.
 
    Neither salvage values nor abandonment costs were provided by Costilla to be
    included in this evaluation.
 
B.  THE ACQUISITION REPORT
 
    A  total of 1,091 properties in 135 fields were evaluated in the Acquisition
    report. Eighteen individual properties had  values greater than 1.0  percent
    of the total DFNR and in aggregate represent 35.5 percent of the DFNR in the
    Acquisition  report.  The most  valued  property, the  H.W.  Glasscock Unit,
    Howard-Glasscock field, Glasscock  County, Texas, has  a projected value  of
    5.7  percent of  the total  DFNR in  the Acquisition  report. The  top eight
    major-value fields  are  World,  Crockett  County,  Texas;  Dimmitt,  Loving
    County,   Texas;  Panna  Maria,  Karnes  County,  Texas;  Giddings,  Various
    Counties, Texas; Caldwell, Burleson  County, Texas; Coletto Creek,  Victoria
    County,  Texas;  Sawyer, Sutton  County,  Texas; and  Jameson,  Coke County,
    Texas. These fields contain 11 of the 18 top value properties and represent,
    in aggregate, 51.9 percent of the total DFNR in the Acquisition report.  The
    remaining  fields represent 48.1 percent with  no field having more than 2.9
    percent of the  DFNR in  the Acquisition  report. A  more detailed  property
    review is included in the Acquisition report.
 
    Area oil prices were provided by Costilla and Parker & Parsley to be used at
    the  effective date with  the written assurance  that the use  of these area
    prices is reasonable on an aggregate  basis and would not materially  affect
    the  income from any major-value property. These area prices were calculated
    by adjusting the West Texas Intermediate  oil April 1, 1996 posted price  of
    $20.75  per  barrel. The  oil price  adjustments as  calculated by  Parker &
    Parsley for  each area  are the  calculated differences  between the  actual
    price  received during 1995 and the posted price for West Texas Intermediate
    oil during that  same period.  After the  effective date,  prices were  held
    constant for the life of the properties. No attempt has been made to account
    for  oil price fluctuations which have  occurred in the market subsequent to
    the effective date of this report.
 
    Gas prices were provided by Costilla and Parker & Parsley to be used at  the
    effective  date. These  prices were  based on the  April 1996  spot price of
    $1.75 per million British thermal units
 
                                      A-5
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 6
    (MMBTU) at the Waha,  Texas receipt point. This  price was adjusted with  an
    area  price adjustment  which was calculated  as the  difference between the
    actual price received during  1995 and the stop  price. The resultant  price
    was  further adjusted for the  BTU content of the gas  for each well. If the
    BTU content was  unknown, it was  assumed to be  one MMBTU per  MCF of  gas.
    After  the effective  date, prices  were held constant  for the  life of the
    properties unless  Costilla  indicated that  changes  were provided  for  by
    contract. All gas prices were applied to projected wellhead volumes.
 
    It  should  be  emphasized  that with  the  current  economic uncertainties,
    fluctuation in market conditions could significantly change the economics of
    the properties included in this report.
 
    Operating expenses  were  provided by  Costilla  and Parker  &  Parsley  and
    represented,  when possible,  the latest  available 12-month  average of all
    recurring expenses  excluding COPAS  and  internal indirect  overhead  costs
    which  are billable to the working interest owners. These expenses included,
    but were  not limited  to,  all direct  operating expenses,  field  overhead
    costs,  and  any  ad valorem  taxes  not deducted  separately.  Expenses for
    workovers, well stimulations, and other maintenance were not included in the
    operating expenses  unless such  work  was expected  on a  recurring  basis.
    Judgments  for  the  exclusion of  the  nonrecurring expenses  were  made by
    Costilla or Parker & Parsley. In accordance with instructions from Costilla,
    Williamson has  excluded  COPAS overhead  which  is billed  to  the  outside
    working   interest  owners  from   the  operating  expenses   for  Parker  &
    Parsley-operated properties.  The  exclusion  of these  costs  for  operated
    properties  results in the calculation of  a lower economic limit and causes
    the economic  lifetime to  be extended.  Williamson has  not calculated  the
    reserves  that have been  added as a  result of this  procedure. For new and
    developing properties where data  were unavailable, operating expenses  were
    estimated  by  Costilla  or  Parker &  Parsley.  Operating  costs  were held
    constant for the life of the properties.
 
    State production  taxes  have  been  deducted  at  the  published  rates  as
    appropriate.  For  operated  properties,  average  county  ad  valorem taxes
    provided by Costilla were  deducted for those  properties located in  states
    for  which the  data were  available. Any  ad valorem  taxes for nonoperated
    properties or for properties in other states were assumed to be included  in
    the operating expenses.
 
    All  capital costs  for drilling  and completion  of wells  and nonrecurring
    workover or operating costs  have been deducted  as applicable. These  costs
    were  provided by Costilla or Parker &  Parsley. No adjustments were made to
    account for the potential effect of inflation on these costs.
 
    Neither salvage values nor abandonment costs were provided by Costilla to be
    included in this evaluation.
 
V.  GENERAL EVALUATION CONSIDERATIONS PERTAINING TO THE COSTILLA AND ACQUISITION
    REPORTS
 
    The individual projections prepared to  produce this summary letter  include
data that describe the production forecasts and associated evaluation parameters
such  as interests, taxes, product prices, operating costs, investments, salvage
values, abandonment costs, and net profit interests, as applicable.
 
    Net income to the evaluated interests  is the future net revenue payable  to
others,  taxes,  operating  expenses, investments,  salvage  values, abandonment
costs, and net profit interests, as applicable. The future net revenue is before
federal income tax and  excludes consideration of  any encumbrances against  the
properties if such exist.
 
                                      A-6
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 7
 
    No  opinion is expressed  by Williamson as  to the fair  market value of the
evaluated properties.
 
    The future  net revenues  presented in  this summary  letter were  based  on
projections  of  oil  and gas  production.  It  was assumed  there  would  be no
significant delay between the date of oil and gas production and the receipt  of
the associated revenue for this production.
 
    This  summary  letter  includes  only those  costs  and  revenues  which are
considered by  Costilla to  be directly  attributable to  individual leases  and
areas.  There  could  exist  other  revenues,  overhead  costs,  or  other costs
associated with Costilla  which are not  included in this  summary letter.  Such
additional costs and revenues are outside the scope of this summary letter. This
summary  letter is not a financial statement for Costilla and should not be used
as the sole basis for any transaction concerning Costilla, Parker & Parsley,  or
the evaluated properties.
 
    The  reserves projections in this summary letter are based on the use of the
available data and accepted industry engineering methods. Future changes in  any
operational   or  economic  parameters  or  production  characteristics  of  the
evaluated properties  could  increase  or decrease  their  reserves.  Unforeseen
changes  in market demand or allowables set by various regulatory agencies could
also cause actual production  rates to vary from  those projected. The dates  of
first production for nonproducing properties were based on estimates by Costilla
or  Williamson and  the actual dates  may vary from  those estimated. Williamson
reserves the right to alter any  of the reserves projections and the  associated
economics  included in  this summary  letter in  any future  evaluation based on
additional data that may be acquired.
 
    All data utilized in the preparation of this summary letter with respect  to
interests, reversionary status, oil and gas prices, gas categories, gas contract
terms,  operating expenses, investments, salvage  values, abandonment costs, net
profit  interests,  well  information  and  current  operating  conditions,   as
applicable, were provided by Costilla, Parker & Parsley, and the operators. Data
obtained  after the effective date of the  report but prior to the completion of
the report were used only if such  data were applied consistently. If such  data
were  used, the reserves category assignments reflect the status of the wells as
of the effective date. In the Costilla report, daily production data after April
1, 1996 were utilized  for new wells  in the South  Buffalo Ridge, Concho  Bluff
(Queen),  East  Goldsmith (Queen),  King  Mountain (Penn),  and  Talbot (Canyon)
fields to  assist in  determining  initial producing  and decline  rates.  Daily
production  since the effective date was also used  for the Pyote Gas Unit 5 No.
1A, Block 16  (Devonian) field, Ward  County, Texas to  establish the  producing
rate  after the well was affected by gas  plant problems and for the State 16-05
well in the  Raymond field, Sheridan  County, Montana to  establish the  initial
rate of production subsequent to the installation of a downhole pump. Production
data  generally through December  1995 or January 1996  provided by Costilla for
the properties in  the Costilla  report and  through November  or December  1995
provided  by Parker & Parsley for the  properties in the Acquisition report were
utilized. All data  have been  reviewed for reasonableness  and, unless  obvious
errors  were detected,  have been accepted  as correct. It  should be emphasized
that revisions to  the projections of  reserves and economics  included in  this
summary  letter may be required if the provided data are revised for any reason.
No inspection of the properties was made  as this was not considered within  the
scope  of  these  projects.  No  investigation  was  made  of  any environmental
liabilities that  might apply  to the  evaluated properties,  and no  costs  are
included for any possible related expenses.
 
    Unless  specifically  identified  and  documented by  Costilla  or  Parker &
Parsley as having curtailment problems, gas production trends have been  assumed
to  be a function of well productivity  and not of market conditions. The effect
of "take or pay" clauses in gas contracts was not considered.
 
                                      A-7
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 8
 
    Oil reserves  are expressed  in  United States  (U.S.)  barrels of  42  U.S.
gallons.  Gas  volumes are  expressed in  thousands  of cubic  feet (MCF)  at 60
degrees Fahrenheit and at the legal pressure base that prevails in the state  in
which the reserves are located. No adjustment of the individual gas volumes to a
common pressure base has been made.
 
    Costilla  represented  to  Williamson  that it  has,  or  can  generate, the
financial and operational capabilities to accomplish those projects evaluated by
Williamson which require capital expenditures.
 
    The estimates of reserves contained  in this summary letter were  determined
by  accepted industry methods and in accordance  with the definitions of oil and
gas reserves set forth  above. Methods utilized in  this summary letter  include
extrapolation  of historical production trends, material balance determinations,
analogy to similar properties, and volumetric calculations.
 
    Where sufficient production history and other data were available,  reserves
for   producing  properties  were  determined  by  extrapolation  of  historical
production trends or through the use of material balance determinations. Analogy
to similar  properties or  volumetric calculations  were used  for  nonproducing
properties  and those  producing properties  which lacked  sufficient production
history and other  data to  yield a  definitive estimate  of reserves.  Reserves
projections  based on analogy are subject to change due to subsequent changes in
the analogous properties or subsequent production from the evaluated properties.
Volumetric calculations are often  based upon limited  log and/or core  analysis
data and incomplete reservoir fluid and formation rock data. Since these limited
data  must frequently be extrapolated over  an assumed drainage area, subsequent
production performance trends  or material  balance calculations  may cause  the
need for significant revisions to the estimates of reserves.
 
    It  should  be  emphasized  that with  the  current  economic uncertainties,
fluctuation in market  conditions could  significantly change  the economics  in
this summary letter.
 
VII.  DECLARATION OF INDEPENDENT STATUS AND CONSENT
 
    We  understand  that our  estimates  are to  be  included in  a Registration
Statement on Form S-1 (the Registration Statement) to be filed with the SEC  and
in  the  Prospectus as  included in  such Registration  Statement which  will be
registered under the Securities Act of 1933, as amended.
 
    Williamson is an independent consulting firm and does not own any  interests
in the oil and gas properties covered by this summary letter. Roy C. Williamson,
Jr.,  Chief Executive Officer, owns a 2.5  percent working interest in six wells
in the Outlook  field, Sheridan  County, Montana, which  have a  total value  of
$138,912  to  the interests  of Costilla.  No employee,  officer or  director of
Williamson is an employee, officer or director of Costilla or Parker &  Parsley.
Neither  the  employment  of  nor the  compensation  received  by  Williamson is
contingent upon the  values assigned to  the oil and  gas properties covered  by
this summary letter.
 
    We  consent  to the  inclusion of  this summary  letter in  the Registration
Statement, the inclusion in  the Registration Statement  of data extracted  from
this  summary  letter and  to  all references  to  our firm  in  the Prospectus,
including any references to our firm as Experts.
 
                                    Yours very truly,
 
                                    WILLIAMSON PETROLEUM CONSULTANTS, INC.
 
                                      A-8
<PAGE>
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
    NO  DEALER, SALESMAN  OR ANY  OTHER PERSON HAS  BEEN AUTHORIZED  TO GIVE ANY
INFORMATION OR TO MAKE  ANY REPRESENTATIONS OTHER THAN  THOSE CONTAINED IN  THIS
PROSPECTUS  IN CONNECTION WITH THE OFFERING  COVERED BY THIS PROSPECTUS, AND, IF
GIVEN OR MADE, SUCH  INFORMATION OR REPRESENTATIONS MUST  NOT BE RELIED UPON  AS
HAVING  BEEN AUTHORIZED BY THE COMPANY OR THE UNDERWRITERS. THIS PROSPECTUS DOES
NOT CONSTITUTE AN  OFFER TO  SELL OR  THE SOLICITATION OF  AN OFFER  TO BUY  THE
SECURITIES  IN ANY JURISDICTION WHERE, OR ANY  PERSON TO WHOM, IT IS UNLAWFUL TO
MAKE SUCH OFFER OR SOLICITATION. NEITHER THE DELIVERY OF THIS PROSPECTUS NOR ANY
SALE MADE HEREUNDER SHALL, UNDER  ANY CIRCUMSTANCES, CREATE AN IMPLICATION  THAT
THERE  HAS NOT BEEN A CHANGE IN THE FACTS SET FORTH IN THIS PROSPECTUS OR IN THE
AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF.
 
                            ------------------------
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                    PAGE
                                                    -----
<S>                                              <C>
Prospectus Summary.............................           3
Risk Factors...................................          11
The Company....................................          17
Common Stock Offering..........................          17
Use of Proceeds................................          18
Capitalization.................................          19
Pro Forma Condensed Financial Statements.......          20
Selected Financial Information.................          28
Management's Discussion and Analysis of
 Financial Condition and Results of
 Operations....................................          29
Business and Properties........................          34
Management.....................................          46
Security Ownership of Certain Beneficial Owners
 and Management................................          49
Executive Compensation and Other Information...          50
Certain Transactions...........................          52
Description of Notes...........................          54
Description of Other Indebtedness..............          81
Description of Capital Stock...................          81
Underwriting...................................          83
Legal Matters..................................          84
Experts........................................          84
Available Information..........................          84
Glossary.......................................          86
Index to Financial Statements..................         F-1
Summary Reserve Report.........................         A-1
</TABLE>
 
                             COSTILLA ENERGY, INC.
 
                           $100,000,000     % SENIOR
                          SUBORDINATED NOTES DUE 2006
 
                             ---------------------
 
                                   PROSPECTUS
 
                             ---------------------
                       NATIONSBANC CAPITAL MARKETS, INC.
 
                       PRUDENTIAL SECURITIES INCORPORATED
 
                                          , 1996
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 13.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.
 
<TABLE>
<S>                                                                 <C>
SEC registration fee..............................................  $  34,483
NASD filing fee...................................................     10,500
Blue Sky fees and expenses........................................     10,000
Accounting fees and expenses......................................      *
Engineering fees and expenses.....................................      *
Trustee fees and expenses.........................................      *
Legal fees and expenses...........................................      *
Printing and mailing expenses.....................................      *
Miscellaneous.....................................................
                                                                    ---------
      TOTAL.......................................................
                                                                    ---------
                                                                    ---------
</TABLE>
 
- ------------------------
* To be provided by amendment.
 
ITEM 14.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
    Section  145 of the General Corporation Law of the State of Delaware permits
a corporation to indemnify certain persons, including officers and directors and
former officers  and  directors,  and  to purchase  insurance  with  respect  to
liability  arising out  of their capacity  or status as  officers and directors.
Such law provides  further that the  indemnification permitted thereunder  shall
not  be deemed exclusive of any other rights to which officers and directors may
be entitled under the corporation's bylaws, any agreement or otherwise.  Article
IX  of  the  Company's Certificate  of  Incorporation, included  in  Exhibit 3.1
hereto, and Article VI of the Company's Bylaws, included in Exhibit 3.2  hereto,
provide, in general, that the Company shall indemnify its directors and officers
under the circumstances defined in Section 145 of the General Corporation Law of
the  State of Delaware and gives authority  to the Company to purchase insurance
with respect to  such indemnification.  The Company may  in the  future seek  to
obtain  insurance providing for indemnification of officers and directors of the
Company and certain other persons  against liabilities and expenses incurred  by
any of them in certain stated proceedings and under certain stated conditions.
 
    In  addition, Section 102(b)(7) of the  General Corporation Law of the State
of Delaware  permits a  corporation  to limit  the  liability of  its  directors
subject  to certain exceptions. In accordance with Section 102(b)(7), Article VI
of the Company's Certificate of  Incorporation, included in Exhibit 3.1  hereto,
provides, in general, that no director of the Company shall be personally liable
for  (i) any  breach of  the directors' duty  of loyalty  to the  Company or its
stockholders, (ii)  acts  or  omissions  not in  good  faith  or  which  involve
intentional misconduct or a knowing violation of law, (iii) unlawful payments of
dividends  or unlawful stock  repurchases or redemptions  as provided in Section
174 of  the  General Corporation  Law  of the  State  of Delaware  or  (iv)  any
transaction from which the director derived an improper personal benefit.
 
    The  Underwriting Agreement provides for  indemnification by the Underwriter
of the Registrant,  its directors  and officers, and  by the  Registrant of  the
Underwriter,  for certain  liabilities, including liabilities  arising under the
Securities Act of 1933 (the "Securities Act").
 
ITEM 15.  RECENT SALES OF UNREGISTERED SECURITIES.
 
    Prior to  the consummation  of the  Notes Offering,  the Company  issued  an
aggregate of 300 shares of Common Stock to Messrs. Liedtke, Grella and Musselman
in  its initial capitalization,  which shares were  cancelled in connection with
the Corporate Reorganization,  and an  aggregate of 6,000,000  shares of  Common
Stock  to the four members of the LLC in the merger of the LLC with and into the
Company. Such shares were  not registered under the  Securities Act in  reliance
upon the exemption from registration provided by Section 4(2) thereof.
 
                                      II-1
<PAGE>
ITEM 16.  EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.
 
    (a) Exhibits
 
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                       DESCRIPTION OF EXHIBIT
- ---------  ---------------------------------------------------------------------------------------------
<C>        <S>
    *1.1   Form of Underwriting Agreement
    *3.1   Certificate of Incorporation of the Company
    *3.2   Bylaws of the Company
    *4.1   Form of Notes or Global Certificate (included as Exhibit A to the form of Indenture filed as
            Exhibit No. 4.2 to this Registration Statement)
    *4.2   Form of Indenture
   **5.1   Opinion of Cotton, Bledsoe, Tighe & Dawson, a Professional Corporation
   **6.1   Purchase and Sale Agreement dated April 3, 1995 by and between Parker & Parsley Development
            L.P. and Parker & Parsley Producing L.P. and Parker & Parsley Gas Processing Co. as Seller
            and Costilla Petroleum Corporation and Costilla Energy, L.L.C. as Purchaser
   **6.2   Purchase and Sale Agreement dated March 8, 1996 by and between Parker & Parsley Development
            L.P. and Parker & Parsley Producing L.P. and Parker & Parsley Gas Processing Co. as Seller
            and Costilla Petroleum Corporation and Costilla Energy, L.L.C. as Purchaser
  **10.1   Form of Credit Agreement to be entered into contemporaneously with the closing of the
            Offerings between the Company as Borrower and                      as Lender.
   *10.2   Lease Agreement dated January 12, 1996 between Independence Plaza, Ltd. and Costilla Energy,
            L.L.C.
   *10.3   Concession Agreement dated July 6, 1996 between the Government of the Republic of Moldova and
            the Resource Development Company, Limited.
   *10.4   Purchase and Joint Exploration Agreement dated February 21, 1996 between the Company and
            Resources Development Limited, L.L.C. (DE).
  **10.5   Consolidation Agreement to be effective contemporaneously with closing of the Offerings to
            consummate the Corporate Reorganization.
  **10.6   1996 Stock Option Plan.
  **10.7   Outside Directors Stock Option Plan.
   *10.8   Employment Agreement between the Company and Bobby W. Page effective June 30, 1996.
  **10.9   Employment Agreement between the Company and Cadell S. Liedtke to be effective
            contemporaneously with the closing of the Offerings.
  **10.10  Employment Agreement between the Company and Michael J. Grella to be effective
            contemporaneously with the closing of the Offerings.
  **10.11  Employment Agreement between the Company and Henry G. Musselman to be effective
            contemporaneously with the closing of the Offerings.
   *10.12  Exchange Agreement dated January 5, 1995 between Costilla Petroleum Corporation and Koch Oil
            Company.
   *10.13  Agreement dated January 2, 1996 between Costilla Petroleum Corporation and Frontier Oil and
            Refining Company.
</TABLE>
 
                                      II-2
<PAGE>
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                       DESCRIPTION OF EXHIBIT
- ---------  ---------------------------------------------------------------------------------------------
<C>        <S>
   *12.1   Computation of Ratio of EBITDA to Interest Expense
   *12.2   Computation of Ratio of Earnings to Fixed Charges
   *12.3   Pro Forma Computation of Ratio of ACNTA to Total Debt
   *21.1   Subsidiaries of the Registrant
   *23.1   Consent of KPMG Peat Marwick LLP
   *23.2   Consent of Williamson Petroleum Consultants, Inc.
   *23.3   Consent of Elms, Faris & Co., P.C.
  **23.4   Consent of Cotton, Bledsoe, Tighe & Dawson, a Professional Corporation (such consent is
            included in the opinion filed as Exhibit 5.1 to this Registration Statement)
   *24.1   Power of Attorney
   *24.2   Certified copy of resolution of Board of Directors of Costilla Energy, Inc. authorizing
            signature pursuant to Power of Attorney
   *25.1   Statement of Eligibility and Qualification of Trustee under 1939 Act on Form T-1
   *27.1   Financial Data Schedule
</TABLE>
 
- ------------------------
*  Filed herewith
** To be filed by amendment
 
    (b) Financial Statement Schedules.
 
ITEM 17.  UNDERTAKINGS
 
    Insofar  as indemnification for liabilities arising under the Securities Act
may  be  permitted  to  directors,  officers  and  controlling  persons  of  the
Registrant  pursuant  to  the  provisions  described  under  Item  14  above, or
otherwise, the Registrant has been advised that in the opinion of the Securities
and Exchange  Commission,  such  indemnification is  against  public  policy  as
expressed  in the Securities Act and  is, therefore, unenforceable. In the event
that a  claim  for indemnification  against  such liabilities  (other  than  the
payment by the Registrant of expenses incurred or paid by a director, officer of
controlling  person of the  Registrant in the successful  defense of any action,
suit or proceeding) is asserted by such directors, officer or controlling person
in connection with the securities being registered, the Registrant will,  unless
in  the  opinion of  its  counsel the  matter  has been  settled  by controlling
precedent, submit to a  court of appropriate  jurisdiction the question  whether
such  indemnification  by  it  is  against public  policy  as  expressed  in the
Securities Act and will be governed by the final adjudication of such issue.
 
    The  undersigned  Registrant  hereby   undertakes  that,  for  purposes   of
determining  any liability under the Securities Act, (i) the information omitted
from the Prospectus  filed as part  of this Registration  Statement in  reliance
upon  Rule 430A under the  Securities Act and contained  in a form of Prospectus
filed by the Registrant pursuant  to Rule 424(b)(1) or  (4) or 497(h) under  the
Securities Act shall be deemed to be part of this Registrant Statement as of the
time  it  was declared  effective and  (ii)  each post-effective  amendment that
contains a form of prospectus shall be deemed to be a new Registration Statement
relating to the securities offered therein, and the offering of such  securities
at that time shall be deemed to be the initial bona fide offering thereof.
 
                                      II-3
<PAGE>
                                   SIGNATURES
 
    Pursuant  to the requirements of the  Securities Act of 1933, the Registrant
has duly caused this Registration  Statement to be signed  on its behalf by  the
undersigned,  thereunder duly authorized in the City of Midland, State of Texas,
on July 25, 1996.
 
                                          COSTILLA ENERGY, INC.
                                          (Registrant)
 
                                          By:                 *
                                          --------------------------------------
                                                      Michael J. Grella
                                                PRESIDENT AND CHIEF OPERATING
                                                         OFFICER
 
    Pursuant  to  the  requirements  of   the  Securities  Act  of  1933,   this
Registration Statement has been signed by the following persons on behalf of the
Registrant and in the capacities and on the dates indicated.
 
<TABLE>
<CAPTION>
                      SIGNATURE                                   TITLE                  DATE
- ------------------------------------------------------  -------------------------  ----------------
 
<C>                                                     <S>                        <C>
                          *                             Chairman of the Board,
     -------------------------------------------         Chief Executive Officer    July 25, 1996
                  Cadell S. Liedtke                      and Director
 
                          *                             President, Chief
     -------------------------------------------         Operating Officer and      July 25, 1996
                  Michael J. Grella                      Director
 
                          *
     -------------------------------------------        Executive Vice President    July 25, 1996
                  Henry G. Musselman                     and Director
 
                  /s/ BOBBY W. PAGE                     Senior Vice Present,
     -------------------------------------------         Treasurer and Chief        July 25, 1996
                    Bobby W. Page                        Financial Officer
 
                          *
     -------------------------------------------        Director                    July 25, 1996
                   Jerry J. Langdon
 
                          *
     -------------------------------------------        Director                    July 25, 1996
                     W.D. Kennedy
 
*By:              /s/ BOBBY W. PAGE
     -------------------------------------------
                    Bobby W. Page
                   ATTORNEY-IN-FACT
</TABLE>
 
                                      II-4
<PAGE>
                               INDEX TO EXHIBITS
 
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                       DESCRIPTION OF EXHIBIT
- ---------  ---------------------------------------------------------------------------------------------
<C>        <S>
    *1.1   Form of Underwriting Agreement
    *3.1   Certificate of Incorporation of the Company
    *3.2   Bylaws of the Company
    *4.1   Form of Notes or Global Certificate (included as Exhibit A to the form of Indenture filed as
            Exhibit No. 4.2 to this Registration Statement)
    *4.2   Form of Indenture
   **5.1   Opinion of Cotton, Bledsoe, Tighe & Dawson, a Professional Corporation
   **6.1   Purchase and Sale Agreement dated April 3, 1995 by and between Parker & Parsley Development
            L.P. and Parker & Parsley Producing L.P. and Parker & Parsley Gas Processing Co. as Seller
            and Costilla Petroleum Corporation and Costilla Energy, L.L.C. as Purchaser
   **6.2   Purchase and Sale Agreement dated March 8, 1996 by and between Parker & Parsley Development
            L.P. and Parker & Parsley Producing L.P. and Parker & Parsley Gas Processing Co. as Seller
            and Costilla Petroleum Corporation and Costilla Energy, L.L.C. as Purchaser
  **10.1   Form of Credit Agreement to be entered into contemporaneously with the closing of the
            Offerings between the Company as Borrower and                      as Lender.
   *10.2   Lease Agreement dated January 12, 1996 between Independence Plaza, Ltd. and Costilla Energy,
            L.L.C.
   *10.3   Concession Agreement dated July 6, 1996 between the Government of the Republic of Moldova and
            the Resource Development Company, Limited.
   *10.4   Purchase and Joint Exploration Agreement dated February 21, 1996 between the Company and
            Resources Development Limited, L.L.C. (DE).
  **10.5   Consolidation Agreement to be effective contemporaneously with closing of the Offerings to
            consummate the Corporate Reorganization.
  **10.6   1996 Stock Option Plan.
  **10.7   Outside Directors Stock Option Plan.
   *10.8   Employment Agreement between the Company and Bobby W. Page effective June 30, 1996.
  **10.9   Employment Agreement between the Company and Cadell S. Liedtke to be effective
            contemporaneously with the closing of the Offerings.
  **10.10  Employment Agreement between the Company and Michael J. Grella to be effective
            contemporaneously with the closing of the Offerings.
  **10.11  Employment Agreement between the Company and Henry G. Musselman to be effective
            contemporaneously with the closing of the Offerings.
   *10.12  Exchange Agreement dated January 5, 1995 between Costilla Petroleum Corporation and Koch Oil
            Company.
   *10.13  Agreement dated January 2, 1996 between Costilla Petroleum Corporation and Frontier Oil and
            Refining Company.
   *12.1   Computation of Ratio of EBITDA to Interest Expense
   *12.2   Computation of Ratio of Earnings to Fixed Charges
   *12.3   Pro Forma Computation of Ratio of ACNTA to Total Debt
   *21.1   Subsidiaries of the Registrant
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                       DESCRIPTION OF EXHIBIT
- ---------  ---------------------------------------------------------------------------------------------
<C>        <S>
   *23.1   Consent of KPMG Peat Marwick LLP
   *23.2   Consent of Williamson Petroleum Consultants, Inc.
   *23.3   Consent of Elms, Faris & Co., P.C.
  **23.4   Consent of Cotton, Bledsoe, Tighe & Dawson, a Professional Corporation (such consent is
            included in the opinion filed as Exhibit 5.1 to this Registration Statement)
   *24.1   Power of Attorney
   *24.2   Certified copy of resolution of Board of Directors of Costilla Energy, Inc. authorizing
            signature pursuant to Power of Attorney
   *25.1   Statement of Eligibility and Qualification of Trustee under 1939 Act on Form T-1
   *27.1   Financial Data Schedule
</TABLE>
 
- ------------------------
*  Filed herewith
** To be filed by amendment


<PAGE>

                                                     [DRAFT of July 19, 1996]

                                 $100,000,000


                            COSTILLA ENERGY, INC.

                            ____% NOTES DUE 2006


                           UNDERWRITING AGREEMENT


                                                       ___________  ___, 1996



NationsBanc Capital Markets, Inc.
Prudential Securities Incorporated
c/o NationsBanc Capital Markets, Inc. 
NationsBank Corporate Center
100 North Tryon Street
Charlotte, North Carolina 28255

Dear Sirs: 

     SECTION 1.  INTRODUCTORY.  Costilla Energy, Inc., a Delaware corporation 
(the "Company"), confirms its agreement with the several Underwriters named 
in Schedule I hereto (the "Underwriters"), to issue and sell $100,000,000 
principal amount of its ____% Notes due 2006 (the "Notes"). The Notes are to 
be issued pursuant to the provisions of an indenture dated as of 
_____________, 1996 (the "Indenture") between the Company and 
___________________, as trustee (the "Trustee").   As provided in the 
Indenture, the Notes are to be fully and unconditionally guaranteed on a 
subordinated basis pursuant to guarantees (the "Subsidiary Guarantees") of 
the Company's subsidiaries (the "Subsidiary Guarantors").  It is understood 
and agreed to by all parties hereof that, prior to the Closing Date (as 
hereinafter defined), the Company will issue in a public offering __________ 
shares of its common stock (the "Stock Offering").  Each of the Company and 
the Subsidiary Guarantors hereby agrees with the Underwriters as follows: 

     SECTION 2.  REPRESENTATIONS, WARRANTIES AND AGREEMENTS OF THE COMPANY.  
The Company and the Subsidiary Guarantors, jointly and severally, represent 
and warrant to, and agree with, the several Underwriters that: 

          (a)      A registration statement on Form S-1 (File No. 
     333-________) with respect to the Notes (i) has been prepared by the 
     Company in conformity with the requirements of the Securities Act of 
     1933, as amended (the "Act"), and the rules and regulations (the "Rules 


<PAGE>


     and Regulations") of the Securities and Exchange Commission (the 
     "Commission") thereunder, (ii) has been filed with the Commission under 
     the Act and (iii) either has become effective under the Act and is not 
     proposed to be amended or is proposed to be amended by amendment or 
     post-effective amendment.  If the Company does not propose to amend such 
     registration statement and if any post-effective amendment to such 
     registration statement has been filed with the Commission prior to the 
     execution and delivery of this Agreement, the most recent such amendment 
     has been declared effective by the Commission.  Copies of such 
     registration statement as amended to date have been delivered by the 
     Company to you.  For purposes of this Agreement, "Effective Time" means 
     the date and the time as of which such registration statement, or the 
     most recent post-effective amendment thereto, if any, was declared 
     effective by the Commission; "Effective Date" means the date of the 
     Effective Time; "Preliminary Prospectus" means each prospectus included 
     in such registration statement, or amendments thereof, before it became 
     effective under the Act and any prospectus filed with the Commission by 
     the Company with the consent of the Underwriters pursuant to Rule 424(a) 
     of the Rules and Regulations prior to the filing of the Prospectus; 
     "Registration Statement" means such registration statement, as amended 
     at the Effective Time, including any documents incorporated by reference 
     therein and, if the Effective Date is on or before the date of this 
     Agreement, all information contained in the final prospectus filed with 
     the Commission pursuant to Rule 424(b) of the Rules and Regulations 
     ("Rule 424(b)") in accordance with Section 5(a) hereof and deemed to be 
     a part thereof as of the Effective Time pursuant to the Rules and 
     Regulations; "Prospectus" means the form of prospectus relating to the 
     Notes, as first used to confirm sales of the Notes; and "described in 
     the Prospectus" or "disclosed in the Prospectus" means described or 
     disclosed, as applicable, in the Prospectus.  The Commission has not 
     issued any order preventing or suspending the use of any Preliminary 
     Prospectus or the Prospectus.

          (b)  At the Effective Time and at all times subsequent thereto up 
     to the Closing Date hereinafter mentioned, the Registration Statement 
     and the Prospectus, and any amendments or supplements thereto, conform 
     in all material respects with the requirements of the Act and the Rules 
     and Regulations, and at the Effective Time the Registration Statement 
     did not include any untrue statement of a material fact or omit to state 
     any material fact required to be stated therein or necessary to make the 
     statements therein not misleading, and the Prospectus, as amended or 
     supplemented at the Closing Date, if applicable, did not contain any 
     untrue statement of a material fact or omit to state a material fact 
     necessary to make the statements contained therein, in the light of the 
     circumstances under which they were made, not misleading; except that 
     the foregoing does not apply to (i) that part of the Registration 
     Statement that constitutes the Statement of Eligibility and 
     Qualification (Form T-1) under the Trust Indenture Act of 1939, as 
     amended (the "1939 Act"), of the Trustee, and (ii) statements or 
     omissions in the Registration Statement or the Prospectus, as amended or 
     supplemented if applicable, based upon written information furnished to 
     the Company by any Underwriter through you specifically for use therein. 

          (c)  The consolidated financial statements included in the 
     Registration Statement and Prospectus present fairly the consolidated 
     financial position of the Company and its consolidated subsidiaries as 
     at the dates indicated and the results of their operations and the 


                                     -2-

<PAGE>


     changes in their consolidated financial position for the periods 
     specified; said financial statements have been prepared in conformity 
     with generally accepted accounting principles applied on a consistent 
     basis during the periods involved, except as indicated therein; and the 
     supporting schedules included in the Registration Statement present 
     fairly the information required to be stated therein.  The pro forma 
     financial statements set forth in the Registration Statement and the 
     Prospectus (the "pro forma financial statements") have been prepared in 
     accordance with the applicable accounting requirements of Rule 11-02 of 
     Regulation S-X; the pro forma adjustments reflected in the pro forma 
     financial statements have been properly applied to the historical 
     amounts in the compilation of such statements; and the assumptions used 
     in the preparation of the pro forma financial statements are, in the 
     opinion of the Company, reasonable.

          (d)  Since the respective dates as of which information is given in 
     the Registration Statement and the Prospectus, except as otherwise 
     stated therein, (i) there has been no material adverse change in the 
     condition, financial or otherwise, earnings, affairs or business 
     prospects of the Company and its subsidiaries considered as a whole, 
     whether or not arising in the ordinary course of business and (ii) there 
     have been no material transactions entered into by the Company or any of 
     its subsidiaries other than those in the ordinary course of business. 

          (e)  The Company has been duly incorporated and is validly existing 
     as a corporation in good standing under the laws of the State of 
     Delaware with corporate power and authority to own, lease and operate 
     its properties and conduct its business as described in the Registration 
     Statement; and the Company is duly qualified as a foreign corporation to 
     transact business and is in good standing in each jurisdiction in which 
     it owns or leases properties or in which the conduct of its business 
     requires such qualification, except to the extent that the failure to be 
     so qualified or be in good standing would not have a material adverse 
     effect on the Company and its subsidiaries considered as a whole. 

          (f)  Each of the subsidiaries of the Company has been duly 
     incorporated or organized and is validly existing as a corporation or 
     limited liability company in good standing under the laws of the 
     jurisdiction of its formation, has corporate power and authority to own, 
     lease and operate its properties and conduct its business as described 
     in the Registration Statement and is duly qualified as a foreign 
     corporation or limited liability company to transact business and is in 
     good standing in each jurisdiction in which it owns or leases properties 
     or in which the conduct of its business requires such qualification, 
     except to the extent that the failure to be so qualified or be in good 
     standing would not have a material adverse effect on the Company and its 
     subsidiaries considered as a whole; all of the issued and outstanding 
     capital stock or other equity interest of each subsidiary has been duly 
     authorized and validly issued and is fully paid and nonassessable, and 
     all such capital stock or other equity interest of each subsidiary is 
     owned by the Company, directly or through subsidiaries, free and clear 
     of any mortgage, pledge, lien, encumbrance, claim or equity. 

          (g)  Neither the Company nor any of its subsidiaries is (i) 
     in violation of its or any of their charters or by-laws or other 
     organizational documents or (ii) in default in the 


                                     -3-

<PAGE>

     performance or observance of any obligation, agreement, covenant or 
     condition contained in any contract, indenture, mortgage, loan 
     agreement, note, lease or other instrument to which it or any of them is 
     a party or by which it or any of them or their properties may be bound 
     except to the extent that such default would not have a material adverse 
     effect on the Company and its subsidiaries considered as a whole; no 
     consent, approval, authorization or order of any court or governmental 
     authority or agency is required for the consummation by the Company of 
     the transactions contemplated by this Agreement, except such as may be 
     required under the Act, the 1939 Act, the Rules and Regulations or state 
     securities or Blue Sky laws; and the execution and delivery of this 
     Agreement, the Indenture and the Notes and the consummation of the 
     transactions contemplated herein and therein will not conflict with or 
     constitute a breach of, or default under, or result in the creation or 
     imposition of any lien, charge or encumbrance upon any property or 
     assets of the Company or any of its subsidiaries pursuant to, any 
     material contract, indenture, mortgage, loan agreement, note, lease or 
     other instrument to which the Company or any of its subsidiaries is a 
     party or by which it or any of them may be bound or to which any of the 
     property or assets of the Company or any of its subsidiaries is subject, 
     nor will such action result in any violation of or conflict with the 
     provisions of the charter or by-laws of the Company or any law, 
     administrative regulation or administrative or court decree. 

          (h)  The Company and its subsidiaries possess adequate 
     certificates, authorities, licenses or permits issued by the appropriate 
     state, federal or foreign regulatory agencies or bodies necessary to 
     conduct the business now operated by them, and neither the Company nor 
     any of its subsidiaries has received any notice of proceedings relating 
     to the revocation or modification of any such certificate, authority, 
     license or permit which, singly or in the aggregate, if the subject of 
     an unfavorable decision, ruling or finding, would materially adversely 
     affect the condition, financial or otherwise, earnings, affairs or 
     business prospects of the Company and its subsidiaries considered as a 
     whole.

          (i)  Except as set forth in the Prospectus, there is no action, 
     suit or proceeding before or by any court or governmental agency or 
     body, domestic or foreign, now pending or, to the knowledge of the 
     Company, threatened against or affecting the Company or any of its 
     subsidiaries, which might result in any material adverse change in the 
     condition, financial or otherwise, earnings, affairs or business 
     prospects of the Company and its subsidiaries considered as a whole, or 
     might materially and adversely affect the properties or assets thereof 
     or might materially and adversely affect the offering of the Notes; and 
     there are no material contracts or other documents which are required to 
     be filed as exhibits to the Registration Statement by the Act or by the 
     Rules and Regulations which have not been so filed.

          (j)  The Company and each of its subsidiaries has good and 
     defensible title to all property and assets owned by it and necessary in 
     the conduct of the business of the Company or such subsidiary in each 
     case free and clear of all liens, encumbrances and defects except (i) 
     such as are referred to in the Prospectus or (ii) such as do not 
     materially adversely affect the value of such property to the Company or 
     such subsidiary, and do not interfere with the use made and proposed to 
     be made of such property by the Company or such subsidiary to 


                                     -4-

<PAGE>

     an extent that such interference would have a material adverse effect on 
     the Company or such subsidiary.

          (k)  This Agreement has been duly authorized, executed and 
     delivered by the Company and each of the Subsidiary Guarantors and is a 
     valid and binding agreement of the Company and each of the Subsidiary 
     Guarantors (subject, as to the enforcement of remedies, to applicable 
     bankruptcy, reorganization, insolvency, moratorium or other laws 
     affecting creditors' rights generally from time to time in effect and to 
     general equitable principles), except as rights to indemnity hereunder 
     may be limited by applicable law.

          (l)  The Indenture has been duly authorized, executed and delivered 
     by the Company and each of the Subsidiary Guarantors and duly qualified 
     under the 1939 Act, and constitutes a legal, valid and binding 
     instrument enforceable against the Company and each of the Subsidiary 
     Guarantors in accordance with its terms (subject, as to the enforcement 
     of remedies, to applicable bankruptcy, reorganization, insolvency, 
     moratorium or other laws affecting creditors' rights generally from time 
     to time in effect and to general equitable principles).

          (m)  The Notes have been duly and validly authorized by the Company 
     for issuance and sale to the Underwriters pursuant to this Agreement 
     and, when executed by the Company and authenticated by the Trustee in 
     accordance with the Indenture and delivered to the Underwriters against 
     payment therefor in accordance with the terms hereof, will have been 
     validly issued and delivered, free of any preemptive or similar rights, 
     and will constitute valid and binding obligations of the Company 
     entitled to the benefits of the Indenture and enforceable against the 
     Company in accordance with their terms (subject, as to the enforcement 
     of remedies, to applicable bankruptcy, reorganization, insolvency, 
     moratorium or other laws affecting creditors' rights generally from time 
     to time in effect and to general equitable principles).  The Notes 
     conform, or will conform, to the description thereof in the Registration 
     Statement and the Prospectus.  Neither the filing of the Registration 
     Statement nor the offering or sale of the Notes as contemplated by this 
     Agreement gives rise to any rights, other than those which have been 
     duly waived or satisfied, for or relating to the registration of any 
     securities of the Company.  The capitalization of the Company as of  the 
     date of the most recent balance sheet included in the Prospectus is as 
     set forth in the Prospectus.  The Company has all requisite corporate 
     power and authority to issue, sell, and deliver the Notes in accordance 
     with and upon the terms and conditions set forth in this Agreement and 
     in the Registration Statement and Prospectus.  All corporate action 
     required to be taken by the Company for the authorization, issuance, 
     sale and delivery of the Notes to be sold by the Company hereunder has 
     been validly and sufficiently taken.

          (n)  The Subsidiary Guarantees have been duly and validly 
     authorized by the Subsidiary Guarantors, and, when executed and endorsed 
     upon the Notes and delivered in accordance with the terms of the 
     Indenture, such Subsidiary Guarantees will be valid and binding 
     obligations of the Subsidiary Guarantors, enforceable against the 
     Subsidiary Guarantors in accordance with their terms (subject, as to the 
     enforcement of remedies, to applicable bankruptcy, reorganization, 
     insolvency, moratorium or other laws affecting 


                                     -5-

<PAGE>


     creditors' rights generally from time to time in effect and to general 
     equitable principles); the issuances of the Subsidiary Guarantees are 
     not subject to preemptive or other similar rights to subscribe to or 
     purchase the same arising by operation of law or under the charter, 
     bylaws or other organizational documents of any of the Subsidiary 
     Guarantors or otherwise; the form of notation to be set forth on each 
     Note to evidence the Subsidiary Guarantees will be in the form 
     contemplated by the Indenture; and the Subsidiary Guarantees conform in 
     all material respects to the description thereof contained in the 
     Registration Statement and the Prospectus.  The issuance and performance 
     of the Subsidiary Guarantees and the consummation of the other 
     transactions contemplated herein and therein, and compliance by the 
     Subsidiary Guarantors with their respective obligations hereunder and 
     thereunder, have been duly and validly authorized by all necessary 
     corporate or partnership action on the part of each of the Subsidiary 
     Guarantors.

          (o)  KPMG Peat Marwick, LLP and Elms Faris & Company, who have 
     certified certain financial statements of the Company and its 
     subsidiaries, are independent public accountants within the meaning of 
     the Securities Act and the rules and regulations thereunder.

          (p)  The Company and each of its subsidiaries maintain a system of 
     internal accounting controls sufficient to provide reasonable assurances 
     that (i) transactions are executed in accordance with management's 
     general or specific authorizations; (ii) transactions are recorded as 
     necessary to permit preparation of financial statements in conformity 
     with generally accepted accounting principles and to maintain asset 
     accountability; (iii) access to assets is permitted only in accordance 
     with management's general or specific authorization; and (iv) the 
     recorded accountability for assets is compared with the existing assets 
     at reasonable intervals and appropriate action is taken with respect to 
     any differences.

          (q)  Neither the Company nor any of its subsidiaries is now or, 
     after giving effect to the issuance of the Notes and the Subsidiary 
     Guarantees, will be (i) insolvent, (ii) left with unreasonably small 
     capital, on a pro forma basis, with which to engage in its anticipated 
     businesses or (iii) incurring debts beyond its ability to pay such debts 
     as they become due.

          (r)  The Company and its subsidiaries own or otherwise possess the 
     right to use all patents, trademarks, service marks, trade names and 
     copyrights, all applications and registrations for each of the 
     foregoing, and all other proprietary rights and confidential information 
     used in the conduct of their respective businesses as currently 
     conducted; and neither the Company nor any of its subsidiaries has 
     received any notice or is otherwise aware, of any infringement of or 
     conflict with the rights of any third party with respect to any of the 
     foregoing which, singly or in the aggregate, if the subject of an 
     unfavorable decision, ruling or finding, would result in a material 
     adverse effect on the Company.

          (s)  The Company and each of its subsidiaries are insured by 
     insurers of recognized financial responsibility against such losses and 
     risks and in such amounts as are prudent and customary in the businesses 
     in which they are engaged; neither the Company nor 


                                     -6-

<PAGE>


     any of its subsidiaries have been refused any insurance coverage sought 
     or applied for; and neither the Company nor any of its subsidiaries have 
     any reason to believe that they will not be able to renew their existing 
     insurance coverage as and when such coverage expires or to obtain 
     similar coverage from similar insurers as may be necessary to continue 
     its business at a cost that would not have a material adverse effect on 
     the Company.

          (t)  The Company has complied and will comply with all the 
     provisions of Section 517.075, Florida Statutes (Chapter 92-198, Laws of 
     Florida) and all regulations promulgated thereunder relating to issuers 
     doing business in Cuba.

          (u)  There are no contracts or other documents which are required 
     to be described in the Prospectus or filed as exhibits to the 
     Registration Statement by the Act or by the Rules and Regulations which 
     have not been described in the Prospectus or filed as exhibits to the 
     Registration Statement or incorporated therein by reference as permitted 
     by the Rules and Regulations.

          (v)  There has been no storage, disposal, generation, manufacture, 
     refinement, transportation, handling or treatment of toxic wastes, 
     medical wastes, hazardous wastes or hazardous substances by the Company 
     or any of its subsidiaries (or, to the knowledge of the Company, any of 
     their predecessors in interest) at, upon or from any of the property now 
     or previously owned or leased by the Company or its subsidiaries in 
     violation of any applicable law, ordinance, rule, regulation, order, 
     judgment, decree or permit, or which would require remedial action under 
     any applicable law, ordinance, rule, regulation, order, judgment, decree 
     or permit, except for any violation or remedial action which would not 
     have, or could not be reasonably likely to have, singularly or in the 
     aggregate with all such violations and remedial actions, a material 
     adverse effect on the general affairs, management, financial position, 
     stockholders' equity or results of operations of the Company and its 
     subsidiaries; there has been no material spill, discharge, leak, 
     emission, injection, escape, dumping or release of any kind onto such 
     property or into the environment surrounding such property of any toxic 
     wastes, medical wastes, solid wastes, hazardous wastes or hazardous 
     substances due to or caused by the Company or any of its subsidiaries or 
     with respect to which the Company or any of its subsidiaries have 
     knowledge, except for any such spill, discharge, leak, emission, 
     injection, escape, dumping or release which would not have or would not 
     be reasonably likely to have, singularly or in the aggregate with all 
     such spills, discharges, leaks, emissions, injections, escapes, dumpings 
     and releases, a material adverse effect on the general affairs, 
     management, financial position, stockholders' equity or results of 
     operations of the Company and its subsidiaries; and the terms "hazardous 
     wastes," "toxic wastes," "hazardous substances" and "medical wastes" 
     shall have the meanings specified in any applicable local, state, 
     federal and foreign laws or regulations with respect to environmental 
     protection.

     SECTION 3.  PURCHASE, SALE AND DELIVERY OF NOTES.  Subject to the terms 
and conditions and in reliance upon the representations and warranties herein 
set forth, the Company agrees to sell to each Underwriter, and each 
Underwriter agrees, severally and not jointly, to 


                                     -7-

<PAGE>

purchase from the Company at a purchase price of _______% of the principal 
amount per Note (the "purchase price per Note"), plus accrued interest, if 
any, from _________, 1996 to the date of payment and delivery, the respective 
principal amount of Notes set forth opposite such Underwriter's name in 
Schedule I hereto.

     Delivery of and payment for the Notes shall be made at __________ a.m. 
New York City time, on __________, 1996, or such later date (not later than 
__________, 1996) as you shall designate, which date and time may be 
postponed by agreement between you and the Company or as provided in Section 
11 hereof (such date and time of delivery and payment for the Notes being 
herein called the "Closing Date").  Delivery of the Notes shall be made to 
you for the respective accounts of the Underwriters against payment by the 
Underwriters through you of the purchase price thereof to or upon the order 
of the Company by certified or official bank check or checks payable in 
immediately available funds; PROVIDED, that the amount of such payment shall 
be reduced by one days' interest on the amount of gross proceeds at the 
Underwriters' cost of borrowing such funds plus any other expenses associated 
with such payment of immediately available funds. Delivery of the Notes shall 
be made at such location as you shall reasonably designate at least one 
business day in advance of the Closing Date and payment for the Notes shall 
be made at the office of Baker & Botts, L.L.P. ("Counsel for the 
Underwriters"), One Shell Plaza, 910 Louisiana, Houston, Texas  77002.

     The Company, Prudential Securities Incorporated (the "Independent 
Underwriter") and the other Underwriter agree to comply in all material 
respects with all of the requirements of Rule 2720 of the Conduct Rules of 
the National Association of Securities Dealers, Inc. ("Rule 2720") applicable 
to them in connection with the offering and sale of the Notes.  The Company 
agrees to cooperate with Underwriters, to enable the Underwriters to comply 
with Rule 2720 and the Independent Underwriter to perform the services 
contemplated by this Agreement.

     The Independent Underwriter hereby consents to the references to it as 
set forth under the caption "Underwriting" in the Prospectus.

     SECTION 4.  OFFERING BY UNDERWRITERS.  The several Underwriters will 
offer the Notes for sale to the public on the terms as set forth in the 
Prospectus. 

     SECTION 5.  COVENANTS OF THE COMPANY.  The Company covenants and agrees 
with the each Underwriter that:

          (a)  The Company will advise you promptly of any proposal to amend 
     or supplement the registration statement as filed, or the related 
     prospectus, prior to the effectiveness of the Registration Statement, 
     and will not effect such amendment or supplement without your consent, 
     which will not be unreasonably withheld; the Company will also advise 
     you promptly of the filing or effectiveness of any amendment or 
     supplement to the Registration Statement or the Prospectus, the receipt 
     of any comments from the Commission with respect to the Registration 
     Statement or the Prospectus or any amendment or supplement thereto, and 
     of receipt of notification of the institution by the Commission or any 
     state of any stop order proceedings in respect of the Registration 
     Statement or the initiation or threatening of any proceeding for such 
     purpose, and will use every reasonable 


                                     -8-

<PAGE>

     effort to prevent the issuance of any such stop order and to obtain as 
     soon as possible its lifting, if issued. The Company will also notify 
     you promptly of any request by the Commission for any amendment of or 
     supplement to the Registration Statement or the Prospectus or for 
     additional information; the Company will prepare and file with the 
     Commission, promptly upon your request, any amendments or supplements to 
     the Registration Statement or the Prospectus which, in your opinion, may 
     be necessary or advisable in connection with the distribution of the 
     Notes; and the Company will not file any amendment or supplement to the 
     Registration Statement or the Prospectus or file any document under the 
     Exchange Act before the termination of the offering of the Notes by the 
     Underwriters if such document would be deemed to be incorporated by 
     reference into the Prospectus, which filing is not consented to by the 
     Underwriters after reasonable notice thereof, such consent not to be 
     unreasonably withheld or delayed.

          (b)  If, during such period of time after the first date of the 
     public offering of the Notes as in the opinion of counsel for the 
     Underwriters a prospectus relating to the Notes is required by law to be 
     delivered in connection with sales by an Underwriter or dealer, any 
     event occurs as a result of which the Prospectus as then amended or 
     supplemented would, in the judgment of the Underwriters and their 
     counsel, include an untrue statement of a material fact, or omit to 
     state a material fact necessary to make the statements therein, in light 
     of the circumstances under which they were made, not misleading, or if 
     it is necessary at any time to amend the Prospectus to comply with the 
     Act or any other law, subject to the requirements of paragraph (a) of 
     this Section 5, the Company promptly will prepare and file with the 
     Commission an amendment or supplement which will correct such statement 
     or omission or an amendment which will effect such compliance and will 
     notify you of such filing, and will prepare and provide to the 
     Underwriters pursuant to paragraph (c) of this Section 5, an amended 
     Prospectus or a supplement to the Prospectus which will correct such 
     statement or omission or effect such compliance. 

          (c)  The Company will make generally available to the Company's 
     security holders as soon as practicable an earning statement covering 
     the twelve month period ending September 30, 1997, that satisfies the 
     provisions of Section 11(a) of the Act and the Rules and Regulations 
     including, without limitation, Rule 158. 

          (d)  The Company will deliver to you, free of charge, (i) as many 
     signed and conformed copies of the Registration Statement (as originally 
     filed) and of each amendment thereto (including exhibits filed therewith 
     or incorporated by reference therein) and of the Prospectus as you may 
     reasonably request and (ii) a conformed copy of the Registration 
     Statement and each amendment thereto for each of the Underwriters and 
     will also deliver to each Underwriter, free of charge, during the period 
     referred to in paragraph (b) of this Section 5, as many copies of the 
     Prospectus and any amendments and supplements thereto as such 
     Underwriter may reasonably request.  

          (e)  The Company will arrange to qualify the Notes for offering and 
     sale under the applicable securities laws of such states and other 
     jurisdictions of the United States as the Underwriters may designate, 
     and will maintain such qualifications in effect for as long as 


                                     -9-

<PAGE>


     may be required for the distribution of the Notes.  The Company will 
     file such statements and reports as may be required by the laws of each 
     jurisdiction in which the Notes have been qualified as above provided.

          (f)  During the period of five years hereafter, the Company will 
     furnish to you and upon request, to each of the other Underwriters, as 
     soon as practicable after the end of each fiscal year, a copy of its 
     annual report to stockholders for such year, and the Company will 
     furnish to you (i) as soon as available, a copy of each report or 
     definitive proxy statement of the Company filed with the Commission 
     under the Exchange Act or mailed to stockholders, and (ii) from time to 
     time, such other information concerning the Company as you may 
     reasonably request.

          (g)  Until the termination of the offering of the Notes, the 
     Company shall timely file all documents and amendments to previously 
     filed documents required to be filed by it pursuant to Section 12, 13, 
     14 or 15(d) of the Exchange Act.

          (h)  The Company shall apply the net proceeds from the sale of the 
     Notes as set forth in the Prospectus.

          (i)  The Company will cooperate with you and use its best efforts 
     to permit the Notes to be eligible for clearance and settlement through 
     The Depository Trust Company.

          (j)  The Company will not, until [_____] days following the Closing 
     Date, without your prior written consent, offer, sell or contract to 
     sell in a public offering, or otherwise dispose of in a public offering, 
     directly or indirectly, or announce the public offering of, any debt 
     securities issued or guaranteed by the Company (other than the Notes).

     SECTION 6.  CONDITIONS OF THE OBLIGATIONS OF THE UNDERWRITERS.  The 
obligations of the several Underwriters to purchase and pay for the Notes on 
the Closing Date will be subject to the accuracy of the representations and 
warranties on the part of the Company herein as of the date hereof and as of 
the Closing Date with the same force and effect as if made as of that date, 
to the accuracy of the statements of the Company made in any certificates 
pursuant to the provisions hereof, to the performance by the Company of its 
obligations hereunder and to the following additional conditions:

          (a)  The Registration Statement shall have become effective (or if 
     a post-effective amendment is required to be filed under the Act, such 
     post-effective amendment shall have become effective) not later than 
     5:00 p.m., New York time, on the date of this Agreement, or such later 
     time or date as shall have been consented to by you; and prior to the 
     Closing Date no stop order suspending the effectiveness of the 
     Registration Statement shall have been issued and no proceedings for 
     that purpose shall have been instituted, or to the knowledge of the 
     Company or you, shall be contemplated by the Commission. 

          (b)  You shall not have advised the Company that the Registration 
     Statement or  Prospectus, or any amendment or supplement thereto, 
     contains an untrue statement of fact 


                                     -10-

<PAGE>

         or omits to state a fact which, you have concluded, is material and 
         in the case of an omission is required to be stated therein or is 
         necessary to make the statements therein not misleading. 

              (c)  You shall have received a favorable opinion of Cotton, 
         Bledsoe, Tighe & Dawson, a Professional Corporation ("Counsel for the 
         Company"), dated the Closing Date to the effect that: 

                   (i)  The Company has been duly incorporated and is validly 
              existing as a corporation in good standing under the laws of 
              Delaware with full corporate power and authority to own, lease
              and operate its properties and conduct its business as described
              in the Registration Statement; and the Company is duly qualified
              as a foreign corporation to transact business and, to the best of
              such counsel's knowledge and information, is in good standing in 
              each jurisdiction which requires such qualification wherein it 
              owns or leases material properties or conducts material business
              except where the failure to so qualify would not have a material
              adverse effect on the properties, prospects, condition (financial
              or otherwise) or results of operations of the Company and its 
              subsidiaries taken as a whole.

                   (ii) Each of the subsidiaries of the Company has been duly 
              incorporated or organized and is validly existing as a corporation
              or limited liability company in good standing under the laws of 
              the jurisdiction of its formation, has corporate power and 
              authority to own, lease and operate its properties and conduct its
              business as described in the Registration Statement, and, to the 
              best of such counsel's knowledge and information, is duly 
              qualified as a foreign corporation or limited liability company to
              transact business and is in good standing in each jurisdiction 
              which requires such qualification wherein it owns or leases 
              material properties or conducts material business except where the
              failure to so qualify would not have a material adverse effect on 
              the properties, prospects, condition (financial or otherwise) or 
              results of operations of the Company and its subsidiaries taken as
              a whole; all of the issued and outstanding capital stock or other 
              equity interest of each subsidiary has been duly authorized and 
              validly issued and is fully paid and non-assessable, and, except 
              as otherwise set forth in the Registration Statement, all of such
              capital stock or other equity interest, to the best of such 
              counsel's knowledge and information, is owned by the Company, 
              directly or indirectly, free and clear of any mortgage, pledge, 
              lien, encumbrance, claim or equity. 

                   (iii) All of the outstanding shares of capital stock of the
              Company have been duly authorized and are validly issued, fully 
              paid and nonassessable.  To the best of such counsel's knowledge,
              neither the filing of the Registration Statement nor the offering
              or sale of the Notes as contemplated by this Agreement gives rise
              to any rights, other than those which have been waived or 
              satisfied, for or relating to the registration of any securities 
              of the Company or any of its subsidiaries, and, to the best of 
              such counsel's knowledge, no person or entity (other than the 
              Underwriters) has the right, contractual or otherwise, to cause 
              the Company to sell or otherwise issue to such person or entity, 
              or permit such person or entity to underwrite the sale 

                                    -11- 
<PAGE>

              of, any of the Notes.  The authorized equity capitalization of the
              Company as of the date of the most recent balance sheet included 
              or incorporated by reference in the Prospectus is as set forth in
              the Prospectus, and the Notes conform as to legal matters to the 
              description thereof contained in the Prospectus.  The Company has
              all requisite corporate power and authority to issue, sell and 
              deliver the Notes in accordance with and upon the terms and 
              conditions set forth in this Agreement and in the Registration 
              Statement and Prospectus.

                   (iv) This Agreement has been duly authorized, executed and 
              delivered by the Company and each of the Subsidiary Guarantors.

                   (v)  The Indenture has been duly authorized, executed and 
              delivered by the Company and each of the Subsidiary Guarantors and
              duly qualified under the 1939 Act, and constitutes a legal, valid 
              and binding instrument enforceable against the Company and each of
              the Subsidiary Guarantors in accordance with its terms (subject, 
              as to the enforcement of remedies, to applicable bankruptcy, 
              reorganization, insolvency, moratorium or other laws affecting 
              creditors' rights generally from time to time in effect and to 
              general equitable principles).

                   (vi) The Notes have been duly and validly authorized and, 
              when executed and authenticated in accordance with the provisions
              of the Indenture and delivered to and paid for by the Underwriters
              pursuant to this Agreement, will constitute legal, valid and 
              binding obligations of the Company entitled to the benefits of the
              Indenture (subject, as to the enforcement of remedies, to 
              applicable bankruptcy, reorganization, insolvency, moratorium or 
              other laws affecting creditors' rights generally from time to time
              in effect and to general equitable principles); and the statements
              set forth under the heading "Description of Notes" in the 
              Prospectus, insofar as such statements purport to summarize 
              certain provisions of the Notes and the Indenture, provide a fair 
              summary of such provisions.

                   (vii) The Subsidiary Guarantees have been duly and validly 
              authorized and executed by the Subsidiary Guarantors, and, when 
              delivered in accordance with the terms of this Agreement, such 
              Subsidiary Guarantees will have been validly issued and delivered
              and will constitute valid and binding obligations of the 
              Subsidiary Guarantors, enforceable against the Subsidiary 
              Guarantors in accordance with their terms (subject, as to the 
              enforcement of remedies, to applicable bankruptcy, reorganization,
              insolvency, moratorium or other laws affecting creditors' rights 
              generally from time to time in effect and to general equitable 
              principles).

                   (viii) The Registration Statement is effective under the 
              Act and, to the best of such counsel's knowledge and information,
              no stop order suspending the effectiveness of the Registration 
              Statement has been issued under the Act or proceedings therefor
              initiated or threatened by the Commission.  All required filings
              by the Company under Rule 424(b) of the Rules and Regulations have
              been timely made.

                                    -12- 
<PAGE>

                   (ix) Statements set forth in the Prospectus under the 
              headings "Business and Properties--Regulation" and "Description
              of Notes," in the Registration Statement, insofar as such 
              statements constitute a summary of the legal matters, documents or
              proceedings referred to therein fairly present the information 
              called for with respect to such legal matters, documents and 
              proceedings.

                   (x)  No consent, approval, authorization or order of any 
              court or governmental authority or agency is required in 
              connection with the transactions contemplated by this Agreement,
              except such as may be required under the Act, the 1939 Act, the 
              Rules and Regulations or state securities or Blue Sky laws and 
              such other approvals (specified in such opinion) as have been 
              obtained; and, to the best of such counsel's knowledge and 
              information, the execution and delivery of this Agreement, the 
              Notes and the Indenture and the consummation of the transactions
              contemplated herein will not conflict with or constitute a breach
              of, or default under, or result in the creation or imposition of 
              any lien, charge or encumbrance upon any property or assets of the
              Company or any of its subsidiaries pursuant to, any contract, 
              indenture, mortgage, loan agreement, note, lease or other 
              instrument to which the Company or any of its subsidiaries is a 
              party or by which it or any of them may be bound or to which any 
              of the property or assets of the Company or any of its 
              subsidiaries is subject; nor will such action result in any 
              violation of the provisions of the charter or by-laws of the 
              Company, or any law, administrative regulation or administrative
              or court decree. 

                   (xi) After due inquiry, such counsel does not know of any 
              legal or governmental proceeding pending or threatened to which
              the Company or any of its subsidiaries is a  party or to which 
              any of the properties of the Company is subject that is required
              to be described in the Registration Statement or the Prospectus 
              and is not so described or of any contract or other document that
              is required to be described in the Registration Statement or the 
              Prospectus or to be filed as an exhibit to the Registration 
              Statement that is not so described or filed as required.

                   (xii) The Registration Statement and the Prospectus and 
              any further amendments or supplements thereto made by the Company
              at the time the Registration Statement and each amendment thereto
              became effective (except that no opinion need be expressed as to 
              the financial statements or notes thereto and other financial and
              statistical data contained therein) and the Form T-1 complied as 
              to form in all material respects with the applicable requirements
              of the Act and the Rules and Regulations and the 1939 Act and the
              rules and regulations thereunder. 

              Such opinion shall also contain a statement that such counsel 
     has no reason to believe that (i) the Registration Statement, as of the 
     Effective Time, or any amendment thereto (other than the engineering 
     data, financial statements and notes thereto and the other engineering,
     financial and statistical data contained therein, as to which such counsel
     need not comment), at the time it became effective, contained any untrue 
     statement of a material fact or omitted to state any material fact required
     to be stated therein or necessary in order to make the 

                                    -13- 
<PAGE>

     statements therein not misleading, or (ii) the Prospectus or any supplement
     or amendment thereto (other than the engineering data, financial statements
     and notes thereto and the other engineering, financial and statistical data
     contained therein, as to which such counsel need not comment), on such 
     Closing Date or at the time such Prospectus or supplement or amendment 
     thereto was issued contains or contained any untrue statement of a material
     fact or omits or omitted to state any material fact required to be stated 
     therein or necessary in order to make the statements therein, in light of 
     the circumstances under which they were made, not misleading.

         (d)  You shall have received from Counsel for the Underwriters such 
     opinion or opinions, dated the Closing Date, with respect to the issuance
     and sale of the Notes, the Registration Statement and Prospectus (as 
     amended or supplemented at the Closing Date) and other related matters as
     the Underwriters may reasonably require, and the Company shall have 
     furnished to such counsel such documents as they request for the purpose
     of enabling them to pass upon such matters.

         (e)  At the Closing Date there shall not have been, since the date 
     of this Agreement or since the respective dates as of which information is
     given in the Registration Statement, any material adverse change in the 
     condition, financial or otherwise, earnings, business affairs or business 
     prospects of the Company and its subsidiaries considered as a whole, 
     whether or not arising in the ordinary course of business, except as set 
     forth in or contemplated by the Prospectus (exclusive of any amendment or
     supplement thereto), and you shall have received a certificate of the 
     Company, signed by the Chairman of the Board or the President and the 
     principal financial or accounting officer of the Company, dated the Closing
     Date, to the foregoing effect, to the effect that the signers of such 
     certificate have carefully examined the Prospectus, any amendment or 
     supplement to the Prospectus and this Agreement, and to the further effect
     that (i) the representations and warranties of the Company contained in 
     this Agreement are true and correct on and as of the Closing Date with the
     same force and effect as though expressly made on and as of the Closing 
     Date, (ii) the Company has performed or complied with all agreements and
     satisfied all conditions on its part to be performed or satisfied at or 
     prior to the Closing Date and (iii) no stop order suspending the 
     effectiveness of the Registration Statement has been issued and no 
     proceedings for that purpose have been initiated or threatened by the 
     Commission or any state.

         (f)  You shall have received from KPMG Peat Marwick, LLP, independent
     public accountants, two letters, the first delivered concurrently with the
     execution of, and dated the date of, this Agreement and the other dated the
     Closing Date, addressed to the Underwriters (with conformed copies for each
     of the Underwriters), in form and substance satisfactory to you, to the 
     effect that:

              (i)  They are independent public accountants with respect to the 
         Company and its subsidiaries within the meaning of the Act and the 
         Rules and Regulations.

                                    -14- 
<PAGE>

              (ii) In their opinion, the consolidated financial statements and 
         supporting schedules of the Company and its subsidiaries and of the 
         properties acquired by the Company in certain material transactions in
         1995 and 1996 examined by them and included or incorporated by 
         reference in the Registration Statement comply as to form in all 
         material respects with the applicable accounting requirements of the
         Act and the Rules and Regulations with respect to registration 
         statements on Form S-1 and the Exchange Act and the rules and 
         regulations promulgated thereunder (the "Exchange Act Regulations").

              (iii) They have performed specified procedures, not constituting
         an audit, including a reading of the latest available interim 
         financial statements of the Company and its indicated subsidiaries, a
         reading of the minute books of the Company and such subsidiaries since
         the end of the most recent fiscal year with respect to which an audit
         report has been issued, inquiries of and discussions with certain 
         officials of the Company and such subsidiaries responsible for 
         financial and accounting matters with respect to the unaudited 
         consolidated financial statements included in the Registration 
         Statement and Prospectus and the latest available interim unaudited 
         financial statements of the Company and its subsidiaries in accordance
         with Statement of Financial Accounting Standards No. 71, and such other
         inquiries and procedures as may be specified in such letters, and on 
         the basis of such inquiries and procedures nothing came to their 
         attention that caused them to believe that: (A) the unaudited 
         consolidated financial statements of the Company and its subsidiaries 
         included in the Registration Statement and Prospectus do not comply as
         to form in all material respects with the applicable accounting 
         requirements of the Exchange Act and the Exchange Act Regulations or 
         were not fairly presented in conformity with generally accepted 
         accounting principles in the United States applied on a basis 
         substantially consistent with that of the audited financial statements
         included or incorporated by reference therein, or (B) at a specified 
         date not more than five days prior to the date of such letters, there
         was any change in the consolidated capital stock or any increase in 
         consolidated long-term debt of the Company and its subsidiaries or any
         decrease in the consolidated net current assets or members' capital of
         the Company and its subsidiaries or any increases or decreases in any 
         other items specified by the Underwriters, in each case as compared 
         with the amounts shown on the most recent balance sheet of the Company
         and its subsidiaries included or incorporated by reference in the 
         Registration Statement and Prospectus or, during the period from the 
         date of such balance sheet to a specified date not more than five days
         prior to the date of such letters, there were any decreases, as 
         compared with the corresponding period in the preceding year, in 
         consolidated net revenues or the total or per share amounts of 
         consolidated net income of the Company and its subsidiaries or any 
         increases or decreases in any other items specified by the 
         Underwriters, except in each such case as set forth in or contemplated
         by the Registration Statement and Prospectus or except for such 
         exceptions enumerated in such letters as shall have been agreed to by 
         the Underwriters and the Company.

                                    -15- 
<PAGE>

              (iv) In addition to the examination referred to in their report 
         included or incorporated by reference in the Registration Statement 
         and the Prospectus, and the specified procedures referred to in clause
         (iii) above, they have carried out certain other specified procedures,
         not constituting an audit, with respect to certain amounts, percentages
         and financial information which are included in the Registration 
         Statement and Prospectus and which are specified by the Underwriters,
         and have found such amounts, percentages and financial information to 
         be in agreement with the relevant accounting and financial records of 
         the Company and its subsidiaries identified in such letters.

              (v)  On the basis of a reading of the unaudited pro forma 
         financial statements included in the Registration Statement and 
         Prospectus; carrying out certain specified procedures; inquiries of
         certain officials of the Company and Parker & Parsley Development L.P.
         and its affiliates who have responsibility for financial and accounting
         matters; and proving the arithmetic accuracy of the application of the 
         pro forma adjustments to the historical amounts in the pro forma 
         financial statements, nothing came to their attention which caused them
         to believe that the pro forma financial statements do not comply in 
         form in all material respects with the applicable accounting 
         requirements of Rule 11-02 of Regulation S-X or that the pro forma 
         adjustments have not been properly applied to the historical amounts in
         the compilation of such statements.

         (g)  At the Closing Date, counsel for the Underwriters shall have 
     been furnished with such other documents and opinions as they may 
     reasonably  require.

         (h)  At the time of the Closing, the Notes shall have a rating of at 
     least _____ by Moody's Investors Service, Inc. and _____ by Standard & 
     Poor's Rating Service, and the Company shall have delivered to the 
     Underwriters a letter, dated the Closing Date, from each such rating agency
     or other evidence satisfactory to the Underwriters, confirming such 
     ratings.  Since the Effective Date, there shall not have occurred any 
     downgrading with respect to any debt securities of the Company or any of
     its Subsidiaries by any "nationally recognized statistical rating 
     organization" as that term is defined by the Commission for purposes of 
     Rule 436(g)(2) under the Act or any public announcement that any such 
     organization has under surveillance or review its rating of any such debt
     securities (other than an announcement with positive implications of a 
     possible upgrading, and no implication of a possible downgrading of such 
     rating).

         (i)  On or prior to the Closing Date, the closing contemplated 
     pursuant to the Stock Offering shall have occurred.

     All such opinions, certificates, letters and documents shall be in 
compliance with the provisions hereof only if they are satisfactory in form 
and substance to you and to counsel for the Underwriters.  The Company shall 
furnish to you conformed copies of such opinions, certificates, letters and 
other documents in such number as you shall reasonably request.  If any of 
the conditions specified in this Section 6 shall not have been fulfilled when 
and as required by this Agreement, this 

                                    -16- 
<PAGE>

Agreement and all obligations of the Underwriters hereunder may be canceled 
at, or at any time prior to, the Closing Date, by you.  Any such cancellation 
shall be without liability of the Underwriters to the Company.  Notice of 
such cancellation shall be given to the Company in writing, or by telegraph 
or telephone and confirmed in writing.

     SECTION 7.  PAYMENT OF EXPENSES.  The Company will pay all costs, 
expenses, fees and taxes incident to (i) the preparation by the Company, 
printing, filing and distribution under the Act of the Registration Statement 
(including financial statements and exhibits), the Prospectus, each 
preliminary prospectus and all amendments and supplements to any of them 
prior to or during the period specified in Section 5(b) (including, without 
limitation, the deliveries thereof pursuant to Section 5(d)), (ii) the 
preparation, printing (including word processing and duplication costs) and 
delivery of this Agreement, the Indenture, the Statement of Eligibility and 
Qualification of the Trustee on Form T-1, Preliminary and Supplemental Blue 
Sky Memoranda, the Notes and all other agreements, memoranda, correspondence 
and other documents printed and delivered in connection with the offering of 
the Notes, (iii) the registration with the Commission and the issuance by the 
Company of the Notes (iv) the registration or qualification of the Notes for 
offer and sale under the securities or Blue Sky laws of the several states as 
described in Section 5(e) (including the reasonable fees and disbursements of 
your counsel relating to such registration or qualification), (v) any fees or 
expenses relating to the use of book-entry notes, (vi) the fees, costs and 
charges of the Trustee, including the fees and disbursements of counsel for 
the Trustee, (vii) the fees and expenses of rating agencies, and (viii) all 
other costs and expenses incident to the performance by the Company of its 
other obligations under this Agreement.  

     If the sale of the Notes provided for herein is not consummated because 
any condition to the obligations of the Underwriters set forth in Section 6 
hereof is not satisfied, because of any termination pursuant to Section 10 
hereof or because of any refusal, inability or failure on the part of the 
Company to perform any agreement herein or comply with any provision hereof 
other than by reason of default by any of the Underwriters in payment for the 
Notes on the Closing Date, the Company will reimburse the Underwriters 
severally upon demand for all out-of-pocket expenses (including reasonable 
fees and disbursements of counsel) that shall have been incurred by them in 
connection with the proposed purchase and sale of the Notes.

         SECTION 8.  INDEMNIFICATION AND CONTRIBUTION.  (a)  The Company and 
     each of the Subsidiary Guarantors, jointly and severally, agree to 
     indemnify and hold harmless each Underwriter, the directors, officers, 
     employees and agents of each Underwriter and each person, if any, who
     controls any Underwriter within the meaning of Section 15 of the Act or
     Section 20 of the Exchange Act, from and against any and all losses, 
     claims, damages, liabilities or judgments (including without limiting the
     foregoing the reasonable legal and other expenses incurred in connection 
     with investigating or defending any action, suit or proceeding or any claim
     asserted) arising out of or based upon any untrue statement or alleged 
     untrue statement in Section 2 hereof or any untrue statement or alleged 
     untrue statement of a material fact contained in the Registration Statement
     or the Prospectus or any preliminary prospectus or in any amendment or 
     supplement thereto, or caused by any omission or alleged omission to state
     therein a material fact required to be stated therein or necessary to make
     the statements therein not misleading, except insofar as such losses, 

                                    -17- 
<PAGE>

     claims, damages, liabilities or expenses are caused by any such untrue 
     statement or omission or alleged untrue statement or omission based upon
     information furnished in writing to the Company by any Underwriter through
     you expressly for use therein; and shall reimburse each Underwriter 
     promptly after receipt of invoices from such Underwriter for any legal or
     other expenses as reasonably incurred by such Underwriter in connection 
     with investigating, preparing to defend or defending against or appearing
     as a third-party witness in connection with any such loss, claim, damage,
     liability or action, notwithstanding the possibility that payments for such
     expenses might later be held to be improper, in which case such payments 
     shall be promptly refunded.  This indemnity agreement will be in addition
     to any liability which the Company may otherwise have to the persons 
     referred to above in this Section 8(a).

         (b)  Each Underwriter agrees, severally and not jointly, to 
     indemnify and hold harmless the Company, each of the Subsidiary Guarantors,
     the directors of the Company, the officers of the Company who sign the 
     Registration Statement and each person, if any, who controls the Company 
     within the meaning of either Section 15 of the Act or Section 20 of the 
     Exchange Act, to the same extent as the foregoing indemnity from the 
     Company to each Underwriter, but only with reference to written information
     relating to such Underwriter furnished to the Company by or on behalf of 
     such Underwriter through you specifically for inclusion in the Registration
     Statement, the Prospectus, any amendment or supplement thereto, or any 
     preliminary prospectus. 

         (c)  Promptly after receipt by an indemnified party under this Section
     8 of notice of the commencement of any action, such indemnified party will,
     if a claim in respect thereof is to be made against the indemnifying party 
     under this Section 8, notify the indemnifying party in writing of the 
     commencement thereof; but the failure so to notify the indemnifying party
     (i) will not relieve it from liability under paragraph (a) or (b) above 
     unless and to the extent it did not otherwise learn of such action and such
     failure results in the forfeiture by the indemnifying party of substantial 
     rights and defenses and (ii) will not, in any event, relieve the 
     indemnifying party from any obligations to any indemnified party other than
     the indemnification obligation provided in paragraph (a) or (b) above.  The
     indemnifying party shall be entitled to appoint counsel of the indemnifying
     party's choice at the indemnifying party's expense to represent the 
     indemnified party in any action for which indemnification is sought (in 
     which case the indemnifying party shall not thereafter be responsible for
     the fees and expense or any separate counsel retained by the indemnified 
     party or parties except as set forth below); PROVIDED, HOWEVER, that such
     counsel shall be satisfactory to the indemnified party.  Notwithstanding 
     the indemnifying party's election to appoint counsel to represent the 
     indemnified party in an action, the indemnified party shall have the right
     to employ separate counsel (including local counsel), and the indemnifying
     party shall bear the reasonable fees, costs and expenses of such separate 
     counsel if (i) the use of counsel chosen by the indemnifying party to 
     represent the indemnified party would present such counsel with a conflict
     of interest, (ii) the actual or potential defendants in, or targets of, any
     such action include both the indemnified party and the indemnifying party 
     and the indemnified party shall have reasonably concluded that there may be
     legal defenses available to it and/or other indemnified parties which are 
     different from or additional to those available to the indemnifying party,
     (iii) the indemnifying party shall not have employed counsel satisfactory 

                                    -18- 
<PAGE>

     to the indemnified party to represent the indemnified party within a 
     reasonable time after notice of the institution of such action or (iv) the
     indemnifying party shall authorize the indemnified party to employ separate
     counsel at the expense of the indemnifying party. An indemnifying party 
     will not, without the prior written consent of the indemnified parties, 
     settle or compromise or consent to the entry of any judgment with respect
     to any pending or threatened claim, action, suit or proceeding in respect
     of which indemnification or contribution may be sought hereunder (whether
     or not the indemnified parties are actual or potential parties to such 
     claim or action) unless such settlement, compromise or consent includes an
     unconditional release of each indemnified party from all liability arising
     out of such claim, action, suit or proceeding.

         (d)  In the event that the indemnity provided in paragraph (a) or (b)
     of this Section 8 is unavailable to or insufficient to hold harmless an 
     indemnified party for any reason, the Company and the Underwriters agree
     to contribute to the aggregate losses, claims, damages and liabilities
     (including legal or other expenses reasonably incurred in connection with
     investigating or defending same) (collectively "Losses") to which the 
     Company and the Subsidiary Guarantors on the one hand and one or more of
     the Underwriters on the other hand may be subject in such proportion as 
     is appropriate to reflect the relative benefits received by the Company 
     and by the Underwriters from the offering of the Notes; PROVIDED, HOWEVER,
     that in no case shall any Underwriter (except as may be provided in any
     agreement among the Underwriters relating to the offering of the Notes) be
     responsible for any amount in excess of the purchase discount or commission
     applicable to the Notes purchased by such Underwriter hereunder.  If the 
     allocation provided by the immediately preceding sentence is unavailable 
     for any reason, the Company and the Subsidiary Guarantors on the one hand
     and the Underwriters on the other hand shall contribute in such proportion
     as is appropriate to reflect not only such relative benefits but also the
     relative fault of the Company and of the Underwriters in connection with 
     the statements or omissions which resulted in such Losses as well as any 
     other relevant equitable considerations.  Benefits received by the Company
     and the Subsidiary Guarantors shall be deemed to be equal to the total net
     proceeds from the offering (before deducting expenses), and benefits 
     received by the Underwriters shall be deemed to be equal to the total 
     purchase discounts and commissions received by the Underwriters from the
     Company in connection with the purchase of the Notes hereunder.  Relative
     fault shall be determined by reference to whether any alleged untrue 
     statement or omission relates to information provided by the Company or the
     Underwriters.  The Company and the Underwriters agree that it would not be 
     just and equitable if contribution were determined by pro rata allocation 
     or any other method of allocation which does not take into account of the 
     equitable considerations referred to above.  Notwithstanding the provisions
     of this paragraph (d), no person guilty of fraudulent misrepresentation 
     (within the meaning of Section 11(f) of the Act) shall be entitled to 
     contribution from any person who was not guilty of such fraudulent 
     misrepresentation. For purposes of this Section 8, each person who controls
     an Underwriter within the meaning of either the Act or the Exchange Act and
     each director, officer, employee and agent of an Underwriter shall have the
     same rights to contribution as such Underwriter, and each person who 
     controls the Company within the meaning of either the Act or Exchange Act 
     and each officer and director of the 

                                    -19- 
<PAGE>

     Company shall have the same rights to contribution as the Company, subject
     in each case to the applicable terms and conditions of this paragraph (d).

         (e)  The Company and each of the Subsidiary Guarantors also agrees 
to indemnify and hold harmless Prudential Securities Incorporated and each 
person, if any, who controls Prudential Securities Incorporated within the 
meaning of either Section 15 of the Act or Section 20 of the Exchange Act, 
from and against any and all losses, claims, damages, liabilities and 
judgments incurred as a result of Prudential Securities Incorporated's 
participation as a "qualified independent underwriter" within the meaning of 
Section b(15) of Rule 2720 in connection with the offering of the Notes, 
except for any losses, claims, damages, liabilities and judgments resulting 
from Prudential Securities Incorporated's, or such controlling person's, 
willful misconduct or gross negligence.

         SECTION 9.  REPRESENTATIONS, WARRANTIES AND AGREEMENTS TO SURVIVE 
DELIVERY.  The respective agreements, representations, warranties, 
indemnities and other statements of the Company or its officers and of the 
Underwriters set forth in or made pursuant to this Agreement will remain in 
full force and effect, regardless of any investigation made by or on behalf 
of the Underwriters or the Company or any of the officers, directors or 
controlling persons referred to in Section 8 hereof, and will survive 
delivery of and payment for the Securities.  The provisions of Sections 7 and 
8 hereof shall survive the termination or cancellation of this Agreement.

         SECTION 10.  EFFECTIVENESS OF AGREEMENT AND TERMINATION. This Agreement
shall become effective upon later of (x) execution and delivery hereof by the 
parties hereto and (y) release of notification of the effectiveness of the 
Registration Statement by the Commission.

         This Agreement may be terminated for any reason at any time prior to 
the Closing Date by NationsBanc Capital Markets, Inc., in its absolute 
discretion, upon the giving of written notice of such termination to the 
Company, if at or prior to the Closing Date (i) the Company shall have 
failed, refused or been unable to perform any agreement on its part to be 
performed hereunder, (ii) any other condition of the Underwriters' obligation 
hereunder is not fulfilled, (iii) there has been, since the respective dates 
as of which information is given in the Registration Statement, any material 
adverse change in the condition, financial or otherwise, earnings, business 
affairs or business prospects of the Company and its subsidiaries considered 
as a whole, whether or not arising in the ordinary course of business, (iv) 
there has occurred any outbreak or escalation of hostilities or other 
calamity or crisis or material change in existing financial, political, 
economic or securities market conditions, the effect of which is such as to 
make it, in the judgment of NationsBanc Capital Markets, Inc., impracticable 
or inadvisable to market the Notes in the manner contemplated in the 
Prospectus or enforce contracts for the sale of the Notes, (v) reporting of 
bid and asked prices has been suspended by the Commission or by the National 
Association of Securities Dealers, Inc. or trading generally on either the 
American Stock Exchange or the New York Stock Exchange has been suspended, or 
minimum or maximum prices for trading have been fixed, or maximum ranges for 
prices for securities have been required, by either of said exchanges or by 
order of the Commission or any other governmental authority, or if a banking 
moratorium has been declared by Federal, New York or Delaware authorities or 
(vi) if there shall have come to the attention of the Underwriters any facts 
that would cause the Underwriters to believe that the Prospectus, at the time 
it was required to 

                                    -20- 
<PAGE>

be delivered to a purchaser of Notes, included an untrue statement of a 
material fact or omitted to state a material fact necessary in order to make 
the statements therein, in light of the circumstances existing at the time of 
such delivery, not misleading.  In the event of any such termination, the 
provisions of Section 7, the indemnity agreement and contribution provisions 
set forth in Section 8, and the provisions of Sections 9 and 14 shall remain 
in effect.

         SECTION 11.  DEFAULT.  If, on the Closing Date, any one or more 
Underwriters shall fail to purchase and pay for any of the Notes agreed to be 
purchased by such Underwriter or Underwriters hereunder and such failure to 
purchase shall constitute a default in the performance of its or their 
obligations under this Agreement, the remaining Underwriters shall be 
obligated severally to take up and pay for (in the respective proportions 
which the principal amount of Notes set forth opposite their names in 
Schedule I hereto bears to the aggregate principal amount of Notes set forth 
opposite the names of all the remaining Underwriters) the Notes which the 
defaulting Underwriter or Underwriters agreed but failed to purchase; 
PROVIDED, HOWEVER, that in the event that the aggregate principal amount of 
Notes which the defaulting Underwriter or Underwriters agreed but failed to 
purchase shall exceed 10% of the aggregate principal amount of Notes set 
forth in Schedule I hereto, the remaining Underwriters shall have the right 
to purchase all, but shall not be under any obligation to purchase any, of 
the Notes, and if such non-defaulting Underwriters do not purchase all the 
Notes, this Agreement will terminate without liability to any non-defaulting 
Underwriter or the Company.  In the event of a default by any Underwriter as 
set forth in this Section 11, the Closing Date shall be postponed for such 
period, not exceeding seven days, as you shall determine in order that the 
required changes in the Registration Statement and in the Prospectus or in 
any other documents or arrangements may be effected.  Nothing contained in 
this Agreement shall relieve any defaulting Underwriter of its liability, if 
any, to the Company or any non-defaulting Underwriter for damages occasioned 
by its default hereunder.

         SECTION 12.  NOTICES.  All notices and other communications 
hereunder shall be in writing and shall be deemed to have been duly given if 
mailed or transmitted by any standard form of telecommunication. Notices to 
the Underwriters shall be directed to you c/o NationsBanc Capital Markets, 
Inc., 100 North Tryon Street, Charlotte, North Carolina 28255;  Attention:  
Syndicate; notices to the Company shall be directed to it at Costilla Energy, 
Inc., 400 West Illinois, Suite 1000, Midland, Texas  79701, to the attention 
of the Secretary with copy to the President.

         SECTION 13.  PARTIES.  This Agreement shall inure to the benefit of 
and be binding upon the Company, the Underwriters, any controlling persons 
referred to herein and their respective successors and assigns.  Nothing 
expressed or mentioned in this Agreement is intended or shall be construed to 
give any other person, firm or corporation any legal or equitable right, 
remedy or claim under or in respect of this Agreement or any provision herein 
contained. This Agreement and all conditions and provisions hereof are 
intended to be for the sole and exclusive benefit of the parties hereto and 
respective successors and said controlling persons and officers and directors 
and their heirs and legal representatives, and for the benefit of no other 
person, firm or corporation.  No purchaser of Notes from any Underwriter 
shall be deemed to be a successor by reason merely of such purchase. 

                                    -21- 
<PAGE>

         SECTION 14.  APPLICABLE LAW.  This Agreement will be governed by and 
construed in accordance with the laws of the State of New York.

         SECTION 15.  BUSINESS DAY.  For purposes of this Agreement, 
"business day" means each Monday, Tuesday, Wednesday, Thursday and Friday 
that is not a day on which banking institutions in The City of New York, New 
York are authorized or obligated by law, executive order or regulation to 
close.

         SECTION 16.  COUNTERPARTS.  This Agreement may be executed in one or 
more counterparts, each of which will be deemed to be an original, but all 
such counterparts will together constitute one and the same instrument.
















                                    -22- 
<PAGE>

         If the foregoing is in accordance with your understanding of our 
agreement, please sign this Agreement and return a counterpart hereof to us, 
whereupon this instrument, along with all counterparts, will become a binding 
agreement between the Underwriters, the Subsidiary Guarantors and the Company 
in accordance with its terms. 

                                    Very truly yours,

                                    COSTILLA ENERGY, INC.



                                    By:                                       
                                       -------------------------------------- 
                                       Name:  
                                       Title: 

                                    [SUBSIDIARY GUARANTORS]



                                    By:                                       
                                       -------------------------------------- 
                                       Name:  
                                       Title: 


Confirmed and Accepted, as of 
the date first above written: 

NATIONSBANC CAPITAL MARKETS, INC.
PRUDENTIAL SECURITIES INCORPORATED
Acting severally on behalf of 
themselves and the several 
Underwriters named herein. 

By: NATIONSBANC CAPITAL MARKETS, INC.



By:                                       
   -------------------------------------- 
   Name:  
   Title: 

[For themselves and the other
Underwriters named in Schedule I
to the foregoing Agreement]


                                      -23- 
<PAGE>

                                    SCHEDULE I

                                                              PRINCIPAL AMOUNT 
                                                                  OF NOTES
UNDERWRITER                                                    TO BE PURCHASED 
- -----------                                                   ---------------- 
NationsBanc Capital Markets, Inc.. . . . . . . . . . . . . . .    $ 

Prudential Securities Incorporated . . . . . . . . . . . . . .  
                                                                  --------- 
                  Total. . . . . . . . . . . . . . . . . . . .    $         
                                                                  --------- 
                                                                  --------- 













                                    -24- 


<PAGE>

                                                                 EXHIBIT 3.1 


                          CERTIFICATE OF INCORPORATION

                                       OF

                              COSTILLA ENERGY, INC.


                                    ARTICLE I

                                      NAME

     The name of the corporation is COSTILLA ENERGY, INC. (the "Corporation").


                                   ARTICLE II

                               PERIOD OF DURATION

     The period of duration of the Corporation is perpetual or until dissolved
or merged or consolidated in some lawful manner.

                                   ARTICLE III

                               PURPOSE AND POWERS

     Section 1.  PURPOSE.  The purpose for which the Corporation is organized is
to engage in any lawful acts or activities for which corporations may be
organized under the General Corporation Law of the State of Delaware (the
"Act").

     Section 2.  POWERS.  Subject to any specific written limitations or
restrictions imposed by the Act, by other law, or by this Certificate of
Incorporation, and solely in furtherance of, but not in addition to, the
purposes set forth in Section 1 of this Article, the Corporation shall have and
exercise all of the powers specified in the Act which  are not inconsistent with
this Certificate of Incorporation.


                                   ARTICLE IV

                  CAPITALIZATION, PREEMPTIVE RIGHTS AND VOTING

     Section 1.  AUTHORIZED SHARES.  The aggregate number of shares of capital
stock which the Corporation shall have authority to issue is Twenty-Three
Million (23,000,000), of which (i) Twenty Million (20,000,000) shall be common
stock, par value $.10 per share; and (ii) three Million (3,000,000) shall be
preferred stock par value, $.10 per share.




                                      1


<PAGE>

     The preferred stock may be issued in one or more series, from time to time,
at the discretion of the Board of Directors without stockholder approval, with
each such series to consist of such number of shares and to have such voting
powers (whether full or limited, or no voting powers) and such designations,
powers, preferences and relative, participating, optional, redemption,
conversion, exchange or other special rights, and such qualifications,
limitations or restrictions thereof, as shall be stated in the resolution or
resolutions providing for the issuance of such series adopted by the Board of
Directors, and the Board of Directors is hereby expressly vested with the
authority, to the full extent now or hereafter provided by law, to adopt any
such resolution or resolutions.  Upon adoption of such resolution or
resolutions, a Certificate of Designations shall be prepared and filed in
accordance with the Act.  Each share of any series of preferred stock shall be
identical with all other shares of such series, except as to the date from which
dividends, if any, shall accrue.

     Section 2.  PREEMPTIVE RIGHTS.  No holder of shares of capital stock of the
Corporation shall, as such holder, have any right to purchase or subscribe for
any capital stock of any class which the Corporation may issue or sell, whether
or not exchangeable for any capital stock of the Corporation of any class or
classes, whether issued out of unissued shares authorized by this Certificate of
Incorporation as originally filed or by any amendment hereof, or out of shares
of capital stock of the Corporation acquired by it after the issue thereof; nor
shall any holder of shares of capital stock of the Corporation, as such holder,
have any right to purchase, acquire or subscribe for any securities which the
Corporation may issue or sell whether or not convertible into or exchangeable
for shares of capital stock of the Corporation of any class or classes, and
whether or not any such securities have attached or are appurtenant to warrants,
options or other instruments which entitle the holders thereof to purchase,
acquire or subscribe for shares of capital stock of any class or classes.

     Section 3.  VOTING.  In the exercise of voting privileges, each holder of
shares of the common stock of the Corporation shall be entitled to one (1) vote
for each share held in his name on the books of the Corporation, and each holder
of any series of preferred stock of the Corporation shall have such voting
rights, if any, as shall be specified for such series.  In all elections of
directors of the Corporation, cumulative voting is expressly prohibited and
directors will be elected by a plurality of votes of shares entitled to vote
thereon and represented at a meeting of the stockholders at which a quorum is
present.  With respect to any action to be taken by the stockholders of the
Corporation as to any matter other than the election of directors and except as
otherwise required by law, the affirmative vote of the holders of a majority of
the shares of the capital stock of the Corporation entitled to vote thereon and
represented in person or by proxy at a meeting of the stockholders at which a
quorum is present shall be sufficient to authorize, affirm, ratify or consent to
such action.  Any action required by the Act to be, or which may be, taken at
any annual or special meeting of the stockholders may be taken without a
meeting, without prior notice, and without a vote, if a consent or consents in
writing, setting forth the action so taken, shall be signed by the holder or
holders of  outstanding stock having not less than the minimum number of votes
that would be necessary to authorize or to take such action at a meeting at
which all shares of the capital stock of the Corporation entitled to vote
thereon were present and voted and shall be delivered to the Corporation by
delivery to its 




                                      2


<PAGE>

registered office in Delaware, its principal place of business or an officer 
or agent of the Corporation having custody of the Corporation's minute book, 
and notice of such action shall be sent to all stockholders not signing a 
consent.

                                    ARTICLE V

                           REGISTERED OFFICE AND AGENT

     The street address of the initial registered office of the Corporation is
1209 Orange Street, Wilmington, New Castle County, Delaware 19801, and the name
of its initial registered agent at such address is The Corporation Trust
Company.


                                   ARTICLE VI

                                    DIRECTORS

     Section 1.  NUMBER AND CLASSIFICATION.  The business and affairs of the
Corporation shall be managed by or be under the direction of the Board of
Directors which shall consist of not less than one (1) director, the exact
number of which shall be determined in accordance with the Bylaws of the
Corporation.  The directors shall be divided into three classes, designated
Class I, Class II and Class III.  Initially, Class I directors shall be elected
for a term extending until the first annual meeting of stockholders, Class II
directors shall be elected for a term extending until the second annual meeting
of stockholders and Class III directors shall be elected for a term extending
until the third annual meeting of stockholders.  At each annual meeting of
stockholders, successors to the class of directors whose term expires at that
annual meeting shall be elected for a term expiring at the third succeeding
annual meeting of stockholders or until their respective successors are in each
case elected and qualified.  If the number of directors is changed, any
additional director of any class elected to fill a vacancy resulting from an
increase in such class shall hold office for a term that shall coincide with the
remaining term of that class, but in no case will a decrease in the number of
directors shorten the term of any incumbent director.  A director shall hold
office until the annual meeting for the year in which his term expires and until
his successor shall be elected and shall qualify, subject, however, to prior
death, resignation, retirement, disqualification or removal from office.  Any
director elected to fill a vacancy not resulting from an increase in the number
of directors shall have the same remaining term as that of his predecessor.  

     Notwithstanding the foregoing, whenever the holders of any one or more
classes or series of preferred stock issued by the Corporation shall have the
right, voting separately by class or series, to elect directors at an annual or
special meeting of stockholders, the election, term of office, filing of
vacancies and other features of such directorships shall be governed by the
terms of the Certificate of Designations applicable thereto, and such directors
so elected shall not be divided into classes pursuant to this Article VI unless
expressly provided by such terms.




                                      3


<PAGE>

Further, any such directors elected by one or more classes or series of 
preferred stock may be removed at any time, with or without cause,  only by 
the affirmative vote of the holders of record of a majority of the 
outstanding shares of such class or series given at a special meeting of such 
stockholders called for such purpose.

     Section 2.  LIMITATION ON LIABILITY OF DIRECTORS.  Pursuant to Section
102(b)(7) of the Act, a director of the Corporation shall not be personally
liable to the Corporation or its stockholders for monetary damages from breach
of fiduciary duty as a director, except for liability (1) for any breach of the
director's duty of loyalty to the Corporation or its stockholders; (2) for acts
or omissions not in good faith or which involve intentional misconduct or a
knowing violation of law; (3) under Section 174 of the Act; or (4) for any
transaction from which the director derived an improper personal benefit.  If
the Act or other applicable provision of Delaware law hereafter is amended to
authorize further elimination or limitation of the liability of directors, then
the liability of a director of this Corporation, in addition to the limitation
on personal liability provided herein, shall be limited to the fullest extent
permitted by the Act or other applicable provision of Delaware law as amended. 
Any repeal or modification of this Section 3 by the stockholders of this
Corporation shall be prospective only, and shall not adversely affect any
limitation on the personal liability of a director of the Corporation existing
at the time of such repeal or modification.


     Section 3.  ELECTION AND REMOVAL OF DIRECTORS.  Election of directors need
not be by written ballot.  Any director or the entire Board of Directors may be
removed, with or without cause, by the holders of a majority of the shares then
entitled to vote at an election of directors, except as otherwise provided by
law.


                                   ARTICLE VII

                      SPECIAL POWERS OF BOARD OF DIRECTORS

     In furtherance and not in limitation of the powers conferred by statute,
the Board of Directors is expressly authorized:

     1.   To adopt, amend or repeal the Bylaws of the Corporation;

     2.   To authorize and cause to be executed mortgages and liens upon the
real and personal property of the Corporation;

     3.   To set apart out of any of the funds of the Corporation available for
dividends a reserve or reserves for any proper purpose, and to abolish any such
reserve in the manner in which it was created;




                                      4


<PAGE>

     4.   By a majority of the whole board, to designate one or more committees,
each committee to consist of two or more of the directors of the Corporation;
the board may designate one or more directors as alternate members of any
committee, who may replace any absent or disqualified member at any meeting of
the committee; any such committee, to the extent provided in the resolution or
in the Bylaws of the Corporation, shall have and may exercise any or all of the
powers of the Board of Directors in the management of the business and affairs
of the Corporation, except to the extent that the Act requires a particular
matter to be authorized by the Board of Directors, and may authorize the seal of
the Corporation to be affixed to all papers which may require it;  and the
Bylaws may provide that in the absence or disqualification of any member of the
committee or committees, the member or members thereof present at any meeting
and not disqualified from voting, whether or not he or they constitute a quorum,
may unanimously appoint another member of the Board of Directors to act at the
meeting in the place of any such absent or disqualified member;

     5.   When and as authorized by the affirmative vote of the holders of a
majority of the stock issued and outstanding having voting power given at a
stockholders meeting duly called upon such notice as is required by statute, or
when authorized by the written consent of the holders of a majority of the
voting stock issued and outstanding, to sell, lease or exchange all or
substantially all of the property and assets of the Corporation, including its
good will and its corporate franchises, upon such terms and conditions and for
such consideration, which may consist in whole or in part of money or property,
including shares of stock in, and/or other securities of, any other corporation
or corporations, as  the Board of Directors shall deem expedient and in the best
interests of the Corporation; and

     6.   Except as specifically provided in the Act, to determine, from time to
time, whether and to what extent and at what times and places and under what
conditions and provisions the accounts and books of the Corporation shall be
maintained and made available for inspection by any stockholder;  no stockholder
shall have any right to inspect any account or books or records of the
Corporation, except as provided in the Act or authorized by the Board of
Directors.


                                  ARTICLE VIII

                           ADDITIONAL POWERS IN BYLAWS

     The Corporation may in its Bylaws confer powers and authorities upon the
Board of Directors in addition to the foregoing and those expressly conferred
upon the board by the Act.



                                      5


<PAGE>

                                   ARTICLE IX

                                 INDEMNIFICATION

     Section 1.  MANDATORY INDEMNIFICATION AND ADVANCEMENT OF EXPENSES.  To the
fullest extent permitted by the Act and other applicable law, each person who
was or is made a party or is threatened to be made a party to or is involved in
any threatened, pending or completed action, suit or proceeding, whether civil,
criminal, administrative, arbitrative or investigative, any appeal in such
action, suit or proceeding, and any inquiry or investigation that could lead to
such an action, suit, or proceeding ("Proceeding"), by reason of the fact that
he is or was an officer or a director of the Corporation, or who, while a
director or officer of the Corporation, is or was serving at the request of the
Corporation as a director, officer, partner, venturer, proprietor, trustee,
employee, agent, or similar functionary of another corporation, partnership,
joint venture, sole proprietorship, trust, employee benefit plan or other
enterprise, shall be indemnified and held harmless by the Corporation  against
all judgments, penalties (including excise and similar taxes), fines,
settlements, and reasonable expenses (including attorneys' fees) actually
incurred by such person in connection with such Proceeding.  Such right shall be
a contract right and shall include, to the fullest extent permitted by the Act
and other applicable law, the right to require advancement by the Corporation of
reasonable expenses (including attorneys' fees) incurred in defending any such
Proceeding in advance of its final disposition; provided, however, that the
payment of such expenses in advance of the final disposition of such Proceeding
shall be made by the Corporation only upon delivery to the Corporation of a
written affirmation by such person of his good faith belief that he has met the
standard of conduct necessary for indemnification under the Act and a written
undertaking, by or on behalf of such person, to repay all amounts so advanced if
it should be ultimately determined that such person has not satisfied such
requirements.

     Section 2.  NATURE OF INDEMNIFICATION.  The indemnification and advancement
of expenses provided for herein shall not be deemed exclusive of any other
rights permitted by law to which a person seeking indemnification may be
entitled under any Bylaw, agreement, vote of stockholders or otherwise, and
shall continue as to a person who has ceased to be a director or officer of the
Corporation and shall inure to the benefit of the heirs, executors and
administrators of such a person.

     Section 3.  INSURANCE.  To the fullest extent permitted by the Act and
other applicable law, the Corporation shall have power to purchase and maintain
insurance or another arrangement on behalf of any person who is or was a
director, officer, employee or agent of the Corporation, or is or was serving at
the request of the Corporation as a director, officer, partner, venturer,
proprietor, trustee, employee, agent, or similar functionary of another
corporation, partnership, joint venture, sole proprietorship, trust, employee
benefit plan or other enterprise against any liability asserted against him and
incurred by him in any such capacity, or arising out of his status as such,
whether or not the Corporation would have the power to indemnify him against
such liability under the provisions of this Article or the Act.




                                      6


<PAGE>

                                    ARTICLE X

                           ARRANGEMENT WITH CREDITORS

     Whenever a compromise or arrangement is proposed between this Corporation
and its creditors or any class of them and/or between this Corporation and its
stockholders or any class of them, any court of equitable jurisdiction within
the State of Delaware may, on the application in a summary way of this
Corporation or of any creditor or stockholder thereof or on the application of
any receiver or receivers appointed for this Corporation under the provisions of
Section 291 of the Act, or on the application of trustees in dissolution or of
any receiver or receivers appointed for this Corporation under the provisions of
Section 279 of the Act, order a meeting of the creditors or class of creditors,
and/or of the stockholders or class of stockholders of this Corporation, as the
case may be, to be summoned in such a manner as the said court directs.  If a
majority in number representing three-fourths in value of the creditors or class
of creditors, and/or the holders of a majority of shares or any class of shares
of capital stock of this Corporation outstanding and entitled to vote thereon,
as the case may be, agree to any compromise or arrangement and to any
reorganization of this Corporation as a consequence of such compromise or
arrangement, the said compromise or arrangement and the said reorganization
shall, if sanctioned by the court to which the said application has been made,
be binding on all the creditors or class of creditors, and/or on all the
stockholders or class of stockholders, of this Corporation, as the case may be,
and also on this Corporation.


                                   ARTICLE XI

                      TRANSACTIONS WITH INTERESTED PARTIES

     No contract or other transaction between the Corporation and any other
corporation and no other acts of the Corporation with relation to any other
corporation shall, in the absence of fraud, in any way be invalidated or
otherwise affected by the fact that any one or more of the directors or officers
of the Corporation are pecuniarily or otherwise interested in, or are directors
or officers of, such other corporation.  Any director or officer of the
Corporation individually, or any firm or association of which any director or
officer may be a member, may be a party to, or may be pecuniarily or otherwise
interested in, any contract or transaction of the Corporation, provided that the
fact that he individually or as a member of such firm or association is such a
party or is so interested shall be disclosed or shall have been known to the
Board of Directors or a majority of such members thereof as shall be present at
any meeting of the Board of Directors at which action upon any such contract or
transaction shall be taken; and any director of the Corporation who is also a
director or officer of such other corporation or who is such a party or so
interested may be counted in determining the existence of a quorum at any
meeting of the Board of Directors which shall authorize any such contact or
transaction and may vote thereat to authorize any such contract or transaction, 
subject to such limitations as are imposed by the Act or other applicable law. 
Any director of the Corporation may vote upon any contract or any other
transaction between the Corporation and any subsidiary or 




                                      7


<PAGE>

affiliated corporation without regard to the fact that he is also a director 
or officer of such subsidiary or affiliated corporation.

     Any contract, transaction, act of the Corporation or of the directors,
which shall be ratified at any annual meeting of the stockholders of the
Corporation or at any special meeting of the stockholders of the Corporation 
shall, insofar as permitted by law, be as valid and as binding as though
ratified by every stockholder of the Corporation; PROVIDED, HOWEVER, that any
failure of the stockholders to approve or ratify any such contract, transaction
or act, when and if submitted, shall not be deemed in any way to invalidate the
same or deprive the Corporation, its directors, officers or employees, of its or
their right to proceed with such contract, transaction or act.


                                   ARTICLE XII

                                   AMENDMENTS

     The Corporation reserves the right to amend, alter, change or repeal any
provision  contained in this Certificate of Incorporation or in its Bylaws in
the manner now or hereafter prescribed by the Act or this Certificate of
Incorporation, and all rights conferred on stockholders herein are granted
subject to this reservation.  The Bylaws of the Corporation, or any provision
thereof, may be adopted, amended or repealed by the Board of Directors at any
meeting or by the stockholders at any meeting.


                                  ARTICLE XIII

                                  INCORPORATOR

     The incorporator is Stephen C. Byrd, whose mailing address is 500 West
Illinois, Suite 300, Midland, Texas 79701.

                                   ARTICLE XIV


     The power of the incorporator shall terminate upon the filing of this
Certificate of Incorporation and the names and mailing addresses of persons who
are to serve as directors until the first annual meeting of stockholders or
until their successors are elected and qualified:




                                      8


<PAGE>

          NAME                     MAILING ADDRESS

          Cadell S. Liedtke        400 West Illinois, Suite 1000
                                   Midland, Texas  79701

          Michael J. Grella        400 West Illinois, Suite 1000
                                   Midland, Texas  79701

          Henry G. Musselman       400 West Illinois, Suite 1000
                                   Midland, Texas  79701



     I, the undersigned, being the incorporator, for the purpose of forming a
corporation under the laws of the State of Delaware, do make, file and record
this Certificate of Incorporation, to certify that the facts herein stated are
true, and accordingly, have hereto set my hand this 25TH day of June, 1996. 





                                          /s/ STEPHEN C. BYRD
                                       --------------------------------------
                                       Stephen C. Byrd






                                     9


<PAGE>


                                                                     EXHIBIT 3.2

                                  TABLE OF CONTENTS

                                 CORPORATE BYLAWS OF
                                COSTILLA ENERGY, INC.
                               (A Delaware corporation)


SECTION                         SUBJECT MATTER                            PAGE
- -------                         --------------                            ----

                          ARTICLE 1: NAME AND OFFICES

1.1      Name  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2      Registered Office and Agent . . . . . . . . . . . . . . . . . . . . .1
              (a)   Registered Office. . . . . . . . . . . . . . . . . . . . .1
              (b)   Registered Agent . . . . . . . . . . . . . . . . . . . . .1
              (c)   Change of Registered Office or Agent . . . . . . . . . . .1
1.3      Other Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

                               ARTICLE 2: STOCKHOLDERS

2.1      Place of Meeting. . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.2      Annual Meeting. . . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.3      Special Meetings. . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.4      Notice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.5      Voting List . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.6      Quorum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
2.7      Requisite Vote. . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2.8      Withdrawal of Quorum. . . . . . . . . . . . . . . . . . . . . . . . .4
2.9      Voting at Meetings. . . . . . . . . . . . . . . . . . . . . . . . . .4
              (a)   Voting Power . . . . . . . . . . . . . . . . . . . . . . .4
              (b)   Exercise of Voting Power; Proxies. . . . . . . . . . . . .4
              (c)   Election of Directors. . . . . . . . . . . . . . . . . . .5
2.10     Record Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
2.11     Action Without Meetings . . . . . . . . . . . . . . . . . . . . . . .5
2.12     Record Date for Action Without Meeting. . . . . . . . . . . . . . . .6
2.13     Preemptive Rights . . . . . . . . . . . . . . . . . . . . . . . . . .7

                                 ARTICLE 3: DIRECTORS

3.1      Management Powers . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.2      Number and Qualification. . . . . . . . . . . . . . . . . . . . . . .7
3.3      Classification of Directors . . . . . . . . . . . . . . . . . . . . .8
3.4      Election and Terms. . . . . . . . . . . . . . . . . . . . . . . . . .8



                                         (i)

<PAGE>

3.5      Voting on Directors . . . . . . . . . . . . . . . . . . . . . . . . .8
3.6      Vacancies and New Directorships . . . . . . . . . . . . . . . . . . .9
3.7      Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.8      Meetings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
              (a)   Place. . . . . . . . . . . . . . . . . . . . . . . . . . 10
              (b)   Annual Meetings. . . . . . . . . . . . . . . . . . . . . 10
              (c)   Regular Meetings . . . . . . . . . . . . . . . . . . . . 10
              (d)   Special Meetings . . . . . . . . . . . . . . . . . . . . 10
              (e)   Notice and Waiver of Notice. . . . . . . . . . . . . . . 10
              (f)   Quorum . . . . . . . . . . . . . . . . . . . . . . . . . 10
              (g)   Requisite Vote . . . . . . . . . . . . . . . . . . . . . 10
3.9      Action Without Meetings . . . . . . . . . . . . . . . . . . . . . . 11
3.10     Committees. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
              (a)   Designation and Appointment. . . . . . . . . . . . . . . 11
              (b)   Members; Alternate Members; Term . . . . . . . . . . . . 11
              (c)   Authority. . . . . . . . . . . . . . . . . . . . . . . . 11
              (d)   Records. . . . . . . . . . . . . . . . . . . . . . . . . 11
              (e)   Change in Number . . . . . . . . . . . . . . . . . . . . 11
              (f)   Vacancies. . . . . . . . . . . . . . . . . . . . . . . . 11
              (g)   Removal. . . . . . . . . . . . . . . . . . . . . . . . . 12
              (h)   Meetings . . . . . . . . . . . . . . . . . . . . . . . . 12
              (i)   Quorum; Requisite Vote . . . . . . . . . . . . . . . . . 12
              (j)   Compensation . . . . . . . . . . . . . . . . . . . . . . 12
              (k)   Action Without Meeting . . . . . . . . . . . . . . . . . 12
              (l)   Responsibility . . . . . . . . . . . . . . . . . . . . . 12
3.11     Compensation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.12     Maintenance of Records. . . . . . . . . . . . . . . . . . . . . . . 13
3.13     Interested Directors and Officer. . . . . . . . . . . . . . . . . . 13

                                  ARTICLE 4: NOTICES

4.1      Method of Notice. . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2      Waiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

                            ARTICLE 5: OFFICERS AND AGENTS

5.1      Designation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2      Election of Officers. . . . . . . . . . . . . . . . . . . . . . . . 15
5.3      Qualifications. . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.4      Term of Office. . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.5      Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.6      Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.7      Vacancies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.8      Compensation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.9      Chairman of the Board . . . . . . . . . . . . . . . . . . . . . . . 16



                                         (ii)

<PAGE>

5.10     Vice Chairman . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.11     Chief Executive Officer . . . . . . . . . . . . . . . . . . . . . . 17
5.12     Chief Operating Officer . . . . . . . . . . . . . . . . . . . . . . 17
5.13     President . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.14     Vice Presidents . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.15     Secretary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.16     Assistant Secretaries . . . . . . . . . . . . . . . . . . . . . . . 19
5.17     Treasurer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.18     Assistant Treasurers. . . . . . . . . . . . . . . . . . . . . . . . 20

                              ARTICLE 6: INDEMNIFICATION

6.1      Mandatory Indemnification . . . . . . . . . . . . . . . . . . . . . 20
6.2      Determination of Indemnification. . . . . . . . . . . . . . . . . . 22
6.3      Advance of Expenses . . . . . . . . . . . . . . . . . . . . . . . . 22
6.4      Permissive Indemnification. . . . . . . . . . . . . . . . . . . . . 23
6.5      Nature of Indemnification . . . . . . . . . . . . . . . . . . . . . 23
6.6      Insurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.7      Notice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

                ARTICLE 7: STOCK CERTIFICATES AND TRANSFER REGULATIONS

7.1      Description of Certificates . . . . . . . . . . . . . . . . . . . . 25
7.2      Entitlement to Certificates . . . . . . . . . . . . . . . . . . . . 25
7.3      Signatures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.4      Issuance of Certificates. . . . . . . . . . . . . . . . . . . . . . 26
7.5      Payment for Shares. . . . . . . . . . . . . . . . . . . . . . . . . 26
              (a)   Consideration. . . . . . . . . . . . . . . . . . . . . . 26
              (b)   Valuation. . . . . . . . . . . . . . . . . . . . . . . . 27
              (c)   Effect . . . . . . . . . . . . . . . . . . . . . . . . . 27
              (d)   Allocation of Consideration. . . . . . . . . . . . . . . 27
7.6      Subscriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.7      Record Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.8      Registered Owners . . . . . . . . . . . . . . . . . . . . . . . . . 28
7.9      Lost, Stolen or Destroyed Certificates. . . . . . . . . . . . . . . 28
              (a)   Proof of Loss. . . . . . . . . . . . . . . . . . . . . . 28
              (b)   Timely Requests. . . . . . . . . . . . . . . . . . . . . 29
              (c)   Bond . . . . . . . . . . . . . . . . . . . . . . . . . . 29
              (d)   Other Requirements . . . . . . . . . . . . . . . . . . . 29
7.10     Registration of Transfers . . . . . . . . . . . . . . . . . . . . . 29
              (a)   Endorsement. . . . . . . . . . . . . . . . . . . . . . . 29
              (b)   Guaranry and Effectiveness of Signature. . . . . . . . . 29
              (c)   Adverse Claim. . . . . . . . . . . . . . . . . . . . . . 29
              (d)   Collection of Taxes. . . . . . . . . . . . . . . . . . . 30
              (e)   Additional Requirements Satisfied. . . . . . . . . . . . 30



                                        (iii)

<PAGE>

7.11     Restrictions on Transfers and Legends on Certificates . . . . . . . 30
              (a)   Shares in Classes or Series. . . . . . . . . . . . . . . 30
              (b)   Restriction on Transfer. . . . . . . . . . . . . . . . . 30
              (c)   Unregistered Securities. . . . . . . . . . . . . . . . . 30

                            ARTICLE 8: GENERAL PROVISIONS

8.1      Dividends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
              (a)   Declaration and Payment. . . . . . . . . . . . . . . . . 31
              (b)   Record Date. . . . . . . . . . . . . . . . . . . . . . . 31
8.2      Reserves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.3      Books and Records . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.4      Annual Statements . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.5      Contracts and Negotiable Instruments. . . . . . . . . . . . . . . . 32
8.6      Fiscal Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.7      Corporate Seal. . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.8      Resignations. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8,9      Amendment of Bylaws . . . . . . . . . . . . . . . . . . . . . . . . 33
8.10     Construction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.11     Telephone Meetings. . . . . . . . . . . . . . . . . . . . . . . . . 34
8.12     Table of Contents; Captions . . . . . . . . . . . . . . . . . . . . 34


                                         (iv)

<PAGE>


                                   CORPORATE BYLAWS

                                          OF

                                COSTILLA ENERGY, INC.
                               (a Delaware Corporation)


                                      ARTICLE 1

                                   NAME AND OFFICES
                                   ----------------

    1.1   NAME.  The name of the Corporation is COSTILLA ENERGY, INC.,
hereinafter referred to as the "Corporation."

    1.2   REGISTERED OFFICE AND AGENT.  The Corporation shall establish,
designate and continuously maintain a registered office and agent in the State
of Delaware, subject to the following provisions:

         (a)   REGISTERED OFFICE.  The Corporation shall establish and
    continuously maintain in the State of Delaware a registered office which
    may be, but need not be, the same as its place of business.

         (b)   REGISTERED AGENT.  The Corporation shall designate and
    continuously maintain in the State of Delaware a registered agent, which
    may be either an individual resident of the State of Delaware whose
    business office is identical with such registered office, or a domestic
    corporation or a foreign corporation authorized to transact business in the
    State of Delaware, having a business office identical with such registered
    office.

         (c)   CHANGE OF REGISTERED OFFICE OR AGENT.  The Corporation may
    change its registered office or change its registered agent, or both, upon
    the filing in the Office of the Secretary of State of Delaware of a
    statement setting forth the facts required by law, and executed for the
    Corporation by its President, a Vice President or other duly authorized
    officer.

    1.3   OTHER OFFICES.  The Corporation may also have other registered agents
and registered offices at such other places outside the State of Delaware as the
Board of Directors may, from time to time, determine that the business of the
Corporation requires.


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                                      ARTICLE 2

                                     STOCKHOLDERS
                                     ------------

    2.1   PLACE OF MEETINGS.  Each meeting of the stockholders of the
Corporation is to be held at the principal offices of the Corporation or at such
other place, either within or without the State of Delaware, as may be
determined by the Board of Directors and specified in the notice of the meeting
or in a duly executed waiver of notice thereof.

    2.2   ANNUAL MEETINGS.  The annual meeting of the stockholders for the
election of directors and for the transaction of such other business as may
properly come before the meeting shall be held within one hundred twenty (120)
days after the close of the fiscal year of the Corporation on a day during such
period to be selected by the Board of Directors; provided, however, that the
failure to hold the annual meeting within the designated period of time or on
the designated date shall not work a forfeiture or dissolution of the
Corporation.

    2.3   SPECIAL MEETINGS.  Special meetings of the stockholders, for any
purpose or purposes, may be called by the Board of Directors, the Chairman of
the Board, the Chief Executive Officer, the President, or the Executive Vice
President, if one is elected.  The notice of a special meeting shall state the
purpose or purposes of the proposed meeting and the business to be transacted at
any such special meeting of stockholders, and shall be limited to the purposes
stated in the notice thereof.

    2.4   VOTING LIST.  The officer or agent having charge and custody of the
stock transfer books of the Corporation shall prepare, at least ten (10) days
before each meeting of the stockholders, a complete list of the stockholders
entitled to vote at such meeting, arranged in alphabetical order and showing the
address of each stockholder and the number of shares having voting privileges
registered in the name of each stockholder.  Such list shall be open to the
examination of any stockholder, for any purpose germane to the meeting, during
ordinary


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business hours for a period of not less than ten (10) days prior to such meeting
either at the principal office of the Corporation or at a place within the city
where the meeting is to be held, which place shall be specified in the notice of
the meeting, or, if not so specified, at the place where the meeting is to be
held.  Such list shall also be produced at the place of the meeting and kept
open during the meeting and shall be subject to the inspection of any
stockholder during the entire time of the meeting.  The original stock ledger or
transfer book, or a duplicate thereof, shall be prima facie evidence as to
identity of the stockholders entitled to examine such list or stock ledger or
transfer book and to vote at any such meeting of the stockholders.  The failure
to comply with the requirements of this Section shall not effect the validity of
any action taken at said meeting.

    2.6   QUORUM.  The holders of a majority of the shares of the capital stock
issued and outstanding and entitled to vote thereat, represented in person or by
proxy, shall be required and shall constitute a quorum at all meetings of the
stockholders for the transaction of business except as otherwise provided by
statute, by the Certificate of Incorporation, or by these Bylaws.  If, however,
such quorum shall not be present or represented at any such meeting of the
stockholders, the stockholders entitled to vote thereat, present in person, or
represented by proxy, shall have the power to adjourn the meeting, from time to
time, without notice other than an announcement at the meeting, until a quorum
shall be present or represented.  At such reconvened meeting at which a quorum
shall be present or represented, any business may be transacted which might have
been transacted at the meeting as originally notified.  If the adjournment is
for more than thirty (30) days or if after the adjournment a new record date is
fixed for the reconvened meeting, a notice of said meeting shall be given to
each stockholder entitled to vote at said meeting.


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<PAGE>


    2.7   REQUISITE VOTE.  If a quorum is present at any meeting, the vote of
the holders of a majority of the outstanding shares of capital stock having
voting power, present in person or represented by proxy, shall determine any
question brought before such meeting, unless the question is one upon which, by
express provision of the Certificate of Incorporation or of these Bylaws, a
different vote shall be required, in which case such express provision shall
govern and control the determination of such question.

    2.8   WITHDRAWAL OF QUORUM.  If a quorum is present at the time of
commencement of any meeting, the stockholders present at such duly convened
meeting may continue to transact any business which may properly come before
said meeting until adjournment thereof, notwithstanding the withdrawal from such
meeting of sufficient holders of the shares of capital stock entitled to vote
thereat which leaves less than a quorum remaining.

    2.9   VOTING AT MEETING.  Voting at meeting of stockholders shall be
conducted and exercised subject to the following procedures and regulations:

         (a)   VOTING POWER.  In the exercise of voting power with respect to
    each matter properly submitted to a vote at any meeting of stockholders,
    each stockholder of the capital stock of the Corporation having voting
    power shall be entitled to one (1) vote for each such share held in his
    name on the books of the Corporation, except to the extent otherwise
    specified by the Certificate of Incorporation or Certificate of
    Designations pertaining to a series of preferred stock.

         (b)   EXERCISE OF VOTING POWER; PROXIES.  Each stockholder entitled to
    vote at a meeting or to express consent or dissent to corporate action in
    writing without a meeting may vote either in person or authorize another
    person or persons to act for him by proxy duly appointed by instrument in
    writing subscribed by such stockholder or by his duly authorized attorney-
    in-fact; provided, however, no such appointment of proxy shall be valid, 
    voted or acted upon after the expiration of three (3) years from the date 
    of such written instrument of appointment, unless a longer period is 
    stated therein.  A proxy shall be revocable unless expressly designated 
    therein as irrevocable and coupled with an interest sufficient in law to 
    support an irrevocable power. Proxies coupled with an interest include, 
    but are not limited to, the appointment as proxy of:  (a) a pledgee; (b) 
    a person who purchased or agreed to purchase or owns or holds an option 
    to purchase the shares voted; (c) a creditor of the Corporation who 
    extended its credit under terms requiring the appointment; (d) an 
    employee of the Corporation whose employment contract requires the 
    appointment; (e) a party to a voting agreement created under Section


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<PAGE>

    218 of the General Corporation Law of Delaware, as amended.  Each proxy
    shall be filed with the Secretary of the Corporation prior to or at the
    time of the meeting.  Any vote may be taken by voice vote or by show of
    hands unless someone entitled to vote at the meeting objects, in which case
    written ballots shall be used.

         (c)   ELECTION OF DIRECTORS.  In all elections of Directors cumulative
    voting shall be prohibited.

    2.10   RECORD DATE.  As more specifically provided in Article 7, Section
7.7 hereof, the Board of Directors may fix in advance a record date for the
purpose of determining stockholders entitled to notice of or to vote at a
meeting of stockholders, which record date shall not precede the date upon which
the resolution fixing the record date is adopted by the Board of Directors, and
which record date shall not be less than ten (10) nor more than sixty (60) days
prior to such meeting.  In the absence of any action by the Board of Directors
fixing the record date, the record date for determining stockholders entitled to
notice of or to vote at a meeting of stockholders shall be at the close of
business on the day before the day on which notice of the meeting is given, or,
if notice is waived, at the close of business on the day before the meeting is
held.

    2.11   ACTION WITHOUT MEETINGS.  Any action permitted or required to be
taken at a meeting of the stockholders of the Corporation may be taken without a
meeting, without prior notice, and without a vote, if a consent or consents in
writing, setting forth the action so taken, shall be signed by the holder or
holders of the outstanding stock having not less than the minimum number of
votes that would be necessary to authorize or take such action at a meeting at
which all shares entitled to vote thereon were present and voted, and such
written consent shall have the same force and effect as the requisite vote of
the stockholders thereon.  Any such executed written consent, or an executed
counterpart thereof, shall be placed in the minute book of the Corporation.
Every written consent shall bear the date of signature of each stockholder who
signs the consent.  No written consent shall be effective to take the action
that is the subject


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<PAGE>

of the consent unless, within sixty (60) days after the date of the earliest
dated consent delivered to the Corporation in the manner required under Section
2.11 hereof, a consent or consents signed by the holders of the minimum number
of shares of the capital stock issued and outstanding and entitled to vote on
and approve the action that is the subject of the consent are delivered to the
Corporation.  Prompt notice of the taking of any action by stockholders without
a meeting by less than unanimous written consent shall be given to those
stockholders who did not consent in writing to the action.

    2.12   RECORD DATE FOR ACTION WITHOUT MEETING.  Unless a record date shall
have previously been fixed or determined by the Board of Directors as provided
in Section 2.10 hereof, whenever action by stockholders is proposed to be taken
by consent in writing without a meeting of stockholders, the Board of Directors
may fix a record date for the purpose of determining stockholders entitled to
consent to that action, which record date shall not precede, and shall not be
more than ten (10) days after, the date upon which the resolution fixing the
record date is adopted by the Board of Directors.  If no record date has been
fixed by the Board of Directors and the prior action of the Board of Directors
is not required by statute or the Certificate of Incorporation, the record date
for determining stockholders entitled to consent to corporate action in writing
without a meeting shall be the first date on which a signed written consent
setting forth the action taken or proposed to be taken is delivered to the
Corporation by delivery to its registered office, its principal place of
business, or an officer or agent of the Corporation having custody of the books
in which proceedings of meetings of stockholders are recorded.  Delivery shall
be by hand or by certified or registered mail, return receipt requested.
Delivery to the Corporation's principal place of business shall be addressed to
the President or principal executive officer of the Corporation.  If no record
date shall have been fixed by the Board of Directors and prior action of the
Board of Directors is required by statute, the record


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<PAGE>

date for determining stockholders entitled to consent to corporate action in
writing without a meeting shall be at the close of business on the day on which
the Board of Directors adopts a resolution taking such prior action.

    2.13   PREEMPTIVE RIGHTS.  No holder of shares of capital stock of the
Corporation shall, as such holder, have any right to purchase or subscribe for
any capital stock of any class which the Corporation may issue or sell, whether
or not exchangeable for any capital stock of the Corporation of any class or
classes, whether issued out of unissued shares authorized by the Certificate of
Incorporation, as amended, or out of shares of capital stock of the Corporation
acquired by it after the issue thereof; nor shall any holder of shares of
capital stock of the Corporation, as such holder, have any right to purchase,
acquire or subscribe for any securities which the Corporation may issue or sell
whether or not convertible into or exchangeable for shares of capital stock of
the Corporation of any class or classes, and whether or not any such securities
have attached or appurtenant thereto warrants, options or other instruments
which entitle the holder thereof to purchase, acquire or subscribe for shares of
capital stock of any class or classes.

                                      ARTICLE 3

                                      DIRECTORS
                                      ---------

    3.1   MANAGEMENT POWERS.  The powers of the Corporation shall be exercised
by or under the authority of, and the business and affairs of the Corporation
shall be managed under the direction of, its Board of Directors which may
exercise all such powers of the Corporation and do all such lawful acts and
things as are not by statute or by the Certificate of Incorporation or by these
Bylaws directed or required to be exercised or done by the stockholders.

    3.2   NUMBER AND QUALIFICATION.  The Board of Directors shall consist of
not less than one (1) member nor more than fifteen (15) members; provided,
however, that the initial Board


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of Directors shall consist of three (3) members.  Directors need not be
residents of the State of Delaware nor stockholders of the Corporation.  Each
Director shall qualify as a Director following election as such by agreeing to
act or acting in such capacity.  The number of Directors shall be fixed, and may
be increased or decreased, from time to time by resolution of the Board of
Directors without the necessity of a written amendment to the Bylaws of the
Corporation; provided, however, no decrease shall have the effect of shortening
the term of any incumbent Director.

    3.3   CLASSIFICATION OF DIRECTORS.  The Directors of the Corporation shall
be divided into three classes designated Class I, Class II, and Class III.  The
initial members of the Board of Directors shall be as set forth in the
Certificate of Incorporation of the Corporation and the class of which such
members belong shall be Class III.  Additional Directors resulting from newly
created directorships shall be elected in the manner set forth in Section 3.6
hereof.

    3.4   ELECTION AND TERM.  Initially, Class I Directors shall be elected for
a term extending until the first annual meeting of stockholders after the date
hereof, Class II Directors shall be elected for a term extending until the
second annual meeting of stockholders after the date hereof, and Class III
Directors shall be elected for a term extending until the third annual meeting
of stockholders after the date hereof.  At each annual meeting of the
stockholders, the stockholders entitled to vote in an election for such class of
Directors whose term expires at that annual meeting shall elect successors for a
term of three years expiring at the third succeeding annual meeting of
stockholders.  Each Director shall hold office for the term for which he is
elected, and until his successor shall be elected and qualified or until his
death, resignation, or removal, if earlier.

    3.5   VOTING ON DIRECTORS.  Directors shall be elected by the vote of the
holders of a plurality of the shares entitled to vote in the election of
Directors and represented in person


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or by proxy at a meeting of stockholders at which a quorum is present.
Cumulative voting in the election of Directors is expressly prohibited.

    3.6   VACANCIES AND NEW DIRECTORSHIPS.  Vacancies and newly created
directorships resulting from any increase in the authorized number of Directors
elected by all the stockholders having the right to vote as a single class may
be filled by the affirmative vote of a majority of the Directors then in office,
although less than a quorum, or by a sole remaining Director, or by the
requisite vote of the stockholders at an annual meeting of the stockholders or
at a special meeting of the stockholders called for that purpose, and the
Directors so elected shall hold office until their successors are elected and
qualified.  If the holders of any class or classes of stock or series of stock
of the Corporation are entitled to elect one or more Directors by the
Certificate of Incorporation or Certificate of Designations applicable to such
class or series, vacancies and newly created directorships of such class or
classes or series may be filled by a majority of the Directors elected by such
class or classes or series thereof then in office, or by a sole remaining
Director so elected, and the Directors so elected shall hold office until the
next election of the class for which such Directors shall have been chosen, and
until their successors shall be elected and qualified.  For purposes of these
Bylaws, a "vacancy" shall be defined as an unfilled directorship arising by
virtue of the death, resignation, or removal of a Director theretofore duly
elected to serve in such capacity in accordance with the relevant provisions of
these Bylaws.

    3.7   REMOVAL.  Any Director may be removed either for or without cause at
any duly convened special or annual meeting of stockholders, by the affirmative
vote of a majority in number of shares of the stockholders present in person or
by proxy at any meeting and entitled to vote for the election of such Director,
provided notice of intention to act upon such matter shall have been given in
the notice calling such meeting.


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    3.8   MEETINGS.  The meetings of the Board of Directors shall be held and
conducted subject to the following regulations:

         (a)   PLACE.  Meetings of the Board of Directors of the Corporation,
    annual, regular or special, are to be held at the principal office or place
    of business of the Corporation, or such other place, either within or
    without the State of Delaware, as may be specified in the respective
    notice, or waivers of notice, thereof.

         (b)   ANNUAL MEETING.  The Board of Directors shall meet each year
    immediately after the annual meeting of the stockholders, at the place
    where such meeting of the stockholders has been held (either within or
    without the State of Delaware), for the purpose of electing officers and
    the consideration of any other business that may properly be brought before
    the meeting.  No notice of any kind to either old or new members of the
    Board of Directors for such annual meeting shall be required.

         (c)   REGULAR MEETINGS.  Regular meetings of the Board of Directors
    may be held without notice at such time and at such place or places as
    shall from time to time be determined and designated by the Board of
    Directors.

         (d)   SPECIAL MEETINGS.  Special meetings of the Board of Directors
    may be called by the Chairman of the Board, the Chief Executive Officer, or
    the President of the Corporation on notice of two (2) days to each Director
    either personally or by mail or by telegram, telex, or facsimile
    transmission and delivery.  Special meetings of the Board of Directors
    shall be called by the Chairman of the Board or the President or Secretary
    in like manner and on like notice on the written request of three (3)
    Directors.

         (e)   NOTICE AND WAIVER OF NOTICE.  Attendance of a Director at any
    meeting shall constitute a waiver of notice of such meeting, except where a
    Director attends for the express purpose of objecting to the transaction of
    any business because the meeting is not lawfully called or convened.
    Neither the business to be transacted at, nor the purpose of, any regular
    meeting of the Board of Directors need be specified in the notice or waiver
    of notice of such meeting.

         (f)   QUORUM.  At all meetings of the Board of Directors, a majority
    of the number of Directors shall constitute a quorum for the transaction of
    business, unless a greater number is required by law or by the Certificate
    of Incorporation.  If a quorum shall not be present at any meeting of
    Directors, the Directors present thereat may adjourn the meeting, from time
    to time, without notice other than announcement at the meeting, until a
    quorum shall be present.

         (g)   REQUISITE VOTE.  The act of a majority of the Directors present
    at any meeting at which a quorum is present shall be the act of the Board
    of Directors unless the act of a greater number is required by statute, by
    the Certificate of Incorporation, or by these Bylaws.


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    3.9   ACTION WITHOUT MEETINGS.  Unless otherwise restricted by the
Certificate of Incorporation or these Bylaws, any action required or permitted
by law to be taken at any meeting of the Board of Directors, or any committee
thereof, may be taken without a meeting, if prior to such action a written
consent thereto is signed by all members of the Board of Directors or of such
committee, as the case may be, and such written consent is filed in the minutes
or proceedings of the Board of Directors or committee.

    3.10   COMMITTEES.  Committees designated and appointed by the Board of
Directors shall function subject to and in accordance with the following
regulations and procedures:

         (a)   DESIGNATION AND APPOINTMENT.  The Board of Directors may, by
    resolution adopted by a majority of the entire Board of Directors,
    designate and appoint one or more committees under such name or names and
    for such purpose or function as may be deemed appropriate.

         (b)   MEMBERS; ALTERNATE MEMBERS; TERMS.  Each committee thus
    designated and appointed shall consist of two or more of the Directors of
    the Corporation, one of whom, in the case of the Executive Committee, shall
    be the Chief Executive Officer of the Corporation.  The Board of Directors
    may designate one or more of its members as alternate members of any
    committee, who may, subject to any limitations imposed by the entire Board
    of Directors, replace absent or disqualified members at any meeting of that
    committee.  The members or alternate members of any such committee shall
    serve at the pleasure of and subject to the discretion of the Board of
    Directors.

         (c)   AUTHORITY.  Each committee, to the extent provided in the
    resolution of the Board of Directors creating same, shall have and may
    exercise such of the powers and authority of the Board of Directors in the
    management of the business and affairs of the Corporation as the Board of
    Directors may direct and delegate, except, however, those matters which are
    required by statute to be reserved unto or acted upon by the entire Board
    of Directors.

         (d)   RECORDS.  Each such committee shall keep and maintain regular
    records or minutes of its meetings and report the same to the Board of
    Directors when required.

         (e)   CHANGE IN NUMBER.  The number of members or alternate members of
    any committee appointed by the Board of Directors, as herein provided, may
    be increased or decreased (but not below two) from time to time by
    appropriate resolution adopted by a majority of the entire Board of
    Directors.

         (f)   VACANCIES.  Vacancies in the membership of any committee
    designated and appointed hereunder shall be filled by the Board of
    Directors, at a regular or special


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    meeting of the Board of Directors, in a manner consistent with the
    provisions of this Section 3.10.

         (g)   REMOVAL.  Any member or alternate member of any committee
    appointed hereunder may be removed by the Board of Directors by the
    affirmative vote of a majority of the entire Board of Directors, whenever
    in its judgment the best interest of the Corporation will be served
    thereby.

         (h)   MEETINGS.  The time, place, and notice (if any) of committee
    meetings shall be determined by the members of such committee.

         (i)   QUORUM:  REQUISITE VOTE.  At meetings of any committee appointed
    hereunder, a majority of the number of members designated by the Board of
    Directors shall constitute a quorum for the transaction of business.  The
    act of a majority of the members and alternate members of the committee
    present at any meeting at which a quorum is present shall be the act of
    such committee, except as otherwise specifically provided by statute or by
    the Certificate of Incorporation or by these Bylaws.  If a quorum is not
    present at a meeting of such committee, the members of such committee
    present may adjourn the meeting from time to time, without notice other
    than an announcement at the meeting, until a quorum is present.

         (j)   COMPENSATION.  Appropriate compensation for members and
    alternate members of any committee appointed pursuant to the authority
    hereof may be authorized by the action of a majority of the entire Board of
    Directors pursuant to the provisions of Section 3.11 hereof.

         (k)   ACTION WITHOUT MEETINGS.  Any action required or permitted to be
    taken at a meeting of any committee may be taken without a meeting if a
    consent in writing, setting forth the action so taken, is signed by all
    members of such committee.  Such consent shall have the same force and
    effect as a unanimous vote at a meeting.  The signed consent, or a signed
    copy, shall become a part of the record of such committee.

         (l)   RESPONSIBILITY.  Notwithstanding any provision to the contrary
    herein, the designation and appointment of a committee and the delegation
    of authority to it shall not operate to relieve the Board of Directors, or
    any member thereof, of any responsibility imposed upon it or him by law.

    3.11   COMPENSATION.  By appropriate resolution of the Board of Directors,
the Directors may be reimbursed their expenses, if any, of attendance at each
meeting of the Board of Directors and may be paid a fixed sum (as determined
from time to time by the vote of a majority of the Directors then in office) for
attendance at each meeting of the Board of Directors or a stated salary as
Director, or both.  No such payment shall preclude any Director from


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serving the Corporation in another capacity and receiving compensation therefor.
Members of special or standing committees may, by appropriate resolution of the
Board of Directors, be allowed similar reimbursement of expenses and
compensation for attending committee meetings.

    3.12   MAINTENANCE OF RECORDS.  The Board of Directors may keep the books
and records of the Corporation, except such as are required by law to be kept
within the State, outside the State of Delaware or at such place or places as
they may, from time to time, determine.

    3.13   INTERESTED DIRECTORS AND OFFICERS.  No contract or other transaction
between the Corporation and one or more of its Directors or officers, or between
the Corporation and any firm of which one or more of its Directors or officers
are members or employees, or in which they are interested, or between the
Corporation and any corporation or association of which one or more of its
Directors or officers are stockholders, members, directors, officers, or
employees, or in which they are interested, shall be void or voidable solely for
this reason, or solely because of the presence of such Director or Directors, or
officer or officers, at the meeting of the Board of Directors of the
Corporation, which acts upon, or in reference to, such contract, or transaction,
if (a) the material facts of such relationship or interest shall be disclosed or
known to the Board of Directors and the Board of Directors shall, nevertheless
in good faith, authorize, approve, and ratify such contract or transaction by a
vote of a majority of the Board of Directors present, such interested Director
or Directors to be counted in determining whether a quorum is present, but not
to be counted in calculating the majority of such quorum necessary to carry such
vote; (b) the material facts of such relationship or interest as to the contract
or transaction are disclosed or are known to the stockholders entitled to vote
thereon, and the contract or transaction is specifically approved in good faith
by the vote of the stockholders; or (c) the contract or transaction is fair to
the Corporation as of the time it is authorized, approved, or ratified by the
Board of Directors, a committee thereof or the stockholders.  The provision of


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this Section shall not be construed to invalidate any contract or other
transaction which would otherwise be valid under the common and statutory law
applicable thereto.

                                      ARTICLE 4

                                       NOTICES
                                       --------

    4.1   METHOD OF NOTICE.  Whenever under the provisions of the General
Corporation Law of Delaware or of the Certificate of Incorporation or of these
Bylaws, notice is required to be given to any Director or stockholder, it shall
not be construed to mean personal notice, but such notice may be given in
writing and delivered personally, through the United States mail, by a
recognized delivery service (such as Federal Express), or by means of telegram,
telex or facsimile transmission, addressed to such Director or stockholder, at
his address or telex or facsimile transmission number, as the case may be, as it
appears on the records of the Corporation, with postage and fees thereon
prepaid.  Such notice shall be deemed to be given at the time when the same
shall be deposited in the United States mail or with an express delivery service
or when transmitted by telex or facsimile transmission or personally delivered,
as the case may be.

    4.2   WAIVER.  Whenever any notice that is required to be given under the
provisions of the General Corporation Law of Delaware or under the provisions of
the Certificate of Incorporation or these Bylaws, a waiver thereof in writing
signed by the person or persons entitled to such notice, whether before or after
the time stated therein, shall be deemed equivalent to the giving of such
notice.  Attendance by such person or persons, whether in person or by proxy, at
any meeting requiring notice shall constitute a waiver of notice of such
meeting, except where such person attends the meeting for the express purpose of
objecting to the transaction of any business because the meeting is not lawfully
called or convened.


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                                      ARTICLE 5

                                 OFFICERS AND AGENTS
                                 -------------------

    5.1   DESIGNATION.  The officers of the Corporation shall be chosen by the
Board of Directors and shall consist of the offices of:

         (a)   Chairman of the Board, Chief Executive Officer, Chief Operating
    Officer, President, Vice President, Treasurer, and Secretary; and

         (b)   Such other offices and officers (including one or more
    additional Vice Presidents) and assistant officers and agents as the Board
    of Directors shall deem necessary.

    5.2   ELECTION OF OFFICERS.  Each officer designated in Section 5.1(a)
hereof shall be elected by the Board of Directors on the expiration of the term
of office of such officer, as herein provided, or whenever a vacancy exists in
such office.  Each officer or agent designated in Section 5.1(b) above may be
elected by the Board of Directors at any meeting.

    5.3   QUALIFICATIONS.  No officer or agent need be a stockholder of the
Corporation or a resident of Delaware.  No officer or agent is required to be a
Director, except the Chairman of the Board.  Any two or more offices may be held
by the same person.

    5.4   TERM OF OFFICE.  Unless otherwise specified by the Board of Directors
at the time of election or appointment, or by the express provisions of an
employment contract approved by the Board, the term of office of each officer
and each agent shall expire on the date of the first meeting of the Board of
Directors next following the annual meeting of stockholders each year.  Each
such officer or agent, unless elected or appointed to an additional term, shall
serve until the expiration of the term of his office or, if earlier, his death,
resignation or removal.

    5.5   AUTHORITY.  Officers and agents shall have such authority and perform
such duties in the management of the Corporation as are provided in these Bylaws
or as may be determined by resolution of the Board of Directors not inconsistent
with these Bylaws.



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    5.6   REMOVAL.  Any officer or agent elected or appointed by the Board of
Directors may be removed with or without cause by the Board of Directors
whenever in its judgment the best interests of the Corporation will be served
thereby.  Such removal shall be without prejudice to the contract rights, if
any, of the person so removed.  Election or appointment of an officer or agent
shall not of itself create contract rights.

    5.7   VACANCIES.  Any vacancy occurring in any office of the Corporation
(by death, resignation, removal, or otherwise) shall be filled by the Board of
Directors.

    5.8   COMPENSATION.  The compensation of all officers and agents of the
Corporation shall be fixed from time to time by the Board of Directors.

    5.9   CHAIRMAN OF THE BOARD.  The Chairman of the Board shall be chosen
from among the Directors.  The Chairman of the Board shall have the power to
call special meetings of the stockholders and of the Board of Directors for any
purpose or purposes, and he shall preside at all meetings of the Board of
Directors, unless he shall be absent or unless he shall, at his election,
designate the Vice Chairman, if one is elected, to preside in his stead.  The
Chairman of the Board shall advise and counsel the Chief Executive Officer and
other officers of the Corporation and shall exercise such powers and perform
such duties as shall be assigned to or required by him from time to time by the
Board of Directors.

    5.10   VICE CHAIRMAN.  The Vice Chairman, if one is elected, shall have the
power to call special meetings of the stockholders and of the Directors for any
purpose or purposes, and, in the absence of the Chairman of the Board, the Vice
Chairman shall preside at all meetings of the Board of Directors unless he shall
be absent.  The Vice Chairman shall advise and counsel the other officers of the
Corporation and shall exercise such powers and perform such duties as shall be
assigned to or required of him from time to time by the Board of Directors.


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    5.11   CHIEF EXECUTIVE OFFICER.  Subject to the supervision of the Board of
Directors, the Chief Executive Officer shall have general supervision,
management, direction, and control of the business and affairs of the
Corporation and shall see that all orders and resolutions of the Board of
Directors are carried into effect.  The Chief Executive Officer shall execute
bonds, mortgages, and other contracts requiring a seal, under the seal of the
Corporation, except where required or permitted by law to be otherwise executed
and except where the execution thereof shall be expressly delegated by the Board
of Directors to some other officer or agent of the Corporation.  The Chief
Executive Officer shall preside at all meetings of the stockholders and, in the
absence of the Chairman of the Board and the Vice Chairman, at all meetings of
the Board of Directors.  The Chief Executive Officer shall be ex officio a
member of the Executive Committee, if any of the Board of Directors.  The Chief
Executive Officer shall have the general powers and duties of management usually
vested in the office of chief executive officer of a corporation and shall
perform such other duties and possess such other authority and powers as the
Board of Directors may from time to time prescribe.  In the event no individual
is elected to the office of Chief Operating Officer, the Chief Executive Officer
shall have the powers and perform the duties of the Chief Operating Officer.

    5.12   CHIEF OPERATING OFFICER.  Subject to the supervision of the Board of
Directors, the Chief Operating Officer, if one is elected, shall have general
supervision of the day-to-day operations of the Corporation.  The Chief
Operating Officer shall be ex officio a member of the Executive Committee, if
any, of the Board of Directors.  The Chief Operating Officer shall have the
general power and duties of management usually vested in the office of chief
operating officer of a corporation and shall perform such other duties and
possess such other authority and powers as the Board of Directors may from time
to time prescribe.


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    5.13   PRESIDENT.  In the absence or disability of the Chief Executive
Officer, the President shall perform all of the duties of the Chief Executive
Officer and when so acting shall have all the powers and be subject to all the
restrictions upon the Chief Executive Officer, including the power to sign all
instruments and to take all actions which the Chief Executive Officer is
authorized to perform by the Board of Directors or the Bylaws.  The President
shall have the general powers and duties usually vested in the office of
president of a corporation and shall perform such other duties and possess such
other authority and powers as the Board of Directors may from time to time
prescribe or as the Chief Executive Officer may from time to time delegate.

    5.14   VICE PRESIDENTS.  The Vice President, or if there shall be more than
one, the Vice Presidents shall perform such duties and have such powers as the
Board of Directors may from time to time prescribe or as the Chief Executive
Officer may from time to time delegate.  The Board of Directors may from time to
time appoint certain Vice Presidents who may have special designations,
including "Executive Vice President," "Senior Vice President," and "Vice
President - Land."  Vice Presidents having such special designation shall have
such powers and perform such duties and services as shall from time to time be
prescribed, assigned, or delegated to them by the Board of Directors, the Chief
Executive Officer, or the President.  The Executive Vice President or other Vice
President designated by the Board of Directors, shall, in the absence or
disability of the President, have the authority and perform the duties of said
office (including the duties and authority of the President as either Chief
Executive Officer or Chief Operating Officer, or both, if the President serves
as such).

    5.15   SECRETARY.  The Secretary shall attend all meetings of the Board of
Directors and all meeting of the stockholders of the Corporation and record all
proceedings of the meetings of the Corporation and of the Board of Directors in
a book to be maintained for that purpose and


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shall perform like duties for the standing committees when required.  The
Secretary shall give, or cause to be given, notice of all meetings of the
stockholders and special meetings of the Board of Directors, and shall perform
such other duties as may be prescribed by the Board of Directors, the Chairman
of the Board, the Chief Executive Officer, or the President.  The Secretary
shall have custody of the corporate seal of the Corporation, if any, and he, or
an Assistant Secretary, shall have authority to affix the same, if any, to any
instrument requiring it, and when so affixed, it may be attested by his
signature or by the signature of such Assistant Secretary.  The Board of
Directors may give general authority to any other officer to affix the seal of
the Corporation, if any, and to attest the affixing by his signature.

    5.16   ASSISTANT SECRETARIES.  The Assistant Secretary, of if there be more
than one, the Assistant Secretaries in the order determined by the Board of
Directors, shall in the absence or disability of the Secretary, perform the
duties and exercise the powers of the Secretary and shall perform such other
duties and have such other powers as the Board of Directors may from time to
time prescribe or as the Chief Executive Officer or the President may from time
to time delegate.

    5.17   TREASURER.  The Treasurer shall be the chief financial officer of
the Corporation and shall have the custody of the corporate funds and securities
and shall keep full and accurate accounts of receipts and disbursements in books
belonging to the Corporation and shall deposit all monies and other valuable
effects in the name and to the credit of the Corporation in such depositories as
may be designated by the Board of Directors.  The Treasurer shall disburse the
funds of the Corporation as may be ordered by the Board of Directors, taking
proper vouchers for such disbursements, and shall render to the Chief Executive
Officer (and Chairman of the Board, if one is elected) and the Board of
Directors, at its regular meetings, or when the Board of Directors so requires,
an account of all his transactions as Treasurer and of the financial


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condition of the Corporation.  If required by the Board of Directors, the
Treasurer shall give the Corporation a bond in such sum and with such surety or
sureties as shall be satisfactory to the Board of Directors for the faithful
performance of the duties of his office and for the restoration to the
Corporation, in case of his death, resignation, retirement, or removal from
office, of all books, papers, vouchers, money, and other property of whatever
kind in his possession or under his control owned by the Corporation.  The
Treasurer shall perform such other duties and have such other authority and
powers as the Board of Directors may from time to time prescribe or as the Chief
Executive Officer or President may from time to time delegate.

    5.18   ASSISTANT TREASURERS.  The Assistant Treasurer, or, if there shall
be more than one, the Assistant Treasurers in the order determined by the Board
of Directors, shall, in the absence or disability of the Treasurer, perform the
duties and exercise the powers of the Treasurer and shall perform such other
duties and have such other powers as the Board of Directors may from time to
time prescribe or as the Chief Executive Officer or President may from time to
time delegate.

                                      ARTICLE 6

                                   INDEMNIFICATION
                                   ---------------

    6.1   MANDATORY INDEMNIFICATION.  Each person who was or is made a party or
is threatened to be made a party or who was or is a witness without being named
a party, to any threatened, pending or completed action, claim, suit or
proceeding, whether civil, criminal, administrative or investigative, any appeal
in such an action, suit or proceeding, whether civil, criminal, administrative
or investigative, any appeal in such an action, suit or proceeding, and any
inquiry or investigation that could lead to such an action, suit or proceeding
(a "Proceeding"), by reason of the fact that such individual is or was a
Director or officer of the Corporation, or while a Director or officer of the
Corporation is or was serving at the request


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<PAGE>

of the Corporation as a director, officer, partner, venturer, proprietor,
trustee, employee, agent or similar functionary of another corporation,
partnership, trust, employee benefit plan or other enterprise, shall be
indemnified and held harmless by the Corporation from and against any judgments,
penalties (including excise taxes), fines, amounts paid in settlement and
reasonable expenses (including court costs and attorneys' fees) actually
incurred by such person in connection with such Proceeding if it is determined
that he acted in good faith and reasonably believed (i) in the case of conduct
in his official capacity on behalf of the Corporation that his conduct was in
the Corporation's best interests, (ii) in all other cases, that his conduct was
not opposed to the best interests of the Corporation, and (iii) with respect to
any Proceeding which is a criminal action, that he had no reasonable cause to
believe his conduct was unlawful; provided, however, that in the event a
determination is made that such person is liable to the Corporation or is found
liable on the basis that personal benefit was improperly received by such
person, the indemnification is limited to reasonable expenses actually incurred
by such person in connection with the Proceeding and shall not be made in
respect of any Proceeding in which such person shall have been found liable for
willful or intentional misconduct in the performance of his duty to the
Corporation.  The termination of any Proceeding by judgment, order, settlement,
conviction, or upon a plea of nolo contendere or its equivalent, shall not, of
itself be determinative of whether the person did not act in good faith and in a
manner which he reasonably believed to be in or not opposed to the best
interests of the Corporation, and, with respect to any Proceeding which is a
criminal action, had reasonable cause to believe that his conduct was unlawful.
A person shall be deemed to have been found liable in respect of any claim,
issue or matter only after the person shall have been so adjudged by a court of
competent jurisdiction after exhaustion of all appeals therefrom.


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    6.2   DETERMINATION OF INDEMNIFICATION.  Any indemnification under the
foregoing Section 6.1 (unless ordered by a court of competent jurisdiction)
shall be made by the Corporation only upon a determination that indemnification
of such person is proper in the circumstances by virtue of the fact that it
shall have been determined that such person has met the applicable standard of
conduct.  Such determination shall be made (1) by a majority vote of a quorum
consisting of Directors who at the time of the vote are not named defendants or
respondents in the Proceeding; (2) if such quorum cannot be obtained, by a
majority vote of a committee of the Board of Directors, designated to act in the
matter by a majority of all Directors, consisting of two or more Directors who
at the time of the vote are not named defendants or respondents in the
Proceeding; (3) by special legal counsel (in a written opinion) selected by the
Board of Directors or a committee of the Board by a vote as set forth in
Subsection (1) or (2) of this Section, or, if such quorum cannot be established,
by a majority vote of all Directors (in which Directors who are named defendants
or respondents in the Proceeding may participate); or (4) by the stockholders of
the Corporation in a vote that excludes the shares held by Directors who are
named defendants or respondents in the Proceeding.

    6.3   ADVANCE OF EXPENSES.  Reasonable expenses, including court costs and
attorney's fees, incurred by a person who was or is a witness or who was or is
named as a defendant or respondent in a Proceeding, by reason of the fact that
such individual is or was a Director or officer of the Corporation, or while a
Director or officer of the Corporation is or was serving at the request of the
Corporation as a director, officer, partner, venturer, proprietor, trustee,
employee, agent or similar functionary of another corporation, partnership,
trust, employee benefit plan or other enterprise, shall be paid by the
Corporation at reasonable intervals in advance of the final disposition of such
Proceeding, and without the determination set forth in



CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
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<PAGE>

Section 6.2, upon receipt of the Corporation of a written affirmation by such
person of his good faith belief that he has met the standard of conduct
necessary for indemnification under this Article 6, and a written undertaking by
or on behalf of such person to repay the amount paid or reimbursed by the
Corporation if it is ultimately determined that he is not entitled to be
indemnified by the Corporation as authorized in this Article 6.  Such written
undertaking shall be an unlimited obligation of such person and it may be
accepted without reference to financial ability to make repayment.

    6.4   PERMISSIVE INDEMNIFICATION.  The Board of Directors of the
Corporation may authorize the Corporation to indemnify employees or agents of
the Corporation, and to advance the reasonable expenses of such persons, to the
same extent, following the same determinations and upon the same conditions as
are required for the indemnification of and advancement of expenses to Directors
and officers of the Corporation.

    6.5   NATURE OF INDEMNIFICATION.  The indemnification and advancement of
expenses provided hereunder shall not be deemed exclusive or any other rights to
which those seeking indemnification may be entitled under the Certificate of
Incorporation, these Bylaws, any agreement, vote of stockholders or
disinterested Directors or otherwise, both as to actions taken in an official
capacity and as to actions taken in any other capacity while holding such
office, shall continue as to a person who has ceased to be a Director, officer,
employee or agent of the Corporation and shall inure to the benefit of the
heirs, executors and administrators of such person.

    6.6   INSURANCE.  The Corporation shall have the power and authority to
purchase and maintain insurance or another arrangement on behalf of any person
who is or was a Director, officer, employee or agent of the Corporation, or who
is or was serving at the request of the Corporation as a director, officer,
partner, venturer, proprietor, trustee, employee, agent, or


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
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<PAGE>

similar functionary of another foreign or domestic corporation, partnership,
joint venture, sole proprietorship, trust, employee benefit plan or other
enterprise, against any liability, claim, damage, loss or risk asserted against
such person and incurred by such person in any such capacity or arising out of
the status of such person as such, irrespective of whether the Corporation would
have the power to indemnify and hold such person harmless against such liability
under the provisions hereof.  If the insurance or other arrangement is with a
person or entity that is not regularly engaged in the business of providing
insurance coverage, the insurance or arrangement may provide for payment of a
liability with respect to which the Corporation would not have the power to
indemnify the person only if including coverage for the additional liability has
been approved by the stockholders of the Corporation.  Without limiting the
power of the Corporation to procure or maintain any kind of insurance or other
arrangement, the Corporation may, for the benefit of persons indemnified by the
Corporation, (1) create a trust fund; (2) establish any form of self-insurance;
(3) secure its indemnity obligation by grant of a security interest or other
lien on the assets of the Corporation; or (4) establish a letter of credit,
guaranty, or surety arrangement.  The insurance or other arrangement may be
procured, maintained, or established with the Corporation or with any insurer or
other person deemed appropriate by the Board of Directors regardless of whether
all or part of the stock or other securities of the insurer or other person are
owned in whole or part by the Corporation.  In the absence of fraud, the
judgment of the Board of Directors as to the terms and conditions of the
insurance or other arrangement and the identity of the insurer or other person
participating in the arrangement shall be conclusive and the insurance or
arrangement shall not be voidable and shall not subject the Directors approving
the insurance or arrangement to liability, on any ground, regardless of whether
the Directors participating in the approval is a beneficiary of the insurance or
arrangement.


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
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<PAGE>

    6.7   NOTICE.  Any indemnification or advance of expenses to a present or
former Director or officer of the Corporation in accordance with this Article 6
shall be reported in writing to the stockholders of the Corporation with or
before the notice or waiver of notice of the next stockholders' meeting or with
or before the next submission of a consent to action without a meeting and, in
any case, within the next twelve month period immediately following the
indemnification or advance.

                                      ARTICLE 7

                     STOCK CERTIFICATES AND TRANSFER REGULATIONS
                     -------------------------------------------

    7.1   DESCRIPTION OF CERTIFICATES.  The shares of the capital stock of the
Corporation shall be represented by certificates in the form approved by the
Board of Directors and signed in the name of the Corporation by the Chairman of
the Board, the Chief Executive Officer, the Chief Operating Officer, the
President or Vice President and the Secretary or an Assistance Secretary of the
Corporation, and, if any, sealed with the seal of the Corporation or a facsimile
thereof.  Each certificate shall state on the face thereof the name of the
holder, the number and class of shares, the par value of shares covered thereby
or a statement that such shares are without par value, and such other matters as
are required by law.  At such time as the Corporation may be authorized to issue
shares of more than one class, every certificate shall set forth upon the face
or back of such certificate a statement of the designations, preferences,
limitations and relative rights of the shares of each class authorized to be
issued, as required by the laws of the State of Delaware, or may state that the
Corporation will furnish a copy of such statement without charge to the holder
of such certificate upon receipt of a written request therefor from such holder.

    7.2   ENTITLEMENT TO CERTIFICATES.  Every holder of the capital stock in
the Corporation shall be entitled to have a certificate signed in the name of
the Corporation by the Chairman of



CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
Page 25


<PAGE>

the Board, the Chief Executive Officer, the Chief Operating Officer, the
President or a Vice President and the Secretary or an Assistant Secretary of the
Corporation, certifying the class of capital stock and the number of shares
represented thereby as owned or held by such stockholder in the Corporation.

    7.3   SIGNATURES.  The signatures of the Chairman of the Board, the Chief
Executive Officer, the Chief Operating Officer, the President, the Vice
President, the Secretary or the Assistant Secretary upon a certificate may be
facsimiles.  In case any officer or officers who have signed, or whose facsimile
signature or signatures have been placed upon any such certificate or
certificates, shall cease to serve as such officer or officers of the
Corporation, whether because of death, resignation, removal or otherwise, before
such certificate or certificates are issued and delivered by the Corporation,
such certificate or certificates may nevertheless be adopted by the Corporation
and be issued and delivered with the same effect as though the person or persons
who signed such certificates or whose facsimile signature or signatures have
been used thereon had not ceased to serve as such officer or officers of the
Corporation.

    7.4   ISSUANCE OF CERTIFICATES.  Certificates evidencing shares of its
capital stock (both treasury and authorized but unissued) may be issued for such
consideration (not less than par value, except for treasury shares which may be
issued for such consideration) and to such persons as the Board of Directors may
determine from time to time.  Shares shall not be issued until the full amount
of the consideration, fixed as provided by law, has been paid.

    7.5   PAYMENT FOR SHARES.  Consideration for the issuance of shares shall
be paid, valued and allocated as follows:

         (a)   CONSIDERATION.  The consideration for the issuance of shares
    shall consist of money paid, labor done (including services actually
    performed for the Corporation), or


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
Page 26

<PAGE>

    property (tangible or intangible) actually received.  Neither promissory
    notes nor the promise of future services shall constitute payment of
    consideration for shares.

         (b)   VALUATION.  In the absence of fraud in the transaction, the
    determination of the Board of Directors as to the value of consideration
    received shall be conclusive.

         (c)   EFFECT.  When consideration, fixed as provided by law, has been
    paid, the shares shall be deemed to have been issued and shall be
    considered fully paid and nonassessable.

         (d)   ALLOCATION OF CONSIDERATION.  The consideration received for
    shares shall be allocated by the Board of Directors, in accordance with
    law, between the stated capital and capital surplus accounts.

    7.6   SUBSCRIPTIONS.  Unless otherwise provided in the subscription
agreement, subscriptions of shares, whether made before or after organization of
the Corporation, shall be paid in full in such installments and at such times as
shall be determined by the Board of Directors.  Any call made by the Board of
Directors for payment on subscriptions shall be uniform as to all shares of the
same class and series.  In case of default in the payment of any installment or
call when payment is due, the Corporation may proceed to collect the amount due
in the same manner as any debt due to the Corporation.

    7.7   RECORD DATE.  For the purpose of determining stockholders entitled to
notice of or to vote at any meeting of stockholders, or any adjournment thereof,
or entitled to receive a distribution by the Corporation (other than a
distribution involving a purchase or redemption by the Corporation of any of its
own shares) or a share dividend, or in order to make a determination of
stockholders for any other proper purpose, the Board of Directors may fix a
record date for any such determination of stockholders, which record date shall
not precede the date upon which the resolution fixing the record date is adopted
by the Board of Directors, and which record date shall not be more than sixty
(60) days, and in the case of a meeting of stockholders, not less than ten (10)
days prior to the date on which the particular action requiring



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<PAGE>

such determination of stockholders is to be taken.  If no record date is fixed
for the determination of stockholders entitled to notice of or to vote at a
meeting of stockholders, or stockholders entitled to receive a distribution
(other than a distribution involving a purchase or redemption by the Corporation
of any of its own shares) or a share dividend, the date before the date on which
notice of the meeting is mailed or the date on which the resolution of the Board
of Directors declaring such distribution or share dividend is adopted, as the
case may be, shall be the record date for such determination of stockholders.
When a determination of stockholders entitled to vote at any meeting of
stockholders has been made as provided in this Section, such determination shall
be applied to any adjournment thereof.

    7.8   REGISTERED OWNERS.  Prior to due presentment for registration of
transfer of a certificate evidencing shares of the capital stock of the
Corporation in the manner set forth in Section 7.10 hereof, the Corporation
shall be entitled to recognize the person registered as the owner of such shares
on its books (or the books of its duly appointed transfer agent, as the case may
be) as the person exclusively entitled to vote, to receive notices and dividends
with respect to, and otherwise exercise all rights and powers relative to such
shares; and the Corporation shall not be bound or otherwise obligated to
recognize any claim, direct or indirect, legal or equitable, to such shares by
any other person, whether or not it shall have actual, express or other notice
thereof, except as otherwise provided by the laws of Delaware.

    7.9   LOST, STOLEN OR DESTROYED CERTIFICATES.  The Corporation shall issue
a new certificate in place of any certificate for shares previously issued if
the registered owner of the certificate satisfies the following conditions:

         (a)   PROOF OF LOSS.  Submits proof in affidavit form satisfactory to
    the Corporation that such certificate has been lost, destroyed or
    wrongfully taken;


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
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<PAGE>

         (b)   TIMELY REQUEST.  Requests the issuance of a new certificate
    before the Corporation has notice that the certificate has been acquired by
    a purchaser for value in good faith and without notice of an adverse claim;

         (c)   BOND.  Gives a bond in such form, and with such surety or
    sureties, with fixed or open penalty, as the Corporation may direct, to
    indemnify the Corporation (and its transfer agent and registrar, if any)
    against any claim that may be made or otherwise asserted by virtue of the
    alleged loss, destruction or theft of such certificate or certificates; and

         (d)   OTHER REQUIREMENTS.  Satisfies any other reasonable requirements
    imposed by the Corporation.


    In the event a certificate has been lost, apparently destroyed or
wrongfully taken, and the registered owner of record fails to notify the
Corporation within a reasonable time after he has notice of such loss,
destruction, or wrongful taking, and the Corporation registers a transfer (in
the manner hereinbelow set forth) of the shares represented by the certificate
before receiving such notification, such prior registered owner of record shall
be precluded from making any claim against the Corporation for the transfer
required hereunder or for a new certificate.

    7.10   REGISTRATION OF TRANSFERS.  Subject to the provisions hereof, the
Corporation shall register the transfer of a certificate evidencing shares of
its capital stock presented to it for transfer if:

         (a)   ENDORSEMENT.  Upon surrender of the certificate to the
    Corporation (or its transfer agent, as the case may be) for transfer, the
    certificate (or an appended stock power) is properly endorsed by the
    registered owner, or by his duly authorized legal representative or
    attorney-in-fact, with proper written evidence of the authority and
    appointment of such representative, if any, accompanying the certificate;

         (b)   GUARANTY AND EFFECTIVENESS OF SIGNATURE.  The signature of such
    registered owner of his legal representative or attorney-in-fact, as the
    case may be, has been guaranteed by a national banking association or
    member of the New York Stock Exchange, and reasonable assurance in a form
    satisfactory to the Corporation is given that such endorsements are genuine
    and effective;

         (c)   ADVERSE CLAIMS.  The Corporation has no notice of an adverse
    claim or has otherwise discharged any duty to inquire into such a claim;



CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
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<PAGE>

         (d)   COLLECTION OF TAXES.  Any applicable law (local, state or
    federal) relating to the collection of taxes relative to the transaction
    has been complied with; and

         (e)   ADDITIONAL REQUIREMENTS SATISFIED.  Such additional conditions
    and documentation as the Corporation (or its transfer agent, as the case
    may be) shall reasonably require, including without limitation thereto, the
    delivery with the surrender of such stock certificate or certificates of
    proper evidence of succession, assignment or other authority to obtain
    transfer thereof, as the circumstances may require, and such legal opinions
    with reference to the requested transfer as shall be required by the
    Corporation (or its transfer agent) pursuant to the provisions of these
    Bylaws and applicable law, shall have been satisfied.


    7.11   RESTRICTIONS ON TRANSFER AND LEGENDS ON CERTIFICATES.

         (a)   SHARES IN CLASSES OR SERIES.  If the Corporation is authorized
    to issue shares of more than one class, the certificate shall set forth,
    either on the face or back of the certificate, a full or summary statement
    of all of the designations, preferences, limitation, and relative rights of
    the shares of each such class and, if the Corporation is authorized to
    issue any preferred or special class in series, the variations in the
    relative rights and preferences of the shares of each such series so far as
    the same have been fixed and determined, and the authority of the Board of
    Directors to fix and determine the relative rights and preferences of
    subsequent series.  In lieu of providing such a statement in full on the
    certificate, a statement on the face or back of the certificate may provide
    that the Corporation will furnish such information to any stockholder
    without charge upon written request to the Corporation at its principal
    place of business or registered office and that copies of the information
    are on file in the office of the Secretary of State.

         (b)   RESTRICTION ON TRANSFER.  Any restrictions imposed by the
    Corporation on the sale or other disposition of its shares and on the
    transfer thereof must be copies at length or in summary form on the face,
    or so copied on the back and referred to on the face, of each certificate
    representing shares to which the restriction applies.  The certificate may
    however state on the face or back that such a restriction exists pursuant
    to a specified document and that the Corporation will furnish a copy of the
    document to the holder of the certificate without charge upon written
    request to the Corporation at its principal place of business.

         (c)   UNREGISTERED SECURITIES.  Any security of the Corporation,
    including, among others, any certificate evidencing shares of the capital
    stock of the Corporation or warrants to purchase shares of capital stock of
    the Corporation, which is issued to any person without registration under
    the Securities Act of 1933, as amended, or the Blue Sky laws of any state,
    shall not be transferable until the Corporation has been furnished with a
    legal opinion of counsel with reference thereto, satisfactory in form and
    content to the Corporation and its counsel, to the effect that such sale,
    transfer or pledge does not involve a violation of the Securities Act of
    1933, as amended, or the Blue Sky laws of any state having jurisdiction.
    The certificate representing such security shall bear substantially the
    following legend:


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
Page 30

<PAGE>

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY
         APPLICABLE STATE SECURITIES LAWS BUT HAVE BEEN ACQUIRED FOR THE
         PRIVATE INVESTMENT OF THE HOLDER HEREOF AND MAY NOT BE OFFERED,
         SOLD OR TRANSFERRED UNTIL EITHER (i) A REGISTRATION STATEMENT
         UNDER SUCH SECURITIES ACT OR SUCH APPLICABLE STATE SECURITIES
         LAWS SHALL HAVE BECOME EFFECTIVE WITH REGARD THERETO, OR (ii) THE
         CORPORATION SHALL HAVE RECEIVED AN OPINION OF COUNSEL ACCEPTABLE
         TO THE CORPORATION AND ITS COUNSEL THAT REGISTRATION UNDER SUCH
         SECURITIES ACT OR SUCH APPLICABLE STATE SECURITIES LAWS IS NOT
         REQUIRED IN CONNECTION WITH SUCH PROPOSED OFFER, SALE OR
         TRANSFER.


                                      ARTICLE 8

                                  GENERAL PROVISIONS
                                  ------------------

    8.1   DIVIDENDS.  Subject to the provisions of the General Corporation Law
of Delaware, as amended, and the Certificate of Incorporation, dividends of the
Corporation shall be declared and paid pursuant to the following regulations:

         (a)   DECLARATION AND PAYMENT.  Dividends on the issued and
    outstanding shares of capital stock of the Corporation may be declared by
    the Board of Directors at any regular or special meeting and may be paid in
    cash, in property, or in shares of capital stock.  Such declaration and
    payment shall be at the discretion of the Board of Directors.

         (b)   RECORD DATE.  The Board of Directors may fix in advance a record
    date for the purpose of determining stockholders entitled to receive
    payment of any dividend, such record date to be not more than sixty (60)
    days prior to the payment date of such dividend, or the Board of Directors
    may close the stock transfer books for such purpose for a period of not
    more than sixty (60) days prior to the payment date of such dividend.  In
    the absence of action by the Board of Directors, the date upon which the
    Board of Directors adopts the resolution declaring such dividend shall be
    the record date.

    8.2     RESERVES.  There may be created by resolution of the Board of
Directors out of the surplus of the Corporation such reserve or reserves as the
Board of Directors from time to time, in its discretion, thinks proper to
provide for contingencies, or to repair or maintain any property of the
Corporation, or for such other purposes as the Board of Directors shall think


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
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<PAGE>

beneficial to the Corporation, and the Board of Directors may modify or abolish
any such reserve in the manner in which it was created.

    8.3   BOOKS AND RECORDS.  The Corporation shall maintain correct and
complete books and records of account and shall prepare and maintain minutes of
the proceedings of its stockholders, its Board of Directors, and each committee
of its Board of Directors.  The Corporation shall keep at its registered office
or principal place of business, or at the office of its transfer agent or
registrar, a record of original issuance of shares issued by the Corporation and
a record of each transfer of those shares that have been presented to the
Corporation for registration or transfer.  Such records shall contain the names
and addresses of all past and present stockholders and the number and class of
the shares issued by the Corporation held by each.

    8.4   ANNUAL STATEMENT.  The Board of Directors shall present at or before
each annual meeting of stockholders a full and clear statement of the business
and financial condition of the Corporation, including a reasonably detailed
balance sheet and income statement under current date.

    8.5   CONTRACTS AND NEGOTIABLE INSTRUMENTS.  Except as otherwise provided
by law or these Bylaws, any contract or other instrument relative to the
business of the Corporation may be executed and delivered in the name of the
Corporation and on its behalf by the Chairman of the Board, the Chief Executive
Officer, the Chief Operating Officer, or the President of the Corporation.  The
Board of Directors may authorize any other officer or agent of the Corporation
to enter into any contract or execute and deliver any contract in the name and
on behalf of the Corporation, and such authority may be general or confined to
specific instances as the Board of Directors may determine by resolution.  All
bills, notes, checks, or other instruments for the payment of money shall be
signed or countersigned by such officer, officers,


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
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<PAGE>

agent, or agents and in such manner as are permitted by these Bylaws and/or as,
from time to time, may be prescribed by resolution of the Board of Directors.
Unless authorized to do so by these Bylaws or by the Board of Directors, no
officer, agent, or employee shall have any power or authority to bind the
Corporation by any contract or engagement, or to pledge its credit, or to render
it liable pecuniarily for any purpose or to any amount.

    8.6   FISCAL YEAR.  The fiscal year of the Corporation shall be the
calendar year.

    8.7   CORPORATE SEAL.  The Corporation seal, if any, shall be in such form
as may be determined by the Board of Directors.  The seal, if any, may be used
by causing it or a facsimile thereof to be impressed or affixed or in any manner
reproduced.

    8.8   RESIGNATIONS.  Any Director, officer, or agent may resign his office
or position with the Corporation by delivering written notice thereof to the
Chairman of the Board, the Chief Executive Officer, the Chief Operating Officer,
the President, or the Secretary.  Such resignation shall be effective at the
time specified therein, or immediately upon delivery if no time is specified.
Unless otherwise specified therein, an acceptance of such resignation shall not
be a necessary prerequisite of its effectiveness.

    8.9   AMENDMENT OF BYLAWS.  These Bylaws may be altered, amended, or
repealed and new Bylaws adopted at any meeting of the Board of Directors or
stockholders at which a quorum is present, by the affirmative vote of a majority
of the Directors or stockholders, as the case may be, present at such meeting,
provided notice of the proposed alteration, amendment, or repeal be contained in
the notice of such meeting.

    8.10   CONSTRUCTION.  Whenever the context so requires herein, the
masculine shall include the feminine and neuter, and the singular shall include
the plural, and conversely.  If any portion or provision of these Bylaws shall
be held invalid or inoperative, then, so far as is reasonable and possible:  (1)
the remainder of these Bylaws shall be considered valid and


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<PAGE>

operative, and (2) effect shall be given to the intent manifested by the portion
or provision held invalid or inoperative.

    8.11   TELEPHONE MEETINGS.  Stockholders, Directors, or members of any
committee may hold any meeting of such stockholders, Directors, or committee by
means of conference telephone or similar communications equipment which permits
all persons participating in the meeting to hear each other and actions taken at
such meeting shall have the same force and effect as if taken at a meeting at
which persons were present and voting in person.  The Secretary of the
Corporation shall prepare a memorandum of the action taken at any such
telephonic meeting.

    8.12   TABLE OF CONTENTS; CAPTIONS.  The table of contents and captions
used in these Bylaws have been inserted for administrative convenience only and
do not constitute matter to be construed in interpretation.

    IN DUE CERTIFICATION WHEREOF, the undersigned, being the Secretary of
COSTILLA ENERGY, INC., confirms the adoption and approval of the foregoing
Bylaws, effective as of the 1st day of July, 1996.


                                /S/ CLIFFORD N. HAIR, JR.
                             -------------------------------------------------

                             CLIFFORD N. HAIR, JR., Secretary


CORPORATE BYLAWS OF COSTILLA ENERGY, INC.
Page 34


<PAGE>







                       COSTILLA ENERGY, INC.,
                             as Issuer,

                Subsidiary Guarantors parties hereto

                            $100,000,000

               ___% SENIOR SUBORDINATED NOTES DUE 2006

                    ____________________________

                              INDENTURE

                    Dated as of ___________, 1996

                STATE STREET BANK AND TRUST COMPANY,

                               Trustee



<PAGE>

                              CROSS-REFERENCE TABLE

         Reconciliation and tie between the Trust Indenture Act of 1939
        as amended, and the Indenture, dated as of ________________, 1996

   TRUST
INDENTURE
    ACT                                                              INDENTURE
  SECTION                                                             SECTION 
- -------------------------------------------------------------------------------
Section 310(a)(1). . . . . . . . . . . . . . . . . . . . . . . . . . . .7.10
         (a)(2). . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.10
         (a)(3). . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (a)(4). . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (a)(5). . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.10
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . .7.08; 7.10
         (c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
Section 311(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.11
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.11
         (c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
Section 312(a) . . . . . . . . . . . . . . . . . . . . . . .7.06(a); 7.06(b)
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.06(c)
         (c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.06(d)
Section 313(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.06(e)
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (c) . . . . . . . . . . . . . . . . . . . . . . . .7.06(e); 7.06(f)
         (d) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.06
Section 314(a) . . . . . . . . . . . . . . . . . . . . . . . . . .4.17; 4.19
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (c)(1). . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.03
         (c)(2). . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.03
         (c)(3). . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (d) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (e) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.04
         (f) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.19
Section 315(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.01(b)
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.05(a)
         (c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.01(a)
         (d) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.01(c)
         (e) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.10
Section 316(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.08
         (a)(1)(A) . . . . . . . . . . . . . . . . . . . . . . . . . . .6.05
         (a)(1)(B) . . . . . . . . . . . . . . . . . . . . . . . . . . .6.04
         (a)(2). . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.07
         (c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.05
Section 317(a)(1). . . . . . . . . . . . . . . . . . . . . . . . . . . .N.A.
         (a)(2). . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.08
         (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.04
Section 318(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.01
         
Note: This reconciliation and tie shall not, for any purpose, be deemed to be
      part of the Indenture.

                                       -i-

<PAGE>

                              TABLE OF CONTENTS
                                                                           Page
                                                                           ----
                                  ARTICLE I        
DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION. . . . . . . . . . . .1
     SECTION 1.01.    DEFINITIONS. . . . . . . . . . . . . . . . . . . . . .  1
     SECTION 1.02.    INCORPORATION BY REFERENCE OF TRUST INDENTURE ACT. . . 20
     SECTION 1.03.    RULES OF CONSTRUCTION. . . . . . . . . . . . . . . . . 21
     SECTION 1.04.    FORM OF DOCUMENTS DELIVERED TO TRUSTEE . . . . . . . . 21
     SECTION 1.05.    ACTS OF HOLDERS. . . . . . . . . . . . . . . . . . . . 22
     SECTION 1.06.    SATISFACTION AND DISCHARGE . . . . . . . . . . . . . . 22

                                  ARTICLE II
THE NOTES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
     SECTION 2.01.    FORM AND DATING. . . . . . . . . . . . . . . . . . . . 23
     SECTION 2.02.    EXECUTION AND AUTHENTICATION . . . . . . . . . . . . . 24
     SECTION 2.03.    REGISTRAR AND PAYING AGENT . . . . . . . . . . . . . . 25
     SECTION 2.04.    PAYING AGENT TO HOLD MONEY IN TRUST. . . . . . . . . . 26
     SECTION 2.05.    GLOBAL NOTES . . . . . . . . . . . . . . . . . . . . . 26
     SECTION 2.06.    TRANSFER AND EXCHANGE. . . . . . . . . . . . . . . . . 27
     SECTION 2.07.    REPLACEMENT NOTES. . . . . . . . . . . . . . . . . . . 28
     SECTION 2.08.    OUTSTANDING NOTES. . . . . . . . . . . . . . . . . . . 29
     SECTION 2.09.    TEMPORARY NOTES. . . . . . . . . . . . . . . . . . . . 30
     SECTION 2.10.    CANCELLATION . . . . . . . . . . . . . . . . . . . . . 30
     SECTION 2.11.    PAYMENT OF INTEREST; INTEREST RIGHTS PRESERVED . . . . 30
     SECTION 2.12.    AUTHORIZED DENOMINATIONS . . . . . . . . . . . . . . . 31
     SECTION 2.13.    COMPUTATION OF INTEREST. . . . . . . . . . . . . . . . 31
     SECTION 2.14.    PERSONS DEEMED OWNERS. . . . . . . . . . . . . . . . . 31
     SECTION 2.15.    CUSIP NUMBERS. . . . . . . . . . . . . . . . . . . . . 31
                                  ARTICLE III
REDEMPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
     SECTION 3.01.    NOTICE TO TRUSTEE. . . . . . . . . . . . . . . . . . . 32
     SECTION 3.02.    SELECTION OF NOTES TO BE REDEEMED. . . . . . . . . . . 32
     SECTION 3.03.    NOTICE OF REDEMPTION . . . . . . . . . . . . . . . . . 32
     SECTION 3.04.    EFFECT OF NOTICE OF REDEMPTION . . . . . . . . . . . . 33
     SECTION 3.05.    DEPOSIT OF REDEMPTION PRICE. . . . . . . . . . . . . . 33
     SECTION 3.06.    NOTES REDEEMED IN PART . . . . . . . . . . . . . . . . 34
                                  ARTICLE IV
COVENANTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
     SECTION 4.01.    PAYMENT OF NOTES . . . . . . . . . . . . . . . . . . . 34
     SECTION 4.02.    MAINTENANCE OF OFFICE OR AGENCY. . . . . . . . . . . . 34
     SECTION 4.03.    MONEY FOR THE NOTE PAYMENTS TO BE HELD IN TRUST. . . . 35

                                     -ii-

<PAGE>

     SECTION 4.04.    CORPORATE EXISTENCE. . . . . . . . . . . . . . . . . . 35
     SECTION 4.05.    MAINTENANCE OF PROPERTY. . . . . . . . . . . . . . . . 35
     SECTION 4.06.    PAYMENT OF TAXES AND OTHER CLAIMS. . . . . . . . . . . 36
     SECTION 4.07.    REPURCHASE AT THE OPTION OF HOLDERS UPON A CHANGE OF 
                      CONTROL. . . . . . . . . . . . . . . . . . . . . . . . 36
     SECTION 4.08.    LIMITATION ON ASSET SALES. . . . . . . . . . . . . . . 38
     SECTION 4.09.    OWNERSHIP OF AND LIENS ON CAPITAL STOCK. . . . . . . . 41
     SECTION 4.10.    UNRESTRICTED SUBSIDIARIES. . . . . . . . . . . . . . . 42
     SECTION 4.11.    RESTRICTED PAYMENTS. . . . . . . . . . . . . . . . . . 43
     SECTION 4.12.    INCURRENCE OF INDEBTEDNESS AND ISSUANCE OF PREFERRED 
                      STOCK. . . . . . . . . . . . . . . . . . . . . . . . . 44
     SECTION 4.13.    LIENS. . . . . . . . . . . . . . . . . . . . . . . . . 46
     SECTION 4.14.    DIVIDENDS AND OTHER PAYMENT RESTRICTIONS AFFECTING 
                      SUBSIDIARIES . . . . . . . . . . . . . . . . . . . . . 46
     SECTION 4.15.    LIMITATION ON LAYERING DEBT. . . . . . . . . . . . . . 47
     SECTION 4.16.    TRANSACTIONS WITH AFFILIATES . . . . . . . . . . . . . 47
     SECTION 4.17.    REPORTS. . . . . . . . . . . . . . . . . . . . . . . . 47
     SECTION 4.18.    WAIVER OF STAY, EXTENSION OR USURY LAWS. . . . . . . . 48
     SECTION 4.19.    COMPLIANCE CERTIFICATE; NOTICE OF DEFAULT OR EVENT OF 
                      DEFAULT. . . . . . . . . . . . . . . . . . . . . . . . 48
     SECTION 4.20.    INVESTMENT COMPANY ACT . . . . . . . . . . . . . . . . 48
     SECTION 4.21.    SALE AND LEASEBACK . . . . . . . . . . . . . . . . . . 49
     SECTION 4.22.    FURTHER INSTRUMENTS AND ACTS . . . . . . . . . . . . . 49
                                   ARTICLE V
CONSOLIDATION, MERGER, CONVEYANCE, LEASE OR TRANSFER . . . . . . . . . . . . 49
     SECTION 5.01.    MERGER, CONSOLIDATION OR SALE OF ASSETS. . . . . . . . 49
     SECTION 5.02.    SUCCESSOR CORPORATION SUBSTITUTED. . . . . . . . . . . 50
                                   ARTICLE VI
DEFAULTS AND REMEDIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
     SECTION 6.01.    EVENTS OF DEFAULT. . . . . . . . . . . . . . . . . . . 50
     SECTION 6.02.    ACCELERATION . . . . . . . . . . . . . . . . . . . . . 52
     SECTION 6.03.    OTHER REMEDIES . . . . . . . . . . . . . . . . . . . . 53
     SECTION 6.04.    WAIVER OF PAST DEFAULTS. . . . . . . . . . . . . . . . 53
     SECTION 6.05.    CONTROL BY MAJORITY. . . . . . . . . . . . . . . . . . 53
     SECTION 6.06.    LIMITATION ON SUITS. . . . . . . . . . . . . . . . . . 54
     SECTION 6.07.    RIGHTS OF HOLDERS TO RECEIVE PAYMENT . . . . . . . . . 54
     SECTION 6.08.    TRUSTEE MAY FILE PROOFS OF CLAIM . . . . . . . . . . . 55
     SECTION 6.09.    PRIORITIES . . . . . . . . . . . . . . . . . . . . . . 55
     SECTION 6.10.    UNDERTAKING FOR COSTS. . . . . . . . . . . . . . . . . 56
     SECTION 6.11.    WAIVER OF STAY OR EXTENSION LAWS . . . . . . . . . . . 56
     SECTION 6.12.    TRUSTEE MAY ENFORCE CLAIMS WITHOUT POSSESSION OF THE 
                      NOTES. . . . . . . . . . . . . . . . . . . . . . . . . 56
     SECTION 6.13.    RESTORATION OF RIGHTS AND REMEDIES . . . . . . . . . . 56

                                     -iii-

<PAGE>


     SECTION 6.14.    RIGHTS AND REMEDIES CUMULATIVE . . . . . . . . . . . . 57
     SECTION 6.15.    DELAY OR OMISSION NOT WAIVER . . . . . . . . . . . . . 57
                                  ARTICLE VII
TRUSTEE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
     SECTION 7.01.    DUTIES OF TRUSTEE. . . . . . . . . . . . . . . . . . . 57
     SECTION 7.02.    RIGHTS OF TRUSTEE. . . . . . . . . . . . . . . . . . . 58
     SECTION 7.03.    INDIVIDUAL RIGHTS OF TRUSTEE . . . . . . . . . . . . . 59
     SECTION 7.04.    TRUSTEE'S DISCLAIMER . . . . . . . . . . . . . . . . . 59
     SECTION 7.05.    NOTICE OF DEFAULTS . . . . . . . . . . . . . . . . . . 59
     SECTION 7.06.    PRESERVATION OF INFORMATION; REPORTS BY TRUSTEE TO 
                      HOLDERS. . . . . . . . . . . . . . . . . . . . . . . . 59
     SECTION 7.07.    COMPENSATION AND INDEMNITY . . . . . . . . . . . . . . 60
     SECTION 7.08.    REPLACEMENT OF TRUSTEE . . . . . . . . . . . . . . . . 61
     SECTION 7.09.    SUCCESSOR TRUSTEE BY MERGER. . . . . . . . . . . . . . 63
     SECTION 7.10.    ELIGIBILITY; DISQUALIFICATION. . . . . . . . . . . . . 63
     SECTION 7.11.    PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY. . . 64
                                 ARTICLE VIII
DEFEASANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
     SECTION 8.01.    COMPANY'S OPTION TO EFFECT LEGAL DEFEASANCE OR COVENANT
                      DEFEASANCE . . . . . . . . . . . . . . . . . . . . . . 64
     SECTION 8.02.    LEGAL DEFEASANCE AND DISCHARGE . . . . . . . . . . . . 64
     SECTION 8.03.    COVENANT DEFEASANCE. . . . . . . . . . . . . . . . . . 65
     SECTION 8.04.    CONDITIONS TO DEFEASANCE OR COVENANT DEFEASANCE. . . . 66
     SECTION 8.05.    DEPOSITED MONEY AND U.S. GOVERNMENT OBLIGATIONS TO BE 
                      HELD IN TRUST; MISCELLANEOUS PROVISIONS. . . . . . . . 67
     SECTION 8.06.    REINSTATEMENT. . . . . . . . . . . . . . . . . . . . . 68
                                  ARTICLE IX
AMENDMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
     SECTION 9.01.    WITHOUT CONSENT OF HOLDERS . . . . . . . . . . . . . . 68
     SECTION 9.02.    WITH CONSENT OF HOLDERS. . . . . . . . . . . . . . . . 69
     SECTION 9.03.    EFFECT OF SUPPLEMENTAL INDENTURES. . . . . . . . . . . 70
     SECTION 9.04.    COMPLIANCE WITH TRUST INDENTURE ACT. . . . . . . . . . 70
     SECTION 9.05.    REVOCATION AND EFFECT OF CONSENTS AND WAIVERS. . . . . 70
     SECTION 9.06.    NOTATION ON OR EXCHANGE OF NOTES . . . . . . . . . . . 71
     SECTION 9.07.    TRUSTEE TO EXECUTE SUPPLEMENTAL INDENTURES . . . . . . 71
     SECTION 9.08.    EFFECT ON SENIOR INDEBTEDNESS. . . . . . . . . . . . . 72
                                   ARTICLE X
SUBORDINATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
     SECTION 10.01.   AGREEMENT TO SUBORDINATE . . . . . . . . . . . . . . . 72
     SECTION 10.02.   LIQUIDATION; DISSOLUTION; BANKRUPTCY . . . . . . . . . 72
     SECTION 10.03.   DEFAULT ON DESIGNATED SENIOR INDEBTEDNESS. . . . . . . 73
     SECTION 10.04.   ACCELERATION OF NOTES. . . . . . . . . . . . . . . . . 74
     SECTION 10.05.   WHEN DISTRIBUTION MUST BE PAID OVER. . . . . . . . . . 74
     SECTION 10.06.   NOTICE BY COMPANY. . . . . . . . . . . . . . . . . . . 74

                                      -iv-

<PAGE>


     SECTION 10.07.   SUBROGATION. . . . . . . . . . . . . . . . . . . . . . 74
     SECTION 10.08.   RELATIVE RIGHTS. . . . . . . . . . . . . . . . . . . . 75
     SECTION 10.09.   SUBORDINATION MAY NOT BE IMPAIRED BY COMPANY . . . . . 75
     SECTION 10.10.   DISTRIBUTION OR NOTICE TO REPRESENTATIVE . . . . . . . 75
     SECTION 10.11.   RIGHTS OF TRUSTEE AND PAYING AGENT . . . . . . . . . . 76
     SECTION 10.12.   AUTHORIZATION TO EFFECT SUBORDINATION. . . . . . . . . 76
     SECTION 10.13.   AMENDMENTS . . . . . . . . . . . . . . . . . . . . . . 76
                                  ARTICLE XI
SUBSIDIARY GUARANTEES. . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
     SECTION 11.01.   UNCONDITIONAL GUARANTEE. . . . . . . . . . . . . . . . 76
     SECTION 11.02.   SUBSIDIARY GUARANTORS MAY CONSOLIDATE, ETC., ON CERTAIN
                      TERMS. . . . . . . . . . . . . . . . . . . . . . . . . 77
     SECTION 11.03.   ADDITION OF SUBSIDIARY GUARANTORS. . . . . . . . . . . 78
     SECTION 11.04.   RELEASE OF A SUBSIDIARY GUARANTOR. . . . . . . . . . . 79
     SECTION 11.05.   LIMITATION OF SUBSIDIARY GUARANTOR'S LIABILITY.. . . . 79
     SECTION 11.06.   CONTRIBUTION . . . . . . . . . . . . . . . . . . . . . 80
     SECTION 11.07.   SEVERABILITY . . . . . . . . . . . . . . . . . . . . . 80
     SECTION 11.08.   SUBSIDIARY GUARANTEES SUBORDINATED TO GUARANTOR SENIOR 
                      INDEBTEDNESS . . . . . . . . . . . . . . . . . . . . . 80
     SECTION 11.09.   LIQUIDATION; DISSOLUTION; BANKRUPTCY . . . . . . . . . 80
     SECTION 11.10.   DEFAULT ON DESIGNATED GUARANTOR SENIOR INDEBTEDNESS. . 81
     SECTION 11.11.   WHEN DISTRIBUTION MUST BE PAID OVER. . . . . . . . . . 82
     SECTION 11.12.   NOTICE BY SUBSIDIARY GUARANTOR . . . . . . . . . . . . 83
     SECTION 11.13.   SUBROGATION. . . . . . . . . . . . . . . . . . . . . . 83
     SECTION 11.14.   RELATIVE RIGHTS. . . . . . . . . . . . . . . . . . . . 83
     SECTION 11.15.   SUBORDINATION MAY NOT BE IMPAIRED BY SUBSIDIARY 
                      GUARANTORS . . . . . . . . . . . . . . . . . . . . . . 83
     SECTION 11.16.   DISTRIBUTION OR NOTICE TO REPRESENTATIVE . . . . . . . 83
     SECTION 11.17.   RIGHTS OF TRUSTEE AND PAYING AGENT . . . . . . . . . . 84
     SECTION 11.18.   AUTHORIZATION TO EFFECT SUBORDINATION. . . . . . . . . 84
     SECTION 11.19.   AMENDMENTS . . . . . . . . . . . . . . . . . . . . . . 85
                                  ARTICLE XII
MISCELLANEOUS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
     SECTION 12.01.   TRUST INDENTURE ACT CONTROLS . . . . . . . . . . . . . 85
     SECTION 12.02.   NOTICES. . . . . . . . . . . . . . . . . . . . . . . . 85
     SECTION 12.03.   CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT . . 85
     SECTION 12.04.   STATEMENTS REQUIRED IN CERTIFICATE OR OPINION. . . . . 86
     SECTION 12.05.   RULES BY TRUSTEE, PAYING AGENT AND REGISTRAR . . . . . 86
     SECTION 12.06.   PAYMENTS ON BUSINESS DAYS. . . . . . . . . . . . . . . 86
     SECTION 12.07.   GOVERNING LAW. . . . . . . . . . . . . . . . . . . . . 86
     SECTION 12.08.   NO RECOURSE AGAINST OTHERS . . . . . . . . . . . . . . 86
     SECTION 12.09.   SUCCESSORS . . . . . . . . . . . . . . . . . . . . . . 86

                                      -v-

<PAGE>

     SECTION 12.10.   COUNTERPARTS . . . . . . . . . . . . . . . . . . . . . 87
     SECTION 12.11.   TABLE OF CONTENTS; HEADINGS. . . . . . . . . . . . . . 87
     SECTION 12.12.   SEVERABILITY . . . . . . . . . . . . . . . . . . . . . 87
     SECTION 12.13.   FURTHER INSTRUMENTS AND ACTS . . . . . . . . . . . . . 87

EXHIBIT A    FORM OF GLOBAL NOTE
EXHIBIT B    FORM OF CERTIFICATED NOTE


                                     -vi-


<PAGE>

     INDENTURE, dated as of _______________, 1996, between COSTILLA ENERGY, 
INC., a Delaware corporation (the "Company"), having its principal office at 
400 West Illinois, Suite 1000, Midland, Texas 79701, the Subsidiary 
Guarantors listed on the signature pages hereof (the "Subsidiary 
Guarantors"), and STATE STREET BANK AND TRUST COMPANY, a Massachusetts trust 
company, as trustee hereunder (the "Trustee"), having its Corporate Trust 
Office at Two International Place, Corporate Trust Department, 4th Floor, 
Boston, Massachusetts 02110.

                           RECITALS OF THE COMPANY

     The Company has duly authorized the creation and issue of its ____% 
Senior Subordinated Notes Due 2006 (the "Notes") of substantially the tenor 
and amount hereinafter set forth, and to provide therefor, the Company has 
duly authorized the execution and delivery of this Indenture.

     Each Subsidiary Guarantor has duly authorized its guarantee of the Notes 
and to provide therefor each Subsidiary Guarantor has duly authorized the 
execution and delivery of this Indenture.

     All things necessary to make the Notes, when executed by the Company and 
authenticated by the Trustee and delivered hereunder and duly issued by the 
Company, the valid obligations of the Company and each Subsidiary Guarantor, 
and to make this Indenture a valid instrument of the Company and each 
Subsidiary Guarantor, in accordance with their respective terms, have been 
done.

     NOW, THEREFORE, THIS INDENTURE WITNESSETH, that, for and in 
consideration of the premises and the purchase of the Notes by the Holders 
thereof, it is mutually covenanted and agreed, for the equal and 
proportionate benefit of all Holders of the Notes, as follows:

                                 ARTICLE I

          DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

     SECTION 1.01.  DEFINITIONS.  For all purposes of this Indenture, except 
as otherwise expressly provided or unless the context otherwise requires:

         (a)  the terms defined in this Article have the meanings assigned 
     to them in this Article, and include the plural as well as the singular; 
     and

         (b)  all accounting terms not otherwise defined herein have the 
     meanings assigned to them in accordance with GAAP.


                                     -1-

<PAGE>

     "ACQUIRED INDEBTEDNESS" means, with respect to any specified Person, (i) 
any Indebtedness of any other Person existing at the time such other Person 
is merged with or into or becomes a Subsidiary of such specified Person, 
including, without limitation, Indebtedness incurred in connection with, or 
in contemplation of, such other Person merging with or into or becoming a 
Subsidiary of such specified Person, and (ii) Indebtedness secured by a Lien 
encumbering any asset acquired by such specified Person.

     "ACT" when used with respect to any Holder, has the meaning set forth in 
Section 1.05 hereof.

     "ADJUSTED CONSOLIDATED NET TANGIBLE ASSETS" means, as of the date of 
determination, without duplication, (a) the sum of (i) discounted future net 
revenue from proved oil and gas reserves of the Company and its Subsidiaries 
calculated in accordance with Commission guidelines before any state or 
federal income taxes, as estimated in a reserve report prepared as of the end 
of the Company's most recently completed fiscal year, which reserve report is 
prepared or audited by independent petroleum engineers, as increased by, as 
of the date of determination, the discounted future net revenue of (A) 
estimated proved oil and gas reserves of the Company and its Subsidiaries 
attributable to any acquisition consummated since the date of such year-end 
reserve report, and (B) estimated oil and gas reserves of the Company and its 
Subsidiary attributable to extensions, discoveries and other additions and 
upward revisions of estimates of proved oil and gas reserves due to 
exploration, development, exploitation, production or other activities 
conducted or otherwise occurring since the date of such year-end reserve 
report which would, in the case of determinations made pursuant to clauses 
(A) and (B), in accordance with standard industry practice, result in such 
additions or revisions, in each case calculated in accordance with Commission 
guidelines (utilizing the prices utilized in such year-end reserve report), 
and decreased by, as of the date of determination, the discounted future net 
revenue of (C) estimated proved oil and gas reserves of the Company and its 
Subsidiaries produced or disposed of since the date of such year-end reserve 
report and (D) reductions in the estimated oil and gas reserves of the 
Company and its Subsidiaries since the date of such year-end reserve report 
attributable to downward revisions of estimates of proved oil and gas 
reserves due to exploration, development, exploitation, production or other 
activities conducted or otherwise occurring since the date of such year-end 
reserve report which would, in the case of determinations made pursuant to 
clauses (C) and (D), in accordance with standard industry practice, result in 
such revisions, in each case calculated in accordance with Commission 
guidelines (utilizing the prices utilized in such year-end reserve report); 
provided that, in the case of each of the determinations made pursuant to 
clauses (A) through (D), such increases and decreases shall be as estimated 
by the Company's engineers, except that if as a result of such acquisitions, 
dispositions, discoveries, extensions or revisions, there is a Material 
Change that is an increase, then such increases and decreases in the 
discounted future net revenue shall be confirmed in writing by independent 
petroleum engineers, (ii) the capitalized costs that are attributable to oil 
and gas properties of the Company and its Subsidiaries to which no proved oil 
and gas reserves are attributed, based on the Company's books and records as 
of a date no earlier than the date of the Company's latest annual or 
quarterly financial statements, (iii) the net working capital (which shall be 
calculated as all current assets of the Company and its  Subsidiaries minus 
all current liabilities of the Company and its  Subsidiaries, except current 
liabilities included in Indebtedness on a date no earlier than the date of 


                                     -2-

<PAGE>

the Company's latest annual or quarterly financial statements) and (iv) the 
greater of (I) the net book value of the other tangible assets of the Company 
and its  Subsidiaries on a date no earlier than the date of the Company's 
latest annual or quarterly financial statements and (II) the appraised value, 
as estimated by independent appraisers, of other tangible assets of the 
Company and its  Subsidiaries as of a date no earlier than the date of the 
Company's latest audited financial statements, minus (b) the sum of (i) 
minority interests of third parties to the extent included in the calculation 
of the immediately preceding clause (a), (ii) the positive remainder, if any, 
obtained by subtracting (I) gas balancing underpayments of the Company and 
its  Subsidiaries reflected in the Company's latest audited financial 
statements and not otherwise included in the calculation of the immediately 
preceding clause (a) from (II) any gas balancing liabilities of the Company 
and its  Subsidiaries reflected in the Company's latest audited financial 
statements and not otherwise included in the calculation of the immediately 
preceding clause (a), and  (iii) the discounted future net revenue, 
calculated in accordance with Commission guidelines (utilizing the same 
prices utilized in the Company's year-end reserve report), attributable to 
oil and gas reserves of the Company and its Subsidiaries subject to 
participation interests, overriding royalty interests or other interests of 
third parties, pursuant to participation, partnership, vendor financing or 
other agreements then in effect other than pursuant to Production Payments, 
or that otherwise are required to be delivered to third parties other than 
pursuant to Production Payments.

     "ADJUSTED CONSOLIDATED NET TANGIBLE ASSETS TO CONSOLIDATED INDEBTEDNESS 
RATIO" means, at any time, the ratio of Adjusted Consolidated Net Tangible 
Assets at such time, to Consolidated Indebtedness at such time.

     "ADJUSTED NET ASSETS" of a Subsidiary Guarantor at any date shall mean 
the amount by which the fair value of the property of such Subsidiary 
Guarantor exceeds the total amount of liabilities of such Subsidiary 
Guarantor, including, without limitation, contingent liabilities (after 
giving effect to all other fixed and contingent liabilities incurred or 
assumed on such date), but excluding liabilities under such Subsidiary 
Guarantor's Subsidiary Guarantee at such date.

     "AFFILIATE" of any specified Person means (i) any other Person directly 
or indirectly controlling or controlled by or under direct or indirect common 
control with such specified Person or (ii) any other Person who is a director 
or executive officer of (a) such specified Person or (b) any Person described 
in the preceding clause (i).  For purposes of this definition, "control" 
(including, with correlative meanings, the terms "controlling," "controlled 
by" and "under common control with"), as used with respect to any Person, 
shall mean the possession, directly or indirectly, of the power to direct or 
cause the direction of the management or policies of such Person, whether 
through the ownership of voting securities, by agreement or otherwise; 
provided that beneficial ownership of 10% or more of any class, or any series 
of any class, of equity securities of a Person, whether or not voting, shall 
be deemed to be control.

     "AFFILIATE TRANSACTION" has the meaning set forth in Section 4.16 hereof.

     "AGENT MEMBER" has the meaning set forth in Section 2.05(a) hereof.


                                     -3-

<PAGE>

     "APPROVED STOCKHOLDERS" means Cadell S. Liedtke, Michael J. Grella and 
Henry G. Musselman and their respective Beneficiaries.

     "ASSET SALE" means with respect to any Person, the sale, lease, 
conveyance or other disposition, that does not constitute a Restricted 
Payment or an Investment, by such Person of any of its assets (including, 
without limitation, by way of a Sale and Leaseback Transaction and including the
issuance, sale or other transfer of any Equity Interests in any Subsidiary or 
the sale or other transfer of any Equity Interests in any Unrestricted 
Subsidiary of such Person) other than to the Company (including the receipt 
of proceeds of insurance paid on account of the loss of or damage to any 
asset and awards of compensation for any asset taken by condemnation, eminent 
domain or similar proceeding, and including the receipt of proceeds of 
business interruption insurance), in each case, in one or a series of related 
transactions; PROVIDED that, notwithstanding the foregoing, the term "Asset 
Sale" shall not include: (a) the sale, lease, conveyance, disposition or 
other transfer of all or substantially all of the assets of the Company, as 
permitted pursuant to Article V, (b) the sale or lease of hydrocarbons or 
other mineral interests in the ordinary course of business and customary in 
the Oil and Gas Business, (c) any Production Payment, (d) a transfer of 
assets by the Company to a Wholly Owned Subsidiary of the Company or by a 
Wholly Owned Subsidiary of the Company to the Company or to another Wholly 
Owned Subsidiary of the Company, (e) an issuance of Equity Interests by a 
Wholly Owned Subsidiary of the Company to the Company or to another Wholly 
Owned Subsidiary of the Company, (f) sale or other disposition of cash or 
Cash Equivalents or (g) any lease, abandonment, disposition, relinquishment 
or farm out of any oil and gas property that are customary in nature and 
scope in the Oil and Gas Business and are entered into in the ordinary course 
of the Oil and Gas Business of the Company and its Subsidiaries.

     "ASSET SALE OFFER" has the meaning set forth in Section 4.08(c) hereof.

     "ASSET SALE PAYMENT DATE" has the meaning set forth in Section 
4.08(d)(ii) hereof.

     "ASSET SALE PURCHASE PRICE" has the meaning set forth in Section 4.08(c) 
hereof

     "BENEFICIARY" when used with respect to any individual, means the 
spouse, lineal descendants, parents and siblings of any such individual, the 
estates and the legal representatives of any such individual and any of the 
foregoing and the trustee of any bona fide trust of which any such individual 
and any of the foregoing are the sole beneficiaries or grantors.

     "BOARD OF DIRECTORS" means, with respect to any Person,  the Board of 
Directors of such Person or any committee thereof duty authorized to act on 
behalf of such Board.

     "BOARD RESOLUTION" means, with respect to any Person, a duly adopted 
resolution of the Board of Directors in full force and effect at the time of 
determination and certified as such by the Secretary or an Assistant 
Secretary of such Person.


                                     -4-


<PAGE>

     "BUSINESS DAY" means each Monday, Tuesday, Wednesday, Thursday and 
Friday that is not a day on which banking institutions in The City of New 
York are authorized or obligated by law, executive order or regulation to 
close.

     "CAPITAL LEASE OBLIGATION" means, at the time any determination thereof 
is to be made, the amount of the liability in respect of a capital lease 
which would at such time be required to be capitalized on a balance sheet in 
accordance with GAAP.

     "CAPITAL STOCK" means (i) in the case of a corporation, capital stock, 
(ii) in the case of an association or business entity, any and all shares, 
interests, participations, rights or other equivalents (however designated) 
of capital stock, (iii) in the case of a partnership, partnership interests 
(whether general or limited) and (iv) any other interest or participation 
that confers on a Person the right to receive a share of the profits and 
losses of, or distributions of assets of, the issuing Person.

     "CASH EQUIVALENT" means (a) securities issued or directly and fully 
guaranteed or insured by the United States of America or any agency or 
instrumentality thereof (provided that the full faith and credit of the 
United States is pledged in support thereof) having maturities not more than 
twelve months from the date of acquisition, (b) U.S. dollar denominated (or 
foreign currency fully hedged) time deposits, certificates of deposit, 
Eurodollar time deposits or Eurodollar certificates of deposit of (i) any 
domestic commercial bank of recognized standing having capital and surplus in 
excess of $500 million or (ii) any bank whose short-term commercial  paper 
rating from S&P is at least A-1 or the equivalent thereof or from Moody's is 
at least P-1 or the equivalent thereof (any such bank being an "Approved 
Lender"), in each case with maturities of not more than twelve months from 
the date of acquisition, and (c) commercial paper issued by any Approved 
Lender (or by the parent company thereof) or any variable rate notes issued 
by, or guaranteed by, any domestic corporation rated A-1 (or the equivalent 
thereof) or better by S&P or P-1 (or the equivalent thereof) or better by 
Moody's and maturing within twelve months of the date of acquisition.

     "CERTIFICATED NOTES" means Notes issued in definitive, fully registered 
form to beneficial owners of interests in the Global Note pursuant to Section 
2.06(a) hereof.

     "CHANGE OF CONTROL" means 

          (i)  any "person" or "group" (as such terms are used in Sections 
     13(d) and 14(d) of the Exchange Act) other than the Approved 
     Stockholders, is or becomes the "beneficial owner" (as defined in Rule 
     13d-3 under the Exchange Act), directly or indirectly, of more than 50% 
     of the total Voting Stock of the Company; or

         (ii)    the Company is merged with or into or consolidated with 
     another Person and, immediately after giving effect to the merger or 
     consolidation, (A) less than 50% of the total voting power of the 
     outstanding Voting Stock of the surviving or resulting Person is then 
     "beneficially owned" (within the meaning of Rule 13d-3 under the 
     Exchange Act) in the aggregate by the stockholders of the Company 
     immediately prior to such merger or consolidation, and (B) 


                                     -5-

<PAGE>

     any "person" or "group" (as defined in Section 13(d)(3) or 14(d)(2) of 
     the Exchange Act) other than the Approved Stockholders, has become the 
     direct or indirect "beneficial owner" (as defined in Rule 13d-3 under 
     the Exchange Act) of more than 50% of the total voting power of the 
     Voting Stock of the surviving or resulting Person; or

          (iii)   the Company, either individually or in conjunction with one 
     or more Subsidiaries, sells, assigns, conveys, transfers, leases or 
     otherwise disposes of, or the Subsidiaries sell, assign, convey, 
     transfer, lease or otherwise dispose of, all or substantially of the 
     properties of the Company and the Subsidiaries, taken as a whole (either 
     in one transaction or a series of related transactions) including 
     Capital Stock of the Subsidiaries, to any Person (other than the Company 
     or a Wholly Owned Subsidiary); or

          (iv)    during any consecutive two-year period, individuals who at 
     the beginning of such period constituted the Board of Directors of the 
     Company (together with any new directors whose election by such Board of 
     Directors or whose nomination for election by the stockholders of the 
     Company was approved by a vote of a majority of the directors then still 
     in office who were either directors at the beginning of such period or 
     whose election or nomination for election was previously so approved) 
     cease for any reason to constitute a majority of the Board of Directors 
     of the Company then in office; or

          (v)   the liquidation or dissolution of the Company.

     "CHANGE OF CONTROL OFFER" has the meaning set forth in Section 4.07(a) 
hereof.

     "CHANGE OF CONTROL PAYMENT DATE" has the meaning set forth in Section 
4.07(a) hereof.

     "CHANGE OF CONTROL PURCHASE PRICE" has the meaning set forth in Section 
4.07(a) hereof.

     "CLEARING AGENCY" has the meaning set forth in Section 3(a)(23) of the 
Exchange Act.

     "CODE" means the Internal Revenue Code of 1986, as amended.

     "COMMISSION" means the United States Securities and Exchange Commission, 
as from time to time constituted, created under the Exchange Act, or, if at 
any time after the execution of this Indenture such commission is not 
existing and performing the duties now assigned to it under the Trust 
Indenture Act, the body performing such duties at such time.

     "COMPANY" means the party named as such in the preamble to this 
Indenture until a successor replaces it pursuant to the applicable provisions 
hereof and, thereafter, means such successor.

     "COMPANY ORDER" means a written order signed in the name of the Company 
by (i) its Chairman of the Board, President, a Vice Chairman or a Vice 
President, and (ii) its Treasurer, an Assistant Treasurer, its Secretary or 
an Assistant Secretary.


                                     -6-

<PAGE>

     CONSOLIDATED EBITDA means, with respect to any Person for any period, 
the sum of, without duplication, (i) the Consolidated Net Income of such 
Person and its Subsidiaries for such period, plus (ii) to the extent deducted 
in the computation of such Consolidated Net Income, the Consolidated Interest 
Expense for such period, plus (iii) to the extent deducted in the computation 
of such Consolidated Net Income, amortization of deferred financing charges 
for such period, plus (iv) provision for taxes based on income or profits for 
such period (to the extent such income or profits were included in computing 
Consolidated Net Income for such period), plus (v) to the extent deducted in 
the computation of such Consolidated Net Income, consolidated depreciation, 
depletion, amortization and other noncash charges of such Person and its 
Subsidiaries required to be reflected as expenses on the books and records of 
such Person, plus (vi) to the extent deducted in the computation of such 
Consolidated Net Income, consolidated exploration and abandonment expenses of 
such Person and its Subsidiaries for such periods, minus (vii) cash payments 
with respect to any nonrecurring, noncash charges previously added back 
pursuant to clause (v), and excluding (viii) the impact of foreign currency 
translations.  Notwithstanding the foregoing, the provision for taxes based 
on the income or profits of, and the depreciation, depletion and amortization 
and other noncash charges of, and the exploration and abandonment expenses 
of, a Subsidiary of a Person shall be added to Consolidated Net Income to 
compute Consolidated EBITDA only to the extent (and in the same proportion) 
that the Net Income of such Subsidiary was included in calculating the 
Consolidated Net Income of such Person and only if a corresponding amount 
would be permitted at the date of determination to be dividended to such 
Person by such Subsidiary without prior approval (unless such approval has 
been obtained), pursuant to the terms of its charter and all agreements, 
instruments, judgments, decrees, orders, statutes, rules and governmental 
regulations applicable to that Subsidiary or its stockholders.

     "CONSOLIDATED INDEBTEDNESS" means, with respect to any Person for any 
time, the Indebtedness of such Person and its Subsidiaries at such time as 
determined on a consolidated basis in accordance with GAAP.

     "CONSOLIDATED INTEREST COVERAGE RATIO" means with respect to any Person 
for any period, the ratio of (i) Consolidated EBITDA of such Person and its 
Subsidiaries for such period to (ii) Consolidated Interest Expense of such 
Person and its Subsidiaries for such period.  In the event that the Company 
or any of its Subsidiaries incurs, assumes, Guarantees or repays or redeems 
any Indebtedness (other than revolving credit borrowings) or issues or 
redeems preferred stock subsequent to the commencement of the four-quarter 
reference period for which the Consolidated Interest Coverage Ratio is being 
calculated but on or prior to the date on which the event for which the 
calculation of the Consolidated Interest Coverage Ratio is made (the 
"Calculation Date"), then the Consolidated Interest Coverage Ratio shall be 
calculated giving pro forma effect to such incurrence, assumption, Guarantee, 
repayment or redemption of Indebtedness, or such issuance or redemption of 
preferred stock, as if the same had occurred at the beginning of the 
applicable four-quarter reference period.  For purposes of making the 
computation referred to above, (i) acquisitions that have been made by the 
Company or any of its Subsidiaries, including through mergers or 
consolidations and including any related financing transactions, during the 
four-quarter reference period or subsequent to such reference period and on 
or prior to the Calculation Date shall be deemed 


                                     -7-

<PAGE>


to have occurred on the first day of the four-quarter reference period, and 
(ii) the Consolidated EBITDA attributable to discontinued operations, as 
determined in accordance with GAAP, and operations or businesses disposed of 
prior to the Calculation Date, shall be excluded, and (iii) the Consolidated 
Interest Expense attributable to discontinued operations, as determined in 
accordance with GAAP, and operations or businesses disposed of prior to the 
Calculation Date, shall be excluded, but only to the extent that the 
obligations giving rise to such Consolidated Interest Expense will not be 
obligations of the referent Person or any of its Subsidiaries following the 
Calculation Date.

     "CONSOLIDATED INTEREST EXPENSE" means, with respect to any Person for 
any period, the sum, without duplication, of (i) the consolidated interest 
expense of such Person and its Subsidiaries for such period including, 
without limitation, amortization of original issue discount, noncash interest 
payments, the interest component of any deferred payment obligations, the 
interest component of all payments associated with Capital Lease Obligations, 
commissions, discounts and other fees and charges incurred in respect of 
letter of credit or bankers' acceptance financings, and net payments (if any) 
pursuant to Hedging Obligations, but excluding amortization of deferred 
financing charges for such period, and (ii) the consolidated interest 
expense of such Person and its Subsidiaries that was capitalized during such 
period, and (iii) any interest expense on Indebtedness of another Person that 
is Guaranteed by such Person or one of its Subsidiaries or secured by a Lien 
on assets of such Person or one of its Subsidiaries (whether or not such 
Guarantee or Lien is called upon), and (iv) the product of (a) all cash 
dividend payments (and noncash dividend payments in the case of a Person that 
is a Subsidiary) on any series of preferred stock of such Person payable to a 
party other than the Company or a Wholly Owned Subsidiary, times (b) a 
fraction, the numerator of which is one and the denominator of which is one 
minus the then current combined federal, state and local statutory tax rate 
of such Person, expressed as a decimal, on a consolidated basis and in 
accordance with GAAP.

     "CONSOLIDATED NET INCOME" means, with respect to any Person for any 
period, the aggregate of the Net Income of such Person and its Subsidiaries 
for such period, on a consolidated basis, determined in accordance with GAAP; 
PROVIDED that (i) the Net Income (but not loss) of any Person that is not a 
Subsidiary or that is accounted for by the equity method of accounting shall 
be included only to the extent of the amount of dividends or distributions 
paid in cash to the referent Person or a Wholly Owned Subsidiary thereof, 
(ii) the Net Income of any Subsidiary shall be excluded to the extent that 
the declaration or payment of dividends or similar distributions by that 
Subsidiary of that Net Income is not at the date of determination permitted 
without any prior governmental approval (unless such approval has been 
obtained) or, directly or indirectly, by operation of the terms of its 
charter or any agreement, instrument, judgment, decree, order, statute, rule 
or governmental regulation applicable to that Subsidiary or its stockholders, 
(iii) the Net Income of any Person acquired in a pooling of interests 
transaction for any period prior to the date of such acquisition shall be 
excluded, (iv) the cumulative effect of a change in accounting principles 
shall be excluded, and (v) the Net Income of, or any dividends or other 
distributions from, any Unrestricted Subsidiary, to the extent otherwise 
included, shall be excluded, unless distributed to the Company or one of its 
Subsidiaries.


                                     -8-

<PAGE>

     "CONSOLIDATED NET WORTH" means, with respect to any Person as of any 
date, the consolidated stockholders' equity of such Person and its 
consolidated Subsidiaries as of such date less (w) the amount of such 
stockholders' equity attributable to Disqualified Stock, (x) all write-ups 
subsequent to the date of this Indenture in the book value of any asset owned 
by such Person or a consolidated Subsidiary of such Person (other than 
purchase accounting adjustments made, in connection with any acquisition of 
any entity that becomes a consolidated Subsidiary of such Person after the 
date of this Indenture to the book value of the assets of such entity), (y) 
all investments as of such date in unconsolidated Subsidiaries and in Persons 
that are not Subsidiaries (except, in each case, Permitted Investments), and 
(z) all unamortized debt discount and expense and unamortized deferred charges
as of such date, all of the foregoing determined in accordance with GAAP.

     "CORPORATE TRUST OFFICE" means the principal office of the Trustee at 
which at any particular time its corporate trust business shall be principally
administered, which office is, at the date of execution of this Indenture, 
located at Two International Place, Corporate Trust Department, 4th Floor, 
Boston, Massachusetts 02110.

     "COVENANT DEFEASANCE" has the meaning set forth in Section 8.03 hereof.

     "CREDIT FACILITY" means a credit facility that may be entered into among 
the Company and the lenders parties thereto, including any related notes, 
guarantees, collateral documents, instruments and agreements executed in 
connection therewith, and in each case as amended, modified, renewed, refunded,
replaced, restated or refinanced from time to time.

     "DEFAULT" means any event that is or with the passage of time or the giving
of notice or both would be an Event of Default.

     "DEFAULTED INTEREST" has the meaning set forth in Section 2.11 hereof.

     "DEPOSITARY" means The Depository Trust Company, its nominees, and their 
respective successors.

     "DESIGNATED GUARANTOR SENIOR INDEBTEDNESS" means (i) so long as the Senior
Bank Indebtedness is outstanding, any Subsidiary Guarantor's Indebtedness in 
respect of the Senior Bank Indebtedness and (ii) thereafter, any other Guarantor
Senior Indebtedness permitted under this Indenture the principal amount of which
is $15.0 million or more and that has been designated by the Company as 
"Designated Guarantor Senior Indebtedness"; PROVIDED that for purposes of 
Section 11.10(a) hereof, "Designated Guarantor Senior Indebtedness" shall also 
mean any other Guarantor Senior Indebtedness permitted under this Indenture the
principal amount of which is $15.0 million or more.

     "DESIGNATED SENIOR INDEBTEDNESS" means (i) so long as the Senior Bank 
Indebtedness is outstanding, the Senior Bank Indebtedness and (ii) thereafter,
any other Senior Indebtedness 




                                    -9-


<PAGE>

permitted under this Indenture the principal amount of which is $15.0 million 
or more and that has been designated by the Company as "Designated Senior 
Indebtedness"; PROVIDED that for purposes of Section 10.03(a) hereof, 
"Designated Senior Indebtedness" shall also mean any other Senior 
Indebtedness permitted under this Indenture the principal amount of which is 
$15.0 million or more.

     "DISQUALIFIED STOCK" means (a) with respect to any Person, Capital Stock 
of such Person that, by its terms (or by the terms of any security into which 
it is convertible or for which it is exchangeable), or upon the happening of 
any event (unless any redemption or repurchase of such Capital Stock upon the 
occurrence of such event is required by any such terms, but only to the extent
that a payment in respect thereof would be permitted under Section 4.11 hereof),
matures or is mandatorily redeemable, pursuant to a sinking fund obligation or
otherwise, or is redeemable at the option of the Holder thereof, in whole or 
in part, on or prior to the date which is one year after the date on which the
Notes mature and (b) with respect to any Subsidiary of such Person (including 
with respect to any Subsidiary of the Company), any Capital Stock other than 
any common stock with no preference, privileges, or redemption or repayment 
provisions.

     "DOLLAR-DENOMINATED PRODUCTION PAYMENTS" means dollar denominated 
payment obligations of the Company or any of its Subsidiaries that are or, 
upon the occurrence of a contingent event, would be recorded as liabilities 
in accordance with GAAP, together with all undertakings and obligations of 
the Company or any of its Subsidiaries in connection therewith, which 
obligations will be deemed to constitute Indebtedness for borrowed money for 
purposes of this Indenture.

     "EQUITY INTERESTS" means Capital Stock and all warrants, options or other
rights to acquire Capital Stock (but excluding any debt security that is 
convertible into, or exchangeable for, Capital Stock), whether outstanding 
prior to, on or after the date of this Indenture.

     "EQUITY OFFERING" means an offer and sale of Qualified Stock of the Company
to a Person other than an Affiliate of the Company.

     "EVENT OF DEFAULT" has the meaning set forth in Section 6.01 hereof.

     "EXCESS PROCEEDS" has the meaning set forth in Section 4.08(b) hereof.

     "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended, and
the rules and regulations promulgated thereunder.

     "EXEMPT AFFILIATE TRANSACTIONS" means (a) transactions between or among 
the Company and/or its Wholly Owned Subsidiaries, (b) advances not to exceed 
$1,000,000 at any time outstanding to officers of the Company or any Subsidiary
of the Company in the ordinary course of business to provide for the payment 
of reasonable expenses incurred by such persons in the performance of their 
responsibilities to the Company or such Subsidiary or in connection with any
relocation, (c) fees and compensation paid to and indemnity provided on behalf
of directors, officers or employees of the Company or any Subsidiary of the 
Company in the ordinary course of business, (d) any employment 




                                   -10-


<PAGE>

agreement that is in effect on the date of the Indenture in the ordinary 
course of business and any such agreement entered into by the Company or a 
Subsidiary after the date of this Indenture in the ordinary course of 
business of the Company or such Subsidiary and (e) payments and transactions 
under Indebtedness of A&P Meter Service and Supply, Inc. ("A&P") 
outstanding on the date of this Indenture and performance of and payment for 
services provided by A&P to the Company and its Subsidiaries in the ordinary 
course of business consistent with past practices.

     "FUNDING GUARANTOR" has the meaning specified in Section 11.06.

     "GAAP" means generally accepted accounting principles set forth in the 
opinions and pronouncements of the Accounting Principles Board of American 
Institute of Certified Public Accountants and statements and pronouncements 
of the Financial Accounting Standards Board or in such other statements by 
such other entity as have been approved by a significant segment of the 
accounting profession, which are in effect on the date of this Indenture.

     "GLOBAL NOTES" has the meaning set forth in Section 2.01(c) hereof.

     "GUARANTEE" means a guarantee (other than by endorsement of negotiable 
instruments for collection in the ordinary course of business), direct or 
indirect, in any manner (including, without limitation, letters of credit and 
reimbursement agreements in respect thereof), of all or any part of any 
Indebtedness.

     "GUARANTOR SENIOR INDEBTEDNESS" means (i) all Guarantees or other 
Indebtedness of a Subsidiary Guarantor in respect of the Senior Bank 
Indebtedness and (ii) any other indebtedness permitted to be incurred by a 
Subsidiary Guarantor under the terms of this Indenture, unless the instrument 
under which such Indebtedness is incurred expressly provides that it is 
subordinated in right of payment to any Indebtedness for money borrowed.  
Notwithstanding anything to the contrary in the foregoing, Guarantor Senior 
Indebtedness will not include (w) any liability for federal, state, local or 
other taxes owed or owing by a Subsidiary Guarantor, (x) any Indebtedness of 
a Subsidiary Guarantor to any of the Company's  Subsidiaries, Unrestricted 
Subsidiaries or other Affiliates, (y) any trade payables or (z) any 
Indebtedness that is incurred in violation of this Indenture.

     "HEDGING OBLIGATIONS" means, with respect to any Person, the obligations 
of such Person under (i) interest rate swap agreements, interest rate cap 
agreements and interest rate collar agreements and (ii) other agreements or 
arrangements designed to protect such Person against fluctuations in (a) 
interest rates, (b) the value of foreign currencies and (c) Oil and Gas 
Purchase and Sales Contracts.

     "HOLDER" means (i) in the case of any Certificated Note, the Person in 
whose name such Certificated Note is registered in the Security Register and 
(ii) in the case of any Global Note, the Depositary.

     "INDEBTEDNESS" means, with respect to any Person, without duplication, 
(a) all liabilities of such Person for borrowed money or for the deferred 
purchase price of property or services (excluding 




                                   -11-


<PAGE>

any trade accounts payable and other accrued current liabilities incurred in 
the ordinary course of business), and all liabilities of such Person incurred 
in connection with any letters of credit, bankers' acceptances or other 
similar credit transactions or any agreement to purchase, redeem, exchange, 
convert or otherwise acquire for value any Capital Stock of such Person, or 
any warrants, rights or options to acquire such Capital Stock outstanding on 
the date of this Indenture or thereafter, if, and to the extent, any of the 
foregoing would appear as a liability upon a balance sheet of such Person 
prepared in accordance with GAAP, (b) all obligations of such Person 
evidenced by bonds, notes, debentures or other similar instruments, if, and 
to the extent, any of the foregoing would appear as a liability upon a 
balance sheet of such Person prepared in accordance with GAAP, (c) all 
Indebtedness of such Person created or arising under any conditional sale or 
other title retention agreement with respect to property acquired by such 
Person (even if the rights and remedies of the seller or lender under such 
agreement in the event of default are limited to repossession or sale of such 
property), but excluding trade accounts payable arising in the ordinary 
course of business, (d) all Capitalized Lease Obligations of such Person, (e) 
all Indebtedness referred to in the preceding clauses of other Persons and 
all dividends of other Persons, the payment of which is secured by (or for 
which the holder of such Indebtedness has an existing right to be secured by) 
any Lien upon property (including, without limitation, accounts and contract 
rights) owned by such Person, even though such Person has not assumed or 
become liable for the payment of such Indebtedness (the amount of such 
obligation being deemed to be the lesser of the value of such property or 
asset or the amount of the obligation so secured) (f) all Production Payments 
of such Person, (g) all guarantees by such Person of Indebtedness referred to 
in this definition, (h) all Disqualified Stock of such Person valued at the 
greater of its voluntary or involuntary maximum fixed repurchase price plus 
accrued dividends and (i) all obligations of such Person under or in respect 
to currency exchange contracts, oil or natural gas price hedging arrangements 
and Hedging Obligations.  For purposes hereof, the "maximum fixed repurchase 
price" of Disqualified Stock which does not have a fixed repurchase price 
shall be calculated in accordance with the terms of such Disqualified Stock 
as if Disqualified Stock were purchased on any date on which Indebtedness 
shall be required to be determined pursuant to this Indenture, and if such 
price is based upon, or measured by, the fair market value of such 
Disqualified Stock, such fair market value shall be determined in good faith 
by the board of directors of the issuer of such Disqualified Stock; provided, 
however, that if such Disqualified Stock is not at the date of determination 
permitted or required to be repurchased, the "maximum fixed repurchase price" 
shall be the book value of such Disqualified Stock.  

     "INDENTURE" means this instrument as originally executed or as it may from
time to time be supplemented or amended by one or more indentures supplemental 
hereto entered into pursuant to the applicable provisions hereof, including, 
for all purposes of this instrument and any such supplemental indenture, the 
provisions of the Trust Indenture Act that are deemed to be a part of and govern
this instrument, and any such supplemental indenture, respectively.

     "INTEREST PAYMENT DATE" means the Stated Maturity of an installment of 
interest on the Notes.

     "INVESTMENTS" means, with respect to any Person, all investments by such 
Person in other Persons (including Affiliates) in the form of direct or 
indirect loans (including guarantees of 




                                   -12-


<PAGE>

Indebtedness or other obligations), advances or capital contributions (excluding
advances to officers and employees of the type specified in clause (b) of the 
definition of Exempt Affiliate Transactions), purchases or other acquisitions 
for consideration of Indebtedness, Equity Interests or other securities and all
other items that are or would be classified as investments on a balance sheet 
prepared in accordance with GAAP or the acquisition, by purchase or 
otherwise, of all or substantially all of the business or assets of any other 
Person.

     "ISSUE DATE" means the date on which the Notes are first authorized and 
delivered under this Indenture.

     "LEGAL DEFEASANCE" has the meaning set forth in Section 8.02 hereof.

     "LIEN" means, with respect to any asset, any mortgage, lien, pledge, 
charge, security interest or encumbrance of any kind in respect of such asset,
whether or not filed, recorded or otherwise perfected under applicable law 
(including any conditional sale or other title retention agreement, any lease
in the nature thereof, any option or other agreement to sell or give a security
interest in and any filing of or agreement to give any financing statement 
under the Uniform Commercial Code (or equivalent statutes) of any jurisdiction).

     "MATERIAL CHANGE" means an increase or decrease (excluding changes that 
result solely from changes in prices) of more than 10% during a fiscal 
quarter in the discounted future net cash flows from proved oil and gas 
reserves of the Company and its Subsidiaries calculated in accordance with 
clause (a)(i) of the definition of Adjusted Consolidated Net Tangible Assets; 
provided, however, that the following will be excluded from the  calculation 
of Material Change: (i) any acquisition during the quarter of oil and gas 
reserves that have been estimated by independent petroleum engineers and on 
which a report or reports exists and (ii) any disposition of properties 
existing at the beginning of such quarter that have been disposed of pursuant 
to the provisions of this Indenture described below under Section 4.08.

     "MATURITY" means, when used with respect to a Note, the date on which 
the principal of such Note becomes due and payable as provided therein or in 
this Indenture, whether on the date specified in such Note as the fixed date 
on which the principal of such Note is due and payable, on the Change of 
Control Payment Date or the Asset Sale Payment Date, or by declaration of 
acceleration, call for redemption or otherwise.

     "MOODY'S" means Moody's Investors Service, Inc., or, if Moody's 
Investors Service, Inc. shall cease rating the specified debt securities and 
such ratings business with respect thereto shall have been transferred to a 
successor Person, such successor Person; PROVIDED that if Moody's Investors 
Service, Inc. ceases rating the specified debt securities and its ratings 
business with respect thereto shall not have been transferred to any 
successor Person or such successor Person is S&P, then "Moody's" shall mean 
any other nationally recognized rating agency (other than S&P) that rates the 
specified debt securities and that shall have been designated by the Company 
in an Officers' Certificate.




                                   -13-


<PAGE>

     "NET INCOME" means, with respect to any Person, the net income (loss) of 
such Person, determined in accordance with GAAP and before any reduction in 
respect of preferred stock dividends, excluding, however, (i) any gain (but 
not loss), together with any related provision for taxes on such gain (but 
not loss), realized in connection with (a) any Asset Sale (including, without 
limitation, dispositions pursuant to Sale and Leaseback Transactions) or (b) 
the disposition of any securities by such Person or any of its Subsidiaries 
or the extinguishment of any Indebtedness of such Person or any of its 
Subsidiaries, (ii) any extraordinary or nonrecurring gain (but not loss), 
together with any related provision for taxes on such extraordinary or 
nonrecurring gain (but not loss), and (iii) any gain (but not loss) from 
currency exchange transactions not in the ordinary course of business 
consistent with past practice.

     "NET PROCEEDS" means the aggregate cash proceeds received by the Company 
or any of its Subsidiaries in respect of any Asset Sale (including, without 
limitation, any cash received upon the sale or other disposition of any 
noncash consideration received in any Asset Sale), net of the direct costs 
relating to such Asset Sale (including, without limitation, legal, accounting 
and investment banking fees, and sales commissions) and any relocation 
expenses incurred as a result thereof, taxes paid or payable as a result 
thereof, and any reserve for adjustment in respect of the sale price of such 
asset or assets established in accordance with GAAP.

     "NON-RECOURSE INDEBTEDNESS" means Indebtedness (i) as to which neither 
the Company nor any of its Subsidiaries (a) provides credit support of any 
kind (including any undertaking, agreement or instrument that would constitute
Indebtedness), (b) is directly or indirectly liable (as a Subsidiary Guarantor
or otherwise), or (c) constitutes the lender; and (ii) no default with respect
to which (including any rights that the holders thereof may have to take 
enforcement action against an Unrestricted Subsidiary) would permit (upon 
notice, lapse of time or both) any holder of any other Indebtedness of the 
Company or any of its Subsidiaries to declare a default on such other 
Indebtedness or cause the payment thereof to be accelerated or payable prior
to its Stated Maturity.

     "NOTES" has the meaning set forth in the Recitals of the Company and more
particularly means any of the Notes authenticated and delivered under this 
Indenture.

     "OBLIGATIONS" means any principal, interest, penalties, fees, 
indemnifications, reimbursements, damages and other liabilities payable under 
the documentation governing any Indebtedness.

     "OFFICER" means the Chairman of the Board of Directors, a Vice Chairman 
of the Board of Directors, the President, a Vice President, the Chief Financial
Officer, the Chief Accounting Officer, the Treasurer, an Assistant Treasurer, 
the Secretary or an Assistant Secretary of the Company or any Subsidiary 
Guarantor.

     "OFFICERS' CERTIFICATE" means a certificate signed by (i) the Chairman 
of the Board of Directors, a Vice Chairman of the Board of Directors, the 
President, the Chief Executive Officer or a Vice President of the Company or 
any Subsidiary Guarantor, and (ii) the Chief Financial Officer, the Chief 
Accounting Officer, the Treasurer, an Assistant Treasurer, the Secretary or 
an Assistant Secretary 




                                   -14-


<PAGE>

of the Company or any Subsidiary Guarantor, and delivered to the Trustee, 
which certificate shall comply with the provisions of Section 11.04 hereof; 
PROVIDED that any Officers' Certificate delivered pursuant to the first 
paragraph of Section 4.19 hereof shall be signed by the Chief Executive 
Officer, the Chief Financial Officer or the Chief Accounting Officer.

     "OIL AND GAS BUSINESS" means the business of the exploration for, and 
development, acquisition, and production of hydrocarbons, together with 
activities ancillary thereto (including with limitation, the gathering, 
processing, treatment, marketing and transportation of such production) and 
other related energy and natural resources businesses.

     "OIL AND GAS PURCHASE AND SALE CONTRACT" means with respect to any 
Person, any oil and gas agreements and other agreements or arrangements or 
any combination thereof entered into by such Person in the ordinary course of 
business and that is designed to provide protection against oil and natural 
gas price fluctuations.

     "OPINION OF COUNSEL" means a written opinion from legal counsel (who may 
be counsel to the Company, any Subsidiary Guarantor or the Trustee) who is 
acceptable to the Trustee, which opinion shall comply with the provisions of 
Section 11.04 hereof; provided that any Opinion of Counsel delivered pursuant 
to Section 8.04 hereof shall not be rendered by an employee of the Company or 
any of its Subsidiaries.

     "PARI PASSU INDEBTEDNESS" means Indebtedness of (a) the Company that is 
PARI PASSU with or subordinated to the Notes (other than the Notes) or (b) 
any Subsidiary Guarantor that is PARI PASSU with or subordinated to such 
Subsidiary Guarantor's Subsidiary Guarantee (other than such Subsidiary 
Guarantee or Indebtedness secured by such Subsidiary Guarantee).

     "PAYING AGENT" means any Person authorized by the Company to make payments
of principal, premium or interest with respect to the Notes on behalf of the 
Company.

     "PERMITTED INVESTMENTS" means (a) any Investments by the Subsidiaries of 
the Company in the Company; (b) any Investments in Cash Equivalents; (c) 
Investments made as a result of the receipt of noncash consideration from an 
Asset Sale that was made pursuant to and in compliance with Section 
4.08(a)(ii); (d) Investments outstanding as of the date of this Indenture; 
(e) Investments in Wholly Owned Subsidiaries that is engaged in the Oil and 
Gas Business and Investments in any Person that, as a result of such 
Investment (or a series of substantially contemporaneous Investments pursuant 
to a single plan) (x) such other Person becomes a Wholly Owned Subsidiary 
engaged in the Oil and Gas Business or (y) such other Person that is engaged 
in the Oil and Gas Business is merged or consolidated with or into, or 
transfers or conveys all or substantially all of its assets to the Company or 
a Wholly Owned Subsidiary in a transaction permitted under the Indenture; (f) 
entry into operating agreements, joint ventures, partnership agreements, 
working interests, royalty interests, mineral leases, processing agreements, 
farm-out agreements, contracts for the sale, transportation or exchange of 
oil and natural gas, unitization agreements, pooling arrangements, area of 
mutual interest agreements or other similar or customary agreements, 
transactions, properties, interests or arrangements, and Investments and 
expenditures in connection therewith or pursuant thereto, in each case made 
or entered into in the ordinary course of the Oil and Gas Business, 
excluding, however, Investments in corporations; (g) entry into any hedging 
arrangements in the ordinary course of business for the purpose of protecting 
the Company's or any Subsidiary's production against fluctuations in oil or 
natural gas prices; (h) shares of money mutual or similar funds having assets 
in excess of $500,000,000, and (i) Investments in an aggregate amount not to 
exceed $5,000,000 at any one time outstanding.

                                   -15-


<PAGE>

     "PERMITTED LIENS" means (a) liens for taxes, assessments and 
governmental charges not then due or the validity of which is being contested 
in good faith by appropriate proceedings, promptly instituted and diligently 
conducted, and for which adequate reserves have been established to the 
extent required by GAAP; (b) mechanics', workmen's, materialman's, operator's 
or similar liens arising in the ordinary course of business; (c) easements, 
rights of way, restrictions and other similar encumbrances incurred in the 
ordinary course of business or minor imperfections in title that do not 
impair the value of property for its intended use; (d) liens on, or related 
to, properties to secure all or part of the costs incurred in the ordinary 
course of business of exploration, drilling, development or operation 
thereof; (e) judgment and attachment liens not giving rise to an Event of 
Default or liens created by or existing from any litigation or legal 
proceeding that are currently being contested in good faith by appropriate 
proceedings, promptly instituted and diligently conducted, and for which 
adequate reserves have been made to the extent required by GAAP; (f) liens on 
deposits made in the ordinary course of business; (g) liens in favor of 
collecting or payor banks having a right of selloff, revocation, refund or 
chargeback with respect to money or instruments of the Company or any 
Subsidiary on deposit with or in possession of such bank (h) liens on 
pipeline or pipeline facilities which arise out of operation of law; (i) 
liens on deposits to secure public or statutory obligations or in lieu of 
surety or appeal bonds entered into in the ordinary course of business; (j) 
liens reserved in oil and gas leases for bonus or rental payments and for 
compliance with the terms of such leases; and (k) liens arising under 
partnership agreements, oil and gas leases, farmout agreements, division 
orders, contracts for the sale, purchase, exchange, transportation or 
processing of oil, gas or other hydrocarbons, unitization and pooling 
declarations and agreements, development agreements, operating agreements, 
area of mutual interest agreements and other agreements that are customary in 
the Oil and Gas Business.

     "PERMITTED REFINANCING INDEBTEDNESS" means any Indebtedness of the 
Company or any of its Subsidiaries issued in exchange for, or the net 
proceeds of which are used to extend, refinance, renew, replace, defease or 
refund, other Indebtedness of the Company or any of its Subsidiaries; 
provided that: (i) the principal amount of such Permitted Refinancing 
Indebtedness does not exceed the principal or accrued amount of the 
Indebtedness so extended, refinanced, renewed, replaced, defeased or refunded 
(plus the amount of reasonable expenses incurred in connection therewith); 
(ii) such Permitted Refinancing Indebtedness has a Weighted Average Life to 
Maturity and a final maturity date equal to or greater than the Weighted 
Average Life to Maturity and a final maturity date, respectively, of the 
Indebtedness being extended, refinanced, renewed, replaced, defeased or 
refunded; (iii) if the Indebtedness being extended, refinanced, renewed, 
replaced, defeased or refunded is subordinated in right of payment to the 
Notes, such Permitted Refinancing Indebtedness has a final maturity date 
later than the final maturity date of, and is subordinated in right of 
payment to, the Notes on terms at least as favorable to the Holders of Notes 
as those contained in the documentation governing the Indebtedness being 
extended, refinanced, renewed, replaced, defeased or refunded; and (iv) such 
Indebtedness is incurred either by the Company or by the Subsidiary who is 
the obligor on the Indebtedness being extended, refinanced, renewed, 
replaced, defeased or refunded.




                                   -16-


<PAGE>

     "PERSON" means any individual, corporation, partnership, joint venture, 
trust, unincorporated organization or government or any agency or political 
subdivision thereof.

     "PRODUCTION PAYMENTS" means, collectively, Dollar-Denominated Production 
Payments and Volumetric Production Payments.

     "PRO FORMA" means, with respect to any calculation made or required to 
be made pursuant to the terms hereof, a calculation in accordance with 
Article 11 of Regulation S-X promulgated under the Securities Act (to the 
extent applicable), as interpreted in good faith by the Board of Directors of 
the Company, or otherwise, a calculation made in good faith by the Board of 
Directors of the Company, as the case may be.

     "PROPERTY" means, with respect to any Person, any interest of such 
Person in any kind of property or asset, whether real, personal or mixed, 
tangible or intangible, excluding Capital Stock in any other Person.

     "PURCHASE MONEY OBLIGATIONS" of any Person means any obligations of such 
Person to any seller or any other Person incurred or assumed to finance the 
construction and/or acquisition of real or personal property to be used in 
the business of such Person or any of its Subsidiaries in an amount that is 
not more than 100% of the cost of such property, and incurred within 180 days 
after the date of such construction or acquisition (excluding accounts 
payable to trade creditors incurred in the ordinary course of business).

     "QUALIFIED STOCK" means, for any Person, any and all Capital Stock of 
such Person, other than Disqualified Stock.  

     "RECORD DATE" means, for the interest payable on any Interest Payment 
Date, the date specified in Section 2.11 hereof.

     "REDEMPTION DATE" means, when used with respect to any Note or part 
thereof to be redeemed hereunder, the date fixed for redemption of such Notes 
pursuant to the terms of the Notes and this Indenture.

     "REDEMPTION PRICE" means when used with respect to any Note or part 
thereof to be redeemed hereunder, the price fixed for redemption of such Note 
pursuant to the terms of the Notes and this Indenture, plus accrued and 
unpaid interest, if any, to the Redemption Date.

     "REGISTRAR" has the meaning set forth in Section 2.03 hereof.

     "REPRESENTATIVE" means the indenture trustee or other trustee, agent or 
representative for any Senior Indebtedness or Guarantor Senior Indebtedness.

     "RESTRICTED INVESTMENT" means an Investment other than a Permitted 
Investment.




                                   -17-


<PAGE>

     "RESTRICTED PAYMENT" has the meaning set forth in Section 4.11 hereof.

     "S&P" means Standard & Poor's Ratings Group, a division of McGraw Hill 
Corporation, or, if Standard & Poor's Ratings Group shall cease rating the 
specified debt securities and such ratings business with respect thereto 
shall have been transferred to a successor Person, such successor Person; 
PROVIDED that if Standard & Poor's Ratings Group ceases rating the specified 
debt securities and its ratings business with respect thereto shall not have 
been transferred to any successor Person or such successor Person is Moody's, 
then "S&P" shall mean any other nationally recognized rating agency (other 
than Moody's) that rates the specified debt securities and that shall have 
been designated by the Company in an Officers' Certificate.

     "SALE AND LEASEBACK TRANSACTION" means, with respect to the Company or 
any of its Subsidiaries, any arrangement with any Person providing for the 
leasing by the Company or any of its Subsidiaries as lessee of any principal 
property, acquired or placed into service more than 180 days prior to such 
arrangement (except leases of two years of less), whereby such property has 
been or is to be sold or transferred by the Company or any of its 
Subsidiaries to such Person or its Affiliates.

     "SECURITIES ACT" means the Securities Act of 1933, as amended, and the 
rules and regulations promulgated thereunder.

     "SECURITY REGISTER" has the meaning set forth in Section 2.03 hereof.

     "SENIOR BANK INDEBTEDNESS" means the Indebtedness outstanding under the 
Credit Facility.

     "SENIOR INDEBTEDNESS" means (i) the Senior Bank Indebtedness and (ii) 
any other Indebtedness permitted to be incurred by the Company under the 
terms of this Indenture, unless the instrument under which such Indebtedness 
is incurred expressly provides that it is subordinated in right of payment to 
any Indebtedness for money borrowed.  Notwithstanding anything to the 
contrary in the foregoing, Senior Indebtedness will not include (w) any 
liability for federal, state, local or other taxes owed or owing by the 
Company, (x) any Indebtedness of the Company to any of its Subsidiaries, 
Unrestricted Subsidiaries or other Affiliates, (y) any trade payables or (z) 
any Indebtedness that is incurred in violation of this Indenture.

     "SENIOR REVOLVING INDEBTEDNESS" means revolving credit borrowings and 
letters of credit under the Credit Facility and/or any successor facility or 
facilities.

     "SPECIAL RECORD DATE" means a date fixed by the Trustee pursuant to 
Section 2.11 for the payment of Defaulted Interest.

     "STATED MATURITY" means, with respect to any security, the date 
specified in such security as the fixed date on which the payment of 
principal of such security is due and payable, including pursuant to any 
mandatory redemption provision (but excluding any provision providing for the 
repurchase of such security at the option of the holder thereof upon the 
happening of any contingency unless such contingency has occurred), and, when 
used with respect to any installment of interest on such security, the fixed 
date on which such installment of interest is due and payable.

     "SUBSIDIARY" means, with respect to any Person, (i) any corporation, 
association or other business entity of which more than 50% of the total 
voting power of shares of Capital Stock entitled (without regard to the 
occurrence of any contingency) to vote in the election of directors, managers 


                                     -18-

<PAGE>


or trustees thereof is at the time owned or controlled, directly or 
indirectly, by such Person or one or more of the other Subsidiaries of that 
Person (or a combination thereof) and (ii) any partnership (a) the sole 
general partner or the managing general partner of which is such Person or a 
Subsidiary of such Person or (b) the only general partners of which are such 
Person or of one or more Subsidiaries of such Person (or any combination 
thereof).  Notwithstanding the foregoing, an Unrestricted Subsidiary shall 
not be a Subsidiary of the Company for any purposes of this Indenture.

     "SUBSIDIARY GUARANTEE" means the guarantee of the Notes by a Subsidiary 
Guarantor pursuant to Article XI or pursuant to a supplemental indenture 
pursuant to which such Subsidiary Guarantor guarantees the Notes.

     "SUBSIDIARY GUARANTOR" means (a) Costilla Petroleum Corporation, 
Costilla Pipeline Company, Statewide Minerals Corporation and Valley 
Gathering Company, (b) each of the Subsidiaries that becomes a Subsidiary 
Guarantor pursuant to Article XI hereof and (c) each of the Subsidiaries 
executing a supplemental indenture in which such Subsidiary agrees to 
guarantee the Notes and to be bound by the terms of this Indenture.

     "TEMPORARY NOTES" has the meaning set forth in Section 2.09 hereof.

     "TRUST INDENTURE ACT" means the Trust Indenture Act of 1939 (15 U.S.C. 
SECTION Section 77aaa-77bbbb) as in effect on the date of this Indenture 
except as required by Section 9.04 hereof; provided that in the event the 
Trust Indenture Act of 1939 is amended after such date, "Trust Indenture Act" 
means, to the extent required by any such amendment, the Trust Indenture Act 
of 1939, as so amended.

     "TRUST OFFICER" means any officer or assistant officer of the Trustee 
assigned by the Trustee to administer this Indenture.

     "TRUSTEE" means the party named as such in this Indenture until a 
successor replaces it in accordance with the provisions of this Indenture 
and, thereafter, means such successor.

     "U.S. GOVERNMENT OBLIGATIONS" means (i) securities that are (a) direct 
obligations of the United States of America for the payment of which the full 
faith and credit of the United States of America is pledged or (b) 
obligations of a Person controlled or supervised by and acting as an agency 
or instrumentality of the United States of America the payment of which is 
unconditionally guaranteed as a full faith and credit obligation by the 
United States of America, which, in either case, are not callable or 
redeemable at the option of the issuer thereof; and (ii) depository receipts 
issued by a bank (as defined in Section 3(a)(2) of the Securities Act) as 
custodian with respect to any U.S. Government Obligation which is specified 
in clause (i) above and held by such bank for the account of the holder of 
such depository receipt, or with respect to any specific payment of principal 
or interest on any U.S. Government Obligation which is so specified and held; 
provided that (except as required by law) such custodian is not authorized to 
make any deduction from the amount payable to the holder of such depository 
receipt from any amount received by the custodian in respect of the U.S. 
Government Obligation or the specific payment of principal or interest of the 
U.S. Government Obligation evidenced by such depository receipt.  Investments 
in U.S. Government Obligations may be made through or with the Trustee.


                                     -19-

<PAGE>

     "UNRESTRICTED SUBSIDIARY" means each entity, if designated by the Board 
of Directors of the Company as Unrestricted Subsidiaries pursuant to a Board 
Resolution pursuant to Section 4.10 hereof.

     "VOLUMETRIC PRODUCTION PAYMENTS" means volumetric production payment 
obligations of the Company or any of its Subsidiaries that are or, upon the 
occurrence of a contingent event, would be recorded as deferred revenue in 
accordance with GAAP, together with all undertakings and obligations of the 
Company or any of its Subsidiaries in connection therewith, which will be 
deemed to constitute debt for borrowed money for purpose of this Indenture.

     "VOTING STOCK" of a corporation means all classes of Capital Stock of 
such corporation then outstanding and normally entitled to vote in the 
election of directors.

     "WEIGHTED AVERAGE LIFE TO MATURITY" means, when applied to any 
Indebtedness at any date, the number of years obtained by dividing (i) the 
sum of the product obtained by multiplying (a) the amount of each then 
remaining installment, sinking fund, serial maturity or other required 
payments of principal, including payments at final maturity, in respect 
thereof, by (b) the number of years (calculated to the nearest one-twelfth) 
that will elapse between such date  and the making of such payment, by (ii) 
the then outstanding principal amount of such Indebtedness.

     "WHOLLY OWNED SUBSIDIARY" of any Person means a Subsidiary of such 
Person (i) all of the outstanding Capital Stock or other ownership interests 
of which (other than directors' qualifying shares) shall at the time be owned 
by such Person or by one or more Wholly Owned Subsidiaries of such Person or 
(ii) organized in a foreign jurisdiction and is required by the applicable 
laws and regulations of such foreign jurisdiction to be partially owned by 
the goernment of such foreign jurisdiction or individual or corporate 
citizens of such foreign jurisdiction in order for such Subsidiary to 
transact business in such foreign jurisdiction, provided that such Person or 
one or more Wholly Owned Subsidiaries of such Person, owns the remaining 
Capital Stock or ownership interest in such Subsidiary and, by contract or 
otherwise, controls the management and business of such Subsidiary and 
derives the economic benefits of ownership of such Subsidiary to 
substantially the same extent as if such Subsidiary were a wholly owned 
Subsidiary. Unrestricted Subsidiaries shall not be included in the definition 
of Wholly Owned Subsidiary for any purposes of this Indenture.

     SECTION 1.02.  INCORPORATION BY REFERENCE OF TRUST INDENTURE ACT. (a)  
This Indenture is expressly made subject to the Trust Indenture Act as if 
this Indenture were, on the date of this Indenture, subject to the Trust 
Indenture Act under the provisions of such statute and such provisions are 
incorporated by reference in this Indenture.

         (b)     Whenever this Indenture refers to a provision of the Trust 
Indenture Act, the provision is incorporated by reference in and made a part 
of this Indenture.  The following Trust Indenture Act terms incorporated by 
reference in this Indenture have the following meanings:

          "indenture securities" means the Notes.

          "indenture security holder" means a Holder.
 
          "indenture to be qualified" means this Indenture.

          "indenture trustee" or "institutional trustee" means the Trustee.


                                     -20-

<PAGE>

          "obligor" on the indenture securities means the Company or other 
     obligor on the Notes, if any.

     All other Trust Indenture Act terms used or incorporated by reference in 
this Indenture that are defined by the Trust Indenture Act, defined by Trust 
Indenture Act reference to another statute or defined by Commission rule have 
the meanings assigned to them therein.

     SECTION 1.03.  RULES OF CONSTRUCTION.  Unless the context otherwise 
requires:

          (a) the words "herein," "hereof" and "hereunder," and other words of 
     similar import, refer to this Indenture as a whole and not to any 
     particular Article, Section or other subdivision;

          (b) "or" is not exclusive;

          (c) "including" means including without limitation;

          (d) the principal amount of any noninterest bearing or other discount 
     security, at any date shall be the principal amount thereof that would be 
     shown on a balance sheet of the issuer dated such date prepared in 
     accordance with GAAP; and

          (e) when used with respect to the Notes, the term "principal amount" 
     shall mean the principal amount thereof at the Stated Maturity of such 
     principal amount.

     SECTION 1.04.  FORM OF DOCUMENTS DELIVERED TO TRUSTEE.  In any case where 
several matters are required to be certified by, or covered by an opinion of, 
any specified Person, it is not necessary that all such matters be certified 
by, or covered by the opinion of, only one such Person, or that they be so 
certified or covered by only one document, but one such Person may certify or 
give an opinion with respect to some matters and one or more other such 
Persons as to other matters, and any such Person may certify or give an 
opinion as to such matters in one or several documents.

     Any certificate or opinion of an officer of the Company or a Subsidiary 
Guarantor may be based, insofar as it relates to legal matters, upon a 
certificate or opinion of, or representations by, counsel, unless such 
officer knows, or in the exercise of reasonable care should know, that the 
certificate or opinion or representations with respect to the matters upon 
which his certificate or opinion is based are erroneous. Any such certificate 
or Opinion of Counsel may be based, insofar as it relates to factual matters, 
upon a certificate or opinion of, or representations by, an officer or 
officers of the Company or a Subsidiary Guarantor stating that the 
information with respect to such factual matters is in the possession of the 
Company or such Subsidiary Guarantor, unless such counsel knows, or in the 
exercise of reasonable care should know, that the certificate or opinion or 
representations with respect to such matters are erroneous.


                                     -21-

<PAGE>

     Where any Person is required to make, give or execute two or more 
applications, requests, consents, certificates, statements, opinions or other 
instruments under this Indenture, they may, but need not, be consolidated and 
form one instrument.

     SECTION 1.05.  ACTS OF HOLDERS. (a)  Any request, demand, authorization, 
direction, notice, consent, waiver or other action provided by this Indenture 
to be given or taken by Holders may be embodied in and evidenced by one or 
more instruments of substantially similar tenor signed by such Holders in 
person or by an agent duly appointed in writing; and, except as herein 
otherwise expressly provided, such action shall become effective when such 
instrument or instruments are delivered to the Trustee and, where it is 
hereby expressly required, to the Company and the Subsidiary Guarantors.  
Such instrument or instruments (and the action embodied therein and evidenced 
thereby) are herein sometimes referred to as the "Act" of the Holders signing 
such instrument or instruments.  Proof of execution of any such instrument or 
of a writing appointing any such agent shall be sufficient for any purpose of 
this Indenture and (subject to Section 7.01) conclusive in favor of the 
Trustee and the Company and the Subsidiary Guarantors, if made in the manner 
provided in this Section.

     (b)  The fact and date of the execution by any Person of any such 
instrument or writing may be proved by the affidavit of a witness of such 
execution or by an acknowledgment of a notary public or other officer 
authorized by law to take acknowledgments of deeds, certifying that the 
individual signing such instrument or writing acknowledged to him the 
execution thereof.  Where such execution is by a signer acting in a capacity 
other than such signer's individual capacity, such certificate or affidavit 
shall also constitute sufficient proof of the signer's authority.  The fact 
and date of the execution of any such instrument or writing, or the authority 
of the person executing the same, may also be proved in any other manner 
which the Trustee deems sufficient.

     SECTION 1.06.  SATISFACTION AND DISCHARGE.  This Indenture shall cease 
to be of further effect and the Trustee, on receipt of a Company Order 
requesting such action, shall execute proper instruments acknowledging 
satisfaction and discharge of this Indenture, when (a) either (i) all 
outstanding Notes have been delivered to the Trustee for cancellation or (ii) 
all such Notes not theretofore delivered to the Trustee for cancellation have 
become due and payable and the Company or the Subsidiary Guarantors have 
irrevocably deposited or caused to be deposited with the Trustee as trust 
funds in trust for the purpose (x) money in an amount, (y) U.S. Government 
Obligations or (z) a combination thereof, sufficient, in the case of deposits 
pursuant to the foregoing clauses (y) or (z), as established in the opinion 
of a nationally recognized firm of independent public accountants expressed 
in a written certification thereof delivered to the Trustee, to pay and 
discharge the entire indebtedness on such Notes, for principal (and premium, 
if any) and interest, if any, to the date of such deposit together with 
irrevocable instructions from the Company in form and substance satisfactory 
to the Trustee directing the Trustee to apply such funds to the payment 
thereof; (b) the Company or the Subsidiary Guarantors have paid or caused to 
be paid all other sums payable hereunder by the Company; and (c) the Company 
or the Subsidiary Guarantors have delivered to the Trustee an Officers' 
Certificate and an Opinion of Counsel, each stating that all conditions 
precedent herein provided for relating to the satisfaction and discharge of 
this Indenture have been complied with. Notwithstanding the satisfaction and 
discharge of this Indenture pursuant to this Section 1.06, the obligations of 
the Company and the Subsidiary Guarantors to the Trustee under Section 7.07 

                                     -22-

<PAGE>

hereof, and, if money shall have been deposited with the Trustee in trust for 
the Holders pursuant to this Section 1.06, the obligations of the Trustee 
under this Section 1.06 hereof shall survive.

     All money deposited with the Trustee pursuant to this Section 1.06 shall 
be held in trust and applied by it, in accordance with the provisions of the 
Notes and this Indenture, to the payment, either directly or through any 
Paying Agent, to the Persons entitled thereto, of the principal (and premium, 
if any) and interest, if any, for the payment of which such money has been 
deposited with the Trustee.  If the Trustee or Paying Agent is unable to 
apply any money [or U.S. Government Obligations] in accordance with this 
Section 1.06 by reason of any legal proceeding or by reason of any order or 
judgment of any court or governmental authority enjoining, restraining or 
otherwise prohibiting such application, the Company's and the Subsidiary 
Guarantors' obligations under this Indenture and the Notes shall be revived 
and reinstated as though no deposit had occurred pursuant to this Section 
1.06 until such time as the Trustee or Paying Agent is permitted to apply all 
such money or U.S. Government Obligations in accordance with this Section 
1.06; PROVIDED, that if the Company or the Subsidiary Guarantors have made 
any payment on any Notes because of the reinstatement of its obligations, the 
Company and the Subsidiary Guarantors shall be subrogated to the rights of 
the Holders of such Notes to receive such payment from the cash or U.S. 
Government Obligations held by the Trustee or Paying Agent.

     The Company and the Subsidiary Guarantors shall pay and indemnify the 
Trustee against any tax, fee or other charges imposed on or assessed against 
the U.S. Government Obligations deposited pursuant to this Section 1.06 or the 
principal and interest received in respect thereof other than any such tax, fee 
or other charge which by law is for the account of the Holders of outstanding 
Notes.

                                 ARTICLE II

                                 THE NOTES

     SECTION 2.01.  FORM AND DATING. (a)  The Notes and the certificate of 
authentication of the Trustee thereon shall be substantially in the form of 
Exhibit A or Exhibit B hereto, as applicable, which are hereby incorporated 
in and expressly made a part of this Indenture.

     (b)  The Notes may have such letters, numbers or other marks of 
identification and such legends and endorsements, stamped, printed, 
lithographed or engraved thereon, (i) as the Company may deem appropriate and 
as are not inconsistent with the provisions of this Indenture, (ii) such as 
may be required to comply with this Indenture, any law or any rule of any 
securities exchange on which the Notes may be listed and (iii) such as may be 
necessary to conform to customary usage.  Each Note shall be dated the date 
of its authentication by the Trustee.

     (c)  The Notes shall be issued initially in the form of a permanent, 
global note in definitive, fully registered form, without coupons, 
substantially in the form of Exhibit A hereto (the "Global Note"). Upon 
issuance, such Global Note shall be duly executed by the Company and 
authenticated by the Trustee as hereinafter provided and deposited with the 
Trustee as custodian for the Depositary.  


                                     -23-

<PAGE>

Any Certificated Note that may be issued pursuant to Section 2.06(a) hereof, 
shall be issued in the form of a note in definitive, fully registered form, 
without coupons, substantially in the form set forth in Exhibit B hereto.  
Upon issuance, any such Certificated Note shall be duly executed by the 
Company and authenticated by the Trustee as hereinafter provided.

     (d)  Each Global Note shall bear the following legend on the face thereof:

     UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE 
     DEPOSITORY TRUST COMPANY TO COSTILLA ENERGY, INC. OR THE REGISTRAR FOR 
     REGISTRATION OF TRANSFER OR EXCHANGE AND ANY NOTE ISSUED IS REGISTERED 
     IN THE NAME OF CEDE & CO. OR SUCH OTHER ENTITY AS HAS BEEN REQUESTED BY 
     AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY 
     PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS HAS BEEN 
     REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST 
     COMPANY), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR 
     OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER 
     HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

     TRANSFER OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN WHOLE, AND 
     NOT IN PART, TO NOMINEES OF THE DEPOSITORY TRUST COMPANY OR TO A 
     SUCCESSOR THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF INTERESTS 
     IN THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE 
     WITH THE RESTRICTIONS SET FORTH IN SECTION 2.06 OF THE INDENTURE, DATED 
     AS OF ________________, 1996, BETWEEN COSTILLA ENERGY, INC.  AND THE 
     TRUSTEE NAMED THEREIN, PURSUANT TO WHICH THIS NOTE WAS ISSUED.

     (e)  Definitive Notes shall be typed, printed, lithographed or engraved 
or produced by any combination of such methods or produced in any other 
manner permitted by the rules of  any securities exchange on which such Notes 
may be listed, all as determined by the officers of the Company executing 
such Notes, as evidenced by their execution of such Notes.

     SECTION 2.02.  EXECUTION AND AUTHENTICATION.  The aggregate principal 
amount of Notes outstanding at any time shall not exceed $100,000,000 except 
as provided in Section 2.07 hereof.  The Notes shall be executed on behalf of 
the Company by its Chief Executive Officer, its President, any Executive Vice 
President or any Senior Vice President, under its corporate seal reproduced 
or imprinted on the Notes by facsimile or otherwise, and shall be attested by 
the Company's Secretary or one of its Assistant Secretaries, in each case by 
manual or facsimile signature.

     The Notes shall be authenticated by manual signature of an authorized 
signatory of the Trustee and shall not be valid for any purpose unless so 
authenticated.


                                     -24-

<PAGE>

     In case any officer of the Company whose signature shall have been 
placed upon any of the Notes shall cease to be such officer of the Company 
before authentication of such Notes by the Trustee and the issuance and 
delivery thereof, such Notes may, nevertheless, be authenticated by the 
Trustee and issued and delivered with the same force and effect as though 
such Person had not ceased to be such officer of the Company.

     Upon compliance by the Company with the provisions of the previous 
paragraph, the Trustee shall, upon receipt of a Company Order requesting such 
action, authenticate Notes for original issuance in an aggregate principal 
amount not to exceed $100,000,000 in the form of the Global Note.  Such 
Company Order shall specify the amount of Notes to be authenticated and the 
date on which the Notes are to be authenticated and shall further provide 
instructions concerning registration, amounts for each Holder and delivery.

     Upon the occurrence of any event specified in Section 2.06(a) hereof and 
compliance by the Company with the provisions of the paragraph preceding the 
immediately preceding paragraph, the Company shall execute and the Trustee 
shall authenticate and make available for delivery to each beneficial owner 
identified by the Depositary, in exchange for such beneficial owner's 
interest in the Global Note or Certificated Notes, as the case may be, 
representing Notes theretofore represented by the Global Note.

     A Note shall not be valid or entitled to any benefit under this 
Indenture or obligatory for any purpose unless executed by the Company and 
authenticated by the manual signature of the Trustee as provided herein.  The 
signature of an authorized signatory of the Trustee shall be conclusive 
evidence, and the only evidence, that such Note has been authenticated and 
delivered under this Indenture.

     The Trustee may appoint an authenticating agent reasonably acceptable to 
the Company to authenticate the Notes.  Unless limited by the terms of such 
appointment, an authenticating agent may authenticate Notes whenever the 
Trustee may do so.  Each reference in this Indenture to authentication by the 
Trustee includes authentication by such agent.  Any authenticating agent of 
the Trustee shall have the same rights hereunder as any Registrar or Paying 
Agent.

     SECTION 2.03.  REGISTRAR AND PAYING AGENT.  The Company shall maintain, 
pursuant to Section 4.02 hereof, an office or agency where the Notes may be 
presented for registration of transfer or for exchange.  The Company shall 
cause to be kept at such office a register (the register maintained in such 
office being herein sometimes referred to as the "Security Register") in 
which, subject to such reasonable regulations as it may prescribe, the 
Company shall provide for the registration of Notes and of transfers of Notes 
entitled to be registered or transferred as provided herein.  The Trustee, at 
its Corporate Trust Office, is initially appointed "Registrar" for the 
purpose of registering Notes and transfers of Notes as herein provided.  The 
Company may, upon written notice to the Trustee, change the designation of 
the Trustee as Registrar and appoint another Person to act as Registrar for 
purposes of this Indenture.  If any Person other than the Trustee acts as 
Registrar, the Trustee shall have the right at any time, upon reasonable 
notice, to inspect or examine the Security Register and 


                                     -25-

<PAGE>

to make such inquiries of the Registrar as the Trustee shall in its 
discretion deem necessary or desirable in performing its duties hereunder.

     The Company shall enter into an appropriate agency agreement with any 
Person designated by the Company as Registrar or Paying Agent that is not a 
party to this Indenture, which agreement shall incorporate the provisions of 
the Trust Indenture Act and shall implement the provisions of this Indenture 
that relate to such Registrar or Paying Agent.  Prior to the designation of 
any such Person, the Company shall, by written notice (which notice shall 
include the name and address of such Person), inform the Trustee of such 
designation.  If the Company fails to maintain a Registrar or Paying Agent, 
the Trustee shall act as such.

     Subject to Section 2.06, upon surrender for registration of transfer of 
any Note at an office or agency of the Company designated for such purpose, 
the Company shall execute, and the Trustee shall authenticate and make 
available for delivery, in the name of the designated transferee or 
transferees, one or more new Notes of any authorized denomination or 
denominations, of like tenor and aggregate principal amount, all as requested 
by the transferor.

     Every Note presented or surrendered for registration of transfer or for 
exchange shall (if so required by the Company, the Trustee or the Registrar) 
be duly endorsed, or be accompanied by a duly executed instrument of transfer 
in form satisfactory to the Company, the Trustee and the Registrar, by the 
Holder thereof or such Holder's attorney duly authorized in writing.

     SECTION 2.04.  PAYING AGENT TO HOLD MONEY IN TRUST.  On or prior to each 
due date of the principal, premium, or any payment of interest, if any, with  
respect to any Note, the Company shall deposit with the Paying Agent a sum 
sufficient to pay such principal, premium or interest when so becoming due.

     The Company shall require each Paying Agent (other than the Trustee) to 
agree in writing that such Paying Agent, shall hold in trust for the benefit 
of Holders or the Trustee all money held by such Paying Agent for the payment 
of principal, premium or interest with respect to the Notes, shall notify the 
Trustee of any default by the Company in making any such payment and at any 
time during the continuance of any such default, upon the written request of 
the Trustee, shall forthwith pay to the Trustee all sums held in trust by 
such Paying Agent.

     The Company at any time may require a Paying Agent to pay all money held 
by it to the Trustee and to account for any funds disbursed by such Paying 
Agent.  Upon complying with this Section 2.04, the Paying Agent shall have no 
further liability for the money delivered to the Trustee.

     SECTION 2.05.  GLOBAL NOTES. (a)  So long as a Global Note is registered 
in the name of the Depositary or its nominee, members of, or participants in, 
the Depositary ("Agent Members") shall have no rights under this Indenture 
with respect to the Global Note held on their behalf by the Depositary or the 
Trustee as its custodian, and the Depositary may be treated by the Company, 
the Trustee and any agent of the Company or the Trustee as the absolute owner 
of such Global Note for 


                                     -26-

<PAGE>

all purposes.  Notwithstanding the foregoing, nothing herein shall (i) 
prevent the Company, the Trustee or any agent of the Company or the Trustee, 
from giving effect to any written certification, proxy or other authorization 
furnished by the Depositary or (ii) impair, as between the Depositary and its 
Agent Members, the operation of customary practices governing the exercise of 
the rights of a Holder of Notes.

     (b)  The Holder of a Global Note may grant proxies and otherwise 
authorize any Person, including Agent Members and Persons that may hold 
interests in such Global Note through Agent Members, to take any action which 
a Holder of Notes is entitled to take under this Indenture or the Notes.

     (c)  Whenever, as a result of an optional redemption of Notes by the 
Company, a Change of Control Offer, an Asset Sale Offer or an exchange 
pursuant to the second sentence of Section 2.06(a) hereof, a Global Note is 
redeemed, repurchased or exchanged in part, such Global Note shall be 
surrendered by the Holder thereof to the Trustee who shall cause an 
adjustment to be made to Schedule A thereof so that the principal amount of 
such Global Note will be equal to the portion of such Global Note not 
redeemed, repurchased or exchanged and shall thereafter return such Global 
Note to such Holder, provided that any such Global Note shall be in a 
principal amount of $1,000 or an integral multiple thereof.

     SECTION 2.06.  TRANSFER AND EXCHANGE.

     (a)  The Global Note shall be exchanged by the Company for one or more 
Certificated Notes if (a) the Depositary (i) has notified the Company that it 
is unwilling or unable to continue as, or ceases to be, a clearing agency 
registered under Section 17A of the Exchange Act and (ii) a successor to the 
Depositary registered as a clearing agency under Section 17A of the Exchange 
Act is not able to be appointed by the Company within 90 calendar days or (b) 
the Depositary is at any time unwilling or unable to continue as Depositary 
and a successor to the Depositary is not able to be appointed by the Company 
within 90 calendar days.  If an Event of Default occurs and is continuing, 
the Company shall, at the request of the Holder thereof, exchange all or part 
of the Global Note for one or more Certificated Notes; PROVIDED that the 
principal amount of each of such Certificated Notes and such Global Note, 
after such exchange, shall be $1,000 or an integral multiple thereof.  In 
addition, the Holder of a beneficial interest in the Global Note may at any 
time exchange such interest for a Certificated Note in a principal amount of 
$1,000 or an integral multiple thereof.  Whenever a Global Note is exchanged 
as a whole for one or more Certificated Notes, such Global Note shall be 
surrendered by the Holder thereof to the Trustee for cancellation.  Whenever 
a Global Note is exchanged in part for one or more Certificated Notes 
pursuant to this Section 2.06(a), it shall be surrendered by the Holder 
thereof to the Trustee and the Trustee shall make the appropriate notations 
thereon pursuant to Section 2.05(c) hereof.  All Certificated Notes issued in 
exchange for a Global Note or any portion thereof shall be registered in such 
names, and delivered, as the Depositary shall instruct the Trustee.


                                     -27-

<PAGE>

     (b)  A Holder may transfer a Note only upon the surrender of such Note 
for registration of transfer.  No such transfer shall be effected until, and 
the transferee shall succeed to the rights of a Holder only upon, final 
acceptance and registration of the transfer in the Security Register by the 
Registrar.  When Notes are presented to the Registrar with a request to register
the transfer of, or to exchange, such Notes, the Registrar shall register the 
transfer or make such exchange as requested if its requirements for such 
transactions and any applicable requirements hereunder are satisfied.  To permit
registrations of transfers and exchanges, the Company shall execute and the 
Trustee shall authenticate Certificated Notes at the Registrar's request.

     (c)  The Company shall not be required to make and the Registrar need 
not register transfers or exchanges of Certificated Notes (i) selected for 
redemption (except, in the case of Certificated Notes to be redeemed in part, 
the portion thereof not to be redeemed) and (ii) for a period of 15 calendar 
days before a selection of Notes to be redeemed.

     (d)  No service charge shall be made for any registration of transfer or 
exchange of Notes, but the Company may require payment by Holders of a sum 
sufficient to cover any tax or other governmental charge that may be imposed 
in connection with any registration of transfer of Notes.

     (e)  All Notes issued upon any registration of transfer or exchange 
pursuant to the terms of this Indenture will evidence the same debt and will 
be entitled to the same benefits under this Indenture as the Notes 
surrendered for such registration of transfer or exchange.

     (f)  Any Holder of a Global Note shall, by acceptance of such Global 
Note, agree that transfers of beneficial interests in such Global Note may be 
effected only through a book entry system maintained by such Holder (or its 
agent), and that ownership of a beneficial interest in the Notes represented 
thereby shall be required to be reflected in book entry form.  Transfers of a 
Global Note shall be limited to transfers in whole and not in part, to the 
Depositary, its successors, and their respective nominees. Interests of 
beneficial owners in a Global Note shall be transferred in accordance with 
the rules and procedures of the Depositary (or its successors).

     SECTION 2.07.  REPLACEMENT NOTES.  If any mutilated Note is surrendered 
to the Trustee, the Company shall execute and upon its written request the 
Trustee shall authenticate and make available for delivery, in exchange for 
any such mutilated Note, a new Note containing identical provisions and of 
like principal amount, bearing a number not contemporaneously outstanding.

     If there shall be delivered to the Company and the Trustee (i) evidence 
to their satisfaction of the destruction, loss or theft of any Note and (ii) 
such security or indemnity as may be required by them to save either of them 
and any agent of each of them harmless, then, in the absence of notice to the 
Company or the Trustee that such Note has been acquired by a bona fide 
purchaser, the Company shall execute and upon its request the Trustee shall 
authenticate and make available for delivery, in lieu of any such destroyed, 
lost or stolen Note, a new Note containing identical provisions and of like 
principal amount, bearing a number not contemporaneously outstanding.



                                   -28-


<PAGE>

     In case any such mutilated, destroyed, lost or stolen Note has become or 
is about to become due and payable, the Company in its discretion may, 
instead of issuing a new Note, pay such Note.

     Upon the issuance of any new Note under this Section 2.07, the Company 
may require the payment by the Holder of a sum sufficient to cover any tax or 
other governmental charge that may be imposed in relation thereto and any 
other expenses (including the fees and expenses of the Trustee) connected 
therewith.

     Every new Note issued pursuant to this Section 2.07 in lieu of any 
destroyed, lost or stolen Note shall constitute an original additional 
contractual obligation of the Company, whether or not the destroyed, lost or 
stolen Note shall be at any time enforceable by anyone, and shall be entitled 
to all the benefits of this Indenture equally and proportionately with any 
and all other Notes duly issued hereunder.

     The provisions of this Section 2.07 are exclusive and shall preclude (to 
the extent lawful) all other rights and remedies with respect to the 
replacement or payment of mutilated, destroyed, lost or stolen Notes.

     SECTION 2.08.  OUTSTANDING NOTES.  Notes outstanding at any time are all
Notes authenticated by the Trustee except for those canceled by it, those 
delivered to it for cancellation, those paid pursuant to Section 2.07 and 
those described in this Section 2.08 as not outstanding.  A Note does not 
cease to be outstanding because the Company or an Affiliate of the Company 
holds such Note.

     If a Note is replaced pursuant to Section 2.07 hereof, it ceases to be 
outstanding unless the Trustee and the Company receive proof satisfactory to 
them that such replaced Note is held by a bona fide purchaser.

     If the Paying Agent segregates and holds in trust, in accordance with 
this Indenture, on a redemption date or Maturity date money sufficient to pay 
all principal, premium, if any, and interest payable on that date with 
respect to the Notes (or portions thereof) to be redeemed or maturing, as the 
case may be, then on and after that date such Notes (or such portions 
thereof) shall cease to be outstanding and interest on them shall cease to 
accrue.

     In determining whether the Holders of the required principal amount of 
Notes have concurred in any direction, waiver or consent or any amendment, 
modification or other change to this Indenture, Notes held or beneficially 
owned by the Company or a Subsidiary or Unrestricted Subsidiary of the 
Company or by an Affiliate of the Company or of a Subsidiary or Unrestricted 
Subsidiary of the Company or by agents of any of the foregoing shall be 
disregarded, except that for the purposes of determining whether the Trustee 
shall be protected in relying on any such direction, waiver or consent or any 
amendment, modification or other change to this Indenture, only Notes which a 
Trust Officer actually knows are so owned shall be so disregarded. Notes so 
owned which have been pledged in good faith shall not be disregarded if the 
pledgee establishes to the satisfaction of the Trustee such 



                                   -29-


<PAGE>

pledgee's right so to act with respect to the Notes and that the pledgee is 
not the Company or an Affiliate of the Company or any of their agents.

     SECTION 2.09.  TEMPORARY NOTES.  Pending the preparation of definitive 
Notes, the Company may execute, and the Trustee shall authenticate, temporary 
notes ("Temporary Notes") which are printed, lithographed, or otherwise 
produced, substantially of the tenor of the definitive Notes in lieu of which 
they are issued and with such appropriate insertions, omissions, 
substitutions and other variations.

     If Temporary Notes are issued, the Company shall cause definitive Notes 
to be prepared without unreasonable delay.  After the preparation of 
definitive Notes, the Temporary Notes shall be exchangeable for definitive 
Notes upon surrender of the Temporary Notes to the Trustee, without charge to 
the Holder.  Until so exchanged, Temporary Notes will evidence the same debt 
and will be entitled to the same benefits under this Indenture as the 
definitive Notes in lieu of which they have been issued.

     SECTION 2.10. CANCELLATION.  The Company at any time may deliver Notes 
to the Trustee for cancellation.  The Registrar and the Paying Agent shall 
forward to the Trustee any Notes surrendered to them for registration of 
transfer, exchange, purchase or payment.  The Trustee shall cancel all Notes 
surrendered for registration of transfer, exchange, purchase, payment or 
cancellation and shall return such canceled Notes to the Company.  The Company
may not issue new Notes to replace Notes it has redeemed or paid or that have
been delivered to the Trustee for cancellation.

     SECTION 2.11. PAYMENT OF INTEREST; INTEREST RIGHTS PRESERVED.  Interest 
on any Note which is payable, and is punctually paid or duly provided for, on 
any Interest Payment Date shall be paid to the Person in whose name such Note 
is registered at the close of business on the Record Date for such interest 
payment, which shall be the ____________ __, or ____________ __ (whether or not 
a Business Day) immediately preceding such Interest Payment Date.

     Any interest on any Note which is payable, but is not punctually paid or 
duly provided for, on any Interest Payment Date (herein called "Defaulted 
Interest") shall forthwith cease to be payable to the registered Holder on 
the relevant Record Date, and, except as hereinafter provided, such Defaulted 
Interest, and any interest payable on such Defaulted Interest, may be paid by 
the Company, at its election, as provided in clause (a) or (b) below:

          (a)  The Company may elect to make payment of any Defaulted Interest,
     and any interest payable on such Defaulted Interest, to the Persons in 
     whose names the Notes are registered at the close of business on a Special
     Record Date for the payment of such Defaulted Interest, which shall be 
     fixed in the following manner.  The Company shall notify the Trustee in 
     writing of the amount of Defaulted Interest proposed to be paid on the 
     Notes and the date of the proposed payment, and at the same time the 
     Company shall deposit with the Trustee an amount of money equal to the 
     aggregate amount proposed to be paid in respect of such Defaulted Interest
     or shall make arrangements satisfactory to the Trustee for such deposit 
     prior to the date of the proposed 



                                   -30-


<PAGE>

     payment, such money when deposited to be held in trust for the benefit of
     the Persons entitled to such Defaulted Interest as provided in this Clause.
     Thereupon the Trustee shall fix a Special Record Date for the payment of 
     such Defaulted Interest which shall be not more than 15 calendar days and 
     not less than 10 calendar days prior to the date of the proposed payment
     and not less than 10 calendar days after the receipt by the Trustee of the
     notice of the proposed payment.  The Trustee shall promptly notify the 
     Company of such Special Record Date and, in the name and at the expense of
     the Company, shall cause notice of the proposed payment of such Defaulted 
     Interest and the Special Record Date therefor to be sent, first class mail,
     postage prepaid, to each Holder at such Holder's address as it appears in 
     the Security Register, not less than 10 calendar days prior to such Special
     Record Date.  Notice of the proposed payment of such Defaulted Interest and
     the Special Record Date therefor having been mailed as aforesaid, such 
     Defaulted Interest shall be paid to the Persons in whose names the Notes 
     are registered at the close of business on such Special Record Date and 
     shall no longer be payable pursuant to the following clause (b).

          (b)  The Company may make payment of any Defaulted Interest, and any
     interest payable on such Defaulted Interest, on the Notes in any other 
     lawful manner not inconsistent with the requirements of any securities 
     exchange on which the Notes may be listed, and upon such notice as may be
     required by such exchange, if, after notice given by the Company to the 
     Trustee of the proposed payment pursuant to this clause, such manner of
     payment shall be deemed practicable by the Trustee.

     Subject to the foregoing provisions of this Section 2.11, each Note 
delivered under this Indenture upon registration of transfer of, or in exchange
for, or in lieu of, any other Note, shall carry the rights to interest accrued
and unpaid, and to accrue, which were carried by such other Note.

     SECTION 2.12.  AUTHORIZED DENOMINATIONS.  The Notes shall be issuable in 
denominations of $1,000 and any integral multiple thereof.

     SECTION 2.13.  COMPUTATION OF INTEREST.  Interest on the Notes shall be 
computed on the basis of a 360-day year of twelve 30-day months.

     SECTION 2.14.  PERSONS DEEMED OWNERS.  Prior to the due presentation for 
registration of transfer of any Note, the Company, the Trustee, the Paying 
Agent, the Registrar or any co-registrar may deem and treat the person in 
whose name such Note is registered as the absolute owner of such Note for the 
purpose of receiving payment of principal of, premium, if any, and interest 
on such Note and for all other purposes whatsoever, whether or not such Note 
is overdue, and none of the Company, the Trustee, the Paying Agent, the 
Registrar or any co-Registrar shall be affected by notice to the contrary.

     SECTION 2.15.  CUSIP NUMBERS.  The Company, in issuing the Notes, may 
use a "CUSIP" number for each series of Notes and, if so, the Trustee shall 
use the relevant CUSIP number in any notices to Holders as a convenience to 
such Holders; provided that any such notice may state that no 



                                   -31-


<PAGE>

representation is made as to the correctness or accuracy of the CUSIP number 
printed in the notice or on the Notes and that reliance may be placed only on 
the other identification numbers printed on the Notes.  The Company shall 
promptly notify the Trustee of any change in any CUSIP number used.

                                 ARTICLE III
                                 REDEMPTION

     SECTION 3.01.  NOTICE TO TRUSTEE.  If the Company elects to redeem Notes
pursuant to paragraph five of the Notes, it shall notify the Trustee in 
writing of the Redemption Date and the principal amount of Notes to be 
redeemed.  The Company shall give each such notice to the Trustee at least 30 
calendar days prior to the Redemption Date unless the Trustee consents to a 
shorter period.  Such notice shall be accompanied by an Officers' Certificate 
and an Opinion of Counsel from the Company to the effect that such redemption 
will comply with any conditions to such redemption set forth herein and in 
the Notes.

     SECTION 3.02.  SELECTION OF NOTES TO BE REDEEMED.  If less than all the 
Notes are to be redeemed at any time, the Trustee shall select the Notes to 
be redeemed on a pro rata basis, provided that the Trustee may select for 
redemption in part only Notes in denominations larger than $1,000.  In 
selecting Notes to be redeemed pursuant to this Section 3.02, the Trustee 
shall make such adjustments, reallocations and eliminations as it shall deem 
proper so that the principal amount of each Note to be redeemed shall be 
$1,000 or an integral multiple thereof, by increasing, decreasing or 
eliminating any amount less than $1,000 which would be allocable to any 
Holder.  If the Notes to be redeemed are Certificated Notes, the Certificated 
Notes to be redeemed shall be selected by the Trustee by prorating, as nearly 
as may be, the principal amount of Certificated Notes to be redeemed among 
the Holders of Certificated Notes registered in their respective names.  
Provisions of this Indenture that apply to Notes called for redemption also 
apply to portions of Notes called for redemption.  The Trustee shall notify 
the Company promptly of the Notes or portions of Notes to be redeemed. 

     SECTION 3.03.  NOTICE OF REDEMPTION.  At least 30 calendar days but not 
more than 60 calendar days before a Redemption Date, the Company shall send a 
notice of redemption, first class mail, postage prepaid, to Holders of Notes 
to be redeemed at the addresses of such Holders as they appear in the Security
Register.

     The notice shall identify the Notes to be redeemed (including CUSIP number)
and shall state:

          (a)  the Redemption Date;

          (b)  the Redemption Price (and shall specify the portion of such 
     Redemption Price that constitutes the amount of accrued and unpaid interest
     to be paid, if any);

          (c)  the name and address of the Paying Agent;



                                   -32-


<PAGE>

          (d)  that the Notes called for redemption must be surrendered to the
     Paying Agent to collect the Redemption Price;

          (e)  if any Global Note is being redeemed in part, the portion of the
     principal amount of such Note to be redeemed and that, after the Redemption
     Date, the Global Note, with a notation on Schedule A thereof adjusting the
     principal amount thereof to be equal to the unredeemed portion, will be 
     returned to the Holder thereof;

          (f)  if any Certificated Note is being redeemed in part, the portion
     of the principal amount of such Note to be redeemed and that, after the 
     Redemption Date, a new Certificated Note or Certificated Notes in principal
     amount equal to the unredeemed portion will be issued;

          (g)  if fewer than all the outstanding Notes are to be redeemed, the
     identification and principal amounts of the particular Notes to be 
     redeemed;

          (h)  that, unless the Company defaults in making the redemption 
     payment, interest on the Notes (or portions thereof) called for redemption
     shall cease and such Notes (or portions thereof) shall cease to accrue 
     interest on and after the Redemption Date;

          (i)  the paragraph of the Notes pursuant to which the Notes are being
     called for redemption; and

          (j)  any other information necessary to enable Holders to comply with
     the notice of redemption.

     At the Company's request, the Trustee shall give the notice of redemption
in the Company's name and at the Company's expense.  In such event, the Company
shall provide the Trustee with the information required by this Section 3.03 
in a timely manner.

     SECTION 3.04.  EFFECT OF NOTICE OF REDEMPTION.  Once notice of redemption
is mailed, Notes called for redemption shall become due and payable on the 
Redemption Date and at the Redemption Price stated in such notice.  Upon 
surrender to the Paying Agent, such Notes shall be paid at the Redemption 
Price stated in such notice.  Failure to give notice or any defect in the notice
to any Holder shall not affect the validity of the notice to any other Holder.

     SECTION 3.05.  DEPOSIT OF REDEMPTION PRICE.  On or prior to 10:00 a.m., 
New York City time, on each Redemption Date, the Company shall deposit with the
Paying Agent (or, if the Company, one of its Subsidiaries or any of their 
Affiliates is the Paying Agent, the Paying Agent shall segregate and hold in 
trust for the benefit of the Holders) money, in federal or other immediately 
available funds, sufficient to pay the Redemption Price on all Notes to be 
redeemed on that date other than Notes or portions of Notes called for 
redemption on such date which have been delivered by the Company to the 
Trustee for cancellation.



                                   -33-


<PAGE>

     So long as the Company complies with the preceding paragraph and the 
other provisions of this Article III, interest on the Notes or portions 
thereof to be redeemed on the applicable Redemption Date shall cease to 
accrue from and after such date and such Notes or  portions thereof shall be 
deemed not to be entitled to any benefit under this Indenture except to 
receive payment of the Redemption Price on the Redemption Date. If any Note 
called for redemption shall not be so paid upon surrender for redemption, 
then, from the Redemption Date until such Redemption Price is paid, interest 
shall be paid on the unpaid principal and premium and, to the extent permitted
by law, on any accrued but unpaid interest thereon, in each case at the rate
prescribed therefor by such Notes.

     SECTION 3.06.  NOTES REDEEMED IN PART.  Upon surrender and cancellation 
of a Certificated Note that is redeemed in part, the Company shall issue and 
the Trustee shall authenticate and make available for delivery to the 
surrendering Holder (at the Company's expense) a new Certificated Note equal 
in principal amount to the unredeemed portion of the Certificated Note 
surrendered and canceled, PROVIDED that each such Certificated Note shall be 
in a principal amount of $1,000 or an integral multiple thereof.

     Upon surrender of a Global Note that is redeemed in part, the Paying 
Agent shall forward such Global Note to the Trustee who shall make a notation 
on Schedule A thereof to reduce the principal amount of such Global Note to 
an amount equal to the unredeemed portion of such Global Note, as provided in 
Section 2.05(c) hereof.


                                  ARTICLE IV
                                   COVENANTS

     SECTION 4.01.  PAYMENT OF NOTES.  The Company shall promptly pay the 
principal of, premium, if any, and interest on, the Notes on the dates and in 
the manner provided in the Notes and in this Indenture. Principal, premium 
and interest shall be considered paid on the date due if, on such date, the 
Trustee or the Paying Agent holds in accordance with this Indenture money 
sufficient to pay all principal, premium and interest then due.

     To the extent lawful, the Company shall pay interest on overdue 
principal, overdue premium, and Defaulted Interest (without regard to any 
applicable grace period), at the interest rate borne on the Notes. The 
Company's obligation pursuant to the previous sentence shall apply whether 
such overdue amount is due at its Stated Maturity, as a result of the Company's
obligations pursuant to Section 3.05, Section 4.07 or Section 4.08 hereof, or
otherwise.

     SECTION 4.02.   MAINTENANCE OF OFFICE OR AGENCY.  The Company shall 
maintain in the Borough of Manhattan, The City of New York, an office or 
agency where Notes may be presented or surrendered for payment, where Notes 
may be surrendered for registration of transfer or exchange and where notices 
and demands to or upon the Company in respect of the Notes and this Indenture 
may be served, which office shall be initially the office of State Street 
Bank and Trust Company, National Association, 61 Broadway, New York, New York 
10006, Concourse Level, Corporate 



                                   -34-


<PAGE>

Trust Window.  The Company shall give prompt written notice to the Trustee of 
any change in the location of such office or agency.  If at any time the 
Company shall fail to maintain any such required office or agency or shall 
fail to furnish the Trustee with the address thereof, such presentations, 
surrenders, notices and demands may be made or served at the Corporate Trust 
Office of the Trustee, and the Company hereby appoints the Trustee its agent 
to receive all presentations, surrenders, notices and demands.

     The Company may also from time to time designate one or more other 
offices or agencies (in or outside of The City of New York) where the Notes 
may be presented or surrendered for any or all of such purposes, and may from 
time to time rescind such designations; provided that no such designation or 
rescission shall in any manner relieve the Company of its obligation to 
maintain an office or agency in The City of New York, for such purposes.  The 
Company shall give prompt written notice to the Trustee of any such 
designation and any change in the location of any such other office or agency.

     SECTION 4.03.  MONEY FOR THE NOTE PAYMENTS TO BE HELD IN TRUST.  If the 
Company, any Subsidiary of the Company or any of their respective Affiliates 
shall at any time act as Paying Agent with respect to the Notes, such Paying 
Agent shall, on or before each due date of the principal of (and premium, if 
any) or interest on any of the Notes, segregate and hold in trust for the 
benefit of the Persons entitled thereto money sufficient to pay the principal 
(and premium, if any) or interest so becoming due until such money shall be 
paid to such Persons or otherwise disposed of as herein provided, and shall 
promptly notify the Trustee of its action or failure so to act.

     Whenever the Company shall have one or more Paying Agents with respect 
to the Notes, it shall, prior to or on each due date of the principal of (and 
premium, if any) or interest on any of the Notes, deposit with a Paying Agent 
a sum sufficient to pay the principal (and premium, if any) or interest so 
becoming due, such sum to be held in trust for the benefit of the Persons 
entitled to such principal, premium or interest and (unless such Paying Agent 
is the Trustee) the Paying Agent shall promptly notify the Trustee of the 
Company's action or failure so to act.

     SECTION 4.04.  CORPORATE EXISTENCE.  Subject to the provisions of 
Article V hereof, the Company shall do or cause to be done all things 
necessary to preserve and keep in full force and effect the corporate 
existence, rights (charter and statutory) and franchises of the Company and 
each of its Subsidiaries; PROVIDED that the Company and any such Subsidiary 
shall not be required to preserve the corporate existence of any such 
Subsidiary or any such right or franchise if the Board of Directors of the 
Company shall determine that the preservation thereof is no longer desirable 
in the conduct of the business of the Company and that the loss thereof is 
not disadvantageous in any material respect to the Holders of Notes.

     SECTION 4.05.  MAINTENANCE OF PROPERTY.  The Company shall cause all 
Property used or useful in the conduct of its business or the business of any 
of its Subsidiaries to be maintained and kept in good condition, repair and 
working order and supplied with all necessary equipment and shall cause to be 
made all necessary repairs, renewals, replacements, betterments and improvements




                                   -35-


<PAGE>

thereof, all as, in the judgment of the Company, may be necessary so that the 
business carried on in connection therewith may be properly and advantageously
conducted at all times; provided that nothing in this Section 4.05 shall prevent
the Company from discontinuing the operation or maintenance of any of such 
Property if such discontinuance is, in the judgment of the Company, desirable in
the conduct of its business or the business of any of its Subsidiaries and not 
disadvantageous in any material respect to the Holders of Notes.

     SECTION 4.06.   PAYMENT OF TAXES AND OTHER CLAIMS.  The Company shall pay 
or discharge or cause to be paid or discharged, before the same shall become 
delinquent, (a) all taxes, assessments and governmental charges levied or 
imposed upon the Company or any of its Subsidiaries or upon the income, 
profits or Property of the Company or any of its Subsidiaries and (b) all 
lawful claims for labor, materials and supplies which, if unpaid, might by 
law become a Lien upon the Property of the Company or any of its Subsidiaries;
PROVIDED that the Company shall not be required to pay or discharge or cause to
be paid or discharged any such tax, assessment, charge or claim whose amount,
applicability or validity is being contested in good faith by appropriate 
proceedings upon stay of execution or the enforcement thereof and for which 
adequate reserves in accordance with GAAP or other appropriate provision has 
been made.

     SECTION 4.07.  REPURCHASE AT THE OPTION OF HOLDERS UPON A CHANGE OF 
CONTROL. (a)  Upon the occurrence of a Change of Control, each Holder of 
Notes shall have the right to require the Company to purchase such Holder's 
Notes, in whole or in part, in a principal amount that is an integral multiple
of $1,000, pursuant to the offer described in Section 4.07(b) hereof (the 
"Change of Control Offer") at a purchase price (the "Change of Control Purchase
Price") in cash equal to 101% of the aggregate principal amount thereof plus 
accrued and unpaid interest thereon to the date of purchase (the "Change of 
Control Payment Date").

     (b)  Within 30 calendar days after the date of any Change of Control, the
Company, or the Trustee at the request and expense of the Company, shall send 
to each Holder by first class mail, postage prepaid, a notice prepared by the 
Company describing the transaction or transactions that constitute the Change 
of Control and stating:

          (i)   that a Change of Control has occurred and a Change of Control 
     Offer is being made pursuant to this Section 4.07, and that all Notes that
     are timely tendered will be accepted for payment;

          (ii)  the Change of Control Purchase Price, and the Change of Control
     Payment Date, which date shall be a Business Day no earlier than 30 
     calendar days nor later than 60 calendar days subsequent to the date such 
     notice is mailed;

          (iii) that any Notes or portions thereof not tendered or accepted for
     payment will continue to accrue interest;



                                   -36-


<PAGE>

          (iv)  that, unless the Company defaults in the payment of the Change 
     of Control Purchase Price with respect thereto, all Notes or portions 
     thereof accepted for payment pursuant to the Change of Control Offer shall
     cease to accrue interest from and after the Change of Control Payment Date;

          (v)   that any Holder electing to have any Notes or portions thereof 
     purchased pursuant to a Change of Control Offer will be required to 
     surrender such Notes, with the form entitled "Option of Holder to Elect 
     Purchase" on the reverse of such Notes completed, to the Paying Agent at 
     the address specified in the notice, prior to the close of business on the
     third Business Day preceding the Change of Control Payment Date;

          (vi)  that any Holder shall be entitled to withdraw such election if
     the Paying Agent receives, not later than the close of business on the 
     second Business Day preceding the Change of Control Payment Date, a 
     facsimile transmission or letter, setting forth the name of the Holder,
     the principal amount of Notes delivered for purchase, and a statement that
     such Holder is withdrawing such Holder's election to have such Notes or 
     portions thereof purchased pursuant to the Change of Control Offer;

          (vii) that any Holder electing to have Notes purchased pursuant to the
     Change of Control Offer must specify the principal amount that is being 
     tendered for purchase, which principal amount must be $1,000 or an integral
     multiple thereof;

          (viii)  if Certificated Notes have been issued pursuant to Section 
     2.06, that any Holder of Certificated Notes whose Certificated Notes are 
     being purchased only in part will be issued new Certificated Notes equal
     in principal amount to the unpurchased portion of the Certificated Note or
     Notes surrendered, which unpurchased portion will be equal in principal 
     amount to $1,000 or an integral multiple thereof;

          (ix)  that the Trustee will return to the Holder of a Global Note 
     that is being purchased in part, such Global Note with a notation on 
     Schedule A thereof adjusting the principal amount thereof to be equal
     to the unpurchased portion of such Global Note; and

          (x)   any other information necessary to enable any Holder to tender
     Notes and to have such Notes purchased pursuant to this Section 4.07.

     (c)   On the Change of Control Payment Date, the Company shall (1) 
accept for payment all Notes or portions thereof properly tendered pursuant 
to the Change of Control Offer, (2) irrevocably deposit with the Paying 
Agent, by 10:00 a.m., New York City time, on such date, in immediately 
available funds, an amount equal to the Change of Control Purchase Price in 
respect of all Notes or portions thereof so accepted and (3) deliver or cause 
to be delivered to the Trustee the Notes so accepted together with an 
Officers' Certificate stating the aggregate principal amount of Notes or 
portions thereof being purchased by the Company.  The Paying Agent shall 
promptly send by first class mail, postage prepaid, to each Holder of Notes 
or portions thereof so accepted for

                                   -37-


<PAGE>

payment the Change of Control Purchase Price for such Notes or portions 
thereof.  The Company shall publicly announce the results of the Change of 
Control Offer on or as soon as practicable after the Change of Control 
Payment Date.  For purposes of this Section 4.07, the Trustee shall act as 
the Paying Agent.

     (d)   Upon surrender and cancellation of a Certificated Note that is 
purchased in part pursuant to the Change of Control Offer, the Company shall 
promptly issue and the Trustee  shall authenticate and deliver to the 
surrendering Holder of such Certificated Note a new Certificated Note equal 
in principal amount to the unpurchased portion of such surrendered 
Certificated Note; provided that each such new Certificated Note shall be in 
a principal amount of $1,000 or an integral multiple thereof.

     Upon surrender of a Global Note that is purchased in part pursuant to a 
Change of Control Offer, the Paying Agent shall forward such Global Note to 
the Trustee who shall make a notation on Schedule A thereof to reduce the 
principal amount of such Global Note to an amount equal to the unpurchased 
portion of such Global Note, as provided in Section 2.05(c) hereof.

     (e)  The Company shall comply with the requirements of Section 14(e) 
under the Exchange Act and any other securities laws or regulations, to the 
extent such laws and regulations are applicable, in connection with the 
purchase of Notes pursuant to a Change of Control Offer.

     (f)  Prior to complying with the provisions of this Section 4.07, but in 
any event within 30 days following a Change of Control, the Company shall 
either repay all outstanding Senior Indebtedness or obtain the requisite 
consents, if any, under all agreements governing outstanding Senior 
Indebtedness to permit the repurchase of Notes required by this Section 4.07.

     SECTION 4.08.  LIMITATION ON ASSET SALES. (a) The Company shall not, and 
shall not permit any of its Subsidiaries, directly or indirectly, to, engage 
in an Asset Sale unless:

          (i)  the Company (or such Subsidiary) receives consideration at the 
     time of such Asset Sale at least equal to the fair market value, and in the
     case of a lease of assets under which the Company or any of its 
     Subsidiaries is the lessor, a lease providing for rent and other conditions
     which are no less favorable to the Company (or such Subsidiary) in any 
     material respect than the then prevailing market conditions (evidenced in 
     each case by a resolution of the Board of Directors of such Person set 
     forth in an Officers' Certificate of such Person delivered to the Trustee)
     of the assets sold or otherwise disposed of, and

          (ii)  at least 85% (100% in the case of such lease payments) of the 
     consideration therefor received by the Company or such Subsidiary is in the
     form of cash or Cash Equivalents or properties used in the Oil and Gas 
     Business of the Company and its Subsidiaries.

     (b)  The Company may apply Net Proceeds of an Asset Sale, at its option, 
(a) to permanently reduce Senior Indebtedness other than Senior Revolving 
Indebtedness, (b) to permanently reduce Senior Revolving Indebtedness (and to 
correspondingly reduce commitments 



                                   -38-


<PAGE>

with respect thereto), or (c) to invest in properties and assets that will be 
used in the Oil and Gas Business of the Company and its Subsidiaries. Pending 
the final application of any such Net Proceeds, the Company may temporarily 
reduce Senior Revolving Indebtedness or otherwise invest such Net Proceeds in 
any manner that is not prohibited by this Indenture.

     Any Net Proceeds from Asset Sales that are not applied within 270 days 
after the consummation of an Asset Sale as provided in the preceding paragraph
will be deemed to constitute "Excess Proceeds."

     (c)  When the aggregate amount of Excess Proceeds exceeds $5.0 million, 
the Company will be required to make an offer to all Holders of Notes, as 
described in Section 4.08(d) hereof (an "Asset Sale Offer"), to purchase from 
all Holders, on a pro rata basis, Notes in an aggregate principal amount equal
to the maximum principal amount of Notes that may be purchased out of the 
then existing Excess Proceeds, at a purchase price (the "Asset Sale Purchase 
Price") in cash in an amount equal to 100% of the principal amount thereof 
plus accrued and unpaid interest thereon to the date of purchase.

     (d)  Within 30 calendar days after the date the amount of Excess Proceeds
exceeds $5.0 million, the Company, or the Trustee at the request and expense of
the Company, shall send to each Holder by first class mail, postage prepaid, a
notice prepared by the Company stating:

          (i)   that an Asset Sale Offer is being made pursuant to this Section
     4.08, and that are Notes that are timely tendered will be accepted for 
     payment, subject to proration in the event the amount of Excess Proceeds is
     less than the aggregate Asset Sale Purchase Price of all Notes timely 
     tendered pursuant to the Asset Sale Offer;

          (ii)  the Asset Sale Purchase Price, the amount of Excess Proceeds 
     that are available to be applied to purchase tendered Notes, and the date
     Notes are to be purchased pursuant to the Asset Sale Offer (the "Asset 
     Sale Payment Date"), which date shall be a Business Day no earlier than 
     30 calendar days nor later than 60 calendar days subsequent to the date
     such notice is mailed;

          (iii)  that any Notes or portions thereof not tendered or accepted
     for payment will continue to accrue interest;

          (iv)  that, unless the Company defaults in the payment of the Asset 
     Sale Purchase Price with respect thereto, all Notes or portions thereof
     accepted for payment pursuant to the Asset Sale Offer shall cease to 
     accrue interest from and after the Asset Sale Payment Date;

          (v)   that any Holder electing to have any Notes or portions thereof
     purchased pursuant to the Asset Sale Offer will be required to surrender 
     such Notes, with the form entitled "Option of Holder to Elect Purchase" on
     the reverse of such Notes completed, to the Paying 



                                   -39-


<PAGE>

     Agent at the address specified in the notice, prior to the close of 
     business on the third Business Day preceding the Asset Sale Payment 
     Date;

          (vi)  that any Holder shall be entitled to withdraw such election if
     the Paying Agent receives, not later than the close of business on the 
     second Business Day preceding the Asset Sale Payment Date, a facsimile 
     transmission or letter, setting forth the name of the Holder, the principal
     amount of Notes delivered for purchase, and a statement that such Holder is
     withdrawing such Holder's election to have such Notes or portions thereof
     purchased pursuant to the Asset Sale Offer;

          (vii) that any Holder electing to have Notes purchased pursuant to the
     Asset Sale Offer must specify the principal amount that is being tendered
     for purchase, which principal amount must be $1,000 or an integral multiple
     thereof;

          (viii) if Certificated Notes have been issued pursuant to Section 
     2.06, that any Holder of Certificated Notes whose Certificated Notes are
     being purchased only in part will be issued new Certificated Notes equal 
     in principal amount to the unpurchased portion of the Certificated Note or
     Notes surrendered, which unpurchased portion will be equal in principal 
     amount to $1,000 or an integral multiple thereof;

          (ix)  that the Trustee will return to the Holder of a Global Note 
     that is being purchased in part, such Global Note with a notation on 
     Schedule A thereof adjusting the principal amount thereof to be equal to
     the unpurchased portion of such Global Note; and

          (x)   any other information necessary to enable any Holder to tender
     Notes and to have such Notes purchased pursuant to this Section 4.08.

     (e)  If the aggregate principal amount of the Notes surrendered by 
Holders exceeds the amount of Excess Proceeds as indicated in the notice 
required by Section 4.08(d) hereof, the Trustee shall select the Notes to be 
purchased on a PRO RATA basis based on the principal amount of the Notes 
tendered, with such adjustments as may be deemed appropriate by the Trustee, 
so that only Notes in denominations of $1,000 or integral multiples thereof 
shall be purchased.

     (f)  On the Asset Sale Payment Date, the Company shall (i) accept for 
payment any Notes or portions thereof properly tendered and selected for 
purchase pursuant to the Asset Sale Offer and Section 4.08(e) hereof; (ii) 
irrevocably deposit with the Paying Agent, by 10:00 a.m., New York City time, 
on such date, in immediately available funds, an amount equal to the Asset 
Sale Purchase Price in respect of all Notes or portions thereof so accepted; 
and (iii) deliver, or cause to be delivered, to the Trustee the Notes so 
accepted together with an Officers' Certificate listing the Notes or portions 
thereof tendered to the Company and accepted for payment.  The Paying Agent 
shall promptly send by first class mail, postage prepaid, to each Holder of 
Notes or portions thereof so accepted for payment the Asset Sale Purchase 
Price for such Notes or portions thereof.  The Company shall 




                                   -40-


<PAGE>

publicly announce the results of the Asset Sale Offer on or as soon as 
practicable after the Asset Sale Payment Date.  For purposes of this Section 
4.08, the Trustee shall act as the Paying Agent.

     (g)  Upon surrender and cancellation of a Certificated Note that is 
purchased in part, the Company shall promptly issue and the Trustee shall 
authenticate and deliver to the surrendering Holder of such Certificated Note 
a new Certificated Note equal in principal amount to the unpurchased portion 
of such surrendered Certificated Note; PROVIDED that each such new 
Certificated Note shall be in a principal amount of $1,000 or an integral 
multiple thereof.

     Upon surrender of a Global Note that is purchased in part pursuant to an 
Asset Sale Offer, the Paying Agent shall forward such Global Note to the 
Trustee who shall make a notation on Schedule A thereof to reduce the 
principal amount of such Global Note to an amount equal to the unpurchased 
portion of such Global Note, as provided in Section 2.05(c) hereof.

     (h)  Upon completion of an Asset Sale Offer (including payment of the 
Asset Sale Purchase Price for accepted Notes), any surplus Excess Proceeds 
that were the subject of such offer shall cease to be Excess Proceeds, and 
the Company may then use such amounts for general corporate purposes.

     (i)  The Company shall comply with the requirements of Section 14(e) 
under the Exchange Act and any other securities laws or regulations, to the 
extent such laws and regulations are applicable, in connection with the 
purchase of Notes pursuant to an Asset Sale Offer.

     SECTION 4.9.   OWNERSHIP OF CAPITAL STOCK.  The Company shall not permit 
any Person (other than the Company or any Wholly Owned Subsidiary of the 
Company) to own any Capital Stock of any Subsidiary of the Company or any 
lien or security interest therein, and shall not permit any Subsidiary of the 
Company to issue Capital Stock (except to the Company or to a Wholly Owned 
Subsidiary of the Company) or create, incur, assume or suffer to exist any 
lien or security interest therein, in each case except (a) directors' 
qualifying shares, (b) Capital Stock issued prior to the time such Person 
becomes a Subsidiary of the Company, (c) if such Subsidiary merges with and 
into another Subsidiary, (d) if another Subsidiary merges with and into such 
Subsidiary, (e) if such Subsidiary ceases to be a Subsidiary (as a result of 
the sale of 100% of the shares of such Subsidiary, the Net Proceeds from 
which are applied in accordance with Section 4.08 hereof), or (f) Capital 
Stock of a Subsidiary organized in a foreign jurisdiction required to be 
issued to, or owned by, the government of such foreign jurisdiction or 
individual or corporate citizens of such foreign jurisdiction in order for 
such Subsidiary to transact business in such foreign jurisdiction.

                                   -41-

<PAGE>


     SECTION 4.10.  UNRESTRICTED SUBSIDIARIES.  The Board of Directors of the 
Company may designate any of its Subsidiaries as Unrestricted Subsidiaries.  
A Subsidiary may only be so designated if (i) immediately after giving effect 
to such designation no Default or Event of Default exists, (ii) the Company 
would, at the time of such designation and after giving pro forma effect 
thereto as if such designation had occurred at the beginning of the 
applicable four-quarter period, have been permitted to incur at least $1.00 
of additional Indebtedness pursuant to the Consolidated Interest Coverage 
Ratio and the Adjusted Consolidated Net Tangible Assets to Consolidated 
Indebtedness Ratio tests set forth in Section 4.12(a) hereof, and (iii) after 
the date of this Indenture and prior to such designation, no assets of the 
Company or of any Subsidiary of the Company (including, without limitation, 
Capital Stock of any such Subsidiary) shall have been transferred, directly 
or indirectly, to any Unrestricted Subsidiary or any of its Subsidiaries, 
other than assets transferred in the ordinary course of business and on terms 
that are no less favorable to the Company or the relevant Subsidiary than 
those that would have been obtained in a comparable transaction by the 
Company or such Subsidiary with an unrelated Person.  Any such designation by 
the Board of Directors of the Company shall be evidenced to the Trustee by 
filing with the Trustee a certified copy of the Board Resolution of the 
Company giving effect to such designation and an Officers' Certificate of the 
Company certifying that such designation complied with the foregoing 
conditions.

     Any Subsidiary of the Company shall continue to be an Unrestricted 
Subsidiary only if it (a) has no Indebtedness other than Non-Recourse 
Indebtedness; (b) is a Person with respect to which neither the Company nor 
any of its Subsidiaries has any direct or indirect obligation (x) to 
subscribe for additional Equity Interests or (y) to maintain or preserve such 
Person's financial condition or to cause such Person to achieve any specified 
levels of operating results; and (c) has not guaranteed or otherwise directly 
or indirectly provided credit support for any Indebtedness of the Company or 
any of its Subsidiaries.  If, at any time, any Unrestricted Subsidiary fails 
to meet the foregoing requirements, such Unrestricted Subsidiary shall 
thereafter cease to be an Unrestricted Subsidiary for purposes of this 
Indenture, such Unrestricted Subsidiary shall execute and deliver a 
supplemental indenture pursuant to which such Person guarantees the payment 
of the Notes on the same terms and conditions as the Subsidiary Guarantees by 
the Subsidiary Guarantors  and any Indebtedness of such Unrestricted 
Subsidiary shall be deemed to be incurred by a Subsidiary of the Company as 
of such date.

     The Board of Directors of the Company may at any time designate any 
Subsidiary, if previously designated as Unrestricted Subsidiaries, to be a 
Subsidiary; provided that such designation shall be deemed to be an 
incurrence of Indebtedness by a Subsidiary of the Company of any outstanding 
Indebtedness of such Subsidiary and such designation shall only be permitted 
if (i) such Indebtedness is permitted under the covenant described under 
Section 4.12 hereof, (ii) no Default or Event of Default would be in 
existence following such designation and (iii) such Subsidiary shall execute 
and deliver a supplemental indenture pursuant to which such Person guarantees 
the payment of the Notes on the same terms and conditions as the Subsidiary 
Guarantees by the Subsidiary Guarantors.


                                     -42-

<PAGE>

     SECTION 4.11.  RESTRICTED PAYMENTS.  The Company shall not, and shall 
not permit any of its Subsidiaries to, directly or indirectly: (i) declare or 
pay any dividend or make any distribution on account of the Company's or any 
of its Subsidiaries' Equity Interests, other than dividends or distributions 
payable in Equity Interests (other than Disqualified Stock) of the Company or 
dividends or distributions payable to the Company or any Wholly Owned 
Subsidiary of the Company; (ii) purchase, redeem or otherwise acquire or 
retire for value any Equity Interests of the Company or any Subsidiary or 
Unrestricted Subsidiary or other Affiliate of the Company (other than Equity 
Interests of the Company, any Subsidiary or Unrestricted Subsidiary owned by 
any Wholly Owned Subsidiary of the Company); (iii) make any principal payment 
on, or purchase, redeem, defease or otherwise acquire or retire for value any 
PARI PASSU Indebtedness prior to a scheduled mandatory sinking fund payment 
date or maturity date, or (iv) make any Restricted Investment (all such 
payments and other actions set forth in clauses (i) through (iv) above being 
collectively referred to as "Restricted Payments"), unless, at the time of 
and after giving effect to such Restricted Payment:

          (a)  no Default or Event of Default shall have occurred and be 
     continuing or would occur as a consequence thereof;

          (b)  the Company would, at the time of such Restricted Payment and 
     after giving pro forma effect thereto as if such Restricted Payment had 
     been made at the beginning of the applicable four-quarter period, have 
     been permitted to incur at least $1.00 of additional Indebtedness 
     pursuant to the Consolidated Interest Coverage Ratio and the Adjusted 
     Consolidated Net Tangible Assets to Consolidated Indebtedness Ratio 
     tests set forth under Section 4.12(a); and

          (c)  such Restricted Payment, together with the aggregate of all 
     other Restricted Payments made by the Company and its Subsidiaries on or 
     after the date of this Indenture (excluding Restricted Payments 
     permitted by clauses (ii), (iii), (iv) and (v) of the next succeeding 
     paragraph), is less than the sum of (i) 50% of the Consolidated Net 
     Income of the Company and its Subsidiaries for the period (taken as one 
     accounting period) from the beginning of the first fiscal quarter 
     commencing after the date of this Indenture to the end of the Company's 
     most recently ended fiscal quarter for which internal financial 
     statements are available at the time of such Restricted Payment (or, if 
     such Consolidated Net Income for such period is a deficit, less 100% of 
     such deficit), plus (ii) 100% of the aggregate net cash proceeds 
     received by the Company as capital contributions to the Company or from 
     the issue or sale after the date of this Indenture of Equity Interests 
     of the Company or of debt securities of the Company that have been 
     converted into such Equity Interests (other than Equity Interests (or 
     convertible debt securities) sold to a Subsidiary or an Unrestricted 
     Subsidiary of the Company and other than Disqualified Stock or 


                                     -43-

<PAGE>

     debt securities that have been converted into Disqualified Stock), 
     except for Capital Stock of the Company issued contemporaneously with 
     the issuance of the Notes.

     The foregoing clauses (b) and (c), however, will not prohibit (i) the 
payment of any dividend within 60 days after the date of declaration thereof, 
if at said date of declaration such payment would have complied with the 
provisions of this Indenture; (ii) the payment of any dividend on Equity 
Interests of the Company (other than Disqualified Stock) payable solely in 
shares of Equity Interests of the Company (other than Disqualified Stock);  
(iii) any dividend or other distribution payable from a Subsidiary of the 
Company to the Company or any Wholly Owned Subsidiary; (iv) the making of any 
Restricted Investment in exchange for, or out of the proceeds of, the 
substantially concurrent sale, issuance or exchange (other than to a 
Subsidiary or any Unrestricted Subsidiary of the Company) of Equity Interests 
of the Company (other than Disqualified Stock); PROVIDED, that any net cash 
proceeds that are utilized for any such Restricted Investment shall be 
excluded from clause (c) of the preceding paragraph; (v) the redemption, 
repurchase, retirement or other acquisition of any Equity Interests of the 
Company in exchange for, or out of the proceeds of, the substantially 
concurrent sale, issuance or exchange (other than to a Subsidiary or any 
Unrestricted Subsidiary of the Company) of other Equity Interests of the 
Company (other than any Disqualified Stock); PROVIDED that any net cash 
proceeds that are utilized for any such redemption, repurchase, retirement or 
other acquisition shall be excluded from clause (c) of the preceding 
paragraph; and (vi) the defeasance, redemption or repurchase of any PARI 
PASSU Indebtedness prior to a scheduled mandatory sinking fund payment date 
or maturity date thereof with the net cash proceeds from an incurrence of 
Permitted Refinancing Indebtedness or the substantially concurrent sale 
(other than to a Subsidiary or any Unrestricted Subsidiary of the Company) of 
Equity Interests of the Company (other than Disqualified Stock) or the 
purchase, redemption or acquisition by the Company of any PARI PASSU 
Indebtedness prior to a scheduled mandatory sinking fund payment date or 
maturity date thereof through the issuance in exchange thereof of Equity 
Interests of the Company (other than Disqualified Stock); PROVIDED, that any 
net cash proceeds that are utilized for any such defeasance, redemption or 
repurchase, purchase or acquisition shall be excluded from clause (c) of the 
preceding paragraph.

     The amount of all Restricted Payments (other than cash) shall be the 
fair market value (evidenced by a resolution of the Board of Directors set 
forth in an Officers' Certificate delivered to the Trustee) on the date of 
the Restricted Payment of the asset(s) proposed to be transferred by the 
Company or such Subsidiary, as the case may be, pursuant to the Restricted 
Payment.  Not later than the date of making any Restricted Payment, the 
Company shall deliver to the Trustee an Officers' Certificate of the Company 
stating that such Restricted Payment is permitted and setting forth the basis 
upon which the calculations required by this Section 4.11 were computed, 
which calculations may be based upon the Company's latest available financial 
statements.

     SECTION 4.12.  INCURRENCE OF INDEBTEDNESS AND ISSUANCE OF PREFERRED 
STOCK. (a)  The Company shall not, and shall not permit any of its 
Subsidiaries to, directly or indirectly, create, incur, issue, assume, 
guarantee or otherwise become directly or indirectly liable, contingently or 
otherwise, with respect to (collectively, "incur") any Indebtedness 
(including Acquired Indebtedness) and the Company shall not issue any 
Disqualified Stock and shall not permit any of its Subsidiaries to issue any 
shares of preferred stock; PROVIDED, HOWEVER, that the Company may incur 
Indebtedness (including Acquired Indebtedness) and the Company may issue 
shares of Disqualified Stock if:  (i) the Consolidated Interest Coverage 
Ratio for the Company's most recently ended four full fiscal quarters for 
which internal financial statements are available immediately preceding the 
date on which 


                                     -44-

<PAGE>


such additional Indebtedness is incurred or such Disqualified Stock is issued 
would have been at least, during the period from the date of this Indenture 
until the first anniversary thereof, 2.25 to 1, and thereafter, 2.50 to 1, 
determined on a pro forma basis (including a pro forma application of the net 
proceeds therefrom), as if the additional Indebtedness had been incurred, or 
the Disqualified Stock had been issued, as the case may be, at the beginning 
of such four-quarter period; (ii) the Adjusted Consolidated Net Tangible 
Assets would have been at least 150% of Consolidated Indebtedness, determined 
on a pro forma basis (including a pro forma application of the net proceeds 
therefrom) and (iii) no Default or Event of Default shall have occurred and 
be continuing or would occur as a consequence thereof; PROVIDED, that no 
Guarantee may be incurred pursuant to this paragraph, unless the guaranteed 
Indebtedness is incurred by the Company or a Subsidiary pursuant to this 
paragraph.

     (b)  The foregoing provisions will not apply to:

          (i)  the incurrence by the Company of Indebtedness under the Credit 
     Facility (and the incurrence by Subsidiaries of Guarantees thereof) in 
     an aggregate principal amount at any time outstanding (with letters of 
     credit being deemed to have a principal amount equal to the maximum 
     potential liability of the Company and its Subsidiaries thereunder) not 
     to exceed $50 million, less the aggregate amount of all Net Proceeds of 
     Asset Sales applied to permanently reduce the outstanding amount or the 
     commitments with respect to such Indebtedness pursuant to Section 4.08 
     hereof;

          (ii)   the incurrence by the Company of Indebtedness represented by 
     the Notes and of its Subsidiaries of Indebtedness represented by the 
     Subsidiary Guarantees;

          (iii)   the incurrence by the Company or any of its Subsidiaries of 
     Permitted Refinancing Indebtedness in exchange for, or the net proceeds 
     of which are used to extend, refinance, renew, replace, defease or 
     refund, any Indebtedness described in Section 4.12(b)(ii) hereof;

          (iv)  the incurrence by the Company or any of its Subsidiaries of 
     intercompany Indebtedness between or among the Company and any of its 
     Wholly Owned Subsidiaries or between or among any Wholly Owned 
     Subsidiaries; PROVIDED that, in the case of Indebtedness of the Company, 
     such obligations shall be unsecured and subordinated in case of an event 
     of default in all respects to the Company's obligations pursuant to the 
     Notes; and PROVIDED, HOWEVER, that (i) any subsequent issuance or 
     transfer of Equity Interests that results in any such Indebtedness being 
     held by a Person other than a Wholly Owned Subsidiary of the Company and 
     (ii) any sale or other transfer of any such Indebtedness to a Person 
     that is not either the Company or a Wholly Owned Subsidiary of the 
     Company shall be deemed, in each case, to constitute an incurrence of 
     such Indebtedness by the Company or such Subsidiary, as the case may be;

          (v)  the incurrence by the Company or Hedging Obligations that are 
     incurred for the purpose of fixing or hedging interest rate risk with 
     respect to any floating rate Indebtedness that is permitted by this 
     Indenture to be incurred; PROVIDED that the notional amount 


                                     -45-

<PAGE>

     of such Hedging Obligations does not exceed the principal amount of the 
     Indebtedness to which such Hedging Obligations relate;

          (vi)  the incurrence by the Company of Hedging Obligations under 
     commodity hedging and currency exchange agreements; PROVIDED that such 
     agreements were entered into in the ordinary course of business for the 
     purpose of limiting risks that arise in the ordinary course of business; 
     and

          (vii)  the incurrence by the Company and its Subsidiaries of 
     Indebtedness (in addition to Indebtedness permitted by any other clause 
     of this Section 4.12) in an aggregate principal amount at any time 
     outstanding not to exceed $10 million.

     SECTION 4.13.  LIENS.  The Company shall not, and shall not permit any 
of its Subsidiaries to, directly or indirectly, create, incur, assume or 
suffer to exist any Lien (other than Permitted Liens but only to the extent 
securing obligations not constituting Indebtedness) on any of its assets, now 
owned or hereafter acquired, securing any Indebtedness other than Senior 
Indebtedness, unless the Notes are secured equally and ratably with such 
other Indebtedness; PROVIDED that, if such Indebtedness is by its terms 
expressly subordinate to the Notes, the Lien securing such subordinate or 
junior Indebtedness shall be subordinate and junior to the Lien securing the 
Notes with the same relative priority as such subordinated or junior 
Indebtedness shall have with respect to the Notes.

     SECTION 4.14.  DIVIDENDS AND OTHER PAYMENT RESTRICTIONS AFFECTING 
SUBSIDIARIES.  The Company shall not, and shall not permit any of its 
Subsidiaries to, directly or indirectly, create or otherwise cause or suffer 
to exist or become effective any encumbrance or restriction on the ability of 
any Subsidiary to (i)(a) pay dividends or make any other distributions to the 
Company or any of its Subsidiaries on its Capital Stock or with respect to 
any other interest or participation in, or measured by, its profits, or (b) 
pay any indebtedness owed to the Company or any of its Subsidiaries, (ii) 
make loans or advances to the Company or any of its Subsidiaries, (iii) 
transfer any of its properties or assets to the Company or any of its 
Subsidiaries, (iv) transfer any of its property or assets to the Company or 
any of its Subsidiaries, (v) grant liens or security interests on the assets 
in favor of the Holders of Notes, or (vi) guarantee the Notes or any renewals 
or refinancings thereof, except for such encumbrances or restrictions 
existing under or by reason of (A) the Credit Facility, this Indenture and 
the Note, (B) applicable law, (C) any instrument governing Acquired 
Indebtedness or Capital Stock of a Person acquired by the Company or any of 
its Subsidiaries as in effect at the time of such acquisition (except to the 
extent such Acquired Indebtedness was incurred in connection with or in 
contemplation of such acquisition), which encumbrance or restriction is not 
applicable to any Person, or the properties or assets of any Person, other 
than the Person, or the property or assets of the Person, so acquired, 
PROVIDED that the Consolidated EBITDA of such Person is not taken into 
account in determining whether such acquisition was permitted by the terms of 
this Indenture, or (D) Permitted Refinancing Indebtedness, PROVIDED that the 
restrictions contained in the agreements governing such Permitted Refinancing 
Indebtedness are no more restrictive than those contained in the agreements 
governing the Indebtedness being refinanced.


                                     -46-

<PAGE>

     SECTION 4.15.  LIMITATION ON LAYERING DEBT.  The Company shall not 
incur, create, issue, assume, guarantee or otherwise become liable for any 
Indebtedness that is subordinate or junior in right of payment to any Senior 
Indebtedness and senior in any respect in right of payment of the Notes.

     SECTION 4.16.  TRANSACTIONS WITH AFFILIATES.  The Company shall not, and 
shall not permit any of its Subsidiaries to, after the date of this 
Indenture, sell, lease, transfer or otherwise dispose of any of its 
properties or assets to, or make any payment to, or purchase any property or 
assets from, or enter into or suffer to exist any transaction or series of 
transactions, or make any agreement, loan, advance or guarantee with, or for 
the benefit of, any Affiliate (each of the foregoing, an "Affiliate 
Transaction"), other than Exempt Affiliate Transactions, unless (i) such 
Affiliate Transaction is on terms that are no less favorable to the Company 
or the relevant Subsidiary (as reasonably determined by the Company) than 
those that would have been obtained in a comparable transaction by the 
Company or such Subsidiary with an unrelated Person and (ii) the Company 
delivers to the Trustee (a) with respect to any Affiliate Transaction entered 
into after the date of this Indenture involving aggregate consideration in 
excess of $10 million, a resolution of the Board of Directors set forth in an 
Officers' Certificate certifying that such Affiliate Transaction complies 
with clause (i) above and that such Affiliate Transaction has been approved 
by a majority of the disinterested members of the Board of Directors and (b) 
with respect to any Affiliate Transaction involving aggregate consideration 
in excess of $5.0 million, an opinion as to the fairness to the Company or 
such Subsidiary of such Affiliate Transaction from a financial point of view 
issued by an investment banking firm of national standing.

     SECTION 4.17.  REPORTS.  Whether or not required by the rules and 
regulations of the Commission, so long as any Notes are outstanding, the 
Company shall furnish to the Holders of Notes, and file with the Trustee, 
within 15 days after it is, or would have been, required to file such with 
the Commission (i) all quarterly and annual financial information that is or 
would be required to be contained in a filing with the Commission on Forms 
10-Q and 10-K if the Company is or were required to file such Forms, 
including a "Management's Discussion and Analysis of Financial Condition and 
Results of Operations" and, with respect to the annual information only, a 
report thereon by the Company's certified independent accountants and (ii) 
all current reports that are or would be required to be filed with the 
Commission on Form 8-K if the Company is or were required to file such 
reports.  In addition, whether or not required by the rules and regulations 
of the Commission, the Company shall file a copy of all such information and 
reports with the Commission for public availability (unless the Commission 
will not accept such a filing) and make such information available to 
securities analysts and prospective investors upon written request.

     Delivery of such reports, information and documents to the Trustee is 
for informational purposes only and the Trustee's receipt of such shall not 
constitute constructive notice of any information contained therein or 
determinable from information contained therein, including the Company's 
compliance with any of its covenants hereunder (as to which the Trustee is 
entitled to rely exclusively on Officers' Certificates).


                                     -47-

<PAGE>

     SECTION 4.18.  WAIVER OF STAY, EXTENSION OR USURY LAWS.  Each of the 
Company and the Subsidiary Guarantors covenants (to the extent that it may 
lawfully do so) that it will not at any time insist upon, or plead, or in any 
manner whatsoever claim or take the benefit or advantage of, any stay or 
extension law or any usury law or other law that would prohibit or forgive 
the Company or such Subsidiary Guarantor from paying all or any portion of 
the principal of or premium, if any, or interest on the Notes as contemplated 
herein, wherever enacted, now or at any time hereafter in force, or that may 
affect the covenants or the performance of this Indenture; and (to the extent 
that it may lawfully do so) the Company or such Subsidiary Guarantor hereby 
expressly waives all benefit or advantage of any such law and covenants that 
it will not hinder, delay or impede the execution of any power herein granted 
to the Trustee, but will suffer and permit the execution of every such power 
as though no such law had been enacted.

     SECTION 4.19.  COMPLIANCE CERTIFICATE; NOTICE OF DEFAULT OR EVENT OF 
DEFAULT. (a)  The Company shall deliver to the Trustee within 120 calendar 
days after the end of each fiscal year of the Company ending after the date 
hereof, an Officers' Certificate stating whether or not, to the best 
knowledge of such officer, the Company has complied with all conditions and 
covenants under this Indenture, and, if the Company shall be in Default, 
specifying all such Defaults and the nature thereof of which such officer may 
have knowledge.

     For the purposes of this Section 4.19(a), compliance shall be determined 
without regard to any period of grace or requirement of notice under this 
Indenture.

     (b)  The Company shall deliver written notice to the Trustee immediately 
upon any executive officer of the Company becoming aware of the occurrence of 
any event which constitutes, or with the giving of notice or the lapse of 
time or both would constitute, a Default or Event of Default, describing such 
Default or Event of Default, its status and what action the Company is taking 
or proposes to take with respect thereto.

     (c)  So long as not contrary to the then-current recommendations of the 
American Instituted of Certified Public Accountants, the year-end financial 
statements delivered pursuant to Section 4.17 hereof shall be accompanied by 
a written statement of the Company's independent public accountants (who 
shall be a firm of established national reputation) that in making the 
examination necessary for certification of such financial statements, nothing 
has come to their attention that would lead them to believe that the Company 
has violated any provisions of Article IV or Article V hereof or, if any such 
violation has occurred, specifying the nature and period of existence 
thereof, it being understood that such accountants shall not be liable 
directly or indirectly to any Person for any failure to obtain knowledge of 
any such violation.

     SECTION 4.20.  INVESTMENT COMPANY ACT.  None of the Company or the 
Subsidiaries or Unrestricted Subsidiaries of the Company shall become an 
investment company subject to registration under the Investment Company Act 
of 1940, as amended.


                                     -48-

<PAGE>

     SECTION 4.21.  SALE AND LEASEBACK.  The Company will not, and will not 
permit any of its Subsidiaries to, enter into any Sale and Leaseback 
Transaction unless (a) the Company or its Subsidiaries entering into such 
Sale and Leaseback Transaction could have incurred the Indebtedness relating 
to such Sale and Leaseback Transaction pursuant to Sections 4.12 and 4.13 and 
(b) the Net Proceeds of such Sale and Leaseback Transaction are at least 
equal to the fair market value of such property as determined by the Board of 
Directors of the Company.

     SECTION 4.22.  FURTHER INSTRUMENTS AND ACTS.  Upon request of the 
Trustee, the Company shall execute and deliver such further instruments and 
do such further acts as may be reasonably necessary or proper to carry out 
more effectively the purpose of this Indenture.

                                  ARTICLE V

                            CONSOLIDATION, MERGER,
                         CONVEYANCE, LEASE OR TRANSFER

     SECTION 5.1.  MERGER, CONSOLIDATION OR SALE OF ASSETS.  The Company 
shall not, and shall not permit any Subsidiary to, in a single transaction or 
series of related transactions consolidate or merge with or into (other than 
the consolidation or merger of a Wholly Owned Subsidiary of the Company with 
another Wholly Owned Subsidiary of the Company or into the Company) (whether 
or not the Company or such Subsidiary is the surviving corporation), or 
directly and/or indirectly through its Subsidiaries sell, assign, transfer, 
lease, convey or otherwise dispose of all or substantially all of its 
properties or assets (determined on a consolidated basis for the Company and 
its Subsidiaries taken as a whole) in one or more related transactions to, 
another corporation, Person or entity unless (i) either (a) the Company, in 
the case of a transaction involving the Company, or such Subsidiary, in the 
case of a transaction involving a Subsidiary, is the surviving corporation or 
(b) in the case of a transaction involving the Company, the entity or the 
Person formed by or surviving any such consolidation or merger (if other than 
the Company) or to which such sale, assignment, transfer, lease, conveyance 
or other disposition shall have been made is a corporation organized or 
existing under the laws of the United States, any state thereof or the 
District of Columbia and assumes all the obligations of the Company under the 
Notes and this Indenture pursuant to a supplemental indenture in a form 
reasonably satisfactory to the Trustee; (ii) immediately after such 
transaction no Default or Event of Default exists; and (iii) the Company or, 
if other than the Company, the entity or Person formed by or surviving any 
such consolidation or merger, or to which such sale, assignment, transfer, 
lease, conveyance or other disposition shall have been made (A) will have 
Consolidated Net Worth immediately after the transaction equal to or greater 
than the Consolidated Net Worth of the Company immediately preceding the 
transaction and (B) will, at the time of such transaction and after giving 
pro forma effect thereto as if such transaction had occurred at the beginning 
of the applicable four-quarter period, be permitted to incur at least $1.00 
of additional Indebtedness pursuant to the Consolidated Interest Coverage 
Ratio and the Adjusted Consolidated Net Tangible Assets to Consolidated 
Indebtedness Ratio tests set forth in Section 4.12(a) hereof.


                                     -49-


<PAGE>

     In connection with any consolidation, merger, conveyance, lease or other 
disposition contemplated by this Section 5.01, the Company shall deliver, or 
cause to be delivered, to the Trustee, in form reasonably satisfactory to the 
Trustee, an Officers' Certificate of the Company and an Opinion of Counsel of 
the Company, each stating that such consolidation, merger, conveyance, lease 
or disposition and any supplemental indenture in respect thereto comply with 
this Section 5.01 and that all conditions precedent herein provided for 
relating to such transaction have been complied with.

     SECTION 5.2.  SUCCESSOR CORPORATION SUBSTITUTED.  Upon any consolidation 
with, or merger by the Company with and into, any other corporation, or any 
sale, assignment, transfer, lease, conveyance or other disposition of all or 
substantially all of the Property of the Company and its Subsidiaries taken 
as a whole in accordance with Section 5.01 hereof, the successor corporation 
formed by such consolidation or into which the Company is merged, or the 
Person to which such sale, conveyance, assignment, transfer, lease, 
conveyance or other disposition is made, shall succeed to, and be substituted 
for, and may exercise every right and power of, the Company under this 
Indenture with the same effect as if such successor Person has been named as 
the Company herein; and thereafter the predecessor corporation shall be 
relieved of all obligations and covenants under this Indenture and the Notes, 
EXCEPT for the obligation to pay the principal of (and premium, if any) and 
interest on the Notes.

                                  ARTICLE VI

                             DEFAULTS AND REMEDIES

     SECTION 6.1.  EVENTS OF DEFAULT.  "Event of Default," wherever used 
herein with respect to the Notes, means any one of the following events 
(whatever the reason for such event, and whether it shall be voluntary or 
involuntary, or be effected by operation of law, pursuant to any judgment, 
decree or order of any court or any order, rule or regulation of any 
administrative or governmental body):

          (a)  The Company or any Subsidiary Guarantor fails to make any 
     payment of interest on any Note when the same becomes due and payable 
     and such failure continues for a period of 30 calendar days, whether or 
     not such payment is prohibited by the provisions of Articles X or XI 
     hereof; or

          (b)  The Company or any Subsidiary Guarantor fails to make any 
     payment of the principal or of premium, if any, on any Note when the 
     same becomes due and payable whether upon maturity, redemption, required 
     repurchase or otherwise, whether or not such payment is prohibited by 
     the provisions of Articles X or XI hereof; or

          (c)  the Company or any Subsidiary fails to observe or perform any 
     covenant, condition or agreement on the part of the Company to be 
     observed or performed pursuant to Section 4.07, 4.08, 4.09, 4.11 or 4.12 
     hereof or Article V hereof; or


                                     -50-

<PAGE>

          (d)  the Company or any Subsidiary fails to comply with any of its 
     other agreements or covenants in, or provisions of, the Notes or this 
     Indenture and such failure continues for the period and after the notice 
     specified below; or

          (e)  a default occurs under any mortgage, indenture or instrument 
     under which there may be issued or by which there may be secured or 
     evidenced any Indebtedness for money borrowed by the Company or any of 
     its Subsidiaries (or the payment of which is Guaranteed by the Company 
     or any of its Subsidiaries), whether such Indebtedness or Guarantee now 
     exists or shall be created after the date of this Indenture, which 
     default (i) is caused by a failure to pay principal of such Indebtedness 
     at final maturity thereof (a "Payment Default) or (ii) results in the 
     acceleration of such Indebtedness prior to its express maturity and, in 
     each case, the principal amount of such Indebtedness, together with the 
     principal amount of any other Indebtedness as to which there has been a 
     Payment Default or the maturity of which has been so accelerated, 
     aggregates $10.0 million or more; or

          (f)  a final judgment or final judgments for the payment of money 
     not fully covered by insurance are entered by a court or courts of 
     competent jurisdiction against the Company or any of its Subsidiaries 
     and such judgment or judgments remain undischarged for a period (during 
     which execution shall not be effectively stayed) of 60 days, PROVIDED 
     that the aggregate of all such undischarged judgments exceeds $1.0 
     million; or

          (g)  the entry by a court having jurisdiction in the premises of 
     (i) a decree or order for relief in respect of the Company or any 
     Subsidiary of the Company in an involuntary case or proceeding under 
     United States bankruptcy laws, as now or hereafter constituted, or any 
     other applicable Federal, state, or foreign bankruptcy, insolvency, or 
     other similar law or (ii) a decree or order adjudging the Company or any 
     Subsidiary of the Company a bankrupt or insolvent, or approving as 
     properly filed a petition seeking reorganization, arrangement, 
     adjustment or composition of, or in respect of, the Company or any 
     Subsidiary of the Company under United States bankruptcy laws, as now or 
     hereafter constituted, or any other applicable Federal, state or foreign 
     bankruptcy, insolvency, or similar law, or appointing a custodian, 
     receiver, liquidator, assignee, trustee, sequestrator or other similar 
     official of the Company or any Subsidiary of the Company or of any 
     substantial part of the Property of the Company or any Subsidiary of the 
     Company, or ordering the winding-up or liquidation of the affairs of the 
     Company or any Subsidiary of the Company, and the continuance of  any 
     such decree or order for relief or any such other decree or order 
     unstayed and in effect for a period of 60 consecutive calendar days; or

          (h)  (i) the commencement by the Company or any Subsidiary of the 
     Company of a voluntary case or proceeding under United States bankruptcy 
     laws, as now or hereafter constituted, or any other applicable Federal, 
     state, or foreign bankruptcy, insolvency or other similar law or of any 
     other case or proceeding to be adjudicated a bankrupt or insolvent; or 
     (ii) the consent by the Company or any Subsidiary of the Company to the 
     entry of a decree or order for relief in respect of the Company or any 
     Subsidiary or Unrestricted Subsidiary of the Company 


                                     -51-

<PAGE>


     in an involuntary case or proceeding under United States bankruptcy 
     laws, as now or hereafter constituted, or any other applicable Federal, 
     state, or foreign bankruptcy, insolvency, or other similar law or to the 
     commencement of any bankruptcy or insolvency case or proceeding against 
     the Company or any Subsidiary of the Company; or (iii) the filing by the 
     Company or any Subsidiary of the Company of a petition or answer or 
     consent seeking reorganization or relief under United States bankruptcy 
     laws, as now or hereafter constituted, or any other applicable Federal, 
     state or foreign bankruptcy, insolvency or other similar law; or (iv) 
     the consent by the Company or any Subsidiary of the Company to the 
     filing of such petition or to the appointment of or taking possession by 
     a custodian, receiver, liquidator, assignee, trustee, sequestrator or 
     similar official of the Company or any Subsidiary of the Company or of 
     any substantial part of the Property of the Company or any Subsidiary of 
     the Company, or the making by the Company or any Subsidiary of the 
     Company of an assignment for the benefit of creditors; or (v) the 
     admission by the Company or any Subsidiary of the Company in writing of 
     its inability to pay its debts generally as they become due; or (vi) the 
     taking of corporate action by the Company or any Subsidiary of the 
     Company in furtherance of any such action; or

          (i)  any Subsidiary Guarantee or any provision thereof shall at any 
     time cease to be the legal, valid and binding obligation of the 
     Subsidiary Guarantor party thereto as represented in the Subsidiary 
     Guarantee, such that the Holders of the Notes could not reasonably be 
     expected to realize the material benefits intended to be provided by 
     such Subsidiary Guarantor under the Subsidiary Guarantee or any 
     Subsidiary Guarantor shall assert that the Subsidiary Guarantee is not a 
     legal, valid and binding obligation or shall purport to revoke its 
     obligations thereunder.

     A Default under clause (d) is not an Event of Default until the Trustee 
notifies the Company, or the Holders of at least 25% in principal amount of 
the then outstanding Notes notify the Company and the Trustee, of the Default 
and the Company does not cure the Default within 60 calendar days after 
receipt of the notice. The notice must specify the Default, demand that it be 
remedied and state that the notice is a "Notice of Default".

     SECTION 6.2.  ACCELERATION.  If an Event of Default (other than an Event 
of Default specified in Section 6. 01(g) or Section 6.01(h)) occurs and is 
continuing, then and in every such case the Trustee by notice to the Company, 
or the Holders of at least 25% in principal amount of the then outstanding 
Notes by written notice to the Company and the Trustee may declare the unpaid 
principal of and any accrued interest on all the Notes then outstanding to be 
immediately due and payable.  Upon such declaration the principal and 
interest shall be due and payable immediately (together with any premium, if 
applicable).  If an Event of Default specified in Section 6.01(g) or Section 
6.01(h) occurs, such an amount shall IPSO FACTO become and be immediately due 
and payable without any declaration or other act on the part of the Trustee 
or any Holder.

     The Holders of a majority in principal amount of the then outstanding 
Notes by written notice to the Trustee may rescind an acceleration and its 
consequences if the rescission would not conflict with any judgment or decree 
and if all existing Events of Default (except nonpayment of principal, 
interest or premium that have become due solely because of the acceleration) 
have been cured or 


                                     -52-

<PAGE>

waived.  No such recession shall affect any subsequent Default or impair any 
right consequent thereon.

     SECTION 6.3.  OTHER REMEDIES.  The Company covenants that if an Event of 
Default specified in Section 6.01(a) or Section 6.01(b) occurs the Company 
shall, upon demand of the Trustee, pay to the Trustee, for the benefit of the 
Holders, the whole amount then due and payable  on the Notes for principal 
(and premium, if any) and interest and, to the extent that payment of such 
interest shall be legally enforceable, interest upon the overdue principal 
(and premium, if any) and upon Defaulted Interest at the rate or rates 
prescribed therefor in such Notes; and, in addition thereto, such further 
amount as shall be sufficient to cover the costs and expenses of collection, 
including the reasonable compensation, expenses, disbursements and advances 
of the Trustee, its agents and counsel and all other amounts due to the 
Trustee pursuant to Section 7.07 hereof.

     If the Company fails to pay such amounts forthwith upon such demand, the 
Trustee, in its own name and as trustee of an express trust, may institute a 
judicial proceeding for the collection of the sums so due and unpaid, and may 
prosecute such proceeding to judgment or final decree, and may enforce the 
same against the Company or any other obligor upon such Notes and collect the 
moneys adjudged or decreed to be payable in the manner provided by law out of 
the Property of the Company or any other obligor upon such Notes, wherever 
situated.

     If an Event of Default with respect to the Notes occurs and is 
continuing, the Trustee may in its discretion proceed to protect and enforce 
its rights and the rights of the Holders by such appropriate judicial 
proceedings as the Trustee shall deem most effectual to protect and enforce 
any such rights, whether for the specific enforcement of any covenant or 
agreement in this Indenture or in aid of the exercise of any power granted 
herein, or to enforce any other proper remedy.

     SECTION 6.4.  WAIVER OF PAST DEFAULTS.  The Holders of not less than a 
majority in principal amount of the outstanding Notes may, on behalf of the 
Holders of all the Notes, waive any past Default and its consequences under 
this Article VI, except Default (a) in the payment of the principal of (or 
premium, if any) or interest on, any Note (except a payment default resulting 
from an acceleration that has been rescinded), or (b) in respect of a 
covenant or provision hereof which under Section 9.02 hereof cannot be 
modified or amended without the consent of the Holder of each outstanding 
Note affected.  Any such waiver may (but need not) be given in connection 
with a tender offer or exchange offer for the Notes.

     SECTION 6.5.  CONTROL BY MAJORITY.  The Holders of not less than a 
majority in principal amount of the outstanding Notes shall have the right to 
direct the time, method and place of conducting any proceeding for any remedy 
available to the Trustee or exercising any trust or power conferred on the 
Trustee; PROVIDED that:


                                     -53-

<PAGE>

          (a)  such direction shall not be in conflict with any rule of law 
     or with this Indenture or unduly prejudicial to the rights of other 
     Holders and would not subject the Trustee to personal liability, and

          (b)  the Trustee may take any other action deemed proper by the 
     Trustee which is not inconsistent with such direction.

     SECTION 6.6.  LIMITATION ON SUITS.  No Holder of Notes shall have any 
right to institute any proceeding, judicial or otherwise, with respect to 
this Indenture, or for the appointment of a receiver or trustee, or for any 
other remedy hereunder, unless

          (a)  such Holder has previously given written notice to the Trustee 
     of a continuing Event of Default with respect to the Notes;

          (b)  the Holders of not less than 25 percent in principal amount of 
     the outstanding Notes shall have made written request to the Trustee to 
     institute proceedings in respect of such Event of Default in its own 
     name as Trustee hereunder;

          (c)  such Holder or Holders have offered to the Trustee security or 
     indemnity satisfactory to the Trustee in its reasonable discretion 
     against the costs, expenses and liabilities to be incurred in compliance 
     with such request;

          (d)  the Trustee for 30 calendar days after its receipt of such 
     notice, request and offer of indemnity has failed to institute any such 
     proceeding; and 

          (e)  no direction inconsistent with such written request has been 
     given to the Trustee during such 30-day period by the Holders of a 
     majority in principal amount of the outstanding Notes;

in any event, it being understood and intended that no one or more Holders of 
Notes shall have any right in any manner whatever by virtue of, or by 
availing of, any provision of this Indenture to affect, disturb or prejudice 
the rights of any other Holders of Notes, or to obtain or to seek to obtain 
priority or preference over any other of such Holders or to enforce any right 
under this Indenture, except in the manner herein provided and for the equal 
and ratable benefit of all Holders of Notes.

     SECTION 6.7.  RIGHTS OF HOLDERS TO RECEIVE PAYMENT.  Notwithstanding any 
other provision of this Indenture, the right of any Holder to receive payment 
of principal of (premium, if any) and interest on the Notes held by such 
Holder, on or after the respective due dates expressed in the Notes or the 
redemption dates or purchase dates provided for therein, or to bring suit for 
the enforcement of any such payment on or after such respective dates, shall 
be absolute and unconditional and shall not be impaired or affected without 
the consent of such Holder.


                                     -54-

<PAGE>

     SECTION 6.8.  TRUSTEE MAY FILE PROOFS OF CLAIM.  In case of the pendency 
of any receivership, insolvency, liquidation, bankruptcy, reorganization, 
arrangement, adjustment, composition or other judicial proceedings, or any 
voluntary or involuntary case under United States bankruptcy laws, as now or 
hereafter constituted, relative to the Company, any Subsidiary Guarantor or 
any other obligor upon the Notes or the Property of the Company, any 
Subsidiary Guarantor or of such other obligor or their creditors, the Trustee 
(irrespective of whether the principal of such Notes shall then be due and 
payable as therein expressed or by declaration or otherwise and irrespective 
of whether the Trustee shall have made any demand on the Company or any 
Subsidiary Guarantor for the payment of overdue principal or interest) shall 
be entitled and empowered, by intervention in such proceeding or otherwise, 
(i) to file and prove a claim for the whole amount of principal (and premium, 
if any) and interest owing and unpaid in respect of the Notes, to file such 
other papers or documents and to take such other actions, including 
participating as a member or otherwise in any official committee of creditors 
appointed in the matter, as may be necessary or advisable in order to have 
the claims of the Trustee (including any claim for the reasonable 
compensation, expenses, disbursements and advances of the Trustee, its agents 
and counsel and all other amounts due to the Trustee pursuant to Section 7.07 
hereof) and of the Holders allowed in such judicial proceeding, and (ii) to 
collect and receive any moneys or other Property payable or deliverable on 
any such claims and to distribute the same; and any receiver, assignee, 
trustee, custodian, liquidator, sequestrator (or other similar official) in 
any such proceeding is hereby authorized by each Holder to make such payments 
to the Trustee, and in the event that the Trustee shall consent to the making 
of such payments directly to the Holders, to pay to the Trustee any amount 
due it for the reasonable compensation, expenses, disbursements and advances 
of the Trustee, its agents and counsel, and any other amounts due the Trustee 
under Section 7.07 hereof.  Nothing contained herein shall be deemed to 
authorize the Trustee to authorize or consent to or accept or adopt on behalf 
of any Holder any plan of reorganization, arrangement, adjustment or 
composition affecting the Notes or the rights of any Holder thereof, or to 
authorize the Trustee to vote in respect of the claim of any Holder in any 
such proceeding.

     SECTION 6.9.  PRIORITIES.  Any money collected by the Trustee pursuant 
to this Article VI shall be applied in the following order, at the date or 
dates fixed by the Trustee and, in case of the distribution of such money on 
account of principal (premium, if any) or interest upon presentation of the 
Notes and the notation thereon of the payment if only partially paid and upon 
surrender thereof if fully paid:

          (a)  FIRST: To the payment of all amounts due the Trustee under 
     Section 7.07 hereof;

          (b)  SECOND: To the payment of the amounts then due and unpaid for 
     principal of (and premium, if any) and interest on the Notes, ratably, 
     without preference or priority of any kind, according to the amounts due 
     and payable on such Notes for principal (and premium, if any) and 
     interest, respectively; and

          (c)  THIRD: To the Company.


                                     -55-

<PAGE>

     The Trustee may fix a record date and payment date for any payment to 
Holders pursuant to this Section 6.09. At least 15 calendar days before such 
record date, the Company shall mail to each Holder and the Trustee a notice 
that states such record date, the payment date and amount to be paid.  The 
Trustee may mail such notice in the name and at the expense of the Company.

     SECTION 6.10.  UNDERTAKING FOR COSTS.  All parties to this Indenture 
agree, and each Holder of any Note by such Holder's acceptance thereof shall 
be deemed to have agreed, that any court may in its discretion require, in 
any suit for the enforcement of any right or remedy under this Indenture, or 
in any suit against the Trustee for any action taken, suffered or omitted by 
it as Trustee, the filing by any party litigant in such suit of an 
undertaking to pay the costs of such suit and that such court may in its 
discretion assess reasonable costs, including reasonable attorneys' fees and 
expenses, against any party litigant in such suit, having due regard to the 
merits and good faith of the claims or defenses made by such party litigant; 
but the provisions of this Section shall not apply to any suit instituted by 
the Trustee, to any suit instituted by any Holder, or group of Holders, 
holding in the aggregate more than 10 percent in principal amount of the 
outstanding Notes, or to any suit instituted by any Holder for the 
enforcement of the payment of the principal of (or premium, if any) or 
interest on any Note on or after its Stated Maturity.

     SECTION 6.11.  WAIVER OF STAY OR EXTENSION LAWS.  The Company and the 
Subsidiary Guarantors (to the extent it or they may lawfully do so) shall not 
at any time insist upon, or plead, or in any manner whatsoever claim or take 
the benefit or advantage of, any stay or extension law wherever enacted, now 
or at any time hereafter in force, which may affect the covenants or the 
performance of this Indenture; and the Company and the Subsidiary Guarantors 
(to the extent that it or they may lawfully do so) hereby expressly waives 
all benefit or advantage of any such law, and shall not hinder, delay or 
impede the execution of any power herein granted to the Trustee, but shall 
suffer and permit the execution of every such power as though no such law had 
been enacted.

     SECTION 6.12.  TRUSTEE MAY ENFORCE CLAIMS WITHOUT POSSESSION OF THE 
NOTES.  All rights of action and claims under this Indenture or the Notes may 
be prosecuted and enforced by the Trustee without the possession of any of 
the Notes or the production thereof in any proceeding relating thereto, and 
any such proceeding instituted by the Trustee shall be brought in its own 
name, as trustee of an express trust, and any recovery of judgment shall, 
after provision for the payment of the reasonable compensation, expenses, 
disbursements and advances of the Trustee, its agents and counsel, be for the 
ratable benefit of the Holders of the Notes.

     SECTION 6.13.  RESTORATION OF RIGHTS AND REMEDIES.  If the Trustee or 
any Holder of Notes has instituted any proceeding to enforce any right or 
remedy under this Indenture and such proceeding has been discontinued or 
abandoned for any reason, or has been determined adversely to the Trustee or 
to such Holder, then and in every such case the Company, the Subsidiary 
Guarantors, the Trustee and the Holders shall, subject to any determination 
in such proceeding, be restored severally and respectively to their former 
positions hereunder, and thereafter all rights and remedies of the Trustee 
and the Holders shall continue as though no such proceeding had been 
instituted.


                                     -56-

<PAGE>

     SECTION 6.14.  RIGHTS AND REMEDIES CUMULATIVE.  Except as otherwise 
provided in Section 2.07 hereof, no right or remedy herein conferred upon or 
reserved to the Trustee or to the Holders is intended to be exclusive of any 
other right or remedy, and every right and remedy shall, to the extent 
permitted by law, be cumulative and in addition to every other right and 
remedy given hereunder or now or hereafter existing at law or in equity or 
otherwise.  The assertion or employment of any right or remedy hereunder, or 
otherwise, shall not prevent the concurrent assertion or employment of any 
other appropriate right or remedy.

     SECTION 6.15.  DELAY OR OMISSION NOT WAIVER.  No delay or omission of 
the Trustee or of any Holder of any Note to exercise any right or remedy 
accruing upon any Event of Default shall impair any such right or remedy or 
constitute a waiver of any such Event of Default or an acquiescence therein.  
Every right and remedy given by this Article VI or by law to the Trustee or 
to the Holders may be exercised from time to time, and as often as may be 
deemed expedient, by the Trustee or by the Holders, as the case may be.

                                 ARTICLE VII

                                   TRUSTEE

     SECTION 7.1.  DUTIES OF TRUSTEE. (a)  If an Event of Default has 
occurred and is continuing, the Trustee shall exercise the rights and powers 
vested in it by this Indenture and shall use the same degree of care and 
skill in their exercise as a prudent person would exercise or use under the 
circumstances in the conduct of such person's own affairs.

     (b)  Except during the continuance of an Event of Default:  (i) the 
Trustee undertakes to perform such duties and only such duties as are 
specifically set forth in this Indenture and no implied covenants or 
obligations shall be read into this Indenture against the Trustee; and (ii) 
in the absence of bad faith on its part, the Trustee may conclusively rely, 
as to the truth of the statements and the correctness of the opinions 
expressed therein, upon certificates or opinions furnished to the Trustee and 
conforming to the requirements of this Indenture; PROVIDED that in the case 
of any such certificates or opinions that by any provision of this Indenture 
are specifically required to be furnished to the Trustee, the Trustee shall 
examine such certificates and opinions to determine whether or not they 
conform to the requirements of this Indenture.

     (c)  The Trustee may not be relieved from liability for its own 
negligent action, its own negligent failure to act or its own willful 
misconduct, PROVIDED that: (i) this paragraph (c) shall not limit the effect 
of paragraph (b) of this Section 7.01; (ii) the Trustee shall not be liable 
for any error of judgment made in good faith by a Trust Officer unless it is 
proved that the Trustee was negligent in ascertaining the pertinent facts; 
and (iii) the Trustee shall not be liable with respect to any action it takes 
or omits to take in good faith in accordance with a direction received by it 
pursuant to Section 6.05 hereof.


                                     -57-

<PAGE>

     (d)  The Trustee shall not be liable for interest on any money received 
by it except as the Trustee may agree in writing with the Company.

     (e)  Money held in trust by the Trustee need not be segregated from 
other funds except to the extent required by law.

     (f)  No provision of this Indenture shall require the Trustee to expend 
or risk its own funds or otherwise incur any financial liability in the 
performance of any of its duties hereunder, or in the exercise of any of its 
rights or powers, if it shall have reasonable grounds for believing that 
repayment of such funds or adequate indemnity against such risk of liability 
is not reasonably assured to it.

     (g)  Every provision of this Indenture relating to the conduct or 
affecting the liability of or affording protection to the Trustee shall be 
subject to the provisions of this Article VII and to the provisions of the 
Trust Indenture Act.

     SECTION 7.2.  RIGHTS OF TRUSTEE. (a) The Trustee may rely on any 
document believed by it to be genuine and to have been signed or presented by 
the proper Person.  Except as provided in Section 7.01(b) hereof, the Trustee 
need not investigate any fact or matter stated in the document.

     (b)  Before the Trustee acts or refrains from acting, it may require an 
Officers' Certificate or an Opinion of Counsel.  The Trustee shall not be 
liable for any action it takes or omits to take in good faith in reliance on 
any Officers' Certificate or Opinion of Counsel.

     (c)  The Trustee may act through agents and shall not be responsible for 
the misconduct or negligence of any such agent; PROVIDED that such agent was 
appointed with due care by the Trustee.

     (d)  The Trustee shall not be liable for any action it takes or omits to 
take in good faith which it believes to be authorized or within its rights or 
powers; PROVIDED that the Trustee's conduct does not constitute willful 
misconduct or gross negligence.

     (e)  The Trustee shall not be charged with knowledge of any Default or 
Event of Default under Sections 6.01(c), 6.01(d), 6.01(e) or 6.01(f) hereof, 
of the identity of any Subsidiary or of the existence of any Change of 
Control or Asset Sale unless either (i) a Trust Officer shall have actual 
knowledge thereof, or (ii) the Trustee shall have received notice thereof in 
accordance with Section 12.02 hereof from the Company or any Holder of Notes.

     (f)  The Trustee may consult with counsel of its selection and the 
advice of such counsel or any Opinion of Counsel shall be full and complete 
authorization and protection in respect of any action taken, suffered or 
omitted by it hereunder in good faith and in reliance thereon.

     (g)  The Trustee shall not be bound to make any investigation into the 
facts or matters stated in any resolution, certificate, statement, 
instrument, opinion, report, notice, request, direction, 


                                     -58-

<PAGE>

consent, order, bond, debenture or other paper or document, but the Trustee, 
in its discretion may make such further inquiry or investigation into such 
facts or matters as it may see fit, and, if the Trustee shall determine to 
make such further inquiry or investigation, it shall be entitled to examine 
the books, records and premises of the Company, personally or by agent or 
attorney.

     SECTION 7.3.  INDIVIDUAL RIGHTS OF TRUSTEE.  The Trustee, any Paying 
Agent or Registrar, in its individual or any other capacity, may become the 
owner or pledgee of Notes and may otherwise deal with the Company or its 
Affiliates with the same rights it would have if it were not Trustee, Paying 
Agent or Registrar hereunder, as the case may be; PROVIDED that the Trustee 
must in any event comply with Section 7.10 and Section 7.11 hereof.

     SECTION 7.4.  TRUSTEE'S DISCLAIMER.  The Trustee shall not be 
responsible for and makes no representation as to the validity or adequacy of 
this Indenture or the Notes, it shall not be accountable for the Company's 
use of the proceeds from the Notes, and it shall not be responsible for any 
statement of the Company in this Indenture, including the recitals contained 
herein, or in any document issued in connection with the sale of the Notes or 
in the Notes other than the Trustee's certificate of authentication.

     SECTION 7.5.  NOTICE OF DEFAULTS.  Within 90 calendar days after the 
occurrence of any Default hereunder with respect to the Notes, the Trustee 
shall transmit by mail to all Holders, as their names and addresses appear in 
the Security Register, notice of such Default hereunder known to the Trustee, 
unless such Default shall have been cured or waived, PROVIDED that, except in 
the case of a Default in the payment of the principal of (or premium, if any) 
or interest on any Note, the Trustee shall be protected in withholding such 
notice if and so long as the board of directors, the executive committee or a 
trust committee of directors and/or Trust Officers of the Trustee in good 
faith determine that the withholding of such notice is in the interest of the 
Holders.

     SECTION 7.6.  PRESERVATION OF INFORMATION; REPORTS BY TRUSTEE TO 
HOLDERS. (a) The Company shall furnish or cause to be furnished to the 
Trustee:

          (i)  semiannually, not less than 10 calendar days prior to each 
     Interest Payment Date, a list, in such form as the Trustee may 
     reasonably require, of the names and addresses of the Holders as of the 
     Record Date immediately preceding such Interest Payment Date, and

          (ii)  at such other times as the Trustee may request in writing, 
     within 30 calendar days after the receipt by the Company of any such 
     request, a list of similar form and content as of a date not more than 
     15 calendar days prior to the time such list is furnished;

PROVIDED, HOWEVER, that if and so long as the Trustee shall be the Registrar 
for the Notes, no such list need be furnished with respect to the Notes.

     (b)  The Trustee shall preserve, in as current a form as is reasonably 
practicable, the names and addresses of Holders contained in the most recent 
list furnished to the Trustee as provided in 


                                     -59-

<PAGE>

Section 7.06(a) hereof and the names and addresses of Holders received by the 
Trustee in its capacity as Registrar, if so acting.  The Trustee may destroy 
any list furnished to it as provided in Section 7.06(a) hereof upon receipt 
of a new list so furnished.

     (c)  Holders may communicate as provided in Section 312(b) of the Trust 
Indenture Act with other Holders with respect to their rights under this 
Indenture or under the Notes.

     (d)  Each Holder of Notes, by receiving and holding the same, agrees 
with the Company and the Trustee that neither the Company nor the Trustee 
shall be held accountable by reason of the disclosure of any such information 
as to the names and addresses of the Holders in accordance with this Section 
7.06, regardless of the source from which such information was derived, and 
that the Trustee shall not be held accountable by reason of mailing any 
material pursuant to a request made under this Section 7.06.

     (e)  Within 60 calendar days after May 15 of each year commencing 
with the year 1997, the Trustee shall transmit by mail to all Holders of 
Notes, a brief report dated as of such May 15 if and to the extent 
required under Section 313(a) of the Trust Indenture Act.

     (f)  The Trustee shall comply with Sections 313(b) and 313(c) of the 
Trust Indenture Act.

     (g)  A copy of each report described in Section 7.06(e) hereof shall, at 
the time of its transmission to Holders, be filed by the Trustee with each 
stock exchange, if any, upon which the Notes are then listed, with the 
Commission and also with the Company.  The Company shall promptly notify the 
Trustee of any stock exchange upon which the Notes are listed.

     SECTION 7.7.  COMPENSATION AND INDEMNITY.  The Company shall pay to the 
Trustee from time to time such compensation for its services as the Company 
and the Trustee shall from time to time agree.  The Company shall reimburse 
the Trustee upon request for all reasonable out-of-pocket expenses incurred 
or made by it, including costs of collection, in addition to the compensation 
for its services.  Such expenses shall include the reasonable compensation 
and expenses, disbursements and advances of the Trustee's agents and counsel. 
 The Trustee's compensation shall not be limited by any law on compensation 
of a trustee of an express trust.

     The Company shall indemnify the Trustee for, and hold it harmless 
against, any and all loss, liability, damage, claim or expense (including 
reasonable attorneys' fees and expenses) arising out of or incurred by it in 
connection with the acceptance or administration of the trust created by this 
Indenture and the performance of its duties hereunder, except as set forth in 
the next paragraph.  The Trustee shall notify the Company promptly of any 
claim for which it may seek indemnity.  Failure by the Trustee to so notify 
the Company shall not relieve the Company of its obligations hereunder.  The 
Company shall defend any such claim and the Trustee shall cooperate in the 
defense of such claim.  The Trustee may have separate counsel and the Company 
shall pay the reasonable fees and expenses of such counsel.  The Company need 
not pay for any settlement made without its consent, which consent shall not 
be unreasonably withheld.


                                     -60-

<PAGE>

         The Company need not reimburse any expense or indemnify against any 
loss, liability or expense incurred by the Trustee through the Trustee's own 
willful misconduct, gross negligence or bad faith.

         To secure the Company's payment obligations in this Section 7.07, 
the Trustee shall have a Lien prior to the Notes on all money or property 
held or collected by the Trustee other than money or property held in trust 
to pay principal of, premium, if any, and interest on, particular Notes.

         The Company's payment obligations pursuant to this Section 7.07 
shall survive the resignation or removal of the Trustee and discharge of this 
Indenture.  Subject to any other rights available to the Trustee under 
applicable bankruptcy law, when the Trustee incurs expenses after the 
occurrence of a Default specified in Section 6.01(g) or Section 6.01(h) 
hereof, the expenses are intended to constitute expenses of administration 
under bankruptcy law.

         SECTION 7.08.   REPLACEMENT OF TRUSTEE.  (a)  No resignation or 
removal of the Trustee and no appointment of a successor Trustee pursuant to 
this Article VII shall become effective until the acceptance of appointment 
by the successor Trustee under this Section 7.08.

         (b)     The Trustee may resign at any time by giving written notice 
thereof to the Company.  If an instrument of acceptance by a successor 
Trustee shall not have been delivered to the Trustee within 30 calendar days 
after the giving of such notice of resignation, the resigning Trustee may 
petition any court of competent jurisdiction for the appointment of a 
successor Trustee.

         (c)     The Trustee may be removed at any time by Act of the Holders 
of a majority in principal amount of the outstanding Notes, delivered to the 
Trustee and to the Company.  If an instrument of acceptance by a successor 
Trustee shall not have been delivered to the Trustee within 30 calendar days 
after the giving of notice of removal, the Trustee being removed may petition 
any court of competent jurisdiction for the appointment of a successor 
Trustee.

         (d)     If at any time:

                 (i)     the Trustee shall fail to comply with Section 310(b) 
     of the Trust Indenture Act after written request therefor by the Company 
     or by any Holder who has been a bona fide Holder of a Note for at least 
     six months, unless the Trustee's duty to resign is stayed in accordance 
     with the provisions of Section 310(b) of the Trust Indenture Act; or

                 (ii)    the Trustee shall cease to be eligible under Section 
     7.10 hereof and shall fail to resign after written request therefor by 
     the Company or by any such Holder; or

                 (iii)   the Trustee shall become incapable of acting or a 
     decree or order for relief by a court having jurisdiction in the 
     premises shall have been entered in respect of the Trustee in an 
     involuntary case under the United States bankruptcy laws, as now or 
     hereafter constituted, or any other applicable Federal or state 
     bankruptcy, insolvency or similar law; or a decree or order 

                                     -61-

<PAGE>

     by a court having jurisdiction in the premises shall have been entered 
     for the appointment of a receiver, custodian, liquidator, assignee, 
     trustee, sequestrator (or other similar official) of the Trustee or of 
     its Property or affairs, or any public officer shall take charge or 
     control of the Trustee or of its Property or affairs for the purpose of 
     rehabilitation, conservation, winding up or liquidation; or

                 (iv)    the Trustee shall commence a voluntary case under the 
     United States bankruptcy laws, as now or hereafter constituted, or any 
     other applicable Federal or state bankruptcy, insolvency or similar law 
     or shall consent to the appointment of or taking possession by a 
     receiver, custodian, liquidator, assignee, trustee, sequestrator (or 
     other similar official) of the Trustee or its Property or affairs, or 
     shall make an assignment for the benefit of creditors, or shall admit in 
     writing its inability to pay its debts generally as they become due, or 
     shall take corporate action in furtherance of any such action,

then, in any such case, (i) the Company by a Board Resolution may remove the 
Trustee with respect to the Notes, or (ii) subject to Section 6.10 hereof, 
any Holder who has been a bona fide Holder of a Note for at least six months 
may, on behalf of such Holder and all others similarly situated, petition any 
court of competent jurisdiction for the removal of the Trustee and the 
appointment of a successor Trustee for the Notes.  If an instrument of 
acceptance by a successor Trustee shall not have been delivered to the 
Trustee within 30 calendar days after the giving of notice of removal, the 
Trustee being removed may petition any court of competent jurisdiction for 
the appointment of a successor Trustee.

         (e)     If the Trustee shall resign, be removed or become incapable 
of acting, or if a vacancy shall occur in the office of Trustee for any 
cause, the Company, by or pursuant to a Board Resolution, shall promptly 
appoint a successor Trustee.  If, within one year after such resignation, 
removal or incapability, or the occurrence of such vacancy, a successor 
Trustee shall be appointed by the Holders of a majority in principal amount 
of the outstanding Notes delivered to the Company and the retiring Trustee, 
the successor Trustee so appointed shall, forthwith upon its acceptance of 
such appointment in accordance with this Section 7.08, become the successor 
Trustee and to that extent replace any successor Trustee appointed by the 
Company. If no successor Trustee shall have been so appointed by the Company 
or the Holders and shall have accepted appointment in the manner hereinafter 
provided, any Holder that has been a bona fide Holder of a Note for at least 
six months may, subject to Section 6.10 hereof, on behalf of himself and all 
others similarly situated, petition any court of competent jurisdiction for 
the appointment of a successor Trustee.

         (f)     The Company shall give notice of each resignation and each 
removal of the Trustee and each appointment of a successor Trustee by mailing 
written notice of such resignation, removal and appointment by first class 
mail, postage prepaid, to the Holders as their names and addresses appear in 
the Security Register.  Each notice shall include the name of the successor 
Trustee with respect to the Notes and the address of its Corporate Trust 
Office.

                                     -62-

<PAGE>

         (g)     In the event of an appointment hereunder of a successor 
Trustee, each such successor Trustee so appointed shall execute, acknowledge 
and deliver to the Company and to the retiring Trustee an instrument 
accepting such appointment, and thereupon the resignation or removal of the 
retiring Trustee shall become effective and such successor Trustee, without 
any further act, deed or conveyance, shall become vested with all the rights, 
powers, trusts and duties of the retiring Trustee but, on request of the 
Company or the successor Trustee, such retiring Trustee shall, upon payment 
of its charges, execute and deliver an instrument transferring to such 
successor Trustee all the rights, powers and trusts of the retiring Trustee, 
and shall duly assign, transfer and deliver to such successor Trustee all 
Property and money held by such former Trustee hereunder, subject to its 
Lien, if any, provided for in Section 7.07 hereof.

         (h)     Upon request of any such successor Trustee, the Company 
shall execute any and all instruments for more fully and certainly vesting in 
and confirming to such successor Trustee all such rights, powers and trusts 
referred to in Section 7.08(g) hereof.

         (i)     No successor Trustee shall accept its appointment unless at 
the time of such acceptance such successor Trustee shall be qualified and 
eligible under this Article VII and under the Trust Indenture Act.

         SECTION 7.09.   SUCCESSOR TRUSTEE BY MERGER.  Any corporation into 
which the Trustee may be merged or converted or with which it may be 
consolidated, or any corporation resulting from any merger, conversion or 
consolidation to which the Trustee shall be a party, or any corporation 
succeeding to all or substantially all of the corporate trust business of the 
Trustee, shall be the successor of the Trustee hereunder; PROVIDED that such 
corporation shall be otherwise qualified and eligible under this Article VII 
and under the Trust Indenture Act, without the execution or filing of any 
paper or any further act on the part of any of the parties hereto.  In case 
any Notes shall have been authenticated, but not delivered, by the Trustee 
then in office, any successor by merger, conversion or consolidation to such 
authenticating Trustee may adopt such authentication and deliver the Notes so 
authenticated with the same effect as if such successor Trustee had itself 
authenticated such Notes.  In the event that any Notes shall not have been 
authenticated by such predecessor Trustee, any such successor Trustee may 
authenticate and deliver such Notes, in either its own name or that of its 
predecessor Trustee, with the full force and effect which this Indenture 
provides for the certificate of authentication of the Trustee.

         SECTION 7.10.   ELIGIBILITY; DISQUALIFICATION.  There shall at all 
times be a Trustee hereunder which shall be

                 (i)          a corporation organized and doing business under 
     the laws of the United States of America, any State or Territory thereof 
     or the District of Columbia, authorized under such laws to exercise 
     corporate trust powers, and subject to supervision or examination by 
     Federal, State, Territorial or District of Columbia authority, or

                                     -63-

<PAGE>

                 (ii)         a corporation or other Person organized and doing
     business under the laws of a foreign government that is permitted to act 
     as Trustee pursuant to a rule, regulation or order of the Commission, 
     authorized under such laws to exercise corporate trust powers, and 
     subject to supervision or examination by authority of such foreign 
     government or a political subdivision thereof substantially equivalent 
     to supervision or examination applicable to United States institutional 
     trustees,
     
in either case having a combined capital and surplus of at least $50,000,000.

         If such Person publishes reports of condition at least annually, 
pursuant to law or to the requirements of the aforesaid supervising or 
examining authority, then for the purposes of this Section 7.10, the combined 
capital and surplus of such corporation shall be deemed to be its combined 
capital and surplus as set forth in its most recent report of condition so 
published.  Neither the Company nor any Affiliate of the Company shall serve 
as Trustee hereunder.  If at any time the Trustee shall cease to be eligible 
to serve as Trustee hereunder pursuant to the provisions of this Section 
7.10, it shall resign immediately in the manner and with the effect specified 
in this Article VII.

         If the Trustee has or shall acquire any "conflicting interest" 
within the meaning of Section 310(b) of the Trust Indenture Act, the Trustee 
and the Company shall in all respects comply with the provisions of Section 
310(b) of the Trust Indenture Act.  Nothing herein shall prevent the Trustee 
from filing with the Commission the application referred to in the 
penultimate paragraph of Section 310(b) of the Trust Indenture Act.

         SECTION 7.11.   PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY.  
The Trustee shall comply with Section 311(a) of the Trust Indenture Act, 
excluding any creditor relationship listed in Section 311(b) of the Trust 
Indenture Act.  A Trustee who has resigned or been removed shall be subject 
to Section 311(a) of the Trust Indenture Act to the extent indicated therein.

                              ARTICLE VIII

                               DEFEASANCE

         SECTION 8.01.    COMPANY'S OPTION TO EFFECT LEGAL DEFEASANCE OR 
COVENANT DEFEASANCE.  The Company may elect, at its option, at any time, to 
have Section 8.02 or Section 8.03 hereof applied to the outstanding Notes (in 
whole and not in part) upon compliance with the conditions set forth below in 
this Article VIII. Such election shall be evidenced by a Board Resolution 
delivered to the Trustee and shall specify whether the Notes are being 
defeased to Stated Maturity or to a specified Redemption Date determined in 
accordance with the terms of this Indenture and the Notes.

         SECTION 8.02.    LEGAL DEFEASANCE AND DISCHARGE.  Upon the Company's 
exercise under Section 8.01 hereof, of its option to have this Section 8.02 
applied to the outstanding Notes (in whole and not in part), the Company 
shall be deemed to have been discharged from its obligations with respect to 
such Notes as provided in this Section 8.02 on and after the date the 
conditions set forth 


                                     -64-

<PAGE>

in Section 8.04 hereof are satisfied (hereinafter called "Legal Defeasance"). 
For this purpose, such Legal Defeasance means that the Company and the 
Subsidiary Guarantors shall be deemed to have paid and discharged the entire 
indebtedness represented by such Notes, which shall thereafter be deemed to 
be "outstanding" only for the purposes of Section 8.05 hereof and the other 
Sections of this Indenture referred to in (a) and (b) below, and to have 
satisfied all its other obligations under such Notes and this Indenture 
insofar as such Notes are concerned (and the Trustee, on demand of and at the 
expense of the Company, shall execute proper instruments acknowledging the 
same), subject to the following which shall survive until otherwise 
terminated or discharged hereunder:

         (a)     the rights of Holders of such Notes to receive, solely from the
     trust fund described in Section 8.04 hereof and as more fully set forth 
     in such Section 8.04 payments in respect of the principal of and any 
     premium and interest on such Notes when payments are due,

         (b)     the Company's and the Subsidiary Guarantors' obligations with 
     respect to such Notes under Sections 2.06, 2.07, 2.09, 4.02, 4.03 and 
     4.04 hereof and Article XI,

         (c)     the rights, powers, trusts, duties and immunities of the 
     Trustee under this Indenture and the Company's obligations in connection 
     therewith,

         (d)     Article III hereof, and

         (e)     this Article VIII.

         Subject to compliance with this Article VIII, the Company may 
exercise its option to have this Section 8.02 applied to the outstanding 
Notes (in whole and not in part) notwithstanding the prior exercise of its 
option to have Section 8.03 hereof applied to such Notes.

         SECTION 8.03.   COVENANT DEFEASANCE.  Upon the Company's exercise 
under Section 8.01 hereof of its option to have this Section 8.03 applied to 
the outstanding Notes (in whole and not in part), (i) the Company and the 
Subsidiary Guarantors shall be released from their obligations under Section 
5.01(iii), Sections 4.05 through 4.17, inclusive, and any covenant added to 
this Indenture subsequent to the date of this Indenture pursuant to Section 
9.01 hereof, (ii) the occurrence of any event specified in Section 6.01(c) or 
Section 6.01(d) hereof, with respect to any of Section 5.01(iii), Sections 
4.05 through 4.17, inclusive, and any covenant added to this Indenture 
subsequent to the date of this Indenture pursuant to Section 9.01 hereof, 
shall be deemed not to be or result in an Event of Default, in each case with 
respect to such Notes as provided in this Section 8.03 on and after the date 
the conditions set forth in Section 8.04 hereof are satisfied (hereinafter 
called "Covenant Defeasance") and the Notes shall thereafter be deemed not 
"outstanding" for the purposes of any direction, waiver consent or 
declaration or act of Holders (and the consequences of any thereof) in 
connection with such covenants, but shall continue to be deemed "outstanding" 
for all other purposes hereunder (it being understood that such Notes shall 
not be deemed outstanding for accounting purposes).  For this purpose, such 
Covenant Defeasance means that, with respect to such Notes, the Company and 
the Subsidiary Guarantors may omit to comply with and shall have no liability 
in 


                                     -65-

<PAGE>

respect of any term, condition or limitation set forth in any such specified 
Section (to the extent so specified in the case of Sections 6.01(c) and 
6.01(d) hereof), whether directly or indirectly, by reason of any reference 
elsewhere herein to any such Section or by reason of any reference in any 
such Section to any other provision herein or in any other document; but the 
remainder of this Indenture and such Notes shall be unaffected thereby.  In 
addition, upon the Company's exercise under Section 8.01 hereof of the option 
applicable to this Section 8.03 hereof, subject to the satisfaction of the 
conditions set forth in Section 8.04 hereof, Sections 6.01 (e) and 6.01(f) 
hereof shall thereafter not constitute Events of Default.

         SECTION 8.04.   CONDITIONS TO DEFEASANCE OR COVENANT DEFEASANCE.  The 
following shall be the conditions to the application of Section 8.02 or 
Section 8.03 hereof to the outstanding Notes:

         (a)     The Company or any Subsidiary Guarantor shall irrevocably have 
     deposited or caused to be deposited with the Trustee as trust funds in 
     trust for the purpose of making the following payments, specifically 
     pledged as security for, and dedicated solely to the benefits of the 
     Holders of such Notes, (i) money in an amount, or (ii) U.S. Government 
     Obligations which through the scheduled payment of principal and 
     interest in respect thereof in accordance with their terms will provide, 
     not later than one day before the due date of any payment, money in an 
     amount, or (iii) a combination thereof, in each case sufficient, in the 
     opinion of a nationally recognized firm of independent public 
     accountants expressed in a written certification thereof delivered to 
     the Trustee, to pay and discharge, and which shall be applied by the 
     Trustee (or any such other qualifying trustee) to pay and discharge, the 
     principal of, premium, if any, and any installment of interest on such 
     Notes on the Stated Maturity thereof or applicable Redemption Date, as 
     the case may be, in accordance with the terms of this Indenture and such 
     Notes.

         (b)     In the event of an election to have Section 8.02 hereof apply 
     to the outstanding Notes, the Company shall have delivered to the 
     Trustee an Opinion of Counsel stating that (i) the Company has received 
     from, or there has been published by, the Internal Revenue Service a 
     ruling or (ii) since the date of this Indenture, there has been a change 
     in the applicable Federal income tax law, in either case (i) or (ii) to 
     the effect that, and based thereon such opinion shall confirm that, the 
     Holders of such Notes will not recognize income, gain or loss for 
     Federal income tax purposes as a result of the deposit, Legal Defeasance 
     and discharge to be effected with respect to such Notes and will be 
     subject to Federal income tax on the same amount, in the same manner and 
     at the same times as would be the case if such deposit, Legal Defeasance 
     and discharge were not to occur.

         (c)     In the event of an election to have Section 8.03 hereof apply 
     to the outstanding Notes, the Company shall have delivered to the 
     Trustee an Opinion of Counsel to the effect that the Holders of such 
     Notes will not recognize income, gain or loss for Federal income tax 
     purposes as a result of the deposit and Covenant Defeasance to be 
     effected with respect to such Notes and will be subject to Federal 
     income tax on the same amount, in the same manner and at the same times 
     as would be the case if such deposit and Covenant Defeasance were not to 
     occur.

                                     -66-

<PAGE>

         (d)     No Default or Event of Default with respect to the outstanding 
     Notes shall have occurred and be continuing at the time of such deposit 
     (other than a Default or Event of Default resulting from the borrowing 
     of funds to be applied to such deposit) after giving effect thereto or, 
     with respect to a Default or Event of Default specified in Section 
     6.01(g) or Section 6.01(h), any time on or prior to the 123rd calendar 
     day after the date of such deposit (it being understood that this 
     condition shall not be deemed satisfied until after such 123rd calendar 
     day).

         (e)     Such Legal Defeasance or Covenant Defeasance shall not cause 
     the Trustee to have a conflicting interest within the meaning of the 
     Trust Indenture Act (assuming for the purpose of this clause (e) that 
     all Notes are in default within the meaning of such Act).

         (f)     Such Legal Defeasance or Covenant Defeasance shall not result 
     in a breach or violation of, or constitute a default under, any material 
     agreement or instrument (other than this Indenture) to which the Company 
     or any of its Subsidiaries is a party or by which the Company or any of 
     its Subsidiaries is bound.

         (g)     The Company shall have delivered to the Trustee an Officers' 
     Certificate stating that the deposit was not made by the Company with 
     the intent of preferring the Holders over any other creditors of the 
     Company or with the intent of defeating, hindering, delaying or 
     defrauding any other creditors of the Company.

         (h)     Such Legal Defeasance or Covenant Defeasance shall not result 
     in the trust arising from such deposit constituting an investment 
     company within the meaning of the Investment Company Act of 1940, as 
     amended, unless such trust shall be registered under such Act or exempt 
     from registration thereunder.

         (i)     The Company shall have delivered to the Trustee an Officers' 
     Certificate and an Opinion of Counsel, each stating that all conditions 
     precedent with respect to such Legal Defeasance or Covenant Defeasance 
     have been complied with.

         SECTION 8.5.   DEPOSITED MONEY AND U.S. GOVERNMENT OBLIGATIONS TO BE 
HELD IN TRUST; MISCELLANEOUS PROVISIONS.  All money and U.S. Government 
Obligations (including the proceeds thereof) deposited with the Trustee 
pursuant to Section 8.04 hereof in respect of the outstanding Notes shall be 
held in trust and applied by the Trustee, in accordance with the provisions 
of such Notes and this Indenture, to the payment, either directly or through 
any such Paying Agent as the Trustee may determine, to the Holders of such 
Notes, of all sums due and to become due thereon in respect of principal and 
any premium and interest, but money so held in trust need not be segregated 
from other funds except to the extent required by law.  The Company shall pay 
and indemnify the Trustee against any tax, fee or other charge imposed on or 
assessed against the U.S. Government Obligations deposited pursuant to 
Section 8.04 hereof or the principal and interest received in respect thereof 
other than any such tax, fee or other charge which by law is for the account 
of the Holders of outstanding Notes.

                                     -67-

<PAGE>

         Anything in this Article VIII to the contrary notwithstanding, the 
Trustee shall deliver or pay to the Company from time to time upon Company 
Order any money or U.S. Government Obligations held by it as provided in 
Section 8.04 hereof which, in the opinion of a nationally recognized firm of 
independent public accountants expressed in a written certification thereof 
delivered to the Trustee, are in excess of the amount thereof that would then 
be required to be deposited to effect the Legal Defeasance or Covenant 
Defeasance, as the case may be, with respect to the outstanding Notes.

         SECTION 8.6.   REINSTATEMENT.  If the Trustee or Paying Agent is 
unable to apply any money in accordance with this Article VIII with respect 
to any Notes by reason of any order or judgment of any court or governmental 
authority enjoining, restraining or otherwise prohibiting such application 
then the obligations under this Indenture and such Notes from which the 
Company has been discharged or released pursuant to Section 8.02 or 8.03 
hereof shall be revived and reinstated as though no deposit had occurred 
pursuant to this Article VIII with respect to such Notes, until such time as 
the Trustee or Paying Agent is permitted to apply all money held in trust 
pursuant to Section 8.05 hereof with respect to such Notes in accordance with 
this Article VIII; provided that if the Company or any Subsidiary Guarantor 
makes any payment of principal of or any premium or interest on any such Note 
following such reinstatement of its obligations, the Company or such 
Subsidiary Guarantor, as the case may be, shall be subrogated to the rights 
(if any) of the Holders of such Notes to receive such payment from the money 
so held in trust.

                                 ARTICLE IX

                                 AMENDMENTS

         SECTION 9.1.    WITHOUT CONSENT OF HOLDERS.  The Company, the 
Subsidiary Guarantors and the Trustee may, at any time, and from time to 
time, without notice to or consent of any Holder of Notes, enter into one or 
more indentures supplemental hereto, in form satisfactory to the Trustee, for 
any of the following purposes:

         (a)     to evidence the succession of another Person to the Company 
     and the assumption by such successor of the covenants of the Company 
     herein and contained in the Notes; or

         (b)     to add to the covenants of the Company, for the benefit of the
     Holders of all of the Notes, or to surrender any right or power herein 
     conferred upon the Company; or

         (c)     to add any additional Events of Default; or

         (d)     to provide for uncertificated Notes in addition to or in place
     of Certificated Notes; or

         (e)     to evidence and provide for the acceptance of appointment 
     hereunder of a successor Trustee; or

         (f)     to secure the Notes; or


                                     -68-

<PAGE>

         (g)      to cure any ambiguity herein, or to correct or supplement 
     any provision hereof which may be inconsistent with any other provision 
     hereof or to add any other provisions with respect to matters or 
     questions arising under this Indenture; provided that such actions shall 
     not adversely affect the interests of the Holders of Notes in any 
     material respect; or

         (h)     to comply with the requirements of the Commission in order to 
     effect or maintain the qualification of this Indenture under the Trust 
     Indenture Act; or

         (i)     to provide for assumption of a Subsidiary Guarantor's 
     obligations under its Subsidiary Guarantee upon a merger, consolidation, 
     sale, assignment, transfer, lease, conveyance or other disposition of 
     all or substantially all of the assets, of such Subsidiary Guarantor, in 
     compliance with Section 11.02; or

         (j)     to add or release a Subsidiary Guarantor in compliance with the
     provisions of Article XI.

         SECTION 9.2.   WITH CONSENT OF HOLDERS.  With the consent of the 
Holders of not less than a majority in principal amount of the outstanding 
Notes (which consent may, but need not, be given in connection with any 
tender offer or exchange offer for the Notes), by Act of said Holders 
delivered to the Company, each of the Subsidiary Guarantors and the Trustee, 
the Company, each of the Subsidiary Guarantors and the Trustee may enter into 
one or more indentures supplemental hereto for the purpose of adding any 
provisions to or changing in any manner or eliminating any of the provisions 
of this Indenture or of modifying in any manner the rights of the Holders 
(including Section 4.07 and Section 4.08 hereof); provided that no such 
supplemental indenture shall, without the consent of the Holder of each 
outstanding Note,

         (a)     reduce the principal amount of Notes whose Holders must consent
     to an amendment, supplement or waiver;

         (b)     reduce the principal of or change the Stated Maturity of any 
     Note or alter or waive any of the provisions with respect to the 
     redemption of the Notes, except as provided above with respect to 
     Sections 4.07 and 4.08 hereof;

         (c)     reduce the rate of or change the time for payment of interest, 
     including Defaulted Interest, on any Note;

         (d)     waive a Default or Event of Default in the payment of principal
     of or premium, if any, or interest on the Notes (except a rescission of 
     acceleration of the Notes by the Holders of at least a majority in 
     aggregate principal amount of the then outstanding Notes and a waiver of 
     the payment default that resulted from such acceleration);

         (e)     make any Note payable in money other than that stated in the
     Notes;


                                     -69-

<PAGE>

         (f)     make any change in the provisions of this Indenture relating 
     to waivers of past Defaults or the rights of Holders of Notes to receive 
     payments of principal of or interest on the Notes;

         (g)     waive a redemption payment with respect to any Note (other than

     a payment required by Section 4.07 or Section 4.08 hereof); 

         (h)     make any change in Section 6.04 or 6.07 hereof or in the 
     foregoing amendment and waiver provisions; or 

         (i)     modify any provisions of this Indenture relating to the 
     relative ranking of the Notes or the Subsidiary Guarantees in a manner 
     adverse to the Holders thereof.

         It shall not be necessary for any Act of Holders under this Section 
9.02 to approve the particular form of any proposed supplemental indenture, 
but it shall be sufficient if such Act shall approve the substance thereof.

         After an amendment or supplement under this Section or a waiver 
under Section 6.04 becomes effective, the Company shall mail to the Holders 
of Notes affected thereby a notice briefly describing the amendment, 
supplement or waiver.  Any failure of the Company to mail such notice, or any 
defect therein, shall not, however, in any way impair or affect the validity 
of any such amended or supplemental Indenture or waiver.

         SECTION 9.03.   EFFECT OF SUPPLEMENTAL INDENTURES.  Upon the 
execution of any supplemental indenture under this Article IX, this Indenture 
shall be modified in accordance therewith, and such supplemental indenture 
shall form a part of this Indenture for all purposes; and every Holder of 
Notes theretofore or thereafter authenticated and delivered hereunder shall 
be bound thereby.

         SECTION 9.04.   COMPLIANCE WITH TRUST INDENTURE ACT.  Every amendment 
or supplement to this Indenture or the Notes shall comply with the Trust 
Indenture Act as then in effect.

         SECTION 9.05.   REVOCATION AND EFFECT OF CONSENTS AND WAIVERS.  A 
consent to an amendment, supplement or a waiver by a Holder of a Note shall 
bind the Holder and every subsequent Holder of such Note or portion of such 
Note that evidences the same debt as the consenting Holder's Note, even if 
notation of the consent or waiver is not made on such Note; provided that any 
such Holder or subsequent Holder may revoke the consent or waiver as to such 
Holder's Note or portion of such Note if the Trustee receives the notice of 
revocation before the date the amendment, supplement or waiver becomes 
effective.  After an amendment, supplement or waiver becomes effective 
pursuant to this Article IX, it shall bind every Holder.

         The Company may, but shall not be obligated to, fix a record date 
for the purpose of determining the Holders entitled to give their consent or 
take any other action described above or 


                                     -70-

<PAGE>

required or permitted to be taken pursuant to this Indenture.  If a record 
date is fixed, then notwithstanding the immediately preceding paragraph, 
those Persons who were Holders at such record date (or their duly designated 
proxies), and only those Persons, shall be entitled to give such consent or 
to revoke any consent previously given or to take any such action, whether or 
not such Persons continue to be Holders after such record date.  No such 
consent shall be valid or effective for more than 120 calendar days after 
such record date.

         SECTION 9.06.   NOTATION ON OR EXCHANGE OF NOTES.  If a supplemental 
indenture changes the terms of a Note, the Trustee may require the Holder 
thereof to deliver such Note to the Trustee.  The Trustee may place an 
appropriate notation on such Note regarding the changed terms and return it 
to the Holder. Alternatively, if the Company or the Trustee so determines, 
the Company in exchange for such Note shall issue and the Trustee shall 
authenticate a new Note that reflects the changed terms.  Failure to make the 
appropriate notation or to issue a new Note shall not affect the validity of 
such amendment or supplement.

         SECTION 9.07.   TRUSTEE TO EXECUTE SUPPLEMENTAL INDENTURES.  The 
Trustee shall execute any supplemental indenture authorized pursuant to this 
Article IX if such supplemental indenture does not adversely affect the 
rights, duties, liabilities or immunities of the Trustee.  If it does, the 
Trustee may, but shall not be required to, execute such supplemental 
indenture.  In executing any supplemental indenture, the Trustee shall be 
entitled to receive indemnity reasonably satisfactory to it and to receive, 
and (subject to Section 7.01 hereof) shall be fully protected in relying 
upon, an Officers' Certificate (which need only cover the matters set forth 
in clause (a) below) and an Opinion of Counsel provided by the Company 
stating that:

         (a)     such supplemental indenture is authorized or permitted by this
     Indenture and that all conditions precedent to the execution, delivery 
     and performance of such supplemental indenture have been satisfied;

         (b)     the Company has all necessary corporate power and authority to
     execute and deliver the supplemental indenture and that the execution, 
     delivery and performance of such supplemental indenture has been duly 
     authorized by all necessary corporate action of the Company;

         (c)     the execution, delivery and performance of the supplemental 
     indenture do not conflict with, or result in the breach of or constitute 
     a default under any of the terms, conditions or provisions of (i) this 
     Indenture, (ii) the charter documents and by-laws of the Company, or 
     (iii) any material agreement or instrument to which the Company is 
     subject;

         (d)     to the best knowledge and belief of legal counsel writing such
     Opinion of Counsel, the execution, delivery and performance of the 
     supplemental indenture do not conflict with, or result in the breach of 
     any of the terms, conditions or provisions of (i) any law or regulation 
     applicable to the Company, or (ii) any material order, writ, injunction 
     or decree of any court or governmental instrumentality applicable to the 
     Company;

                                     -71-

<PAGE>

         (e)     such supplemental indenture has been duly and validly executed
     and delivered by the Company, and this Indenture together with such 
     supplemental indenture constitutes a legal, valid and binding obligation 
     of the Company enforceable against the Company in accordance with its 
     terms, except as such enforceability may be limited by applicable 
     bankruptcy, insolvency or similar laws affecting the enforcement of 
     creditors' rights generally and general equitable principles; and

         (f)     this Indenture together with such amendment or supplement
     complies with the Trust Indenture Act.

         SECTION 9.08.   EFFECT ON SENIOR INDEBTEDNESS.  No supplemental 
indenture shall adversely affect the rights of holders of Senior Indebtedness 
under Article X hereof or the holders of Guarantor Senior Indebtedness under 
Sections 11.08, 11.09, 11.10, 11.11, 11.12, 11.13, 11.14, 11.15, 11.16, or 
11.19 hereof unless expressly consented to in writing by or on behalf of such 
holders (or by any specified percentage of holders of a class of Senior 
Indebtedness or Guarantor Senior Indebtedness, as the case may be, required 
to consent thereto pursuant to the terms of the agreement or instrument 
creating, evidencing or governing such Senior Indebtedness or Guarantor 
Senior Indebtedness, as the case may be), in which event such supplemental 
indenture shall be binding on all successors and assigns of such holders and 
on all persons who become holders of such Senior Indebtedness or Guarantor 
Senior Indebtedness issued after the date of such amendment or modification. 

                                 ARTICLE X

                                SUBORDINATION

         SECTION 10.01.   AGREEMENT TO SUBORDINATE.  The Company agrees, and 
each Holder by accepting a Note agrees, that the Indebtedness evidenced by 
the Note and the payment of the principal of (and premium, if any, on) and 
interest on, such Note is expressly made subordinate and subject in right of 
payment, to the extent and in the manner provided in this Article X, to the 
prior payment in full of all Senior Indebtedness (whether outstanding on the 
date hereof or hereafter created, incurred, assumed or guaranteed), and that 
the subordination is for the benefit of the holders of Senior Indebtedness.  
This Article X shall constitute a continuing offer to all Persons who become 
holders of, or continue to hold, Senior Indebtedness, and such provisions are 
made for the benefit of the holders of Senior Indebtedness.

         SECTION 10.02.   LIQUIDATION; DISSOLUTION; BANKRUPTCY.  Upon any 
distribution to creditors of the Company in a liquidation or dissolution of 
the Company or in a bankruptcy, reorganization, insolvency, receivership or 
similar proceeding relating to the Company or its property, in an assignment 
for the benefit of creditors or any marshaling of the Company's assets and 
liabilities:

         (a)     holders of Senior Indebtedness shall be entitled to receive 
     payment in full in cash of all Obligations due in respect of such Senior 
     Indebtedness (including interest after the commencement of any such 
     proceeding at the rate specified in the applicable Senior Indebtedness) 
     before Holders shall be entitled to receive any payment with respect to 
     principal of (or premium, if any, on) or interest on the Notes or on 
     account of the purchase, redemption or other acquisition of the Notes 
     (including pursuant to an Asset Sale Offer or Change of Control Offer) 
     (except that Holders may receive (i) securities that are subordinated to 
     at least the same extent as the Notes are subordinated

                                     -72-

<PAGE>

     to (A) Senior Indebtedness and (B) any securities issued in exchange for 
     Senior Indebtedness and (ii) payments and other distributions made from 
     any defeasance trust created pursuant to Section 8.01 hereof); and

         (b)     until all Obligations with respect to Senior Indebtedness (as 
     provided in subsection (a) above) are paid in full in cash, any 
     distribution to which Holders would be entitled but for this Article 
     shall be made to holders of Senior Indebtedness (except that Holders may 
     receive (i) securities that are subordinated to at least the same extent 
     as the Notes to (A) Senior Indebtedness and (B) any securities issued in 
     exchange for Senior Indebtedness and (ii) payments and other 
     distributions made from any defeasance trust created pursuant to Section 
     8.01 hereof), as their interests may appear.

         SECTION 10.03.   DEFAULT ON DESIGNATED SENIOR INDEBTEDNESS.  The 
Company may not make any payment or distribution to the Trustee or any Holder 
in respect of Obligations with respect to the Notes and may not acquire from 
the Trustee or any Holder any Notes for cash or property (other than (i) 
securities that are subordinated to at least the same extent as the Notes to 
(A) Senior Indebtedness and (B) any securities issued in exchange for Senior 
Indebtedness and (ii) payments and other distributions made from any 
defeasance trust created pursuant to Section 8.01 hereof) until all principal 
and other Obligations with respect to the Senior Indebtedness have been paid 
in full if:

         (a)     a default in the payment of any principal, premium, if any, or
     interest with respect to Designated Senior Indebtedness occurs and is 
     continuing beyond any applicable grace period in the agreement, 
     indenture or other document governing such Designated Senior 
     Indebtedness; or

         (b)     a default, other than such payment default, on Designated 
     Senior Indebtedness occurs and is continuing that then permits holders 
     of such Designated Senior Indebtedness to accelerate its maturity and 
     the Trustee receives a notice of such default (a "Payment Blockage 
     Notice") from a Person who may give it pursuant to Section 10.11 hereof. 
      If the Trustee receives any such Payment Blockage Notice, no subsequent 
     Payment Blockage Notice shall be effective for purposes of this Section 
     10.03 unless and until at least 360 days shall have elapsed since the 
     effectiveness of the immediately prior Payment Blockage Notice.  No 
     default specified in this clause (b) that existed or was continuing on 
     the date of delivery of any Payment Blockage Notice to the Trustee shall 
     be, or be made, the basis for a subsequent Payment Blockage Notice.

         The Company may and shall resume payments on and distributions in 
respect of the Notes and may acquire them upon the earlier of:

         (i)     in the case of a default referred to in Section 10.03(a),
     the date upon which such default is cured or waived, or

         (ii)    in the case of a default referred to in Section 10.03(b) 
     hereof, the earlier of the date on which such default is cured or waived
     or 179 days after the date on which the applicable 


                                     -73-

<PAGE>

     Payment Blockage Notice is received, unless the maturity of such
     Designated Senior Indebtedness has been accelerated,

if, and only if, this Article X otherwise permits the payment, distribution 
or acquisition at the time of such payment or acquisition.

         SECTION 10.04.  ACCELERATION OF NOTES.  If payment of the Notes is 
accelerated because of an Event of Default, the Company shall promptly notify 
the Representatives of holders of Designated Senior Indebtedness and 
Designated Guarantor Senior Indebtedness of the acceleration.

         SECTION 10.05.  WHEN DISTRIBUTION MUST BE PAID OVER.  In the event 
that the Trustee or any Holder receives any payment of any Obligations with 
respect to the Notes at a time when the Trustee or such Holder, as 
applicable, has actual knowledge that such payment is prohibited by Section 
10.03 hereof, such payment shall be held by the Trustee or such Holder, in 
trust for the benefit of, and shall be paid forthwith over and delivered, 
upon written request, to, the holders of Senior Indebtedness as their 
interests may appear or their Representative under the indenture or other 
agreement (if any) pursuant to which Senior Indebtedness may have been 
issued, for application to the payment of all Obligations with respect to 
Senior Indebtedness remaining unpaid to the extent necessary to pay such 
Obligations in full in accordance with their terms, after giving effect to 
any concurrent payment or distribution to or for the holders of Senior 
Indebtedness.

         With respect to the holders of Senior Indebtedness, the Trustee 
undertakes to perform only such obligations on the part of the Trustee as are 
specifically set forth in this Article X, and no implied covenants or 
obligations with respect to the holders of Senior Indebtedness shall be read 
into this Indenture against the Trustee.  The Trustee shall not be deemed to 
owe any fiduciary duty to the holders of Senior Indebtedness, and shall not 
be liable to any such holders if the Trustee shall pay over or distribute to 
or on behalf of Holders or the Company or any other Person money or assets to 
which any holders of Senior Indebtedness shall be entitled by virtue of this 
Article X, except if such payment is made as a result of the willful 
misconduct or gross negligence of the Trustee.

         SECTION 10.06.   NOTICE BY COMPANY.  The Company shall promptly notify 
the Trustee and the Paying Agent of any facts known to the Company that would 
cause a payment of any Obligations with respect to the Notes to violate this 
Article X, but failure to give such notice shall not affect the subordination 
of the Notes to the Senior Indebtedness as provided in this Article X.

         SECTION 10.07.   SUBROGATION.  After all Senior Indebtedness is paid 
in full and until the Notes are paid in full, Holders shall be subrogated 
(equally and ratably with all other Indebtedness PARI PASSU with the Notes) 
to the rights of holders of Senior Indebtedness to receive distributions 
applicable to Senior Indebtedness to the extent that distributions otherwise 
payable to the Holders have been applied to the payment of Senior 
Indebtedness.  A distribution made under this Article X to holders of Senior 
Indebtedness that otherwise would have been made to Holders is not, as 
between the Company and Holders, a payment by the Company on the Notes.


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<PAGE>

     SECTION 10.08. RELATIVE RIGHTS.  This Article X defines the relative 
rights of Holders and holders of Senior Indebtedness.  Nothing in this 
Indenture shall:

          (i)   impair, as between the Company and Holders, the obligation of 
     the Company, which is absolute and unconditional, to pay principal of, 
     premium, if any, on and interest on the Notes in accordance with their 
     terms;

          (ii)  affect the relative rights of Holders and creditors of the 
     Company other than their rights in relation to holders of Senior 
     Indebtedness; or

          (iii) prevent the Trustee or any Holder from exercising its available
     remedies upon a Default or Event of Default, subject to the rights of 
     holders and owners of Senior Indebtedness to receive distributions and 
     payments otherwise payable to Holders.

     If the Company fails because of this Article X to pay principal of, 
premium, if any, on or interest on a Note on the due date, the failure is still
a Default or Event of Default.

     SECTION 10.09.  NO WAIVER OF SUBORDINATION.  (a) No right of any holder 
of Senior Indebtedness to enforce the subordination of the Indebtedness 
evidenced by the Notes shall be impaired by any act or failure to act by the 
Company or any Holder or by the failure of the Company or any Holder to 
comply with this Indenture.

     (b) Without in any way limiting the generality of paragraph (a) of this 
Section, the holders of any Senior Indebtedness, in accordance with the terms 
of the instrument or agreement evidencing their Senior Indebtedness, may, at 
any time and from time to time, without the consent of or notice to the 
Trustee or the Holders, without incurring responsibility to the Holders and 
without impairing or releasing the subordination or other benefits provided in 
this Article X, or the obligations hereunder of the Holders to the holders of 
Senior Indebtedness, do any one or more of the following: (i) change the 
manner, place or terms of payment or extend the time of payment of, or renew, 
exchange, amend, increase or alter, Senior Indebtedness or the terms of any 
instrument evidencing the same or any agreement under which Senior 
Indebtedness is outstanding or any liability of any obligor thereon (unless 
such change, extension, amendment, increase or other alteration results in 
such Indebtedness no longer being Senior Indebtedness as defined in this 
Indenture); (ii) sell, exchange, release or otherwise deal with any Property 
pledged, mortgaged or otherwise securing Senior Indebtedness; (iii) settle or 
compromise any Senior Indebtedness or any liability of any obligor thereon or 
release any Person liable in any manner for the collection of Senior 
Indebtedness; and (iv) exercise or refrain from exercising any rights against 
the Company and any other Person.

     SECTION 10.10. DISTRIBUTION OR NOTICE TO REPRESENTATIVE.  Whenever a 
distribution is to be made or a notice given to holders of Senior Indebtedness,
the distribution may be made and the notice given to their Representative.

     Upon any payment or distribution of assets of the Company referred to in 
this Article X, the Trustee and the Holders shall be entitled to rely upon any
order or decree made by any court of competent jurisdiction or upon any 
certificate of such Representative or of the liquidating trustee or agent or 
other Person making any distribution to the Trustee or to the Holders for the 
purpose of ascertaining the Persons entitled to participate in such 
distribution, the holders of the Senior Indebtedness and other Indebtedness 
of the Company, the amount thereof or payable thereon, the amount or amounts 
paid or distributed thereon and all other facts pertinent thereto or to this 
Article X.

     The Trustee shall be entitled to rely on the delivery to it of a written 
notice by a Person representing himself to be a holder of Senior Indebtedness 
(or a trustee or agent on behalf of such holder) to establish that such notice
has been given by a holder of Senior Indebtedness (or a trustee or agent on 
behalf of any such holder).  In the event that the Trustee determines in good
faith that further evidence is required with respect to the right of any Person
as a holder of Senior Indebtedness to participate in any payment or 
distribution pursuant to this Article X, the Trustee may request such Person 
to furnish evidence to the reasonable satisfaction of the Trustee as to the 
amount of Senior Indebtedness held by such Person, the extent to which such 
Person is entitled to participate in such 




                                   -75-


<PAGE>

payment or distribution and any other facts pertinent to the rights of such 
Person under this Article X, and if such evidence is not furnished, the 
Trustee may defer any payment which it may be required to make for the benefit
of such Person pursuant to the terms of this Indenture pending judicial 
determination as to the rights of such Person to receive such payment.

     SECTION 10.11. RIGHTS OF TRUSTEE AND PAYING AGENT.  Notwithstanding the 
provisions of this Article X or any other provision of this Indenture, the 
Trustee shall not be charged with knowledge of the existence of any facts 
that would prohibit the making of any payment or distribution by the Trustee, 
and the Trustee and the Paying Agent may continue to make payments on the 
Notes, unless the Trustee shall have received at its Corporate Trust Office 
at least five Business Days prior to the date of such payment written notice 
of facts that would cause the payment of any Obligations with respect to the 
Notes to violate Article X or XI. Only the holders of Designated Senior 
Indebtedness or a Representative thereof may give the notice. Nothing in 
Article X or XI shall impair the claims of, or payments to, the Trustee under 
or pursuant to Section 7.07 hereof.

     The Trustee in its individual or any other capacity may hold Senior 
Indebtedness with the same rights it would have if it were not Trustee.  Any 
Paying Agent may do the same with like rights.

     SECTION 10.12. AUTHORIZATION TO EFFECT SUBORDINATION.  Each Holder of a 
Note by the Holder's acceptance thereof authorizes and directs the Trustee on 
the Holder's behalf to take such action as may be necessary or appropriate to 
effectuate the subordination as provided in this Article X, and appoints the 
Trustee to act as the Holder's attorney-in-fact for any and all such purposes.
If the Trustee does not file a proper proof of claim or proof of debt in the 
form required in any judicial proceeding relative to the Company (or any other
obligor upon the Notes), its creditors or its property at least 30 days before
the expiration of the time to file such claim, any Representative is hereby 
authorized to file an appropriate claim for and on behalf of the Holders of 
the Notes.

     SECTION 10.13. AMENDMENTS.  The provisions of this Article X shall not 
be amended or modified in a manner materially adverse to the Holders of Senior
Indebtedness without the written consent of the holders of all Designated 
Senior Indebtedness.

                                  ARTICLE XI

                            SUBSIDIARY GUARANTEES

     SECTION 11.01.  UNCONDITIONAL GUARANTEE.

     Each Subsidiary Guarantor hereby, jointly and severally, unconditionally 
guarantees (such guarantee to be referred to herein as this "Subsidiary 
Guarantee" with all such guarantees being referred to herein as the 
"Subsidiary Guarantees") to each Holder and to the Trustee the due and 
punctual payment of the principal of, premium, if any, and interest on the 
Notes and all other amounts due and payable under this Indenture and the 
Notes by the Company, whether at maturity, by acceleration, redemption, 
repurchase or otherwise, including, without limitation, interest on the 



                                   -76-


<PAGE>

overdue principal of, premium, if any, and interest on the Notes, to the extent
lawful, all in accordance with the terms hereof and thereof; subject, however,
to the limitations set forth in Section 11.05.

     Failing payment when due of any amount so guaranteed for whatever 
reason, the Subsidiary Guarantors will be jointly and severally obligated to 
pay the same immediately.  Each Subsidiary  Subsidiary Guarantor hereby 
agrees that its obligations hereunder shall be unconditional irrespective of 
the validity, regularity or enforceability of the Notes or this Indenture, 
the absence of any action to enforce the same, any waiver or consent by any 
Holder of the Notes with respect to any provisions hereof or thereof, the 
recovery of any judgment against the Company, any action to enforce the same 
or any other circumstance which might otherwise constitute a legal or equitable
discharge or defense of a Subsidiary Guarantor.  Each Subsidiary Guarantor 
hereby waives diligence, presentment, demand of payment, filing of claims 
with a court in the event of insolvency or bankruptcy of the Company, any 
right to require a proceeding first against the Company, protest, notice and 
all demands whatsoever and covenants that this Subsidiary Guarantee will not 
be discharged except by complete performance of the obligations contained in 
the Notes, this Indenture and in this Subsidiary Guarantee.  If any Holder or 
the Trustee is required by any court or otherwise to return to the Company, 
any Subsidiary Guarantor, or any custodian, trustee, liquidator or other 
similar official acting in relation to the Company or any Subsidiary Guarantor,
any amount paid by the Company or any Subsidiary Guarantor to the Trustee or 
such Holder, this Subsidiary Guarantee, to the extent theretofore discharged, 
shall be in full force and effect.  Each Subsidiary Guarantor agrees it shall 
not be entitled to any right of subrogation in relation to the Holders in 
respect of any obligations guaranteed hereby until payment in full of all 
obligations guaranteed hereby.  Each Subsidiary Guarantor further agrees 
that, as between each Subsidiary Guarantor, on the one hand, and the Holders 
and the Trustee, on the other hand, (x) the maturity of the obligations 
guaranteed hereby may be accelerated as provided in Article VII for the 
purposes of this Subsidiary Guarantee, notwithstanding any stay, injunction 
or other prohibition preventing such acceleration in respect of the obligations
guaranteed hereby, and (y) in the event of any acceleration of such obligations
as provided in Article VII and subject to the rescission thereof as provided 
therein, such obligations (whether or not due and payable) shall forthwith 
become due and payable by each Subsidiary Guarantor for the purpose of this
Subsidiary Guarantee. 

     SECTION 11.02. SUBSIDIARY GUARANTORS MAY CONSOLIDATE, ETC., ON CERTAIN 
TERMS.

          (a)  Except as set forth in Articles IV and V, nothing contained in 
     this Indenture or in any of the Notes shall prevent any consolidation or 
     merger of a Subsidiary Guarantor, with or into the Company or another 
     Subsidiary Guarantor or shall prevent any sale, assignment, transfer, 
     lease, conveyance or other disposition of the property of a Subsidiary 
     Guarantor as an entirety or substantially as an entirety, to the Company
     or another Subsidiary Guarantor.

          (b)  Except as set forth in Articles IV and V hereof, nothing 
     contained in this Indenture or in any of the Notes shall prevent any 
     consolidation or merger of a Subsidiary Guarantor with or into a Person
     other than the Company or a Subsidiary Guarantor (whether or not 
     affiliated with



                                   -77-


<PAGE>

     the Subsidiary Guarantor), or successive consolidations or mergers in which
     a Subsidiary Guarantor or its successor or successors shall be a party or 
     parties, or shall prevent any sale, assignment, transfer, lease, conveyance
     or other disposition of all or substantially all of the property of a 
     Subsidiary Guarantor, to a Person other than the Company or another 
     Subsidiary Guarantor (whether or not affiliated with the Subsidiary 
     Guarantor); PROVIDED, that (i) if the surviving Person is not the Company 
     or a Subsidiary Guarantor, the surviving corporation agrees to assume such
     Subsidiary Guarantor's Subsidiary Guarantee and all its obligations 
     pursuant to this Indenture (except to the extent that Section 11.04 would
     result in the release of such Subsidiary Guarantee), (ii) immediately 
     after giving effect to such transaction no Default or Event of Default 
     would exist or be continuing, and (iii) each Subsidiary Guarantor hereby
     covenants and agrees that, upon any such consolidation, merger, sale, 
     conveyance or other disposition, such Subsidiary Guarantor's Subsidiary 
     Guarantee set forth in this Article XI, and the due and punctual 
     performance and observance of all of the covenants and conditions of this
     Indenture to be performed by such Subsidiary Guarantor, shall be expressly
     assumed (in the event that the Subsidiary Guarantor is not the surviving
     corporation in a merger), by supplemental indenture reasonably satisfactory
     in form to the Trustee, executed and delivered to the Trustee, by such 
     Person formed by such consolidation, or into which the Subsidiary Guarantor
     shall have merged, or by the Person that shall have acquired such Property
     (except to the extent the following Section 11.04 would result in the 
     release of such Subsidiary Guarantee, in which case such surviving Person
     or transferee of such Property shall not have to execute any such 
     supplemental indenture and shall not have to assume such Subsidiary 
     Guarantor's Subsidiary Guarantee).  In the case of any such consolidation,
     merger, sale, conveyance or other disposition and upon the assumption by 
     the successor Person, by supplemental indenture executed and delivered to
     the Trustee and reasonably satisfactory in form to the Trustee of the due
     and punctual performance of all of the covenants and conditions of this 
     Indenture to be performed by the Subsidiary Guarantor, such successor 
     Person shall succeed to and be substituted for the Subsidiary Guarantor
     with the same effect as if it had been named herein as the initial 
     Subsidiary Guarantor.

     SECTION 11.03.  ADDITION OF SUBSIDIARY GUARANTORS. 

          (a)  The Company agrees to cause each Person that shall become a 
     Subsidiary after the date of this Indenture to execute and deliver a 
     supplemental indenture pursuant to which such Person guarantees the payment
     of the Notes on the same terms and conditions as the Subsidiary Guarantees
     by the Subsidiary Guarantors.

          (b)  Any Person that was not a Subsidiary Guarantor on the date of 
     this Indenture may become a Subsidiary Guarantor by executing and 
     delivering to the Trustee (i) a supplemental indenture in form and 
     substance satisfactory to the Trustee, which subjects such Person to the
     provisions of this Indenture as a Subsidiary Guarantor and (ii) an 
     Opinion of Counsel and Officers' Certificate to the effect that such
     supplemental indenture has been duly authorized and executed by such 
     Person and constitutes the legal, valid, binding and enforceable 
     obligation of such Person (subject to such customary exceptions 
     concerning creditors' rights and equitable principles as may 



                                   -78-


<PAGE>

     be acceptable to the Trustee in its discretion and provided that no 
     opinion need be rendered concerning the enforceability of the Subsidiary
     Guarantee).

     SECTION 11.04.  RELEASE OF A SUBSIDIARY GUARANTOR.

          (a)  Upon the sale or other disposition (by merger or otherwise) of
     a Subsidiary Guarantor (or all or substantially all of its assets) to a 
     Person other than the Company or another Subsidiary Guarantor and pursuant
     to a transaction that is otherwise in compliance with this Indenture 
     (including as described in Section 11.02 or Article V), such Subsidiary 
     Guarantor shall be deemed released from all of its Subsidiary Guarantees
     and related obligations in this Indenture; PROVIDED, HOWEVER, that any such
     termination shall occur only to the extent that all obligations of such 
     Subsidiary Guarantor under all of its guarantees of, and under all of its
     pledges of assets or other security interests which secure, other 
     Indebtedness of the Company or any Subsidiary shall also terminate or be
     released upon such sale or other disposition.

          (b)  Each Subsidiary Guarantor that is designated as an Unrestricted
     Subsidiary by the Company in accordance with the provisions of this 
     Indenture shall be deemed released from all of its Subsidiary Guarantees
     and related obligations in this Indenture for so long as it remains an 
     Unrestricted Subsidiary.

          (c)  The Trustee shall deliver an appropriate instrument evidencing 
     such release upon receipt of a request by the Company accompanied by an 
     Officers' Certificate and an Opinion of Counsel certifying that such sale
     or other disposition was made by the Company or the Subsidiary Guarantor,
     as the case may be, in accordance with the provisions of this  Indenture.
     Any Subsidiary Guarantor not so released remains liable for the full amount
     of principal of and interest on the Notes as provided in this Article XI.

          (d)  Any Subsidiary Guarantor not released in accordance with this 
     Section 11.04 shall remain liable for the full amount of principal of (and
     premium, if any, on) and interest on the Securities as provided in this 
     Article XI.

     SECTION 11.05. LIMITATION OF SUBSIDIARY GUARANTOR'S LIABILITY.

     Each Subsidiary Guarantor and by its acceptance hereof each Holder 
hereby confirms that it is the intention of all such parties that the 
guarantee by such Subsidiary Guarantor pursuant to its Subsidiary Guarantee 
not constitute a fraudulent transfer or conveyance for purposes of the 
Federal Bankruptcy Code, the Uniform Fraudulent Conveyance Act, the Uniform 
Fraudulent Transfer Act or any similar federal, state or foreign law.  To 
effectuate the foregoing intention, the Holders and each Subsidiary Guarantor 
irrevocably agree that the obligations of each Subsidiary Guarantor under the 
Subsidiary Guarantee shall be limited to the maximum amount as will, after 
giving effect to all other contingent and fixed liabilities of such 
Subsidiary Guarantor and after giving effect to any collections from or 
payments made by or on behalf of any other Subsidiary Guarantor in respect of 
the obligations of such other Subsidiary Guarantor under its Subsidiary 
Guarantee or pursuant to 



                                   -79-


<PAGE>

Section 11.06, result in the obligations of such Subsidiary Guarantor under 
its Subsidiary Guarantee not constituting a fraudulent conveyance or 
fraudulent transfer under federal, state or foreign law.  This Section 11.05 
is for the benefit of the creditors of each Subsidiary Guarantor, and, for 
purposes of the Federal Bankruptcy Code, the Uniform Fraudulent Conveyance 
Act, the Uniform Fraudulent Transfer Act and each other similar federal, 
state or foreign law, any Indebtedness of a Subsidiary Guarantor incurred 
from time to time pursuant to the Credit Facility shall be deemed to have 
been incurred prior to the incurrence by such Subsidiary Guarantor of 
liability under its Subsidiary Guarantee.

     SECTION 11.06. CONTRIBUTION.  In order to provide for just and equitable 
contribution among the Subsidiary Guarantors, the Subsidiary Guarantors 
agree, INTER SE, that in the event any payment or distribution is made by any 
Subsidiary Guarantor (a "Funding Guarantor") under the Subsidiary Guarantee, 
such Funding Guarantor shall be entitled to a contribution from each other 
Subsidiary Guarantor in a pro rata amount based on the Adjusted Net Assets of 
each Subsidiary Guarantor (including the Funding Guarantor) for all payments, 
damages and expenses incurred by the Funding Guarantor in discharging the 
Company's obligations with respect to the Notes or, subject to this Section 
11.06, any other Subsidiary Guarantor's obligations with respect to the 
Subsidiary Guarantee.

     SECTION 11.07.  SEVERABILITY.  In case any provision of this Subsidiary 
Guarantee shall be invalid, illegal or unenforceable, that portion of such 
provision that is not invalid, illegal or unenforceable shall remain in 
effect, and the validity, legality, and enforceability of the remaining 
provisions shall not in any way be affected or impaired thereby.

     SECTION 11.08.  SUBSIDIARY GUARANTEES SUBORDINATED TO GUARANTOR SENIOR 
INDEBTEDNESS.  Each Subsidiary Guarantor agrees, and each Holder by accepting 
a Note agrees, that the Indebtedness evidenced by its Subsidiary Guarantee is 
subordinate and subject in right of payment, to the extent and in the manner 
provided in this Article XI, to the prior payment in full of all Guarantor 
Senior Indebtedness (whether outstanding on the date hereof or hereafter 
created, incurred, assumed or guaranteed), and that the subordination is for 
the benefit of the holders of Guarantor Senior Indebtedness, PROVIDED, 
HOWEVER, that the Subsidiary Guarantee of such Subsidiary Guarantor, the 
Indebtedness represented thereby and the payment of the principal of (and 
premium, if any, on) and the interest on the Notes pursuant to such 
Subsidiary Guarantee in all respects shall rank PARI PASSU with, or prior to, 
all existing and future unsecured indebtedness (including, without 
limitation, Indebtedness) of such Subsidiary Guarantor that is subordinated 
to its Guarantor Senior Indebtedness.  This Article XI shall constitute a 
continuing offer to all Persons who become holders of, or continue to hold, 
Guarantor Senior Indebtedness, and such provisions are made for the benefit 
of the holders of Guarantor Senior Indebtedness.

     SECTION 11.09.  LIQUIDATION; DISSOLUTION; BANKRUPTCY.  Upon any 
distribution to creditors of any Subsidiary Guarantor in a liquidation or 
dissolution of such Subsidiary Guarantor or in a bankruptcy, reorganization, 
insolvency, receivership or similar proceeding relating to any Subsidiary 



                                   -80-


<PAGE>

Guarantor or its property, in an assignment for the benefit of creditors or 
any marshaling of any Subsidiary Guarantor's assets and liabilities:

     (a)  holders of such Subsidiary Guarantor's Guarantor Senior 
Indebtedness shall be entitled to receive payment in full in cash of all 
Obligations due in respect of such Guarantor Senior Indebtedness (including 
interest after the commencement of any such proceeding at the rate specified 
in the applicable Guarantor Senior Indebtedness) before Holders shall be 
entitled to receive any payment with respect to such Subsidiary Guarantor's 
Subsidiary Guarantee (except that Holders may receive (i) securities that are 
subordinated to at least the same extent as such Subsidiary Guarantor's 
Subsidiary Guarantee to (A) Guarantor Senior Indebtedness and (B) any 
securities issued in exchange for Guarantor Senior Indebtedness and (ii) 
payments and other distributions made from any defeasance trust created 
pursuant to Section 8.01 hereof); and

     (b)  until all Obligations with respect to such Subsidiary Guarantor's 
Guarantor Senior Indebtedness (as provided in subsection (a) above) are paid 
in full in cash, any distribution to which Holders would be entitled but for 
this Article shall be made to holders of Guarantor Senior Indebtedness 
(except that Holders may receive (i) securities that are subordinated to at 
least the same extent as such Subsidiary Guarantor's Subsidiary Guarantee to 
(A) Guarantor Senior Indebtedness and (B) any securities issued in exchange 
for Guarantor Senior Indebtedness and (ii) payments and other distributions 
made from any defeasance trust created pursuant to Section 8.01 hereof), as 
their interests may appear.

     SECTION 11.10.  DEFAULT ON DESIGNATED GUARANTOR SENIOR INDEBTEDNESS.  No 
Subsidiary Guarantor may make any payment or distribution to the Trustee or 
any Holder in respect of Obligations with respect to such Subsidiary 
Guarantor's Subsidiary Guarantee and may not acquire from the Trustee or any 
Holder any Notes for cash or property (other than (i) securities that are 
subordinated to at least the same extent as such Subsidiary Guarantor's 
Subsidiary Guarantee to (A) Guarantor Senior Indebtedness and (B) any 
securities issued in exchange for Guarantor Senior Indebtedness and (ii) 
payments and other distributions made from any defeasance trust created 
pursuant to Section 8.01 hereof) until all principal and other Obligations 
with respect to the Guarantor Senior Indebtedness have been paid in full if:

     (a)  a default in the payment of any principal, premium, if any, or 
interest with respect to Guarantor Designated Senior Indebtedness occurs and 
is continuing beyond any applicable grace period in the agreement, indenture 
or other document governing such Designated Guarantor Senior Indebtedness; or

     (b)  a default, other than such payment default, on Designated Guarantor 
Senior Indebtedness occurs and is continuing that then permits holders of such
Designated Guarantor Senior Indebtedness to accelerate its maturity and the 
Trustee receives a notice of such default (a "Subsidiary Guarantor Payment 
Blockage Notice") from a Person who may give it pursuant to Section 11.17 
hereof.  If the Trustee receives any such Subsidiary Guarantor Payment 
Blockage Notice, no subsequent Subsidiary Guarantor Payment Blockage Notice 
shall be effective for purposes of this 



                                   -81-


<PAGE>

Section 11.10 unless and until at least 360 days shall have elapsed since the 
effectiveness of the immediately prior Subsidiary Guarantor Payment Blockage 
Notice.  No default specified in this clause (b) that existed or was continuing
on the date of delivery of any Subsidiary Guarantor Payment Blockage Notice to
the Trustee shall be, or be made, the basis for a subsequent Subsidiary 
Guarantor Payment Blockage Notice.

     Such Subsidiary Guarantor may and shall resume payments on and 
distributions in respect of its Subsidiary Guarantee and may acquire them 
upon the earlier of:

          (i)  in the case of a default referred to in Section 11.10(a), the 
     date upon which such default is cured or waived, or

          (ii)  in the case of a default referred to in Section 11.10(b) hereof,
     the earlier of the date on which such default is cured or waived or 179 
     days after the date on which the applicable Subsidiary Guarantor Payment 
     Blockage Notice is received, unless the maturity of such Designated
     Guarantor Senior Indebtedness has been accelerated,

if, and only if,  this Article XI otherwise permits the payment, distribution 
or acquisition at the time of such payment or acquisition.

     SECTION 11.11.  WHEN DISTRIBUTION MUST BE PAID OVER.  In the event that 
the Trustee or any Holder receives any payment of any Obligations with 
respect to any Subsidiary Guarantee at a time when the Trustee or such 
Holder, as applicable, has actual knowledge that such payment is prohibited 
by Section 11.09 or 11.10 hereof, such payment shall be held by the Trustee 
or such Holder, in trust for the benefit of, and shall be paid forthwith over 
and delivered, upon written request, to, the holders of Guarantor Senior 
Indebtedness of the applicable Subsidiary Guarantor as their interests may 
appear or their Representative under the indenture or other agreement (if 
any) pursuant to such Guarantor Senior Indebtedness may have been issued, for 
application to the payment of all Obligations with respect to such Subsidiary 
Guarantor's Guarantor Senior Indebtedness remaining unpaid to the extent 
necessary to pay such Obligations in full in accordance with their terms, 
after giving effect to any concurrent payment or distribution to or for the 
holders of such Subsidiary Guarantor's Guarantor Senior Indebtedness.

     With respect to the holders of any Guarantor Senior Indebtedness, the 
Trustee undertakes to perform only such obligations on the part of the 
Trustee as are specifically set forth in this Article XI, and no implied 
covenants or obligations with respect to the holders of any Guarantor Senior 
Indebtedness shall be read into this Indenture against the Trustee.  The 
Trustee shall not be deemed to owe any fiduciary duty to the holders of 
Guarantor Senior Indebtedness, and shall not be liable to any such holders if 
the Trustee shall pay over or distribute to or on behalf of Holders or the 
Company or any other Person money or assets to which any holders of Guarantor 
Senior Indebtedness shall be entitled by virtue of this Article XI, except if 
such payment is made as a result of the willful misconduct or gross negligence
of the Trustee.



                                   -82-


<PAGE>

     SECTION 11.12.  NOTICE BY SUBSIDIARY GUARANTOR.  Each Subsidiary 
Guarantor shall promptly notify the Trustee and the Paying Agent of any facts 
known to such Subsidiary Guarantor that would cause a payment of any 
Obligations with respect to such Subsidiary Guarantor's Subsidiary Guarantee 
to violate this Article XI, but failure to give such notice shall not affect 
the subordination of such Subsidiary Guarantor's Subsidiary Guarantee to such 
Subsidiary Guarantor's Guarantor Senior Indebtedness as provided in this 
Article XI.

     SECTION 11.13.  SUBROGATION.  After all Guarantor Senior Indebtedness of 
a Subsidiary Guarantor is paid in full and until the Notes are paid in full, 
Holders shall be subrogated (equally and ratably with all other Indebtedness 
of such Subsidiary Guarantor PARI PASSU the Notes) to the rights of holders 
of such Guarantor Senior Indebtedness to receive distributions applicable to 
such Guarantor Senior Indebtedness to the extent that distributions otherwise 
payable to the Holders have been applied to the payment of such Guarantor 
Senior Indebtedness.  A distribution made under this Article XI to holders of 
such Guarantor Senior Indebtedness that otherwise would have been made to 
Holders is not, as between such Subsidiary Guarantor and Holders, a payment 
by such Subsidiary Guarantor on its Subsidiary Guarantee.

     SECTION 11.14.  RELATIVE RIGHTS.  This Article XI defines the relative 
rights of Holders and holders of Guarantor Senior Indebtedness.  Nothing in 
this Indenture shall:

          (i)  impair, as between the Subsidiary Guarantors and Holders, the 
     obligation of the Subsidiary Guarantors, which is absolute and 
     unconditional, to pay principal of, premium, if any, on and interest on 
     the Subsidiary Guarantees in accordance with their terms;

          (ii)  affect the relative rights of Holders and creditors of the 
     Subsidiary Guarantors other than their rights in relation to holders of 
     Guarantor Senior Indebtedness; or

          (iii)  prevent the Trustee or any Holder from exercising its 
     available remedies upon a Default or Event of Default, subject to the 
     rights of holders and owners of Guarantor Senior Indebtedness to receive 
     distributions and payments otherwise payable to Holders.

     If the Subsidiary Guarantors fail because of this Article XI to pay 
principal of, premium, if any, on or interest on a Note on the due date, the 
failure is still a Default or Event of Default.

     SECTION 11.15.  NO IMPAIRMENT OF SUBORDINATION BY SUBSIDIARY GUARANTORS 
OR HOLDERS.  (a) No right of any holder of Guarantor Senior Indebtedness to 
enforce the subordination of the Indebtedness evidenced by any Subsidiary 
Guarantor's Subsidiary Guarantee shall be impaired by any act or failure to 
act by such Subsidiary Guarantor or any Holder or by the failure of 
Subsidiary Guarantors or any Holder to comply with this Indenture.

     (b) Without in any way limiting the generality of paragraph (a) of this 
Section, the holders of any Guarantor Senior Indebtedness, may, at any time 
and from time to time, without the consent of or notice to the Trustee or the 
Holders, without incurring responsibility to the Holders and without impairing 
or releasing the subordination or other benefits provided in this Article XI, 
or the obligations hereunder of the Holders to the holders of Guarantor 
Senior Indebtedness, do any one or more of the following: (i) change the 
manner, place or terms of payment or extend the time of payment of, or renew, 
exchange, amend, increase or alter, Guarantor Senior Indebtedness or the 
terms of any instrument evidencing the same or any agreement under which 
Guarantor Senior Indebtedness is outstanding or any liability of any obligor 
thereon (unless such change, extension, amendment, increase or other 
alteration results in such Indebtedness no longer being Guarantor Senior 
Indebtedness as defined in this Indenture); (ii) sell, exchange, release or 
otherwise deal with any Property pledged, mortgaged or otherwise securing 
Guarantor Senior Indebtedness; (iii) settle or compromise any Guarantor 
Senior Indebtedness or any liability of any obligor thereon or release any 
Person liable in any manner for the collection of Guarantor Senior 
Indebtedness; and (iv) exercise or refrain from exercising any rights against 
the Company and any other Person.

     SECTION 11.16.  DISTRIBUTION OR NOTICE TO REPRESENTATIVE.  Whenever a 
distribution is to be made or a notice given to holders of Guarantor Senior 
Indebtedness, the distribution may be made and the notice given to their 
Representative.


                                     -83-
<PAGE>

     Upon any payment or distribution of assets of any Subsidiary Guarantor 
referred to in this Article XI, the Trustee and the Holders shall be entitled 
to rely upon any order or decree made by any court of competent jurisdiction 
or upon any certificate of such Representative or of the liquidating trustee 
or agent or other Person making any distribution to the Trustee or to the 
Holders for the purpose of ascertaining the Persons entitled to participate 
in such distribution, the holders of such Guarantor Senior Indebtedness and 
other Indebtedness of such Subsidiary Guarantor, the amount thereof or 
payable thereon, the amount or amounts paid or distributed thereon and all 
other facts pertinent thereto or to this Article XI.

     The Trustee shall be entitled to rely on the delivery to it of a written 
notice by a Person representing himself to be a holder of Guarantor Senior 
Indebtedness (or a trustee or agent on behalf of such holder) to establish 
that such notice has been given by a holder of such Guarantor Senior 
Indebtedness (or a trustee or agent on behalf of any such holder).  In the 
event that the Trustee determines in good faith that further evidence is 
required with respect to the right of any Person as a holder of such 
Guarantor Senior Indebtedness to participate in any payment or distribution 
pursuant to this Article XI, the Trustee may request such Person to furnish 
evidence to the reasonable satisfaction of the Trustee as to the amount of 
such Guarantor Senior Indebtedness held by such Person, the extent to which 
such Person is entitled to participate in such payment or distribution and 
any other facts pertinent to the rights of such Person under this Article XI, 
and if such evidence is not furnished, the Trustee may defer any payment 
which it may be required to make for the benefit of such Person pursuant to 
the terms of this Indenture pending judicial determination as to the rights 
of such Person to receive such payment.

     SECTION 11.17.  RIGHTS OF TRUSTEE AND PAYING AGENT.  Notwithstanding the 
provisions of this Article XI or any other provision of this Indenture, the 
Trustee shall not be charged with knowledge of the existence of any facts 
that would prohibit the making of any payment or distribution by the Trustee, 
and the Trustee and the Paying Agent may continue to make payments on the 
Notes, unless the Trustee shall have received at its Corporate Trust Office 
at least five Business Days prior to the date of such payment written notice 
of facts that would cause the payment of any Obligations with respect to any 
Subsidiary Guarantee to violate this Article XI. Only the holders of 
Designated Guarantor Senior Indebtedness or a Representative thereof may give 
the notice.  Nothing in this Article XI shall impair the claims of, or 
payments to, the Trustee under or pursuant to Section 7.07 hereof.

     The Trustee in its individual or any other capacity may hold Guarantor 
Senior Indebtedness with the same rights it would have if it were not 
Trustee.  Any Paying Agent may do the same with like rights.

     SECTION 11.18.  AUTHORIZATION TO EFFECT SUBORDINATION.  Each Holder of a 
Note by the Holder's acceptance thereof authorizes and directs the Trustee on 
the Holder's behalf to take such action as may be necessary or appropriate to 
effectuate the subordination as provided in this Article XI, and appoints the 
Trustee to act as the Holder's attorney-in-fact for any and all such 
purposes.  If the Trustee does not file a proper proof of claim or proof of 
debt in the form required in any 


                                     -84-
<PAGE>

judicial proceeding relative to any Subsidiary Guarantor (or any other 
obligor upon the Notes), its creditors or its property at least 30 days 
before the expiration of the time to file such claim, any Representative is 
hereby authorized to file an appropriate claim for and on behalf of the 
Holders of the Notes.

     SECTION 11.19.  AMENDMENTS.  The provisions of this Article XI shall not 
be amended or modified in a manner materially adverse to the Holders of 
Guarantor Senior Indebtedness without the written consent of the holders of 
all Designated Guarantor Senior Indebtedness.

                                 ARTICLE XII

                                MISCELLANEOUS

     SECTION 12.01.  TRUST INDENTURE ACT CONTROLS.  If and to the extent that 
any provision of this Indenture limits, qualifies or conflicts with the 
duties imposed by, or with another provision (an "incorporated provision") 
included in this Indenture by operation of, Sections 310 to 318, inclusive, 
of the Trust Indenture Act, such imposed duties or incorporated provision 
shall control.

     SECTION 12.02.  NOTICES.  Any notice or communication shall be in writing 
and delivered in person or mailed by first class mail, postage prepaid, 
addressed as follows: if to the Company or any Subsidiary Guarantor:  400 
West Illinois, 10th Floor, Midland, Texas  79701, Attention: Chief Financial 
Officer; if to the Trustee: State Street Bank and Trust Company, Two 
International Place, 4th Floor, Boston, Massachusetts  02110, Attention: 
Corporate Trust Department.

     The Company, the Subsidiary Guarantors or the Trustee, by notice to the 
other, may designate additional or different addresses for subsequent notices 
or communications.  Any notice or communication mailed to a Holder shall be 
sent to the Holder by first class mail, postage prepaid, at the Holder's 
address as it appears in the Security Register and shall be duly given if so 
sent within the time prescribed. Failure to mail a notice or communication to 
a Holder or any defect in it shall not affect its sufficiency with respect to 
other Holders.  If a notice or communication is mailed to the Company, the 
Trustee or a Holder in the manner provided above, it is duly given, whether 
or not the addressee receives it.  In case by reason of the suspension of 
regular mail service or by reason of any other cause it shall be 
impracticable to give notice by mail to Holders, then such notification as 
shall be made with the approval of the Trustee shall constitute a sufficient 
notification for every purpose hereunder.

     SECTION 12.03.  CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT.  Upon 
any request or application by the Company or any Subsidiary Guarantor to the 
Trustee to take or refrain from taking any action under this Indenture, the 
Company or such Subsidiary Guarantor shall furnish to the Trustee: (a) an 
Officers' Certificate stating that, in the opinion of the signers, all 
conditions precedent, if any, provided for in this Indenture relating to the 
proposed action have been complied with; and 


                                     -85-

<PAGE>

(b) an Opinion of Counsel stating that, in the opinion of such counsel, all 
such conditions precedent have been complied with.

     SECTION 12.04.  STATEMENTS REQUIRED IN CERTIFICATE OR OPINION.  Each 
certificate or opinion with respect to compliance with a covenant or 
condition provided for in this Indenture (other than pursuant to Section 4.19 
hereof) shall include: (a) a statement that the individual making such 
certificate or opinion has read such covenant or condition; (b) a brief 
statement as to the nature and scope of the examination or investigation upon 
which the statements or opinions contained in such certificate or opinion are 
based; (c) a statement that, in the opinion of such individual, such person 
has made such examination or investigation as is necessary to enable such 
person to express an informed opinion as to whether or not such covenant or 
condition has been complied with; and (d) a statement as to whether or not, 
in the opinion of such individual, such covenant or condition has been 
complied with.

     SECTION 12.05.  RULES BY TRUSTEE, PAYING AGENT AND REGISTRAR.  The 
Trustee may make reasonable rules for action by or a meeting of Holders, and 
any Registrar and Paying Agent may make reasonable rules for their functions; 
provided that no such rule shall conflict with terms of this Indenture or the 
Trust Indenture Act.

     SECTION 12.06.  PAYMENTS ON BUSINESS DAYS.  If a payment hereunder is 
scheduled to be made on a date that is not a Business Day, payment shall be 
made on the next succeeding day that is a Business Day, and no interest shall 
accrue with respect to that payment during the intervening period.  If a 
regular record date is a date that is not a Business Day, such record date 
shall not be affected.

     SECTION 12.07.  GOVERNING LAW.  THIS INDENTURE AND THE NOTES SHALL BE 
GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW 
YORK APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED IN SAID STATE.

     SECTION 12.08.  NO RECOURSE AGAINST OTHERS.  No director, officer, 
employee, incorporator or stockholder of the Company or any Subsidiary 
Guarantor, as such, shall have any liability for any obligations of the 
Company or any Subsidiary Guarantor under the Notes or this Indenture or for 
any claim based on, in respect of, or by reason of, such obligations or their 
creation, solely by reason of its status as a director, officer, employee, 
incorporator or stockholder of the Company or any Subsidiary Guarantor.  By 
accepting a Note, each Holder waives and releases all such liability (but 
only such liability) as part of the consideration for issuance of such Note 
to such Holder.

     SECTION 12.09.  SUCCESSORS.  All agreements of the Company and the 
Subsidiary Guarantors in this Indenture and the Notes shall bind its 
successors and assigns whether so expressed or not.  All agreements of the 
Trustee in this Indenture shall bind its successors and assigns whether so 
expressed or not.


                                     -86-

<PAGE>

     SECTION 12.10.  COUNTERPARTS.  This Indenture may be executed in any 
number of counterparts and by the parties thereto in separate counterparts, 
each of which when so executed shall be deemed to be an original and all of 
which taken together shall constitute one and the same agreement.

     SECTION 12.11.  TABLE OF CONTENTS; HEADINGS.  The table of contents, 
cross-reference table and headings of the Articles and Sections of this 
Indenture have been inserted for convenience of reference only, are not 
intended to be considered a part hereof and shall not modify or restrict any 
of the terms or provisions hereof.

     SECTION 12.12.  SEVERABILITY.  In case any provision in this Indenture 
or in the Notes shall be invalid, illegal or unenforceable, the validity, 
legality and enforceability of the remaining provisions shall not in any way 
be affected or impaired thereby.

     SECTION 12.13.  FURTHER INSTRUMENTS AND ACTS.  Upon request of the 
Trustee, the Company and the Subsidiary Guarantors will execute and deliver 
such further instruments and do such further acts as may be reasonably 
necessary or proper to carry out more effectively the purposes of this 
Indenture.

     IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be 
duly executed as of the day and year first above written.

                                       COSTILLA ENERGY, INC.

                                       By
                                         -----------------------------------
                                       Name:
                                       Title:

                                       STATE STREET BANK AND TRUST, as Trustee

                                       By
                                         -----------------------------------
                                       Name:
                                       Title:






                                     -87-

<PAGE>

                                       SUBSIDIARY GUARANTORS:

                                       COSTILLA PETROLEUM CORPORATION
                                       COSTILLA PIPELINE COMPANY
                                       STATEWIDE MINERALS CORPORATION
                                       VALLEY GATHERING COMPANY

                                       By
                                         -----------------------------------
                                       Name:
                                       Title:




























                                     -88-

<PAGE>
STATE OF NEW YORK                 )
                                  )         SS.:
COUNTY OF NEW YORK                )

     On the __ day of ______________, 1996, before me personally came 
_______________________, to me known, who, being by me duly sworn, did depose 
and say that he is ______________________ of Costilla Energy, Inc., one of 
the corporations described in and which executed the foregoing instrument, 
and that he signed his name thereto by authority of the Board of Directors of 
said corporation.

                                     --------------------------------------
                                                Notary Public

                                                State of New York
                                                My commission expires 
                                                                      -----

[Seal]


STATE OF NEW YORK                 )
                                  )         SS.:
COUNTY OF NEW YORK                )

     On the ____ day of __________________, 1996, before me personally came 
________________________, to me known, who, being by me duly sworn, did 
depose and say that ______ is ______________________ of State Street Bank and 
Trust Company, one of the corporations described in and which executed the 
foregoing instrument, and that he signed his name thereto by authority of the 
Board of Directors of said corporation.

                                  --------------------------------------
                                           Notary Public

                                  State of New York
                                  My commission expires 
                                                        ----------------
[Seal]






                                     -89-

<PAGE>
 
STATE OF NEW YORK                 )
                                  )         SS.:
COUNTY OF NEW YORK                )

     On the ____ day of __________________, 1996, before me personally came 
________________________, to me known, who, being by me duly sworn, did 
depose and say that ______ is ______________________ of Costilla Petroleum 
Corporation, one of the corporations described in and which executed the 
foregoing instrument, and that he signed his name thereto by authority of the 
Board of Directors of said corporation.

                                 -----------------------------------------
                                             Notary Public

                                 State of New York
                                 My commission expires 
                                                       -----------
[Seal]

STATE OF NEW YORK                 )
                                  )         SS.:
COUNTY OF NEW YORK                )

     On the ____ day of __________________, 1996, before me personally came 
________________________, to me known, who, being by me duly sworn, did 
depose and say that ______ is ______________________ of Costilla Pipeline 
Company, one of the corporations described in and which executed the 
foregoing instrument, and that he signed his name thereto by authority of the 
Board of Directors of said corporation.


                                 -----------------------------------------
                                             Notary Public

                                 State of New York
                                 My commission expires 
                                                       -----------
[Seal]









                                     -90-

<PAGE>

 
STATE OF NEW YORK                 )
                                  )         SS.:
COUNTY OF NEW YORK                )

     On the ____ day of __________________, 1996, before me personally came 
________________________, to me known, who, being by me duly sworn, did 
depose and say that ______ is ______________________ of Statewide Minerals 
Corporation, one of the corporations described in and which executed the 
foregoing instrument, and that he signed his name thereto by authority of the 
Board of Directors of said corporation.

                                 -----------------------------------------
                                             Notary Public

                                 State of New York
                                 My commission expires 
                                                       -----------
[Seal]

STATE OF NEW YORK                 )
                                  )         SS.:
COUNTY OF NEW YORK                )

     On the ____ day of __________________, 1996, before me personally came 
________________________, to me known, who, being by me duly sworn, did 
depose and say that ______ is ______________________ of Valley Gathering 
Company, one of the corporations described in and which executed the 
foregoing instrument, and that he signed his name thereto by authority of the 
Board of Directors of said corporation.

                                 -----------------------------------------
                                             Notary Public

                                 State of New York
                                 My commission expires 
                                                       -----------
[Seal] 












                                     -91-

<PAGE>


                                                                     EXHIBIT A

                           FORM OF FACE OF GLOBAL NOTE

                              COSTILLA ENERGY, INC.

No. ______                                               CUSIP No. ___________

     THIS NOTE IS A GLOBAL NOTE WITHIN THE MEANING OF THE INDENTURE 
     HEREINAFTER REFERRED TO.

     UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE 
     DEPOSITORY TRUST COMPANY TO COSTILLA ENERGY, INC. OR THE REGISTRAR FOR 
     REGISTRATION OF TRANSFER OR EXCHANGE AND ANY NOTE ISSUED IS REGISTERED 
     IN THE NAME OF CEDE & CO. OR SUCH OTHER ENTITY AS HAS BEEN REQUESTED BY
     AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY 
     PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS HAS BEEN
     REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY),
     ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO 
     ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS
     AN INTEREST HEREIN.

     TRANSFER OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN WHOLE, AND 
     NOT IN PART, TO NOMINEES OF THE DEPOSITORY TRUST COMPANY OR TO A SUCCESSOR
     THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF INTERESTS IN THIS 
     GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE 
     RESTRICTIONS SET FORTH IN SECTION 2.06 OF THE INDENTURE, DATED AS OF
     ___________________, 1996, BETWEEN COSTILLA ENERGY, INC., CERTAIN 
     SUBSIDIARY GUARANTORS, AND THE TRUSTEE NAMED THEREIN, PURSUANT TO WHICH 
     THIS NOTE WAS ISSUED.


<PAGE>

                                   GLOBAL NOTE                              
REPRESENTING ____% SENIOR SUBORDINATED NOTES DUE 2006

     Costilla Energy, Inc., a Delaware corporation, for value received, 
hereby promises to pay to CEDE & CO., or its registered assigns, the 
principal sum indicated on Schedule A hereof, on __________________, 2006.

     Reference is hereby made to the further provisions of this Note set 
forth on the reverse hereof, which further provisions shall for all purposes 
have the same effect as if set forth at this place.

     Unless the certificate of authentication hereon has been duly executed 
by the Trustee referred to on the reverse hereof by manual signature, this 
Note shall not be entitled to any benefit under the Indenture or be valid or 
obligatory for any purposes.
 
     IN WITNESS WHEREOF, the Company has caused this Note to be duly executed 
under its corporate seal.

                                         COSTILLA ENERGY, INC.

                                         By:                                  
                                            --------------------------------- 
                                         Name:  
                                         Title: 

[Corporate Seal]

Attest:

By:                                        
   --------------------------------- 
Name:  
Title: 

Dated:

TRUSTEE'S CERTIFICATE OF AUTHENTICATION

STATE STREET BANK AND TRUST COMPANY,
  as Trustee, certifies that this is one of
  the Notes referred to in the Indenture.

By:                                        
   ---------------------------------- 
         Authorized Signatory 


                                  A-2 
<PAGE>

                 FORM OF REVERSE SIDE OF GLOBAL NOTE

                         COSTILLA ENERGY, INC.
                              GLOBAL NOTE

         REPRESENTING ___% SENIOR SUBORDINATED NOTES DUE 2006

     1.  INDENTURE.

         This Note is one of a duly authorized issue of debt securities of 
the Company (as defined below) designated as its "____% Senior Subordinated 
Notes due 2006" (herein called the "Notes") limited in aggregate principal 
amount to $100,000,000, issued under an indenture dated as of _______________,
1996 (as amended or supplemented from time to time, the "Indenture") between 
the Company, certain subsidiaries of the Company (the "Subsidiary 
Guarantors") and State Street Bank and Trust Company, as trustee (the 
"Trustee," which term includes any successor Trustee under the Indenture), to 
which Indenture reference is hereby made for a statement of the respective 
rights, limitations of rights, duties and immunities thereunder of the 
Company, the Subsidiary Guarantors, the Trustee and each Holder of Notes and 
of the terms upon which the Notes are, and are to be, authenticated and 
delivered.  The summary of the terms of this Note contained herein does not 
purport to be complete and is qualified by reference to the Indenture.  All 
terms used in this Note which are not defined herein shall have the meanings 
assigned to them in the Indenture.

         The Indenture restricts, among other things, the Company's and its 
Subsidiaries' ability to incur additional indebtedness and issue preferred 
stock, incur liens to secure PARI PASSU or subordinated indebtedness, pay 
dividends or make certain other restricted payments, apply net proceeds from 
certain asset sales, enter into certain transactions with affiliates, incur 
indebtedness that is subordinate in right of payment to any Senior 
Indebtedness and senior in right of payment to the Notes, merge or 
consolidate with any other person, sell stock of Subsidiaries or sell, 
assign, transfer, lease, convey or otherwise dispose of substantially all of 
the assets of the Company.  The Indenture permits, under certain 
circumstances, Subsidiaries of the Company to be deemed Unrestricted 
Subsidiaries and thus not subject to the restrictions of the Indenture.

     2.  PRINCIPAL AND INTEREST.

         Costilla Energy, Inc., a Delaware corporation (such corporation, and 
its successors and assigns under the Indenture hereinafter referred to, being 
herein called the "Company"), promises to pay the principal amount set forth 
on Schedule A of this Note to the Holder hereof on ___________, 2006.

         The Company shall pay interest on this Note at a rate of ____%, per 
annum semiannually in arrears on ________________ __, and ________________ 
__, of each year, commencing on ____________ __, 1997, to the Holder hereof 
until the principal amount hereof is paid or duly provided for.  Interest 
shall accrue from __________________, 1996 or from the most 

                                  A-3 
<PAGE>

recent Interest Payment Date thereafter to which interest has been paid or 
duly provided for. The interest so payable, and punctually paid or duly 
provided for, on any Interest Payment Date will, subject to certain 
exceptions provided in the Indenture, be paid to the Person in whose name 
this Note (or the Note in exchange or substitution for which this Note was 
issued) is registered at the close of business on the Record Date for 
interest payable on such Interest Payment Date.  The Record Date for any 
interest payment is the close of business on ______________ __, or 
______________ __, as the case may be, whether or not a Business Day, 
immediately preceding the Interest Payment Date on which such interest is 
payable.  Any such interest not so punctually paid or duly provided for 
("Defaulted Interest") shall forthwith cease to be payable to the Holder on 
such Record Date and shall be paid as provided in Section 2.11 of the 
Indenture.  Interest will be computed on the basis of a 360-day year of 
twelve 30-day months.

         Each payment of interest in respect of an Interest Payment Date will 
include interest accrued through the day before such Interest Payment Date.  
If an Interest Payment Date falls on a day that is not a Business Day, the 
interest payment to be made on such Interest Payment Date will be made on the 
next succeeding Business Day with the same force and effect as if made on 
such Interest Payment Date, and no additional interest will accrue as a 
result of such delayed payment.

         To the extent lawful, the Company shall pay interest on overdue 
principal, overdue premium, and Defaulted Interest (without regard to any 
applicable grace period), at the interest rate borne on the Notes.  The 
Company's obligation pursuant to the previous sentence shall apply whether 
such overdue amount is due at its Stated Maturity, as a result of the 
Company's obligations pursuant to Section 3.05, Section 4.07 or Section 4.08 
of the Indenture, or otherwise.

     3.  METHOD OF PAYMENT.

         The Company, through the Paying Agent, shall pay interest on this 
Note to the registered Holder of this Note, as provided above.  The Holder 
must surrender this Note to a Paying Agent to collect principal payments.  
The Company will pay principal, premium, if any, and interest in money of the 
United States of America that at the time of payment is legal tender for 
payment of all debts public and private. Principal, premium, if any, and 
interest will be payable at the office of the Paying Agent but, at the option 
of the Company, interest may be paid by check mailed to the registered 
Holders at their registered addresses; PROVIDED that all payments with 
respect to Notes the Holders of which have given wire transfer instructions 
to the Company will be required to be made by wire transfer of immediately 
available funds to the accounts specified by the Holders thereof.

     4.  PAYING AGENT AND REGISTRAR.

         Initially, the Trustee will act as Paying Agent and Registrar under 
the Indenture.  The Company may, upon written notice to the Trustee, appoint 
and change any Paying Agent or Registrar.  The Company or any of its 
subsidiaries may act as Paying Agent or Registrar.

                                  A-4 
<PAGE>

     5.  OPTIONAL REDEMPTION.

         The Notes may not be redeemed at the Company's option prior to 
_____, 2001.  Thereafter, the Notes will be subject to redemption at the 
option of the Company, in whole or in part, upon not less than 30 calendar 
days' nor more than 60 calendar days' notice, at the redemption prices 
(expressed as percentages of principal amount) set forth below, plus accrued 
and unpaid interest thereon (if any) to the applicable Redemption Date, if 
redeemed during the twelve-month period beginning on _________ of the years 
indicated below:

              YEAR                                  PERCENTAGE 
              ----                                  ---------- 
              2001                                    _______%
              2002                                    _______%
              2003                                    _______%
              2004 and thereafter                     100.000%

         Notwithstanding the foregoing, at any time on or before 
_____________, 1999, the Company may (but shall not have the obligation to) 
redeem up to 30% of the original aggregate principal amount of the Notes at a 
redemption price of _______% of the principal amount thereof, plus accrued 
and unpaid interest thereon to the Redemption Date, with the net proceeds of 
an Equity Offering made by the Company; PROVIDED that at least 70% of the 
aggregate principal amount of Notes originally issued remain outstanding 
immediately after the occurrence of such redemption; and PROVIDED, FURTHER, 
that such redemption shall occur within 75 days of the date of the closing of 
such Equity Offering.

         The Notes are not subject to any sinking fund.

     6.  NOTICE OF REDEMPTION.

         At least 30 calendar days but not more than 60 calendar days before 
a Redemption Date, the Company will send a notice of redemption, first-class 
mail, postage prepaid, to Holders of Notes to be redeemed at the addresses of 
such Holders as they appear in the Security Register.

         If less than all of the Notes are to be redeemed at any time, the 
Notes to be redeemed will be chosen by the Trustee in accordance with the 
Indenture.  If any Note is redeemed subsequent to a Record Date with respect 
to any Interest Payment Date specified above and on or prior to such Interest 
Payment Date, then any accrued interest will be paid on such Interest Payment 
Date to the Holder of the Note at the close of business on such Record Date.  
If money in an amount sufficient to pay the Redemption Price of all Notes (or 
portions thereof) to be redeemed on the Redemption Date is deposited with the 
Paying Agent on or before the applicable Redemption Date and certain other 
conditions are satisfied, interest on the Notes or portions thereof to be 
redeemed on the applicable Redemption Date will cease to accrue.



                                  A-5 
<PAGE>

     7.  REPURCHASE AT THE OPTION OF HOLDERS UPON CHANGE OF CONTROL.

         Upon the occurrence of a Change of Control, each Holder of Notes 
shall have the right to require the Company to purchase such Holder's Notes, 
in whole or in part, in a principal amount that is an integral multiple of 
$1,000, pursuant to a Change of Control Offer, at a purchase price in cash 
equal to 101% of the aggregate principal amount thereof plus accrued and 
unpaid interest thereon to the Change of Control Payment Date.

         Within 30 calendar days following any Change of Control, the Company 
shall send, or cause to be sent, by first-class mail, postage prepaid, a 
notice regarding the Change of Control Offer to each Holder of Notes.  The 
Holder of this Note may elect to have this Note or a portion hereof in an 
authorized denomination purchased by completing the form entitled "Option of 
Holder to Elect Purchase" appearing below and tendering this Note pursuant to 
the Change of Control Offer.  Unless the Company defaults in the payment of 
the Change of Control Purchase Price with respect thereto, all Notes or 
portions thereof accepted for payment pursuant to the Change of Control Offer 
will cease to accrue interest from and after the Change of Control Payment 
Date.

     8.  REPURCHASE AT THE OPTION OF HOLDERS UPON ASSET SALE.

         If at any time the Company or any Subsidiary engages in any Asset 
Sale, the Company shall, within 30 calendar days of the date the amount of 
Excess Proceeds exceeds $5.0 million, use the then-existing Excess Proceeds 
to make an offer to purchase from all Holders, on a pro rata basis, Notes in 
an aggregate principal amount equal to the maximum principal amount that may 
be purchased out of the then-existing Excess Proceeds, at a purchase price in 
cash in an amount equal to 100% of the principal amount thereof plus accrued 
and unpaid interest thereon, if any, to the Asset Sale Payment Date.  Upon 
completion of an Asset Sale Offer (including payment of the Asset Sale 
Purchase Price for accepted Notes), any surplus Excess Proceeds that were the 
subject of such offer shall cease to be Excess Proceeds, and the Company may 
then use such amounts for general corporate purposes.

         Within 30 calendar days of the date the amount of Excess Proceeds 
exceeds $5.0 million, the Company shall send, or cause to be sent, by 
first-class mail, postage prepaid, a notice regarding the Asset Sale Offer to 
each Holder of Notes.  The Holder of this Note may elect to have this Note or 
a portion hereof in an authorized denomination purchased by completing the 
form entitled "Option of Holder to Elect Purchase" appearing below and 
tendering this Note pursuant to the Asset Sale Offer.  Unless the Company 
defaults in the payment of the Asset Sale Purchase Price with respect 
thereto, all Notes or portions thereof selected for payment pursuant to the 
Asset Sale Offer will cease to accrue interest from and after the Asset Sale 
Payment Date.

     9.  THE GLOBAL NOTE.

         So long as this Global Note is registered in the name of the 
Depositary or its nominee, members of, or participants in, the Depositary 
("Agent Members") shall have no rights under the 

                                  A-6 
<PAGE>

Indenture with respect to this Global Note held on their behalf by the 
Depositary or the Trustee as its custodian, and the Depositary may be treated 
by the Company, the Trustee and any agent of the Company or the Trustee as 
the absolute owner of this Global Note for all purposes.  Notwithstanding the 
foregoing, nothing herein shall (i) prevent the Company, the Trustee or any 
agent of the Company or the Trustee, from giving effect to any written 
certification, proxy or other authorization furnished by the Depositary or 
(ii) impair, as between the Depositary and its Agent Members, the operation 
of customary practices governing the exercise of the rights of a Holder of 
Notes.

         The Holder of this Global Note may grant proxies and otherwise 
authorize any Person, including Agent Members and Persons that may hold 
interests in this Global Note through Agent Members, to take any action which 
a Holder of Notes is entitled to take under the Indenture or the Notes.

         Whenever, as a result of optional redemption by the Company, a 
Change of Control Offer, an Asset Sale Offer or an exchange for Certificated 
Notes, this Global Note is redeemed, repurchased or exchanged in part, this 
Global Note shall be surrendered by the Holder thereof to the Trustee who 
shall cause an adjustment to be made to Schedule A hereof so that the 
principal amount of this Global Note will be equal to the portion not 
redeemed, repurchased or exchanged and shall thereafter return this Global 
Note to such Holder; PROVIDED that this Global Note shall be in a principal 
amount of $1,000 or an integral multiple of $1,000.

     10. TRANSFER AND EXCHANGE.

         The Holder of this Global Note shall, by acceptance of this Global 
Note, agree that transfers of beneficial interests in this Global Note may be 
effected only through a book entry system maintained by such Holder (or its 
agent), and that ownership of a beneficial interest in the Notes represented 
thereby shall be required to be reflected in book entry form.

         Transfers of this Global Note shall be limited to transfers in whole 
and not in part, to the Depositary, its successors, and their respective 
nominees.  Interests of beneficial owners in this Global Note shall be 
transferred in accordance with the rules and procedures of the Depositary (or 
its successors).

         This Global Note shall be exchanged by the Company for one or more 
Certificated Notes if (a) the Depositary (i) has notified the Company that it 
is unwilling or unable to continue as, or ceases to be, a clearing agency 
registered under Section 17A of the Exchange Act and (ii) a successor to the 
Depositary registered as a clearing agency under Section 17A of the Exchange 
Act is not able to be appointed by the Company within 90 calendar days or (b) 
the Depositary is at any time unwilling or unable to continue as Depositary 
and a successor to the Depositary is not able to be appointed by the Company 
within 90 calendar days.  If an Event of Default occurs and is continuing, 
the Company shall, at the request of the Holder hereof, exchange all or part 
of this Global Note for one or more Certificated Notes; PROVIDED that the 
principal amount of each of such Certificated Notes and this Global Note, 
after such exchange, shall be $1,000 or an integral multiple 

                                  A-7 
<PAGE>

thereof.  Whenever this Global Note is exchanged as a whole for one or more 
Certificated Notes, it shall be surrendered by the Holder to the Trustee for 
cancellation.  Whenever this Global Note is exchanged in part for one or more 
Certificated Notes, it shall be surrendered by the Holder to the Trustee and 
the Trustee shall make the appropriate notations hereon pursuant to Section 
2.05(c) of the Indenture.  All Certificated Notes issued in exchange for this 
Global Note or any portion hereof shall be registered in such names, and 
delivered, as the Depositary shall instruct the Trustee.

         The Holder of this Note shall have the right to obtain from the 
Company the information specified in Section 4.17 of the Indenture.

     11. DENOMINATIONS.

         The Notes are issuable only in registered form without coupons in 
denominations of $1,000 and integral multiples thereof of principal amount.

     12. UNCLAIMED MONEY.

         If money for the payment of principal, premium, if any, or interest 
remains unclaimed for two years, the Trustee or Paying Agent shall pay the 
money back to the Company at its request unless an abandoned property law 
designates another Person. After any such payment, Holders entitled to the 
money must look only to the Company and not to the Trustee for payment unless 
such abandoned property law designates another Person.

     13. DISCHARGE AND DEFEASANCE.

         Subject to certain conditions, the Company at any time may terminate 
some or all of its obligations under the Notes and the Indenture if the 
Company irrevocably deposits with the Trustee money or U.S. Government 
Obligations for the payment of principal, premium, if any, and interest on 
the Notes to redemption or maturity, as the case may be.

     14. AMENDMENT, WAIVER.

         Subject to certain exceptions set forth in the Indenture, (i) the 
Indenture or the Notes may be amended with the written consent of the Holders 
of at least a majority in principal amount of the outstanding Notes and (ii) 
any past Default and its consequences may be waived with the written consent 
of the Holders of at least a majority in principal amount of the outstanding 
Notes. Subject to certain exceptions set forth in the Indenture, without the 
consent of any Holder of Notes, the Company, the Subsidiary Guarantors and 
the Trustee may amend the Indenture or the Notes (i) to evidence the 
succession of another Person to (A) the Company and the assumption by such 
successor of the covenants of the Company under the Indenture and contained 
in the Notes or (B) a Subsidiary Guarantor and the assumption by such 
successor of the covenants of such Subsidiary Guarantor under the Indenture 
and contained in its Subsidiary Guarantee; (ii) to add additional covenants 
or to surrender rights and powers conferred on the Company or any Subsidiary 
Guarantor; (iii) to add any 

                                  A-8 
<PAGE>

additional Events of Default; (iv) to provide for uncertificated Notes in 
addition to or in place of Certificated Notes; (v) to evidence and provide 
for the acceptance of appointment under the Indenture of a successor Trustee; 
(vi) to secure the Notes; (vii) to cure any ambiguity in the Indenture, to 
correct or supplement any provision in the Indenture which may be 
inconsistent with any other provision therein or to add any other provisions 
with respect to matters or questions arising under the Indenture, PROVIDED 
that such actions shall not adversely affect the interests of the Holders in 
any material respect; (viii) to comply with the requirements of the 
Commission in order to effect or maintain the qualification of the Indenture 
under the Trust Indenture Act; or (ix) to release any Subsidiary Guarantor 
pursuant to the Indenture.

     15. DEFAULTS AND REMEDIES.

         If an Event of Default occurs and is continuing, the Trustee or the 
Holders of at least 25% in principal amount of the Notes, subject to certain 
limitations, may declare all the Notes to be immediately due and payable.  
Certain events of bankruptcy or insolvency are Events of Default and shall 
result in the Notes being-immediately due and payable upon the occurrence of 
such Events of Default without any further act of the Trustee or any Holder.

         Holders of Notes may not enforce the Indenture or the Notes except 
as provided in the Indenture.  The Trustee may refuse to enforce the 
Indenture or the Notes unless it receives reasonable indemnity or security.  
Subject to certain limitations, Holders of a majority in principal amount of 
the Notes may direct the Trustee in its exercise of any trust or power under 
the Indenture.  The Holders of a majority in principal amount of the then 
outstanding Notes, by written notice to the Trustee, may rescind any 
declaration of acceleration and its consequences if the rescission would not 
conflict with any judgment or decree, and if all Events of Default have been 
cured or waived except nonpayment of principal, interest or premium that has 
become due solely because of the acceleration.

     16. SUBORDINATION.

         The payment of principal of, premium, if any, and interest on the 
Notes will be subordinated in right of payment to the prior payment in full 
of Senior Indebtedness as set forth in Article X of the Indenture.

     17. SUBSIDIARY GUARANTEE.  

         Subject to the limitations set forth in the Indenture, the payment 
of principal of, premium, if any, and interest on the Notes will be 
guaranteed by each Subsidiary Guarantor and all additional Subsidiary 
Guarantors.  The obligations of the Subsidiary Guarantors to the Holders or 
the Trustee pursuant to the Subsidiary Guarantees and the Indenture will be 
subordinated in right of payment to the prior payment in full of Guarantor 
Senior Indebtedness as set forth in Article XI of the Indenture.

                                  A-9 
<PAGE>

     18. INDIVIDUAL RIGHTS OF TRUSTEE.

         Subject to certain limitations imposed by the Trust Indenture Act, 
the Trustee or any Paying Agent or Registrar, in its individual or any other 
capacity, may become the owner or pledgee of Notes and may otherwise deal 
with the Company or its Affiliates with the same rights it would have if it 
were not Trustee, Paying Agent or Registrar, as the case may be, under the 
Indenture.

     19. NO RECOURSE AGAINST CERTAIN OTHERS.

         No director, officer, employee, incorporator or stockholder of the 
Company or any Subsidiary Guarantor, as such, shall have any liability for 
any obligations of the Company or such Subsidiary Guarantor under the Notes 
or the Indenture or for any claim based on, in respect of, or by reason of, 
such obligations or their creation, solely by reason of its status as a 
director, officer, employee, incorporator or stockholder of the Company or 
any Subsidiary Guarantor.  By accepting a Note, each Holder waives and 
releases all such liability (but only such liability) as part of the 
consideration for issuance of such Note to such Holder.

     20. GOVERNING LAW.

         THE INDENTURE AND THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED IN 
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS 
MADE AND TO BE PERFORMED IN SAID STATE.

         The Company will furnish to any Holder of Notes upon written request 
and without charge to the Holder a copy of the Indenture which has in it the 
text of this Note.  Requests may be made to:

                                      Costilla Energy, Inc.
                                      400 West Illinois, 10th Floor
                                      Midland, Texas  79701
                                      Attention:  Chief Financial Officer





                                  A-10 
<PAGE>

                               SCHEDULE A

                       SCHEDULE OF PRINCIPAL AMOUNT

The initial principal amount at maturity of this Note shall be $100,000,000.  
The following decreases/increase in the principal amount at maturity of this 
Note have been made:

                                             TOTAL PRINCIPAL 
                                             AMOUNT AT       
                DECREASE IN   INCREASE IN    MATURITY        
DATE OF         PRINCIPAL     PRINCIPAL      FOLLOWING SUCH    NOTATION MADE   
DECREASE/       AMOUNT AT     AMOUNT AT      DECREASE/         BY OR ON BEHALF 
INCREASE        MATURITY      MATURITY       INCREASE          OF TRUSTEE      
- ---------       -----------   -----------    ---------------   --------------- 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 

_____________   ___________   ___________    _______________   _______________ 


                                  A-11 
<PAGE>

                               ASSIGNMENT

               (To be executed by the registered Holder
            if such Holder desires to transfer this Note)

FOR VALUE RECEIVED __________________ hereby sells, assigns and transfers unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
TAX IDENTIFYING NUMBER OF TRANSFEREE

_______________________________

_____________________________________________________________________________ 

              (Please print name and address of transferee) 
 
this Note, together with all right, title and interest herein, and does 
hereby irrevocably constitute and appoint ______________________________ 
Attorney to transfer this Note on the Security Register, with full power of 
substitution.

Dated:________________________ 


_______________________________        ______________________________________ 
Signature of Holder                    Signature Guaranteed by an institution 
                                       member of the Signature Guaranty 
                                       Medallion Program:


NOTICE:  The signature to the foregoing Assignment must correspond to the 
Name as written upon the face of this Note in every particular, without 
alteration or any change whatsoever.





                                  A-12 
<PAGE>

                               ASSIGNMENT

               (To be executed by the registered Holder
            if such Holder desires to transfer this Note)

FOR VALUE RECEIVED __________________ hereby sells, assigns and transfers unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
TAX IDENTIFYING NUMBER OF TRANSFEREE

_______________________________

_____________________________________________________________________________ 

              (Please print name and address of transferee) 
 
this Note, together with all right, title and interest herein, and does 
hereby irrevocably constitute and appoint ______________________________ 
Attorney to transfer this Note on the Security Register, with full power of 
substitution.

Dated:________________________ 


_______________________________        ______________________________________ 
Signature of Holder                    Signature Guaranteed by an 
                                       institution member of the
                                       Signature Guaranty Medallion
                                       Program


NOTICE:  The signature to the foregoing Assignment must correspond to the 
Name as written upon the face of this Note in every particular, without 
alteration or any change whatsoever.





                                  A-12 
<PAGE>

                     OPTION OF HOLDER TO ELECT PURCHASE
                           (check as appropriate)

/ /  In connection with the Change of Control Offer made pursuant to Section 
     4.07 of the Indenture, the undersigned hereby elects to have

     / /  the entire principal amount

     / /  $_________________ ($1,000 in principal amount or an integral multiple
           thereof) of this Note 

          repurchased by the Company.  The undersigned hereby directs the 
          Trustee or Paying Agent to pay it or ____________________ an amount
          in cash equal to 101% of the principal amount indicated in the 
          preceding sentence, plus accrued and unpaid interest thereon, if any,
          to the Change of Control Payment Date.

/ /  In connection with the Asset Sale Offer made pursuant to Section 4.08 of
     the Indenture, the undersigned hereby elects to have

     / /  the entire principal amount

     / /  $_________________ ($1,000 in principal amount or an integral multiple
          thereof) of this Note

          repurchased by the Company.  The undersigned hereby directs the 
          Trustee or Paying Agent to pay it or ____________________ an amount
          in cash equal to 100% of the principal amount indicated in the 
          preceding sentence, plus accrued and unpaid interest thereon, if any,
          to the Asset Sale Payment Date.

Dated:________________________ 


_______________________________        ______________________________________ 
Signature of Holder                    Signature Guaranteed by an institution
                                       member of the Signature Guaranty 
                                       Medallion Program 



NOTICE:  The signature to the foregoing must correspond to the Name as 
written upon the face of this Note in every particular, without alteration or 
any change whatsoever. 


                                     A-13 
<PAGE>

                                                                   EXHIBIT B

                      FORM OF FACE OF CERTIFICATED NOTE

                             COSTILLA ENERGY, INC.

No._________                                            CUSIP No. ___________



                    ___% SENIOR SUBORDINATED NOTE DUE 2006

     Costilla Energy, Inc., a Delaware corporation, for value received, hereby 
promises to pay to _________________ or its registered assigns, the principal 
amount of _____________ on ____________, 2006.

     Reference is hereby made to the further provisions of this Note set forth
on the reverse hereof, which further provisions shall for all purposes have the
same effect as if set forth at this place.

     Unless the certificate of authentication hereon has been duly executed 
by the Trustee referred to on the reverse hereof by manual signature, this 
Note shall not be entitled to any benefit under the Indenture or be valid or 
obligatory for any purposes.


<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Note to be duly executed 
under its corporate seal.

                                       COSTILLA ENERGY, INC.

                                       By:
                                           ----------------------------------
                                       Name:
                                       Title:


[Corporate Seal]

Attest:

By: 
   ---------------------------
Name:
Title:

Dated:

TRUSTEE'S CERTIFICATE OF AUTHENTICATION

STATE STREET BANK AND TRUST COMPANY,
    as Trustee, certifies that this is one of
    the Notes referred to in the Indenture.


By: 
   ---------------------------
       Authorized Signatory






                                    B-2


<PAGE>

                   FORM OF REVERSE SIDE OF CERTIFICATED NOTE

                              COSTILLA ENERGY, INC.

                  ____% SENIOR SUBORDINATED NOTE DUE 2006

     1.   INDENTURE.

          This Note is one of a duly authorized issue of debt securities of 
the Company (as defined below) designated as its "____% Senior Subordinated 
Notes due 2006" (herein called the "Notes") limited in aggregate principal 
amount to $100,000,000, issued under an indenture dated as of ________________,
1996 (as amended or supplemented from time to time, the "Indenture") between 
the Company, certain subsidiaries of the Company (the "Subsidiary Guarantors")
and State Street Bank and Trust Company, as trustee (the "Trustee," which 
term includes any successor Trustee under the Indenture), to which Indenture 
reference is hereby made for a statement of the respective rights, limitations
of rights, duties and immunities thereunder of the Company, the Subsidiary 
Guarantors, the Trustee and each Holder of Notes and of the terms upon which 
the Notes are, and are to be, authenticated and delivered.  The summary of the
terms of this Note contained herein does not purport to be complete and is 
qualified by reference to the Indenture.  All terms used in this Note which are
not defined herein shall have the meanings assigned to them in the Indenture.

          The Indenture restricts, among other things, the Company's and its 
Subsidiaries' ability to incur additional indebtedness and issue preferred 
stock, incur liens to secure PARI PASSU or subordinated indebtedness, pay 
dividends or make certain other restricted payments, apply net proceeds from 
certain asset sales, enter into certain transactions with affiliates, incur 
indebtedness that is subordinate in right of payment to any Senior Indebtedness
and senior in right of payment to the Notes, merge or consolidate with any 
other person, sell stock of Subsidiaries or sell, assign, transfer, lease, 
convey or otherwise dispose of substantially all of the assets of the Company.
The Indenture permits, under certain circumstances, Subsidiaries of the Company
to be deemed Unrestricted Subsidiaries and thus not subject to the restrictions
of the Indenture.

     2.   PRINCIPAL AND INTEREST.

          Costilla Energy, Inc., a Delaware corporation (such corporation, and
its successors and assigns under the Indenture hereinafter referred to, being 
herein called the "Company"), promises to pay the principal amount set forth on
the face hereof to the Holder hereof on __________________, 2006.

          The Company shall pay interest on this Note at a rate of ____%, per 
annum semiannually in arrears on _______________ __, and _____________ __ of 
each year, commencing on ____________ __, 1997, to the Holder hereof until 
the principal amount hereof is paid or duly provided for.  Interest shall 
accrue from _________________, 1996 or from the most recent Interest Payment 
Date thereafter to which interest has been paid or duly provided for.  The 
interest so 




                                    B-3


<PAGE>

payable, and punctually paid or duly provided for, on any Interest Payment 
Date will, subject to certain exceptions provided in the Indenture, be paid 
to the Person in whose name this Note (or the Note in exchange or substitution
for which this Note was issued) is registered at the close of business on the 
Record Date for interest payable on such Interest Payment Date.  The Record 
Date for any interest payment is the close of business on _________ __, or 
__________ __, as the case may be, whether or not a Business Day, immediately 
preceding the Interest Payment Date on which such interest is payable.  Any 
such interest not so punctually paid or duly provided for ("Defaulted Interest")
shall forthwith cease to be payable to the Holder on such Record Date and shall
be paid as provided in Section 2.11 of the Indenture.  Interest will be computed
on the basis of a 360-day year of twelve 30-day months.

          Each payment of interest in respect of an Interest Payment Date 
will include interest accrued through the day before such Interest Payment 
Date.  If an Interest Payment Date falls on a day that is not a Business Day, 
the interest payment to be made on such Interest Payment Date will be made on 
the next succeeding Business Day with the same force and effect as if made on 
such Interest Payment Date, and no additional interest will accrue as a 
result of such delayed payment.

          To the extent lawful, the Company shall pay interest on overdue 
principal, overdue premium, and Defaulted Interest (without regard to any 
applicable grace period), at the interest rate borne on the Notes.  The 
Company's obligation pursuant to the previous sentence shall apply whether 
such -overdue amount is due at its Stated Maturity, as a result of the 
Company's obligations pursuant to Section 3.05, Section 4.07 or Section 4.08 
of the Indenture, or otherwise.

     3.   METHOD OF PAYMENT.

          The Company, through the Paying Agent, shall pay interest on this 
Note to the registered Holder of this Note, as provided above.  The Holder 
must surrender this Note to a Paying Agent to collect principal payments.  The
Company will pay principal, premium, if any, and interest in money of the United
States of America that at the time of payment is legal tender for payment of all
debts public and private. Principal, premium, if any, and interest will be 
payable at the office of the Paying Agent but, at the option of the Company,
interest may be paid by check mailed to the registered Holders at their 
registered addresses; provided that all payments with respect to Notes the 
Holders of which have given wire transfer instructions to the Company will be
required to be made by wire transfer of immediately available funds to the 
accounts specified by the Holders thereof.

     4.   PAYING AGENT AND REGISTRAR.

          Initially, the Trustee will act as Paying Agent and Registrar under 
the Indenture.  The Company may, upon written notice to the Trustee, appoint and
change any Paying Agent or Registrar.  The Company or any of its subsidiaries 
may act as Paying Agent or Registrar.




                                    B-4


<PAGE>

     5.   OPTIONAL REDEMPTION.

          The Notes may not be redeemed at the Company's option prior to 
2001.  Thereafter, the Notes will be subject to redemption at the option of 
the Company, in whole or in part, upon not less than 30 calendar days' nor 
more than 60 calendar days' notice, at the redemption prices (expressed as 
percentages of principal amount) set forth below, plus accrued and unpaid 
interest thereon (if any) to the applicable Redemption Date, if redeemed 
during the twelve-month period beginning on ______________ of the years 
indicated below:

               Year                                Percentage
               2001                                 _______%
               2002                                 _______%
               2003                                 _______%
               2004 and thereafter                  100.000%

          Notwithstanding the foregoing, at any time on or before _____________,
1999, the Company may (but shall not have the obligation to) redeem up to 30% 
of the original aggregate principal amount of the Notes at a redemption price 
of _____% of the principal amount thereof, plus accrued and unpaid interest 
thereon to the Redemption Date, with the net proceeds of an Equity Offering 
made by the Company; provided that at least 70% of the aggregate principal 
amount of Notes originally issued remain outstanding immediately after the 
occurrence of such redemption; and provided, further, that such redemption 
shall occur within 75 days of the date of the closing of such Equity Offering.

     The Notes are not subject to any sinking fund.

     6.   NOTICE OF REDEMPTION.

          At least 30 calendar days but not more than 60 calendar days before 
a Redemption Date, the Company will send a notice of redemption, first-class 
mail, postage prepaid, to Holders of Notes to be redeemed at the addresses of 
such Holders as they appear in the Security Register.

          If less than all of the Notes are to be redeemed at any time, the 
Notes to be redeemed will be chosen by the Trustee in accordance with the 
Indenture.  If any Note is redeemed subsequent to a Record Date with respect 
to any Interest Payment Date specified above and on or prior to such Interest 
Payment Date, then any accrued interest will be paid on such Interest Payment 
Date to the Holder of the Note at the close of business on such Record Date.  
If money in an amount sufficient to pay the Redemption Price of all Notes (or 
portions thereof) to be redeemed on the Redemption Date is deposited with the 
Paying Agent on or before the applicable Redemption Date and certain other 
conditions are satisfied, interest on the Notes or portions thereof to be 
redeemed on the applicable Redemption Date will cease to accrue.





                                    B-5


<PAGE>

     7.   REPURCHASE AT THE OPTION OF HOLDERS UPON CHANGE OF CONTROL.

          Upon the occurrence of a Change of Control, each Holder of Notes 
shall have the right to require the Company to purchase such Holder's Notes, 
in whole or in part, in a principal amount that is an integral multiple of 
$1,000, pursuant to a Change of Control Offer, at a purchase price in cash 
equal to 101% of the aggregate principal amount thereof plus accrued and 
unpaid interest thereon to the Change of Control Payment Date.

          Within 30 calendar days following any Change of Control, the 
Company shall send, or cause to be sent, by first-class mail, postage 
prepaid, a notice regarding the Change of Control Offer to each Holder of 
Notes.  The Holder of this Note may elect to have this Note or a portion 
hereof in an authorized denomination purchased by completing the form 
entitled "Option of Holder to Elect Purchase" appearing below and tendering 
this Note pursuant to the Change of Control Offer.  Unless the Company 
defaults in the payment of the Change of Control Purchase Price with respect 
thereto, all Notes or portions thereof accepted for payment pursuant to the 
Change of Control Offer will cease to accrue interest from and after the 
Change of Control Payment Date.

     8.   REPURCHASE AT THE OPTION OF HOLDERS UPON ASSET SALE.

          If at any time the Company or any Subsidiary engages in any Asset 
Sale, the Company shall, within 30 calendar days of the date the amount of 
Excess Proceeds exceeds $5.0 million, use the then-existing Excess Proceeds 
to make an offer to purchase from all Holders, on a pro rata basis, Notes in 
an aggregate principal amount equal to the maximum principal amount that may 
be purchased out of the then-existing Excess Proceeds, at a purchase price in 
cash in an amount equal to 100% of the principal amount thereof plus accrued 
and unpaid interest thereon, if any, to the Asset Sale Payment Date.  Upon 
completion of an Asset Sale Offer (including payment of the Asset Sale 
Purchase Price for accepted Notes), any surplus Excess Proceeds that were the 
subject of such offer shall cease to be Excess Proceeds, and the Company may 
then use such amounts for general corporate purposes.

          Within 30 calendar days of the date the amount of Excess Proceeds 
exceeds $5.0 million, the Company shall send, or cause to be sent, by 
first-class mail, postage prepaid, a notice regarding the Asset Sale Offer to 
each Holder of Notes.  The Holder of this Note may elect to have this Note or 
a portion hereof in an authorized denomination purchased by completing the 
form entitled "Option of Holder to Elect Purchase" appearing below and 
tendering this Note pursuant to the Asset Sale Offer.  Unless the Company 
defaults in the payment of the Asset Sale Purchase Price with respect 
thereto, all Notes or portions thereof selected for payment pursuant to the 
Asset Sale Offer will cease to accrue interest from and after the Asset Sale 
Payment Date.

     9.   TRANSFER AND EXCHANGE.

          A Holder may transfer a Note only upon the surrender of such Note 
for registration of transfer.  No such transfer shall be effected until, and 
such transferee shall succeed to the rights 



                                    B-6


<PAGE>

of a Holder only upon, final acceptance and registration of the transfer in 
the Security Register by the Registrar.  When Notes are presented to the 
Registrar with a request to register the transfer of, or to exchange, such 
Notes, the Registrar shall register the transfer or make such exchange as 
requested if its requirements for such transactions and any applicable 
requirements hereunder are satisfied.

          No service charge shall be made for any registration of transfer or 
exchange of Notes, but the Company may require payment of a sum sufficient to 
cover any tax or other governmental charge that may be imposed in connection 
with any registration of transfer of Notes.  

          The Holder of this Note shall have the right to obtain from the 
Company the information specified in Section 4.17 of the Indenture.

     10.  DENOMINATIONS.

          The Notes are issuable only in registered form without coupons in 
denominations of $1,000 and integral multiples thereof of principal amount.

     11.  UNCLAIMED MONEY.

          If money for the payment of principal, premium, if any, or interest 
remains unclaimed for two years, the Trustee or Paying Agent shall pay the 
money back to the Company at its request unless an abandoned property law 
designates another Person.  After any such payment, Holders entitled to the 
money must look only to the Company and not to the Trustee for payment unless 
such abandoned property law designates another Person.

     12.  DISCHARGE AND DEFEASANCE.

          Subject to certain conditions, the Company at any time may 
terminate some or all of its obligations under the Notes and the Indenture if 
the Company irrevocably deposits with the Trustee money or U.S. Government 
Obligations for the payment of principal, premium, if any, and interest on 
the Notes to redemption or maturity, as the case may be.

     13.  AMENDMENT, WAIVER.

          Subject to certain exceptions set forth in the Indenture, (i) the 
Indenture or the Notes may be amended with the written consent of the Holders 
of at least a majority in principal amount of the outstanding Notes and (ii) 
any past Default and its consequences may be waived with the written consent 
of the Holders of at least a majority in principal amount of the outstanding 
Notes.  Subject to certain exceptions set forth in the Indenture, without the 
consent of any Holder of Notes, the Company, the Subsidiary Guarantors and 
the Trustee may amend the Indenture or the Notes (i) to evidence the 
succession of another Person to (A) the Company and the assumption by such 
successor of the covenants of the Company under the Indenture and contained 
in the Notes or (B) a Subsidiary Guarantor and the assumption by such 
successor of the covenants of such Subsidiary Guarantor under 




                                    B-7


<PAGE>

the Indenture and contained in its Subsidiary Guarantee; (ii) to add 
additional covenants or to surrender rights and powers conferred on the 
Company or any Subsidiary Guarantor; (iii) to add any additional Events of 
Default; (iv) to provide for uncertificated Notes in addition to or in place 
of Certificated Notes; (v) to evidence and provide for the acceptance of 
appointment under the Indenture of a successor Trustee; (vi) to secure the 
Notes; (vii) to cure any ambiguity in the Indenture, to correct or supplement 
any provision in the Indenture which may be inconsistent with any other 
provision therein or to add any other provisions with respect to matters or 
questions arising under the Indenture, PROVIDED that such actions shall not 
adversely affect the interests of the Holders in any material respect; (viii) 
to comply with the requirements of the Commission in order to effect or 
maintain the qualification of the Indenture under the Trust Indenture Act; or 
(ix) to release any Subsidiary Guarantor pursuant to the Indenture.

     14.  DEFAULTS AND REMEDIES.

          If an Event of Default occurs and is continuing, the Trustee or the 
Holders of at least 25% in principal amount of the Notes, subject to certain 
limitations, may declare all the Notes to be immediately due and payable.  
Certain events of bankruptcy or insolvency are Events of Default and shall 
result in the Notes being immediately due and payable upon the occurrence of 
such Events of Default without any further act of the Trustee or any Holder.

          Holders of Notes may not enforce the Indenture or the Notes except 
as provided in the Indenture.  The Trustee may refuse to enforce the 
Indenture or the Notes unless it receives reasonable indemnity or security.  
Subject to certain limitations, Holders of a majority in principal amount of 
the Notes may direct the Trustee in its exercise of any trust or power under 
the Indenture.  The Holders of a majority in principal amount of the then 
outstanding Notes, by written notice to the Trustee, may rescind any 
declaration of acceleration and its consequences if the rescission would not 
conflict with any judgment or decree, and if all Events of Default have been 
cured or waived except nonpayment of principal, interest or premium that has 
become due solely because of the acceleration.

     15.  SUBORDINATION.

          The payment of principal of, premium, if any, and interest on the 
Notes will be subordinated in right of payment to the prior payment in full 
of Senior Indebtedness as set forth in Article X of the Indenture.

     16.  SUBSIDIARY GUARANTEE.

          Subject to the limitations set forth in the Indenture, the payment 
of principal of, premium, if any, and interest on the Notes will be 
guaranteed by each Subsidiary Guarantor and all additional Subsidiary 
Guarantors.  The obligations of the Subsidiary Guarantors to the Holders or 
the Trustee pursuant to the Subsidiary Guarantees and the Indenture will be 
subordinated in right of payment to the prior payment in full of Guarantor 
Senior Indebtedness as set forth in Article XI of the Indenture.




                                    B-8


<PAGE>

     17.  INDIVIDUAL RIGHTS OF TRUSTEE.

          Subject to certain limitations imposed by the Trust Indenture Act, 
the Trustee or any Paying Agent or Registrar, in its individual or any other 
capacity, may become the owner or pledgee of Notes and may otherwise deal 
with the Company or its Affiliates with the same rights it would have if it 
were not Trustee, Paying Agent or Registrar, as the case may be, under the 
Indenture.

     18.  NO RECOURSE AGAINST CERTAIN OTHERS.

          No director, officer, employee, incorporator or stockholder of the 
Company or any Subsidiary Guarantor, as such, shall have any liability for 
any obligations of the Company or such Subsidiary Guarantor under the Notes 
or the Indenture or for any claim based on, in respect of, or by reason of, 
such obligations or their creation, solely by reason of its status as a 
director, officer, employee, incorporator or stockholder of the Company or 
any Subsidiary Guarantor.  By accepting a Note, each Holder waives and 
releases all such liability (but only such liability) as part of the 
consideration for issuance of such Note to such Holder.

     19.  GOVERNING LAW.

          THE INDENTURE AND THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED IN 
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS 
MADE AND TO BE PERFORMED IN SAID STATE.

          The Company will furnish to any Holder of Notes upon written request
and without charge to the Holder a copy of the Indenture which has in it the 
text of this Note.  Requests may be made to:


                                       Costilla Energy, Inc.
                                       400 West Illinois, 10th Floor
                                       Midland, Texas  79701
                                       Attention: Chief Financial Officer




                                    B-9


<PAGE>

                                  ASSIGNMENT

                   (To be executed by the registered Holder
                if such Holder desires to transfer this Note)

FOR VALUE RECEIVED __________________________ hereby sells, assigns and 
transfers unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
TAX IDENTIFYING NUMBER OF TRANSFEREE

- -------------------------
                         |
- -----------------------------------------------------------------------------
                   (Please print name and address of transferee) 

- -----------------------------------------------------------------------------
this Note, together with all right, title and interest herein, and does hereby
irrevocably constitute and appoint ______________________________ Attorney to
transfer this Note on the Security Register, with full power of substitution.

Dated: 
       ------------------------

- ---------------------------------      ----------------------------------------
Signature of Holder                    Signature Guaranteed by an institution
                                       member of the Signature Guaranty 
                                       Medallion Program


NOTICE:  The signature to the foregoing Assignment must correspond to the Name 
as written upon the face of this Note in every particular, without alteration
or any change whatsoever. 





                                   B-10


<PAGE>

                      OPTION OF HOLDER TO ELECT PURCHASE
                             (check as appropriate)

/ /       In connection with the Change of Control Offer made pursuant to 
          Section 4.07 of the Indenture, the undersigned hereby elects to have

          / /     the entire principal amount

          / /     $_________________ ($1,000 in principal amount or an integral
                  multiple thereof) of this Note

          repurchased by the Company.  The undersigned hereby directs the 
          Trustee or Paying Agent to pay it or ____________________ an amount
          in cash equal to 101% of the principal amount indicated in the
          preceding sentence, plus accrued and unpaid interest thereon, if any,
          to the Change of Control Payment Date.

/ /       In connection with the Asset Sale Offer made pursuant to Section 4.08
          of the Indenture, the undersigned hereby elects to have

          / /     the entire principal amount

          / /     $_________________ ($1,000 in principal amount or an integral
                 multiple thereof) of this Note

          repurchased by the Company.  The undersigned hereby directs the 
          Trustee or Paying Agent to pay it or ____________________ an amount
          in cash equal to 100% of the principal amount indicated in the
          preceding sentence, plus accrued and unpaid interest thereon, if any,
          to the Asset Sale Payment Date.

Dated: 
       -------------------

- --------------------------------       ---------------------------------------
Signature of Holder                    Signature Guaranteed by an institution
                                       member of the Signature Guaranty 
                                       Medallion Program



NOTICE:  The signature to the foregoing must correspond to the Name as written 
upon the face of this Note in every particular, without alteration or any change
whatsoever.





                                   B-11



<PAGE>


                                                                    EXHIBIT 10.2

                                   LEASE AGREEMENT

STATE OF TEXAS

COUNTY OF MIDLAND

THIS LEASE AGREEMENT made and entered into this the 12th day of Jan., 1996,
between INDEPENDENCE PLAZA, LTD., a Texas Limited Partnership, (hereinafter
called "Landlord"), whose address for purposes hereof is 400 W. Illinois,
Midland, Texas 79701, and COSTILLA ENERGY, a Texas Corporation, (hereinafter
called "Tenant").

                                     WITNESSETH:

Section 1.  Premises
- --------------------

(I)      Subject to and upon the terms, provisions, and conditions hereinafter
set forth, and each in consideration of the duties, covenants, and obligations
of the other hereunder, Landlord does hereby lease, demise, and let to Tenant,
and the Tenant does hereby lease from Landlord, those certain premises being
approximately 22,500 square feet of net rentable area (the "Leased Premises") on
the 10TH Floor, Suite 1000, and the 11th Floor, Suite 1180, of the building
known as Independence Plaza, at 400 W. Illinois, Midland, Texas 79701, (The
"Building"), located on real property more particularly described on Exhibit A
attached hereto and made a part hereof for all purposes.

(II)          The term "Net Rentable Area" shall refer to (a) in the case of a
single tenancy floor, the entire area bounded by the outside surfaces of the
four exterior glass walls (or the outside surface of the permanent exterior
wall where there is no glass) of the Building on such floor less the area
contained within the exterior walls of the building stairs, fire towers,
vertical ducts, elevator shafts, flues, vents, stacks and pipe shafts plus all
the area on any single tenant floor that is used for elevator lobbies,
corridors, special stairways, restrooms, mechanical rooms, electrical rooms,
telephone and janitor closets, and all vertical penetrations that are included
for the special use of Tenant, and columns and other structural portions and/or
(b) in the case of a floor to be occupied by more than one (1) tenant, the
total of (i) the entire area included within the Leased Premises covered by
such lease, being the area bounded by the inside surface of any exterior glass
walls (or the inside surface of the permanent exterior wall where there is no
glass) of the Building bounding such Leased Premises, the exterior of all
walls separating such Leased Premises from any public corridors or other
public areas on such floor and the centerline of all walls separating such
Leased Premises from other areas leased or to be leased to other tenants on such
floor and (ii) a pro rata portion of the area covered by the elevator lobbies,
corridors, restrooms, mechanical rooms, electrical rooms, telephone and janitor
closets situated on such floor or other floors which may service such single
tenant floors.  The Net Rentable Area for the entire Building shall be deemed to
be 153,400 square feet for the purposes of the Lease.

(III)    The Net Rentable Area contained within the Leased Premises shall be
confirmed by an architect upon completion of Tenant Improvements and the Net
Rentable Area for the Leased Premises shall be amended accordingly on the basis
of the foregoing definition.  The Leased Premises are more particularly
designated on the floor plan of such Leased Premises attached hereto as Exhibit
B, attached hereto and made a part hereof for all purposes.

Section 2.  Term
- ----------------

Subject to and upon the terms and conditions set forth herein, or in any exhibit
or addendum hereto, this Lease shall commence on the 1st day of April, 1996,
(the "Commencement Date"), and shall end (unless sooner terminated) on the 31st
day of March, 2006.

Section 3.  Base Rental
- -----------------------

(I)      For the first five (5) annual periods of the Lease Term, Tenant hereby
agrees to pay to Landlord, without setoff or reduction whatsoever, a base annual
rental ("Base Rental") of $135,000.00, in monthly installments of $11,250.00.
For the subsequent five (5) annual periods of the Lease Term, Tenant hereby
agrees to pay Landlord $180,000.00, in monthly installments of $15,000.00.
Tenant shall also pay, as additional rent, all such other sums of money as shall
become due and payable under this Lease and all such other sums of money payable
as shall sometimes hereinafter collectively be called "Additional Rent." The
nonpayment of Base Rental shall entitle Landlord to exercise all such rights and
remedies as are herein provided.  The annual Base Rental, together with any
adjustment or increase thereto then in effect shall be due and payable in
advance in twelve (12) equal installments on the first (1st) day of each
calendar month during the term of this lease at Landlord's address provided
herein (or such other address as may be designated by Landlord or Landlord's
agent in writing from time to time).  If the term of this Lease commences on a
day other than the first (1st) day of a month or terminates on a day other than
the last day of a month, then the installments of Base Rental and any
adjustments thereto for such month shall be prorated, based on thirty (30) days
per month, and the installment or installments so prorated shall be paid in
advance.

(II)     All past due installments of rent shall bear interest at the annual
rate of 10% or the maximum lawful rate, whichever is lesser, until paid.

Section 4.  Base Rental Adjustment
- ----------------------------------

(I)      For the purposes of ascertaining the Base Rental Adjustment, the
following terms shall have the following meanings:


                                          1

<PAGE>


    (A)  "Base Rental Amount" shall mean $6.00 per square foot of Net
Rentable Area per annum, for the first five (5) annual periods, and $8.00 per
rentable square foot per annum for the subsequent five (5) annual periods.
    (B)  "Estimated Operating Expenses" shall mean Landlord's good faith
projection of Operating expenses for the forthcoming calendar year;
    (C)  "Tenant's Share" shall mean the ratio determined by dividing the Net
Rentable Area of the Leased Premises by the Net Rentable Area in the Building;
and
    (D)  "Operating Expenses" shall mean all expenses, costs, and disbursements
(but not replacement of capital investment items nor specific costs especially
billed to and paid by specific tenants) of every kind and nature which Landlord
shall pay or become obligated to pay because of or in connection with the
ownership and operation of the Building, including, but not limited to the
following:
    1.   Wages, salaries and fees of all personnel directly engaged in the
operation, maintenance, leasing (but not to include third party leasing
commissions), or security of the Building and personnel who may provide traffic
control relating to ingress and egress from the parking areas for the Building
to the adjacent public streets.  All taxes, insurance, and benefits relating to
employees providing these services shall also be included.
    2.   All supplies and material used in the operation and maintenance of the
Building.
    3.   Costs of all utilities for the building including, but not limited to,
the cost of water, electric energy, natural gas, other power, heating, lighting,
air conditioning, and ventilation.
    4.   Costs of all maintenance, janitorial, and service agreements for the
Building and the equipment therein, including but not limited to, alarm service,
window cleaning, and elevator maintenance.
    5.   Cost of all insurance relating to the Building including, but not
limited to, the cost of casualty and comprehensive liability insurance and
Landlord's personal property used in connection therewith.
    6.   All Taxes, assessments, and other governmental charges, whether
federal, state, county or municipal, and whether they be by taxing districts or
authorities presently taxing the Leased Premises or by others, subsequently
created or otherwise, and any other taxes and assessments attributable to the
Building or its operation.  Tenant will be responsible for taxes on its personal
property.
    7.   Cost of labor in performing repairs and general maintenance in
connection with the Building (excluding repairs and maintenance paid by proceeds
of insurance or by Tenant or other third parties).
    8.   Amortization of the cost of installation of capital investment items
which have a payout of 5 years or less and which are primarily for the purpose
of reducing operating costs of the Building or which may be required by
governmental authority.  All such costs shall be amortized over the reasonable
life of the capital investment items by an additional rent, with the reasonable
life and amortization schedule being determined by Landlord in accordance with
generally accepted accounting principles, but in no event to extend beyond the
reasonable life of the Building.
    9.   Landlord's reasonable accounting, auditing and legal costs applicable
to the usual and customary operations of the Building.
    10.  Landlord's actual annual cost for third-party management of the
Building or if Landlord itself manages the Building, the cost Landlord would
incur if it engaged a first-class property management firm located in the
Midland, Texas area to manage on Landlord's behalf.

(II)     The Base Rental adjustment shall be calculated in accordance with the
following factors:
    (A)  Tenant's Base Rental Amount includes a component applicable to
Operating Expenses equal to $4.08 per square foot of Net Rentable Area 
(commonly called expense stop).
    (B)  Prior to Tenant's occupancy of the Leased Premises, Landlord will
provide an updated estimate of Operating Expenses for the year in which
occupancy occurs.  If this estimate exceeds $4.08 per square foot of Net
Rentable Area, then Tenant's Base Rental shall be adjusted upward by the amount
of this excess.
    (C)  Prior to the commencement of each calendar year of Tenant's occupancy,
Landlord shall provide Tenant with its Estimated Operating Expenses for said
calendar year.  Tenant shall pay a Base Rental for said calendar year adjusted
upward or downward, as appropriate, by the amount of difference between the
prior calendar year's estimated Operating Expenses and the coming year's
Estimated Operating expenses.
    (D)  Within 120 days of the conclusion of each calendar year during the
lease term, or as soon thereafter as possible, Landlord shall furnish to Tenant
a statement of Landlord's Operating Expenses for said lease year.  A lump suit
payment will be made from Landlord to Tenant or from Tenant to Landlord, as
appropriate, within 30 days of the delivery of such statement equal to the
difference in actual Operating Expenses and Estimated Operating Expenses for the
just-completed year.  The effect of this reconciliation payment is that Tenant
will pay during the Term of this Lease Tenant's Proportionate Share of Operating
Expenses increases over the original $4.08 per square foot estimate and no more.
    (E)  The Proportionate Share to be paid by Tenant shall be fifteen percent
(15%) which is the approximate proportion which the Net Rentable Area contained
in the Leased Premises bears to the Total Net Rentable Area contained in the
Building.
    (F)  Tenant at its expense shall have the right at all reasonable times,
following prior written notice to Landlord to audit Landlord's books and records
relating to this Lease for any year or years for which Base Rental is adjusted
pursuant to Section 4. (II) hereof with the right to take copies or extras
thereof.  In addition, Landlord nay provide such an audit to Tenant as may have
been prepared by a certified public accountant.
    (G)  If this Lease shall terminate on a day other that the last day of a
calendar year, the amount of any adjustment between Estimated Operating Expenses
and actual operating Expenses shall be prorated on the basis which the number of
days from the commencement of such calendar year to and including such
termination date bears to 360; and any amount payable by Landlord to Tenant or
Tenant to Landlord with respect to such adjustment shall be payable within
thirty (30) days after delivery by Landlord to Tenant of the statement of actual
Operating Expenses with respect to such calendar year.
    (H)  Notwithstanding any other provisions herein to the contrary, in
determining the amount of the Operating Expenses for the Base Year and for any
subsequent year, if less than 95 percent of the Net Rentable Area for the
Building shall have been occupied by tenants at any time during such year,
Operating Expenses shall be deemed for such year to be an amount equal to the
like expenses which would normally be expected to be incurred


                                          2

<PAGE>

had such occupancy been 95 percent throughout such year and provided with
services as enumerated in Section 6 below.
    Nothing contained in this Paragraph II shall be construed at any tine so as
to reduce the monthly installments of Base Rental payable hereunder below the
amount set forth in Section 3 of this Lease.

Section 5.  Security Deposit
- ----------------------------

Intentionally omitted.

Section 6.  Services to be Furnished by Landlord
- ------------------------------------------------

Landlord shall furnish (at Landlord's cost) to Tenant while occupying the Leased
Premises the following services:
    (A)  Hot and cold water at those points of supply provided for general use
of the tenants in the Building;
    (B)  Heat and air conditioning in season, during normal business hours for
the Building at such temperatures and in such amounts as are considered by
Landlord to be standard.  Normal business hours are 7:00 am to 6:00 pm, Monday
through Friday and 7:00 am to 1:00 pm on Saturday.  Such service at times other
than normal business hours shall be optional on the part of Landlord, provided
that upon reasonable prior notice such service will be provided to Tenant at
Tenant's expense, at an hourly charge of $25.00;
    (C)  Elevator service in common with other tenants for ingress and egress
to and from the Building;
    (D)  Janitorial service on a five (5) day week basis provided that Tenant's
floor covering or other improvements are building standard.  If Tenant's
improvements require other than standard janitorial services, Tenant may
contract directly with a janitor, approved by Landlord, to clean those above
standard improvements at Tenant's cost.
    (E)  Electric current (110 volts) for normal office usage in the Leased
Premises and electric lighting service for all public areas and special service
areas of the Building.

Failure by Landlord to any extent to furnish, or any stoppage of, these defined
services, resulting from causes beyond the reasonable control of Landlord, or
from any other cause, shall not render Landlord liable in any respect for
damages to either person or property, nor shall be construed as an eviction of
Tenant, nor work as an abatement of rent, nor relieve Tenant from fulfillment of
any covenant or agreement hereof.  Should any equipment or machinery break down,
or for any cause cease to function properly, Landlord shall use reasonable
diligence to repair the same promptly.  Tenant shall have no claim for rebate of
rent or damages on account of any interruptions in service occasioned thereby or
resulting therefrom.

Notwithstanding the above, if there is an interruption in electricity, heating,
ventilating and air conditioning or water service to the Leased Premises and
such interruption continues for a period of five (5) consecutive business days
after receipt by Landlord of written notice from Tenant of such interruption,
the Tenant shall be entitled to an abatement of all Rental amounts (Base Rental
and any adjustments to rent) due effective from the time of interruption, which
abatement shall continue until such services are restored.

Section 7.  Keys and Locks
- --------------------------

Landlord shall furnish Tenant sixty (60) keys for each corridor door entering
the Leased Premises.  Additional keys will be furnished at a charge of $2.00
each by Landlord on receipt of an order signed by Tenant or Tenant's authorized
representative.  All such keys shall remain the property of Landlord.  No
additional locks shall be allowed on any door of the Leased Premises without
Landlord's written permission, and Tenant shall not make or permit to be made
any duplicate keys, except those furnished by Landlord.  Upon termination of
this Lease, Tenant shall surrender to Landlord all keys to the Leased Premises.
Landlord shall not be liable to Tenant for losses due to theft or burglary or
for damages done by unauthorized persons on the Leased Premises, unless such
theft or burglary or damages are caused by Landlord's negligence.

Section 8.  Signage
- -------------------

(I)      Landlord shall provide and install, at Landlord's cost, all letters or
numbers adjacent to Tenant's main door to corridor and on lobby directory upon
occupancy by Tenant of Leased Premises after Tenant has given written
instructions to Landlord stating exact name Tenant wishes to have appear on
signage, in the standard graphics for the Building.  Landlord shall further add
signage or change signage upon written instructions of Tenant to Landlord, if
space allows and at Tenant's cost.

(II)     Tenant shall not place signs or any other items on the Leased Premises
which may be visible from outside the Building or visible to the common areas
inside the Building, without first obtaining the written consent of Landlord in
each such instance.

Section 9.  Improvements to be Made by Landlord
- -----------------------------------------------

See Exhibit E.

Section 10.  Maintenance and Repairs by Landlord
- ------------------------------------------------

Unless otherwise stipulated herein, Landlord shall be required to maintain and
repair only the structural portions of the Building, both exterior and interior,
including the heating, ventilating, and air conditioning systems and equipment,
the public foyers, atriums and lobbies, the corridors, parking areas, elevators,
stairwells and restrooms and all other areas serving more than one tenant of the
Building; provided however that maintenance and repair of


                                          3

<PAGE>

interior partitioning walls, carpeting and other portions of the Leased Premises
which night otherwise be considered building standard finish shall not be the
obligation of Landlord.

Section 11.  Repairs by Tenant
- ------------------------------

Tenant covenants and agrees with Landlord that upon ten (10) days written
notice, at Tenant's own cost and expense, to repair or replace any damage or
injury done to the Leased Premises, Building, or any part thereof, caused by
Tenant or Tenant's agents and employees, along with any such damages done by
Tenant's employees, agents, invitees, or visitors in the Leased Premises, and
such repairs shall restore the Building to the same or as good a condition as it
was in prior to such injury or damage, and shall be effected in compliance with
all building and fire codes and other applicable laws and regulations; provided,
however, if Tenant fails to make such repairs or replacements promptly, Landlord
may, at its option, make such repairs or replacements, and Tenant shall repay
the cost thereof, plus an additional 15% charge to cover overhead, to Landlord
on demand.

SECTION 12.  CARE OF THE PREMISES
- ---------------------------------

Tenant covenants and agrees with Landlord to take good care of the Leased
Premises and the fixtures and appurtenances therein and, at Tenant's expense, to
make all non-structural repairs thereto as and when needed to preserve them in
good order and condition except for reasonable wear and tear.  Tenant shall not
commit or allow any waste or damage to be committed on any portion of the Leased
Premises, and at the termination of the Lease, by lapse of time or otherwise, to
deliver up the Leased premises to Landlord in as good a condition as at the date
of the commencement of the term of this Lease, ordinary wear and tear excepted,
and upon any termination of this Lease, Landlord shall have the right to re-
enter and resume possession of the Leased Premises.

Section 13.  Parking
- --------------------

During the term of this Lease, Tenant shall have, at no additional charge, sixty
(60) covered parking spaces, with initial parking cards provided at no charge.
Replacement of lost parking cards will be at a charge of $10.00 each.  Tenant
shall have the non-exclusive use in common with Landlord, other tenants of the
Building and their guests and invitees, of the common automobile parking areas,
driveways, and footways serving the Building, subject to rules and regulations
for the use thereof as prescribed from time to time by Landlord.  Landlord shall
not be liable or responsible for any loss of or damage to any car or vehicle or
equipment or other property therein or damage to property or injuries (fatal or
non-fatal), unless such loss, damage or injury is proximately caused by the
gross negligence of Landlord or its employees.  Landlord may make, modify, and
enforce reasonable rules and regulations relating to the parking of automobiles
and Tenant will abide by such rules and regulations.

Section 14.  Common Areas
- -------------------------

All automobile parking areas, driveways, entrances and exits thereto, and other
facilities furnished by Landlord, including all parking areas, stairways, and
other areas and improvements provided by Landlord for the general use, in
common, of tenants, their officers, agents, employees, invitees, licensees,
visitors and customers shall be at all times subject to the exclusive control
and management of Landlord, and Landlord shall have the right from time to time
to establish, modify and enforce reasonable rules and regulations with respect
to all facilities and areas mentioned in this paragraph.  Landlord shall have
the right to construct, maintain and operate lighting facilities in or on said
areas; amend the level, and location and arrangement of parking areas and other
facilities hereinabove referred to; to restrict parking by and enforce parking
charges to tenants, their officers, agents, invitees, employees, licensees,
visitors and customers; to close all or any portion of said area or facilities
to such extent as may, in the opinion of Landlord's counsel, be legally
sufficient to prevent a dedication thereof or the accrual of any rights to any
person or the public therein; to close temporarily all or any portion of the
public areas or facilities; to discourage noncustomer parking, to charge a fee
for visitor and/or customer parking in such garage facility, and to do and
perform such other acts in and to said areas and improvements as, in the use of
good business judgment, the Landlord shall determine to be advisable with a view
to the improvement of the convenience and use thereof by tenants, their
officers, agents, employees, invitees, visitors, licensees and customers.



Section 15.  Peaceful Enjoyment
- -------------------------------

Tenant shall, and may peacefully have, hold, and enjoy the Leased Premises,
subject to all other terms hereof, provided that Tenant pays the rent and other
sums herein recited to be paid by Tenant and performs all of Tenant's covenants
and agreements herein contained.  It is understood and agreed that this covenant
and any and all other covenants of Landlord contained in the Lease shall be
binding upon Landlord and its successors only with respect to breaches occurring
during its or their respective periods of ownership of Landlord's interest
hereunder, provided that any change of ownership of the Building will not in and
of itself discharge Landlord of any liability to Tenant incurred prior to such
ownership change.

Section 16.  Holding Over
- -------------------------

In the event of holding over the Leased Premises by Tenant without the written
consent of Landlord after the expiration or other termination of the Lease,
Tenant shall, throughout the entire holdover period, pay rent equal to one
hundred and fifty per cent (150%) of the Base Rental and Additional Rent which
would have been applicable had the term of this Lease continued for a period of
ninety (90) days.  No holding over by Tenant after the expiration of the term of
this Lease shall be construed to extend the term of this Lease; and in the event
of any unauthorized holding over, Tenant shall indemnify Landlord against all
claims for damages by any other tenant or prospective tenant to whom Landlord
may have leased all or any part of the Leased Premise effective before or after
the expiration of the term of this Lease, resulting from delay by Tenant in
delivering possession of all or any part


                                          4

<PAGE>

of the Leased Premises.  Any holding over with the written consent of Landlord
shall thereafter constitute a lease from month-to-month, under the terms and
provisions of this Lease to the extent applicable to a tenancy from month-to-
month.  Landlord shall have the right at all times during such holding over
period and without notice to enter and show the Leased Premises to prospective
tenants and real estate representatives.

Section 17.  Alterations, Additions and Improvements
- ----------------------------------------------------

Tenant covenants and agrees with Landlord not to make any material alterations
or physical additions in or to the Leased Premises without first obtaining the
written consent of Landlord in each such instance.  Landlord shall have the sole
right to refuse Tenant's request for improvements if these improvements are not
appropriate for the Building or Leased Premises.  All such improvements or
additions made to the Leased Premises shall at once become the property of
Landlord and shall be surrendered to Landlord upon Lease termination, excepting
Tenant's file systems.  Tenant shall be responsible for any lien filed against
the Leased Premise or any portion of the Building for work claimed to have been
done for, or materials claimed to have been furnished to Tenant.  Any and all
such alterations, physical additions, or improvements, when made to the Leased
Premises by Tenant, shall be at the Tenant's expense and shall at once become
the property of the Landlord and shall be surrendered to Landlord upon
termination of this Lease by lapse of time or otherwise; provided, however, this
clause shall not apply to movable fixtures, office equipment, and other personal
property owned by Tenant.

Section 18.  Use of Premises
- ----------------------------

The Leased Premises are to be used and occupied by Tenant solely for office
purposes and for no other purposes or use.  By execution of this Lease, Tenant
agrees to accept the Leased Premises, subject to Exhibit "E."

Section 19.  Laws and Regulations, Building Rules
- -------------------------------------------------

Tenant covenants and agrees with Landlord to reasonably comply with all laws,
ordinances, rules, and regulations of any state, federal, municipal or other
government or governmental agency having jurisdiction over the Leased Premises
and with all those reasonable rules and regulations established by Landlord,
attached hereto as Exhibit"D" and made a part hereof, and as may be altered by
Landlord from time to time for the proper operation, safety, care, and
cleanliness of the Leased Premises and Building and for the preservation of good
order therein, all changes to which will be sent by Landlord to Tenant in
writing and shall be thereafter carried out and observed by Tenant.  In the
event of a conflict or inconsistency between the provisions of this Lease and
the provisions of the Rules and Regulations, this Lease shall control.

Section 20.  Nuisance
- ---------------------

Tenant covenants and agrees with Landlord to conduct its business and to control
its agents, employees, invitees, and visitors in such manner as not to create
any nuisance, or interfere with, annoy, or disturb any other tenant or Landlord
in its operation of the Building.

Section 21.  Entry by Landlord
- ------------------------------

Tenant covenants and agrees upon receipt of reasonable notice from Landlord to
permit Landlord or its agents or representatives to enter into and upon any part
of the Leased Premises at all reasonable hours with prospective purchasers,
prospective tenants of the Building, mortgagees, or insurers, to clean or make
repairs, alterations, or additions thereto, as Landlord may deem necessary or
desirable, and Tenant shall not be entitled to any abatement or reduction of
rent by reasons thereof.

Section 22.  Assignment and Subletting
- --------------------------------------

(I)      Tenant shall not, without the prior written consent of Landlord, which
shall not be unreasonably withheld, (A) assign or in any manner transfer this
Lease or any estate or interest therein, or (B) permit any assignment or
transfer of this Lease, or (C) sublease the Leased Premises or any part thereof,
or (D) grant any license, concession, or other right of occupancy of any portion
of the Leased Premises.  Consent by Landlord to one or more assignments or
sublettings shall not operate as a waiver of Landlord's rights as to any
subsequent assignments and sublettings.  Notwithstanding any approved assignment
or subletting, Tenant shall at all times remain fully responsible and liable for
the payment of the rent herein specified and for compliance with all of Tenant's
other obligations under this Lease and in the event of any assignment, by
operation of law, merger, consolidation or otherwise, any assignee shall assume
and agree to perform all obligations of Tenant hereunder.  If an event of
default, as hereinafter defined, should occur while the Leased Premises or any
part thereof are then assigned or sublet, Landlord, in addition to any other
remedies herein provided or provided by law, may at its option, collect directly
from such assignee or sub-tenant, and apply such rent against any sums due to
Landlord by Tenant hereunder and Tenant hereby authorizes and directs any such
assignee or sub-tenant to make such payments of rent directly to Landlord upon
receipt of notice from Landlord.  No direct collection by Landlord from any such
assignee or sub-tenant shall be construed to constitute a novation or a release
of Tenant from the further performance of its obligations hereunder.  Receipt by
Landlord of rent from any assignee, sub-tenant, or occupant of the Leased
Premises shall not be deemed a waiver of the covenant contained in this Lease
against assignment and subletting or a release of Tenant under this Lease.
Tenant shall not mortgage, pledge, or otherwise encumber its interest in this
Lease or in the Leased Premises.  Any attempted assignment or sublease by Tenant
in violation of the terms and covenants of this paragraph shall be void.

(II)     In the event Tenant desires Landlord's consent to an assignment of the
Lease or subletting of all or a part of the Leased Premises and as a condition
to the granting of such consent, Tenant shall submit to Landlord in


                                          5

<PAGE>

writing the name of the proposed assignee or sub-tenant, the proposed
commencement date of such assignment or subletting, the nature and character of
the business of the assignee or sub-tenant and such financial information as
shall be reasonably necessary for Landlord to determine the credit worthiness of
such proposed assignee or sub-tenant, Landlord shall have the option (to be
exercised within thirty (30) days from submission of Tenant's written request),
(A) to refuse to consent to Tenant's assignment or subleasing of such space and
to compel Tenant to continue this Lease in full force and effect as to the
entire Leased Premises; or (B) to permit Tenant to assign or sublet such space;
subject, however, to provisions satisfactory to Landlord for payment to Landlord
of any consideration to be paid by such proposed assignee or subtenant in
connection with such assignment or subletting in excess of Base Rental otherwise
payable by Tenant and for payment to Landlord of any lump sum payment in
connection with such assignment or subletting.  If Landlord should fail to
notify Tenant in writing of its election as described above within such thirty
(30) day period, Landlord shall be deemed to have elected option (B) above.

Section 23.  Transfers of Landlord
- ----------------------------------

Landlord shall have the right to transfer and assign, in whole or in part, all
its rights and obligations hereunder and in the Building and property referred
to herein, and provided Landlord's transferee assumes the duties and obligations
of Landlord arising from and after the date of any such transfer or assignment,
upon such transfer or assignment Landlord shall be released from any further
obligations hereunder, and Tenant agrees to look solely to such successor-in-
interest of Landlord for the performance of such obligations.  Landlord shall
advise Tenant in writing of its assignee and all requisite contact names,
addresses and phone numbers prior to the effective date of assignment.
Notwithstanding the above, no such assignment will relieve Landlord of any
obligation to the Lease existing prior to such assignment and/or transfer.

Section 24.  Subordination to Mortgage
- --------------------------------------

This Lease shall be subject and subordinate to any mortgage or deed of trust
which may hereafter encumber the Building, and to all renewals, modifications,
consolidations, replacements, and extensions thereof, which contain (or which
are included in a separate agreement) provisions to the effect that if there
should be a foreclosure or sale under power under such mortgage or deed of
trust, Tenant shall not be made a party defendant thereto, nor shall such
foreclosure or sale under power disturb Tenant's possession under this Lease,
provided always Tenant shall not be in default under this Lease.  This clause
shall be self-operative and no further instrument of subordination need be
required by any mortgagee.  In confirmation of such subordination, however,
Tenant shall at Landlord's request, execute promptly, and in any event, not
later than ten (10) business days, any certificate or instrument evidencing such
subordination, but no more than four (4) times in a twelve (12) month period.
In the event of the enforcement by the trustee or the beneficiary under any such
mortgage or deed of trust of the remedies provided for by law or by such
mortgage or deed of trust, Tenant will, upon request of any person or party
succeeding to the interest of Landlord as a result of such enforcement,
automatically become the Tenant of such successor-in-interest without change in
the terms or other provisions of this Lease.

Section 25.  Mechanics Liens
- ----------------------------

Tenant will not permit any mechanic's lien or liens to be placed upon the Leased
Premises or improvements thereon or the Building during the term hereof caused
by or resulting from any work performed, materials furnished, or obligation
incurred by or at the request of Tenant, and nothing contained in this Lease
shall be deemed or construed in any way as constituting the consent or request
of Landlord, express or implied, by inference or otherwise, to any contractor,
sub-contractor, laborer, or materialman for the performance of any labor or the
furnishing of any materials for any specific improvement, alteration, or repair
of or to the Leased Premises, or any part thereof, nor as giving Tenant any
right, power, or authority to contract for or permit the rendering of any
services or the furnishing of any materials that would give rise to the filing
of any mechanic's or other liens against the interest of Landlord in the Leased
Premises.  In the case of the filing of any lien on the interest of Landlord or
Tenant in the Leased Premises, Tenant shall cause the same to be discharged of
record within ten (10) days after the filing of same by paying the amount
claimed to be due and procuring the discharge of such lien.  If Tenant shall
fail to discharge such mechanic's lien within such period, then, in addition to
any other right or remedy of Landlord, Landlord may, but shall not be obligated
to, discharge the same, either by paying the amount claimed to be due, or by
procuring the discharge of such lien by deposit in court or bonding.  However,
if such lien is being contested by Tenant, Landlord may cure only in the event
of a pending sale or refinancing of the property.  Any amount paid by Landlord
shall be repaid by Tenant to Landlord on demand, including interest thereon at
the rate of ten per cent (10%) per annum or the highest lawful rate, whichever
is the less.

Section 26.  Estoppel Certificates
- ----------------------------------

Tenant will, from time to time, upon not less than ten (10) days prior request
by Landlord, and at Landlord's reasonable request, but no more than four (4)
times in a twelve (12) month period, execute, acknowledge, and deliver to
Landlord promptly, and in any event not later than ten (10) business days, a
statement in writing executed by Tenant certifying that Tenant is in possession
of the Leased Premises under the terms of the Lease, that this Lease is
unmodified and in full effect (or, if there have been modifications, that this
Lease is in full effect as modified, and setting forth such modifications), and
that as of such date the rent has been paid, and either stating that to the
knowledge of Tenant no default exists hereunder, or specifying each such default
of which Tenant may have knowledge, and such other matters as may be reasonably
requested by Landlord; it being intended that any such statement by Tenant may
be relied upon by any prospective purchaser or mortgagee of the Building.

Section 27.  Events of Default
- ------------------------------

(I)      The following events shall be deemed to be "Events of Default" by
Tenant under this Lease:


                                          6

<PAGE>


    (A)  Failure to pay any installment of the Base Rental or other sums of
money payable hereunder when due and the continuance of such failure for ten
(10) days after receipt of written notice thereof;
    (B)  Failure to comply with any term, provision, or covenant of this Lease,
other than the payment of rent, and not curing such failure within a ten (10)
day grace period after written notice thereof to Tenant, or, if such failure
cannot reasonably be cured within such ten (10) day period, Tenant shall
commence such actions as are necessary to cure such defect within such ten (10)
day period and thereafter diligently prosecute such curative action.
    (C)  Tenant shall become insolvent, or shall make a transfer in fraud of
creditors, or shall commit any act of bankruptcy, or shall make an assignment
for the benefit of creditors or admission in writing of its inability to pay its
debts as they become due.
    (D)  Tenant shall file a petition with any bankruptcy court under any
section or chapter of the United States Bankruptcy Code, as amended, or under
any similar law or statute of the United States or any state thereof, or Tenant
shall be the subject of an order for relief issued under the United States
Bankruptcy Code, as amended, or under any similar law or statute, or Tenant
shall have filed any petition or answer seeking any reorganization, arrangement,
composition, readjustment, liquidation, dissolution, or similar relief under any
present or future federal or state act or law relating to bankruptcy, insolvency
or other relief of debtors, or Tenant shall be the subject of any order,
judgment or decree entered into by a court of competent jurisdiction approving a
petition filed against Tenant for any reorganization, arrangement, composition,
readjustment, liquidation, dissolution or similar relief under any present or
future federal or state act relating to bankruptcy, insolvency or other relief
for debtors.
    (E)  A receiver, conservator or trustee shall be appointed for all or
substantially all of the assets of Tenant or of the Leased Premises or any of
Tenant's property located thereon in any proceeding brought by Tenant, or any
such receiver or trustee shall be appointed in any proceeding brought against
Tenant and shall not be discharged within sixty (60) days after such
appointment, or tenant shall consent or acquiesce in such appointment.
    (F)  The Leased Premises hereunder shall be taken on execution or other
process of law in any action against Tenant.

(II)     If an Event of Default shall have occurred, Landlord shall have the
right at its election, then or at any time thereafter (and upon the expiration
of any applicable grace period, Tenant shall not be entitled to cure same and be
reinstated as "Tenant' in good standing hereunder), to pursue any one or more of
the following remedies in addition to all other rights or remedies provided
herein or at law or in equity:
    (A)  Landlord may terminate this Lease and forthwith repossess the Leased
Premises and shall be entitled to recover forthwith as damages a sum of money
equal to the total of (1) the cost of recovering the Premises, (2) the unpaid
rent earned at the time of termination, plus interest thereon at the rate of ten
percent (10%) per annum or the maximum legal rate, whichever is lesser, from the
due date, (3) the balance of the rent for the remainder of the term less the
fair market value of the Leased Premises for such period, and (4) any other sum
of money and damages owed by Tenant to Landlord in accordance herewith.
    (B)  Landlord may terminate Tenant's right of possession (but not the
Lease) and may repossess the Leased Premises by legal means or detainer suit,
without demand or notice of any kind to Tenant and without terminating this
Lease, in which event Landlord may, but shall be under no obligation to do so,
relet the same for the account of Tenant for such rent and upon such terms as
shall be satisfactory to Landlord.  For the purpose of such reletting, Landlord
is authorized to decorate or to make any reasonable repairs, changes,
alterations, or additions in or to the Leased Premises and to incur leasing
commissions that may be necessary or convenient and reasonable, and (1) if
Landlord shall fail or refuse to relet the Leased Premises or (2) if the same
are relet and a sum equal to the rent that would have otherwise been paid by
Tenant over time, discounted to obtain present value shall not be realized from
such reletting after paying the unpaid Base Rental Amount and Additional Rent
due hereunder earned, but unpaid at the time of reletting, plus ten percent
(10%) interest thereon or the highest lawful rate, whichever is lesser, the cost
of recovering possession, and all of the reasonable costs and expenses of such
decorations, repairs, changes, alterations and additions, and leasing
commissions and the expense of such reletting and of the collection of the rent
accruing therefrom to satisfy the rent provided for in this Lease to be paid,
then Tenant shall pay to Landlord as damages a sum equal to the amount of the
rent reserved in this Lease for such period or periods, or if the Leased
Premises have been relet Tenant shall satisfy and pay any such deficiency upon
demand therefor from time to time, and Tenant agrees that Landlord may file suit
to recover any sums falling due under the terms of this Section 27 from time to
time; and that no delivery or recovery of any portion due Landlord hereunder
shall be any defense in any action to recover any amount not theretofore reduced
to judgement in favor of Landlord, nor shall such reletting be construed as an
election on the part of Landlord to terminate this Lease unless a written notice
of such intention be given to Tenant by Landlord.  Notwithstanding any such
reletting without termination, Landlord may at any time thereafter elect to
terminate this Lease for such previous breach.

Section 28.  Landlord's Right to Relet
- --------------------------------------

In the event of default by Tenant in any of the terms or covenants of this Lease
or in the event the Leased Premises are abandoned by Tenant, Landlord shall take
reasonable steps to relet same for the remainder of the term provided for
herein, and if the rent received through reletting does not at least equal the
rent that would have otherwise been paid by Tenant over time, discounted to
obtain present value, Tenant shall pay and satisfy the deficiency between the
amount of the rent so provided for and that received through reletting,
including, but not limited to, the reasonable cost of renovating, altering and
decorating for a new occupant as well as any reasonable leasing commissions
incurred in connection therewith.  Nothing herein shall be construed as in any
way denying Landlord the right, in the event of abandonment of the Leased
Premises or other breach of this Lease by Tenant, to treat the same as an entire
breach of this Lease and any and all damages which Landlord suffers thereby.

Section 29.  Lien for Rent
- --------------------------

Landlord shall have a statutory lien as provided for by the laws of the State of
Texas.


                                          7

<PAGE>



Section 30.  Attorney's Fees
- ----------------------------

If on account of any breach or default by Tenant in its obligations hereunder,
Landlord shall employ an attorney to present, enforce or defend any of
Landlord's rights or remedies hereunder, Tenant agrees to pay any reasonable
attorney's fees incurred by Landlord in such connection.

Section 31.  No Implied Waiver
- ------------------------------

The failure of Landlord to insist at any time upon the strict performance of any
covenant or agreement or to exercise any option, right, power, or remedy
contained in this Lease shall not be construed as a waiver or a relinquishment
thereof for the future.  The waiver of or redress for any violation of any term,
covenant, agreement, or condition contained in the Lease shall not prevent a
subsequent act, which would have originally constituted a violation, from having
all the force and effect of an original violation.  No express waiver shall
affect any condition other than the one specified in such waiver and that one
only for the time and in the manner specifically stated.  A receipt by Landlord
of any rent with knowledge of the breach of any covenant or agreement contained
in this Lease shall not be deemed a waiver of such breach, and no waiver by
Landlord of any provision of this Lease shall be deemed to have been made unless
expressed in writing and signed by Landlord.  No payment by Tenant or receipt by
Landlord of a lesser amount than the monthly installment of rent due under this
Lease shall be deemed to be other than on account of the earliest rent due
hereunder, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment as rent be deemed an accord and satisfaction,
and Landlord may accept such check or payment without prejudice to Landlord's
right to recover the balance of such rent or pursue any other remedy in this
Lease provided.

Section 32.  Insurance
- ----------------------

PROPERTY:     Landlord shall maintain fire and extended coverage insurance on
the Building.  Such insurance shall be maintained with an insurance company
authorized to do business in Texas, in amounts desired by Landlord and at the
expense of Landlord (as a part of the Operating Expenses), and payments for
losses thereunder shall be made solely to Landlord.  If the annual premiums to
be paid by Landlord shall exceed the standard rates because Tenant's operations,
contents of the Leased Premises, or improvements with respect to the Leased
Premises are beyond building standard, Tenant shall pay the excess amount of the
premium within ten (10) days of receipt of written request by Landlord.  Tenant
acknowledges and agrees that insurance coverage carried by Landlord will not
cover Tenant's property within the Leased Premises or the Building and that
Tenant shall be responsible, at Tenant's sole cost and expense, for providing
insurance coverage for Tenant's movable equipment, furnishings, trade fixtures
and other personal property in or upon the Leased Premise or the building, and
for any alteration, additions or improvements to or of the Leased Premises or
any part thereof made by Tenant, in the event of damage or loss thereto from any
cause whatsoever.  Tenant reserves the right to self-insure the movable
equipment, furnishings, trade fixtures and other personal property in or upon
the Leased Premises or the building.

Tenant shall procure and maintain throughout the term of this Lease a policy or
policies of insurance, at its sole cost and expense, insuring Tenant and
Landlord against any and all liability for injury to or death of a person or
persons, occasioned by or arising out of or in connection with the use or
occupancy of the Leased Premises, the limits of such policy or policies to be in
an amount not less than $1,000,000 with respect to injuries to or death of any
person and in an amount of not less that $1,000,000 with respect to any one
accident or disaster, and shall furnish evidence satisfactory to Landlord of the
maintenance of such insurance.  Tenant shall obtain a written obligation on the
part of such insurance company to notify Landlord at least 10 days prior to
cancellation of such insurance.  It is recommended that Tenant carry fire and
extended coverage insurance on its personal property, as Landlord shall in no
event be required to rebuild, repair or replace any part of the furniture,
equipment, fixtures and other improvements which may have been placed by Tenant
on or within the Leased Premises.

Section 33.  Legal Use and Violations of Insurance Coverage
- -----------------------------------------------------------

Tenant covenants and agrees with Landlord not to occupy or use, or permit any
portion of the Leased Premises to be occupied or used, for any business or
purpose which is unlawful, disreputable, or deemed to be extra-hazardous on
account of fire, or permit anything to be done which would in any way increase
the rate of fire, liability, or any other insurance coverage on the Building
and/or its contents.  Landlord hereby agrees to provide Tenant written notice
from Landlord's insurer that Tenant's actions have resulted in an increase in
the rate of fire, liability, or any other insurance coverage on the Building
and/or its contents.

Section 34.  Indemnity
- ----------------------
Each party to this Agreement agrees to indemnify the other for and defend and
hold the other harmless from and against all fines, suits, claims, demands,
liabilities and actions (including reasonable costs and expenses of defending
against such claims) resulting or alleged to result from any breach, violation
or non-performance of any covenant or condition hereof, or from the use or
occupancy of the Leased Premises, by said party or its agents, employees,
licensees, or invitees, for any damage to person or property resulting from any
act or omission or negligence of any co-tenant, visitor or other occupancy of
the Leased Premises except as the party's own negligence may contribute thereto.

Section 35.  Waiver of Subrogation Rights
- -----------------------------------------

Anything in this Lease to the contrary notwithstanding, Landlord and Tenant each
hereby waives any and all rights of recovery, claim, action, or cause of action,
against the other, its agents, officers, or employees, for any loss or damage
that may occur to the Leased Premises, or any improvements thereto, or any
personal property of such party


                                          8

<PAGE>

therein, by reason of fire, the elements, or any other cause which are insured
against under the terms of standard fire and extended coverage of policies,
regardless of cause or origin, including negligence of the other party hereto,
its agents, officers, or employees, and covenants that no insurer shall hold any
right of subrogation against such other party.

Section 36.  Casualty Damage
- ----------------------------

If the Leased Premises or any part thereof shall be damaged by fire or other
casualty, Tenant shall give prompt written notice thereof to Landlord.  In case
the Building shall be damaged by fire or other casualty, but shall not be
rendered untenantable in whole or in part, Landlord shall, at its sole expense,
cause such damage to be repaired with reasonable diligence to substantially the
same condition in which it was immediately prior to the happening of the
casualty, and the Base Rental Amount hereunder shall not be abated; however, in
case the Building shall be so damaged by fire or other casualty that substantial
alteration or reconstruction of the Building shall, in the agreement of Landlord
and Tenant, or if they cannot agree, in the opinion of an independent third
party architect, be required (whether or not the Leased Premises shall have been
damaged by such fire or other casualty), or in the event any mortgagee under a
mortgage or deed of trust covering the Building should require that the
insurance proceeds payable as a result of said fire or other casualty be used to
retire the mortgage debt, Landlord or Tenant may, at their option, terminate
this Lease and the term and estate hereby granted by notifying Tenant in writing
of such termination within sixty (60) days after the date of such damage.  If
Landlord does not thus elect to terminate this Lease, Landlord shall within
seventy-five (75) days after the date of such damage commence to repair and
restore the Building and shall proceed with reasonable diligence to restore the
Building which restoration shall be completed no later than 120 days from the
date of such damage to substantially the same condition as in Exhibit E and in
which it was immediately prior to the happening of the casualty, except that
Landlord shall not be required to rebuild, repair, or replace any part of
Tenant's fixtures, equipment or other personal property removable by Tenant
under the provisions of this Lease, and Landlord shall not in any event be
required to spend for such work an amount in excess of the insurance proceeds
actually received by Landlord as a result of the fire or other casualty.
Landlord shall not be liable for any inconvenience or annoyance to Tenant or
injury to the business of tenant resulting in any way from such damage or the
repair thereof, except that, subject to the provisions of the next sentence,
Landlord shall allow Tenant a proportionate diminution of rent based on the
percentage of the Leased Premises that is affected during the time and to the
extent the Leased Premises, or any portion thereof, are unfit for occupancy.  If
the Premises or any other portion of the Building shall be damaged by fire or
other casualty resulting from the fault or negligence of Tenant or any of
Tenant's agents, employees, or invitees in the Leased Premises, the rent
hereunder shall not be diminished during the repair of such damage, and Tenant
shall be liable to Landlord for the cost and expense of the repair of such
damage, and Tenant shall be liable to Landlord for the cost and expense of the
repair and restoration of the Building caused thereby to the extent such cost
and expense is not covered by insurance proceeds.  Any insurance which may be
carried by Landlord or Tenant against loss or damage to the Building or to the
Leased Premises shall be for the sole benefit of the party carrying such
insurance and under its sole control.

Section 37.  Condemnation
- -------------------------

If the whole or substantially the whole of the Leased Premises should be taken
for any public or quasi-public use under any governmental law, ordinance, or
regulation or by right of eminent domain, or should be sold to the condemning
authority in lieu of condemnation, then this Lease shall terminate as of the
date when physical possession of the Leased Premises is taken by the condemning
authority.  If less than the whole or substantially the whole Building or the
Leased Premises is thus taken or sold, Landlord (whether or not the Leased
Premises are affected thereby) may terminate this Lease by giving written notice
thereof to Tenant within sixty (60) days after the right of election accrues, in
which event this Lease shall terminate as of the date when physical possession
of such portion of the Building or Leased Premises is taken by the condemning
authority.  If upon any such taking or sale of less than the whole or
substantially less than the whole of the Building or the Leased Premises, this
Lease shall not be thus terminated, the Base Rental Amount payable thereunder
shall be diminished by an amount representing that part of the Base Rental
Amount as shall properly be in Landlord's reasonable judgment, be allocable to
the portion of the Leased Premises which was so taken or sold or affected, and
Landlord shall, at Landlord's sole expense, restore and reconstruct the Parking
Area, Building or the Leased Premises, as the case may be, to substantially
their former condition to the extent that the same, in Landlord's judgment, may
be feasible; Landlord shall not in any event be required to spend for such work
an amount in excess of the amount received by Landlord as compensation awarded
upon a taking of any part or all of the Parking Area, Building or the Leased
Premises, and Tenant shall not be entitled to and expressly waives all claim to
any such compensation.  Tenant, however, reserves Tenant's right to make any
claim against the condemning authority which Tenant, at Tenant's sole
discretion, deems to be appropriate.

Section 38.  Notices and Cure
- -----------------------------

In the event of any act or omission by Landlord which would give Tenant the
right to damages from Landlord or the right to terminate this Lease by reason of
the constructive or actual eviction from all or part of the Leased Premises or
otherwise, Tenant shall not sue for such damages or exercise any such right to
terminate until it shall have given written notice of such act or omission to
Landlord, and a reasonable period of time for remedying such act or omission
shall have elapsed following the giving of such notice, during which time
Landlord and such holder(s) or either of them, their agents or employees, shall
be entitled to enter upon the Leased Premises and do therein whatever may be
necessary to remedy such act or omission.  During the period after the giving of
such notice and during the remedying of such act or omission, all Rental Amounts
payable by Tenant for such period as provided in this Lease shall be abated and
apportioned only to the extent that all or any part of the Leased Premises shall
be untenantable.


                                          9

<PAGE>


Section 39.  Personal Liability
- -------------------------------

The liability of Landlord for any default by Landlord under the terms of this
Lease shall be limited to the interest of Landlord in the building and the land
on which the building is situated, and Tenant agrees to look solely to
Landlord's interest in the Building and the land on which the Building is
situated for the recovery of any judgment from Landlord, it being intended that
Landlord shall not be personally liable for any judgment of deficiency.  This
clause shall not be deemed to limit or deny any remedies which Tenant may have
in the event of a default by Landlord hereunder which do not involve the
personal liability of Landlord.

Section 40.  Notice
- -------------------

Any notice, communication, request, reply, or advice (hereinafter severally and
collectively called "notice") in this Lease provided for or permitted to be
given, made, or accepted by either party to the other must be in writing, and
may, unless otherwise in this Lease expressly provided, be given or be served by
depositing the same in the United States mail, postpaid and certified and
address to the party to be notified, with return receipt requested, or by
delivering the same in person to any office of such party, or by prepaid
telegram, when appropriate, addressed to the party to be notified.  Notice
deposited in the mail in the manner herein above described shall be effective,
unless otherwise stated in this Lease, from and after the expiration of three
(3) days after it is so deposited.  Notice given in any other manner shall be
effective only if and when received by the party to be notified.  For purposes
of notice, the addresses of the parties shall, until changed as herein provided,
be as follows:

    For Landlord:       Independence Plaza, Ltd.
                        c/o The Bonner Group, Inc.
                        400 W. Illinois
                        Midland, Texas 79701

    For Tenant:         Costilla Energy
                        400 W. Illinois, Suite 1000
                        Midland, Texas 79701

The parties hereto and their respective heirs, successors, legal
representatives, and assigns shall have the right from time to time and at any
time to change their respective addresses and each shall have the right to
specify as its address any other address by at least fifteen (15) days written
notice to the other party delivered in compliance with this Section 40.

Section 41.  Surrender
- ----------------------

On the last day of the term of this Lease or upon the earlier termination of
this Lease, Tenant shall peaceably surrender the Leased Premises to Landlord in
good order, repair, and condition at least equal to the condition when delivered
to Tenant, excepting only reasonable wear and tear resulting from normal use,
the damage by fire or other casualty covered by the insurance carried by
Landlord.  All movable fixtures, office equipment, and other personal property
of Tenant shall remain the property of Tenant, and upon the expiration date or
earlier termination of this Lease may be removed from the Leased Premises by
Tenant, subject, however, to Landlord's lien for rent described herein;
provided, however, that Tenant shall repair and restore in a good and
workmanlike manner (reasonable wear and tear excepted) any damage to the Leased
Premises or Building caused by such removal.  Any of such movable fixtures,
office equipment and other personal property not so removed by Tenant at or
prior to the expiration date or earlier termination of this Lease shall become
the property of Landlord.  All other property as a part of the Leased Premises
attached or affixed to the floor, wall or ceiling of the Leased Premises
(including wall-to-wall carpeting, paneling or other wall covering) are the
property of Landlord and shall remain upon and be surrendered with the Leased
Premises as a part thereof at the termination of this Lease by lapse of time or
otherwise, Tenant hereby waiving all rights to any payment or compensation
therefor.  Notwithstanding anything herein to the contrary, Tenant's surrender
of the Leased Premises shall in no way affect Tenant's obligation to pay rent to
the date of expiration of this Lease, whether or not the amount of such
obligation has been ascertained either as of the date Tenant surrenders the
Leased Premises or as of the date of expiration of this Lease.



Section 42.  Relocation
- -----------------------

Intentionally omitted.

Section 43.  Captions
- ---------------------

The captions of each section of this Lease are inserted and included solely for
convenience and shall never be considered or given any effect in construing this
Lease, or any provisions hereof, or in connection with the duties, obligations,
or liabilities of the respective parties hereto, or in ascertaining intent, if
any questions of intent exists.

Section 44.  Entirety and Amendments
- ------------------------------------

This Lease embodies the entire contract between the parties hereto relative to
the subject matter hereof.  No variations, modifications, changes or amendments
herein or hereof shall be binding upon any party hereto unless in writing,
executed by a duly authorized officer or a duly authorized agent of the
particular party.  All exhibits referred to in this Lease and attached hereto
are incorporated herein for all purposes.


                                          10

<PAGE>


Section 45.  Severability
- -------------------------

If any term or provision of this Lease, or the application thereof to any person
or circumstance, shall, to any extent, be invalid or unenforceable, the
remainder of this Lease, or the application of such term or provision to
personae or circumstances other than those as to which it is held invalid or
unenforceable, shall not be affected thereby, and each term and provision of
this Lease shall be valid and enforced to the fullest extent permitted by law.

Section 46.  Binding Effect
- ---------------------------

Subject to Section 22, all covenants and obligations as contained within this
Lease shall bind, extend, and inure to the benefit of Landlord, its successors
and assigns, and shall be binding upon Tenant, its permitted successors and
assigns.

Section 47.  Number and Gender of Words
- ---------------------------------------

All personal pronouns used in this Lease shall include the other gender, whether
used in the masculine, feminine, or neuter gender, and singular shall include
the plural whenever and as often as may be appropriate.

Section 48.  Recordation
- ------------------------

Tenant agrees not to record this Lease, but on request of Landlord, will execute
a short form lease in a form recordable and complying with applicable Texas
laws.  In no event shall such document set forth the rental or other charges
payable by Tenant under this Lease; and any such document shall expressly state
that it is executed pursuant to the provisions contained in this Lease and is
not intended to vary the terms and conditions of this Lease.

Section 49.  Governing Law
- --------------------------

This Lease and rights and obligations of the parties hereto shall be
interpreted, construed, and
enforced in accordance with the laws of the State of Texas.

Section 50.  Force Majeure
- --------------------------

Whenever a period of time is herein prescribed for the taking of any action by
Landlord, Landlord shall not be liable or responsible for, and there shall be
excluded from the computation of such period of time, any delays due to strikes,
riots, acts of God, shortages of labor or materials, war, governmental laws,
regulations or restrictions, or any act, omission, delay or neglect of Tenant or
any of Tenant's employees or agents, or any other cause whatsoever beyond the
control of Landlord.  Furthermore, the foregoing shall in no manner release,
relieve or affect the independent obligation of Tenant to pay rent hereunder.

Section 51.  Relationship of Parties
- ------------------------------------

Nothing contained herein shall create any relationship between the parties
hereto other than that of Landlord and Tenant, and it is acknowledged and agreed
that Landlord does not in any way or for any purpose intend, nor shall this
Lease be construed to create as between Landlord and Tenant the relation of
partner, joint venturer or member of a joint or common enterprise with Tenant.

IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease in multiple
original counterparts as of the date and year first above written.

    Signed at Midland, Texas, this 12th day of Jan., 1996.
                                   ----        ----

LANDLORD                               TENANT

Independence Plaza, Ltd                Costilla Energy
By: 400 W. Illinois L.C.
    General Partner

By:    /S/ A. W. RUTTER, JR.           By:     /S/ MICHAEL J. GRELLA
   -----------------------------           ----------------------------
Title:     MANAGING PART.              Title:     PRESIDENT
      --------------------------              -------------------------
                                                  M. GRELLA


                                          11

<PAGE>

                                     EXHIBIT "A"
                                  LEGAL DESCRIPTION


TRACT 1
- -------

All of Lot six (6) and the south half (S/2) of Lot five (5) in Block twenty-
eight (28) of Original Town of Midland, Midland County, Texas, according to the
map or plat thereof recorded in Volume 3, Page 232 of the Deed Records of
Midland County, Texas.



TRACT 2
- -------

The south 25 feet of Lot three (3), all of Lot four (4) and the north half (N/2)
of Lot five (5) in Block twenty-eight (28) of Original Town of Midland, Midland
County, Texas, according to the map or plat thereof recorded in Volume 3, Page
232 of the Deed Records of Midland County, Texas.


                                          12

<PAGE>

                                     EXHIBIT "D"
                        LAWS AND REGULATIONS:  BUILDING RULES
                    --------------------------------------


1.  Landlord agrees to furnish Tenant with adequate keys to access the Building
and the Leased Premises.  Additional keys will be furnished at a normal charge.

2.  Tenant will refer all contractors, contractor's representatives and
installation technicians, rendering any service on or to the Leased Premises for
Tenant, to Landlord for Landlord's approval, and supervision before performance
of any contractual service, such approval shall not be unreasonably withheld.
This provision shall apply to all work performed in the Building including
installation of telephones, telegraph equipment, electrical devices and
attachments and installations of any nature affecting floors, walls, woodwork,
trim, windows, ceilings, equipment of any other physical portion of the
Building.

3.  Tenant shall at no time occupy part of the Building as sleeping or lodging
quarters.

4.  Tenant shall not place, install or operate on the Leased Premises or in any
part of the Building, any engine, stove or machinery, or conduct mechanical
operations or cook thereon or therein, or place or use in or about the leased
Premises any explosives, gasoline, kerosene, oil, acids, caustics, or any
inflammable, explosive, or hazardous material without written consent of
Landlord.

5.  Landlord will not be responsible except in the event of Landlord's willful
or gross negligence for lost or stolen personal property, equipment, money, or
jewelry from Tenant's area or public rooms regardless of whether such loss
occurs when area is locked against entry or not.

6.  No birds, fowl or animals shall be brought into or kept in or about the
Building, with.the exception of seeing-eye dogs.

7.  Employees of Landlord shall not receive or carry messages for or to any
Tenant or other person, nor contract with or render free or paid services to any
Tenant or Tenant's agents, employees or invitees.

8.  Landlord will not permit entrance to Tenant's offices by use of pass key
controlled by Landlord, to any person at any time without written permission by
Tenant, except employees, contractors or service personnel directly supervised
by Landlord.

9.  None of the entries, passages, doors, elevators, hallways or stairways
shall be blocked or obstructed, or any rubbish, litter, trash, or material of
any nature placed, emptied or thrown into these areas, nor any such areas by
used at any time except for ingress and egress by Tenant, Tenant's agents,
employees or invitees.

10. The water closets and other water fixtures shall not be used for any
purpose other than those for which they were constructed, and any damage
resulting to them from misuse or by the defacing or injury of any part of the
Building shall be borne by the person who shall occasion it.  No person shall
waste water by interfering with the faucets of otherwise.

11. Nothing shall be thrown out of the windows of the Building or down the
stairways or other passages.

12. Tenant agrees to reasonable parking control measures, which may be placed
into effect from time to time by Landlord through the use of signs, identifying
decals, or other instructions.

13. Movement in or out of the Building of furniture or office supplies and
equipment, or dispatch or receipt by Tenant of any merchandise or materials,
which requires use of elevators or stairways, or movement through the building
entrances, or lobby, shall be restricted to hours designated by Landlord.  All
such movement shall be under supervision of Landlord and carried out in the
manner agreed between Tenant and Landlord by prearrangement before performance.
Such prearrangement will include determination by Landlord of time, method, and
routing of movement and limitations imposed by safety or other concerns which
may prohibit any article, equipment or any other item from being brought into
the Building.  Tenant assumes, and shall indemnify Landlord against all risks
and claims of damage to persons and properties arising in connection with any
said movement.

14. No smoking is allowed in the Building lobbies, elevators, restrooms,
stairways, or any other common areas.

15. Landlord will provide and maintain an alphabetical directory board in the
ground floor lobby of the Building and allot one (1) name strip for Tenant.

16. The Landlord shall not be liable for damages from stoppage of elevators for
necessary or desirable repairs or improvements, or delays of any sort of
duration in connection with the elevator service.

17. All deliveries of any and all furniture, supplies, etc., will be made at
the back entrance of the Building.  Tenant will instruct the suppliers of this
delivery location.

18. Areas in the Parking Garage designated as Visitor Parking will be reserved
as such during normal working hours.  Tenants and their employees will observe
and respect this rule.


                                          13

<PAGE>


The Landlord reserves the right to make such other and further reasonable rules
and regulations as in its judgment may from time to time be needful, for the
safety, care and cleanliness of the Building and Leased Premises, and for the
preservation of good order therein; subject only to the terms and conditions of
the attached Lease.




/S/ MICHAEL J. GRELLA
Tenant



                                          14

<PAGE>

                                     EXHIBIT "F"

                                  SPECIAL PROVISIONS

1.  Right of First Refusal for Additional Space:

    Notwithstanding any of the provisions of this Lease to the contrary, as
long as Tenant is not in default under any of the provisions of this Lease
Agreement, Tenant shall have the right of first refusal to lease any additional
space that becomes available for lease on both the eleventh and the ninth floors
of the Building.  Rent for said space shall be no more than market rent for
space of comparable size and utility located in the Building.

    Any lease for additional space in the building which is in "slab"
condition, shall require a minimum lease term of five (5) years at a rental rate
of no less than $8.00 per rentable square foot during the first five (5) years
of the Lease Term, and no less than $10.00 per rentable square foot for any
additional space during the subsequent five (5) year term.



2.  Right of Optional Cancellation:

    Not later than forty-eight (48) months following the effective date of the
Lease Agreement, Tenant may notify Landlord of its intention to vacate the
Leased Premises at the end of sixty (60) months following the effective date,
without penalty whatsoever, (the "Optional Cancellation").  The Optional
Cancellation may be exercised ONLY to the extent Tenant, or any of its
affiliates, do NOT exercise that certain purchase option granted to Cadell S.
Liedtke and Michael J. Grella, pursuant to that certain option agreement dated
January 10, 1996.



                                          15




<PAGE>

                                                                 EXHIBIT 10.3


                              CONCESSION AGREEMENT

     THIS AGREEMENT is made and entered into, this 6TH day of July 1995

                                     BETWEEN

                    THE GOVERNMENT OF THE REPUBLIC OF MOLDOVA

                                       AND
                                        
             THE RESOURCE DEVELOPMENT COMPANY, LIMITED (REDECO, Ltd)

                                       TO

                  EXPLORE FOR AND DEVELOP OIL AND GAS RESOURCES
                           IN THE REPUBLIC OF MOLDOVA

PREAMBLE

     This agreement is concluded between the Government of the Republic of 
Moldova and the Resource Development Company, Limited (REDECO), chartered in 
the State of Delaware in the United States of America:

     Whereby:

     The Government, in consideration of a work commitment by REDECO that 
includes:  [1] development and production in the Valeni Oil Field commencing 
in 1995, and the Victorophka gas fields in 1996; [2] commencement of a 
multiyear 300-400 kilometer seismic survey beginning in 1996; [3] 
commencement of exploratory drilling in 1997; and [4] development of newly 
discovered fields as appropriate; and as stipulated and agreed to in the 
Agreement of Intent between the Government of Moldova and REDECO, signed by 
the Prime Minister of the Republic of Moldova and the President of REDECO on 
the 16th of December 1994, and further explained as follows:

ARTICLE A  TERMINOLOGY AND INTERPRETATION

     The following terms are hereby defined, and are to be interpreted as 
follows:

     "Barrel of Oil" is defined as 43 gallons, or as one-seventh of one ton 
of oil.

     "Competent Authorities" means any proper authority belonging to the 
State or Private sector, responsible to proceed to any action or deed 
designated by the Constitution of the Republic of Moldova, statute of 
administrative deed, including the Parliament, Government of the Republic of 
Moldova (including any ministry, department, government agency, municipality, 
or state enterprise, existing or to be established), or in any way having or 
granted jurisdiction over a specific case or matter, whether directly or 
indirectly.

<PAGE>

     "Concession" is the treaty between the State and Concessionaire whereby 
the State conveys its mineral resources to the Concession-holding company for 
a defined period of time.

     "Concession Area" is hereby defined as the entire territory of the 
Republic of Moldova.

     "Concession Commencement Date" means the date of signing of this 
agreement by the Government of the Republic of Moldova whereby the 
concessionaire will be held responsible for the design, finance, 
construction, operation, exploitation and maintenance of the Concession 
Project, pursuant to the terms of this Agreement.

     "Drilling" includes both actual boring, as well as ongoing operations 
requiring the presence of an operational drilling rig and its related 
equipment, to include workover rigs, rathole drilling rigs, and extends to 
downtime whereby on-site rigs are not operated due to testing requirements, 
engineering related analysis, equipment breakdown or other reasonable project 
related delays.

     "Easement" includes actual points of access, routes of travel and entry, 
and related rights-of-way used to access, service, and otherwise maintain and 
conduct exploration and development activities as defined by this Agreement.

     "Equipment" means both moveable and fixed equipment as necessary for 
REDECO to accomplish its concession commitments to include oil and gas 
exploration, field development, seismic exploration, and related facilities 
operation.

     "Exploration" is hereby defined as those activities related to the 
search for and discovery of oil and gas, to include field surveys, aerial 
surveys, seismic surveys, drilling site preparation, drilling, and well 
testing.

     "Facilities" permitted by this Agreement include refineries, tank farms, 
pipelines, and gas stations.

     "First Production" is defined as that point in time at which the first 
ton of oil reaches an in-field oil storage tank; or, at that point in time at 
which the first cubic meter of gas flows through a meter and into a gas 
pipeline transmission system.

     "Government" means any ministry, department, government agency, 
statutory executive authority existing or to be established.

     "Infrastructure" includes facilities required to gain access to 
exploration and development activities and other facilities in accordance 
with this Agreement.

     "Production" is hereby defined as the extraction of oil and gas and 
related by-products, the transportation and sale of these liquids and gases.

     "Retail" is defined as the selling of both unrefined and refined 
products to the commercial marketplace.

<PAGE>

     "Royalty" is defined as the Government's total share of gross production 
from any development activities permitted by this agreement, and that the 
gross figure will be calculated after the separation of water and associated 
waste gases and liquids normally removed at the field by industrial separator 
equipment as may be required.

     "Taxes" are those moneys, to include tariffs, customs, corporate and 
individual income taxes, severance taxes, dividend taxes, and windfall profit 
taxes as might be incurred during the course of normal business operations 
that include commercial business activities and the import and export of 
equipment and products (both natural and manufactured) and as may be further 
defined by the laws of the Republic of Moldova.

ARTICLE B   RIGHTS AND PRIVILEGES  

     1.   The Government of the Republic of Moldova grants the following 
rights and privileges to REDECO in return for REDECO's commitment to perform 
exploration and development work at its own expense:

     1.1. The exclusive right to develop the existing abandoned oil field of 
Valeni, with approved development activity to include the drilling and 
completion of production wells, installation of wellheads, pumps, gathering 
lines, oil storage tanks, separators, storage and maintenance buildings, 
roads, and the construction of well sites.  Development rights for the Valeni 
Oil Field are hereby granted for twnety years, from 1995 to 2015, with an 
option to approve development and production for an additional twenty years, 
from 2015 to 2035.  Development rights for the Victorophka Gas Field are 
hereby granted for twenty years, from 1996 to 2016, with an option to approve 
development and production for an additional twenty years, from 2016 to 2036.

     1.2. The exclusive right to explore for oil and gas in the Republic of 
Moldova for a period of ten years, from 1995 to 2005.  Exploration rights may 
be extended for second ten year period, from 2005 to 2015.  Also conveyed is 
the right to convert discovered oil and gas resources to twenty-year 
development projects on a field-by-field basis.

     1.3. The right to build and operate refineries, equipment, facilities, 
infrastructure, perform seismic surveys, drill exploratory wells, test and 
complete wells that prove to have commercial quantities of oil and gas, and 
utilize the information and technical resources of SPAF, the Institute of 
Geophysics and Geology, and AGEOM as according to the appropriate charter of 
each agency, and also conveyed are the rights to manufacture urea, liquid 
natural gas, compressed natural gas and to sell these products.  Regarding 
information provided by AGEOM, it is understood by REDECO that information 
obtained from AGEOM's Geological Archives must be purchased at approved 
official published rates.  Joint Ventures may be explored between the 
Government and REDECO only if Government investment capital is applied.

     2.   DEVELOPMENT RIGHTS.  Development rights granted for a period of 
twenty years, on a field-by-field basis (as new fields are discovered and 
developed for oil and gas and related by-product production) to REDECO are:

<PAGE>

     2.1. The exclusive right to develop and operate the Valeny Oil Field, 
the Victorophka Gas Field (which includes structures at both Baimaclia and 
Enichioi), and to this end, to perform activities involved in the drilling 
and operation of oil and gas wells and their attendant production facilities. 
All of these works will be done in conformity with project design plans to 
include environmental impact assessments and the State's ecological expertise.

     2.2. The right to develop and operate other oil and gas fields as may be 
found as a result of REDECO's exploration activities.

     2.3  Development activities approved include the right to build and 
operate: roads, pipelines, oil storage facilities, maintenance and storage 
facilities and buildings, pumps and pumping stations, oil and gas separators, 
and the maintenance of oil and gas wells, and the operations of downstream 
facilities to include wholesale and retail oil terminals and gas stations.

     2.4.  Development activities will include the abandonment of 
non-producing wells requiring the cementing of the hole back to the surface 
of the casing string of pipe.  Abandoned drilling and production sites will 
be environmentally recovered to the previous ecology within the best efforts 
and limits of generally acceptable site remediation practices, methods, and 
technologies. Development activities will include environmental site surveys, 
related studies, and documentation as required by Moldovan law.

     2.5  Technical and geologic information will be provided solely to the 
State Geological Archives.  Production and economic data will be provided 
solely to SPAF and MOLDOVAGAS.

     2.6.  REDECO will have the right to import its equipment, and the 
equipment of its contractors and their subcontractors, without penalty of 
import taxes or customs duties; and, the Government guarantees the extraction 
of REDECO equipment from the Republic without penalty of tax or duty.  These 
rights extend to exploration activities.

     2.7.  In the case of threat of terrorism, sabotage, or armed conflict, 
the Government guarantees that to the best of its ability it will provide the 
security for all producing oil fields, pipelines, storage facilities, and 
refineries, and for exploration and drilling sites.

     2.8  The Government guarantees REDECO the right to hire and fire 
Moldovan citizen employees as may the pleasure of REDECO management and 
within the statutes of Moldovan Law.

     2.9.  The Government guarantees the movement of REDECO personnel and the 
personnel of its contractors into and out of the Republic.  These personnel 
will be registered by the State which will arrange for long-term visas.  
REDECO will sponsor the visits of Moldovan personnel involved in this 
project's activities to the United States to the extent of Visa sponsorship.

     2.10.  Equipment, geologic samples, and technical information will be 
protected as proscribed by Moldovan and United States laws and this data will 
be protected by both parties from release to third parties without the mutual 
consent of SPAF and REDECO, and these export samples and data will be 
provided with expedited import and export from the territory 

<PAGE>

of Moldova.  REDECO will institute appropriate internal company security 
measures to ensure the protection of project information, and to this end, 
will ensure that geological and geophysical information utilized by 
subcontractors will be fully recovered from those subcontractors and that any 
residual information will be appropriately destroyed to deny the access of 
said information to unauthorized third parties.  REDECO will maintain a 
master record of all of its project data holdings, and will provide and 
updated record to SPAF on a routine basis.

     2.11.  The Government grants REDECO the right to export REDECO's share 
of oil roduction.  In this regard, the STATE (SPAF) has the right of first 
refusal to purchase any and all oil produced for which it will pay in 
currency at the prevailing market rate under conditions of Franco wellhead 
and as determined by the price paid for the same quality crude oil in the 
currently quoted Mediterranean oil market (Italy), less transportation and 
insurance costs if any are included, and less a five percent (5%) discount 
with said discount reserved for State buyers only.  Pricing information will 
be quoted by REDECO in both barrels and tons.  The State will pay said market 
price for oil and gas at the wellhead.  By right REDECO can sell its share of 
oil defined in Article C paragraphs 1.6 and 1.7.  The Government grants that 
said 5% discount does not extend to royalty payments made by REDECO from its 
gross production as defined in the royalty payment schedule in Article C 
paragraph 1.6.  SPAF and MOLDOVAGAS guarantee cash payment in full to REDECO 
within thirty (30) days of taking delivery of oil and gas.

     2.12.  Development rights are granted for a twenty year period, 
commencing in the year that first production is attained, and development 
rights may be extended for a second twenty year period by mutual agreement 
between the Government and REDECO.

     2.13.  The Government of Moldova agrees to indemnify REDECO of any 
environmental liability or associated damages due to, but not limited to, 
acts of God (natural disasters), third party negligence or damage, acts of 
sabotage or other forms of destruction.  In turn, REDECO agrees to safeguard 
its activities to the best of its abilities.

     2.14.  The royalty due to the Government, and as further defined in 
Article C paragraph 1.6, and extends to all by-products of oil and gas 
production to include gas condensates, sulphur, helium, carbon dioxide, and 
asphalt.

     2.15.  The Government agrees that REDECO will have certain rights to 
develop any other mineral resources that it encounters in during its 
exploration and development work if REDECO begins to develop said resources 
within 24 months of discovery.  After two years, REDECO forfeits its first 
rights and the Government may then assign these rights to a third party.  All 
of the mining and development details, to include royalty payments to the 
Government, will be defined upon discovery and during the course of said two 
year first-right period.  Application of discovery will be made to the 
Republic's Department of Norms and Standards.

     2.16.  REDECO agrees to turn over all facilities and equipment related 
to development operations, without any pecuniary compensation, upon 
termination of its development concession (defined in Article B, paragraphs 
1.1, 1.2 and 1.3) whether termination is an act of the Government, REDECO or 
mutually agreed to by both parties.  If the Government terminates REDECO's 
development activities prior to the periods defined in Article B, paragraphs 
1.1, 1.2 and 1.3, then the Government guarantees full payment for all 
facilities and related equipment. 

<PAGE>

This does not include REDECO's company offices located in Chisinau, which 
remain REDECO property in perpetuity.

     2.17.  KEEP WHOLE AGREEMENT.  The case of war, border disputes, internal 
strife or any other unanticipated political problem that would impede 
exploration and development activities as defined by this Agreement, the 
Government hereby guarantees that it will honor the terms of this Agreement 
through the period of crisis and will permit the resumption of normal 
exploration and development activities after it has declared that the crisis 
has ended.  If during a period of crisis REDECO finds that it must suspend 
operations it will do so after appropriate notification to the Government, 
and after receipt of the Government's permission.  During a period of crisis, 
the Government will make every reasonable effort to protect and defend oil 
field property and equipment operated by REDECO.  The State agrees not to 
introduce any subsequent legislation that in any way detrimentally effects 
the rights and intentions of this Agreement.

     2.18.  Upon implementation of this Agreement by virtue of its signing by 
the Government, SPAF RM and REDECO will conclude a technical contract for 
oil, and between the State Concern MOLDOVAGAS and REDECO for gas, prior to 
the commencement of REDECO's field operations.  The contracts will define the 
technical and management relationships related to technical and 
organizational issues between SPAF, MOLDOVAGAS and REDECO to include:  
allocation of government lands, registration of alien REDECO personnel while 
working in-country, the exact nature and timing of operational permissions, 
definition of ecological and environmental programs, responsibilities for 
local government relationships and contracts as may be necessary, liaison 
with national and local utilities companies, and coordination of engineering 
projects.

     2.19.  REDECO agrees not to produce more than five million tons per year 
of oil equivalent without the expressed agreement of the Government.

     2.20.  The projects will be performed in accordance with the 
environmental laws of Moldova, and in conformance with international 
conventions to which Moldova is a signatory.  If projects are performed in 
sensitive ecological reserves, then the special environmental laws governing 
those properties will be observed.  If work is performed in the vicinity of 
surface waters the special Moldovan laws refering to the protection of 
surface waters will be observed.  

     2.21.  LICENSING.  REDECO will be issued a ten (10) year exploration 
license by AGEOM, and a twenty (20) year development license by the 
Department of Standards and Technical Norms.

     3.   EXPLORATION RIGHTS.  The Government guarantees the following 
exploration rights and privileges:

<PAGE>

     3.1.  The right to have access to any approved surface lands for the 
purpose of conducting seismic surveys, and the right to ingress and egress 
property as may be required by seismic crews.

     3.2.  The right to export seismic, well and geological data as may be 
required for technical and laboratory analysis and evaluation.  The analysis 
of any such exported data will be provided to AGEOM.  The export of all data 
will be coordinated with AGEOM and other authorized Sate entities as may be 
appropriate.  Both parties guarantee to safeguard and protect this project's 
information from release or exposure to third parties; and, that all said 
technical information will remain confidential and may not be released or 
sold in any manner to third parties without the mutual consent of AGEOM and 
REDECO.

     3.3.  The right to construct drilling sites and to operate drilling rigs 
and associated facilities for the purpose of drilling exploratory wells, and 
the right to complete exploratory wells and the conversion of these to 
development wells upon declaration of commercial discovery.

     3.4.  The right to build roads and temporary storage and maintenance 
facilities as may be needed to conduct and perform exploration activities.

     3.5.  Exploration rights are hereby granted to REDECO for a ten (10) 
year period, commencing in 1995 and lasting until 2005, and may be extended 
for a second ten year period, from 2005 until 2015, through the mutual 
agreement of the Government and REDECO.

     3.6.  The Government guarantees REDECO's access to all approved surface 
lands related to exploration, development, and extraction of oil, gas and 
related by-products.  Land use will be guaranteed by the Government; and, the 
Government accepts full responsibility and liability for the use of said 
lands. REDECO also agrees to pay full site remediation and reclaimation costs 
to ensure that once drilling and production operations have been completed, 
that the land will be returned to its natural condition, defined as the 
condition that it was in before field activities began.

ARTICLE C.  REDECO WORK COMMITMENTS AND OBLIGATIONS

     1.   DEVELOPMENT PROJECTS - VALENI OIL AND VICTOROPHKA GAS FIELDS.  
REDECO commits to performing the following work related to the commercial 
development of oil and gas production from the two fields conveyed for 
development rights by virtue of Article B, paragraphs 1.1, 1.2 and 1.3:

     1.1. REDECO will drill a sufficient number of wells as necessary to 
establish commercial oil production with each well completed to a depth of at 
least 450 meters at Valeni, and 700 meters at Victorophka, and that it will 
cement casing to the surface, log, test, and complete each well for which the 
commercial presence of oil or gas is indicated.

     1.2.  REDECO will install oil production equipment as necessary to 
operate each well, and to operate the field.  This may include the 
installation, operation and maintenance of pumps, 

<PAGE>

generators, buildings, storage and maintenance facilities, oil and brine 
water storage tanks, gathering lines, roads, protective berms and dikes, 
raised production pads, fencing and related equipment and facilities.

     1.3.  REDECO will perform geologic analysis and will provide results of 
this AGEOM.

     1.4.  REDECO will transport oil and gas as required, and this will 
include transport by truck, railroad, or pipeline.  REDECO will build and 
operate pipelines as it deems may be required.

     1.5.  REDECO, through its Moldovan subsidiary REDECO-Moldova, will hire 
Moldovan citizens for at least 95% of its worker, technical, and professional 
employee positions in the Republic, and will provide requisite technical 
training as may be required.  Subcontractors are excluded from this clause, 
as is the parent company, REDECO Ltd.

     1.6.  REDECO will pay the Government a royalty of twenty percent (20%) 
of the total amount of oil, gas, and by-products (by products defined in 
Article B, paragraph 2.13) during the first ten years of production from each 
well, rising by five percent (5%) every five years after the first ten year 
period, to the following scale:

     Year 1-10 of production (by well)            20%
     Year 11-15                                   25%
     Year 16-20                                   30%
     Year 21-25                                   35%
     Year 26-30                                   40%
     Year 31-35                                   45%
     Year 36-40                                   50%

     The Government will be paid its royalty in cash (US Dollars or Moldovan 
Lei) or in kind (crude oil or gas), determined at the State's discretion.

     Taking into consideration risky nature of this project the State hereby 
grants REDECO a permanent exemption of fifty percent (50%) from net profit 
taxes owed by REDECO as are defined by current tax tariff rates expressed in 
Moldovan law.  The State also requires REDECO's employees to pay personal 
income tax and directs the company to pay its employees State social security 
tax.  REDECO is hereby exempted from all other taxes and duties as may be 
usually required under Moldovan law.

     1.7.  REDECO reserves the right to refine its oil produced, and may 
refine the State's share of oil production if required, and to market this 
oil first in the Republic of Moldova.  The State has right-of-first-refusal 
to purchase REDECO's oil production, and MOLDOVAGAS will have right-of-first 
refusal to buy REDECO's gas production; these purchase rights must be 
exercised within fifteen days of notification to buy a production contract.  
Both parties agree to pay prevailing market rates for production, pursuant to 
the five percent (5%) discount identified in Article B, paragraph 2.10.  In 
the event that the Government does not exercise its purchase rights, is 
unable to make payments or otherwise fails to purchase the refined oil or the 
initially-

<PAGE>

produced crude oil, then REDECO will have the right to market its production 
within the Republic first, and secondly, to export its production for sale, 
with this pertaining to both unrefined and refined products.  In the event 
that the Government is unable to pay for oil and gas production already 
received (i.e., purchased and delivered), and for which it has pledged 
payment in good faith, REDECO will have the right to recover its payment in 
the form of crude oil or gas production as subtracted from ongoing royalty 
payments in an amount not to exceed fifty percent (50%) of any given royalty 
payment.

     1.8.  Each well will be independently metered and royalties due will be 
calculated from the metered production at the well head.  Payment in-kind 
(crude oil and gas) will be made at, and collected by the Government at, each 
field's crude oil storage tanks, or in the case of gas, at the point where 
the field's production enters a gas transmission system (pipeline).  Cash 
payment will be made by deducting the royalty percentage from the amount due 
in all oil delivered to SPAF and gas delivered to MOLDOVAGAS, as calculated 
from gross sales to these two agencies.

     1.9.  REDECO agrees that its construction standards will comply with 
accepted international standards, and with Moldovan law, and will be 
performed according to approved technical project plans.

     2.  EXPLORATION PROJECT - REPUBLIC OF MOLDOVA.  Commencing in 1996, 
REDECO agrees to perform the following work:

     2.1.  In 1996, REDECO will commence a multiyear 300-400 kilometer 
seismic survey, concentrating in the southern areas of the Republic.  Both 
two and three dimensional data will be collected and processed into digital 
models.  Copies of all data will be provided to AGEOM to include certified 
duplications of original digital data according to established regulations.

     2.2.  In 1997, REDECO will commence an exploratory drilling program, 
guaranteeing the drilling of a sufficient number of deep wells on locations 
selected by REDECO and its contractors, according to the results of seismic 
investigations, to test for oil and gas in the Jurassic and Devonian 
formations. The plans for this program will be coordinated with SPAF.

     2.3.  Appropriate State specialists may reside and work on-site and 
REDECO will provide quarters and food to such qualified State personnel.  
Redeco will contract logging, cementing, and other well site services with 
qualified contractors who are in good standing with the international oil 
industry.

     2.4.  REDECO will pay all expenses involved with: mobilizing and 
shipping equipment and contractors, drilling activities, and related 
administrative and logistic activities.  The Government agrees to waive all 
taxes, and to not levy any taxes, related to this Agreement and its sponsored 
projects, according to the legislation of the Government of Moldova, beyond 
that of the production royalty, land payment and 50% from net profit taxes as 
specified in Article C paragraphs 1.6 and 4.1.

<PAGE>

     3.  OTHER COMMITMENTS

     3.1.  REPORTING.  REDECO will commence monthly reporting to SPAF 
beginning in the month following ratification of this Concession Agreement.  
Copies of technical and geologic data will be provided monthly to AGEOM, and 
production and economic data will be provided monthly to SPAF appended to 
REDECO's monthly production report.

     3.2.  PLANNING.  All plans for exploration and development activities 
will be provided to an authorized agency for approval.  Review and approval 
will be conducted in good faith and in an expeditious manner, and that 
authorized agency will do its best to accelerate its performance and that of 
other government agencies that may be involved.  When possible, joint 
planning will occur.  The Government reserves the right to suspend this 
agreement if REDECO fails to fulfill any aspects of this agreement related to 
performance and schedule.  The Government will allow for reasonable delay 
with at least thirty (30) days prior notification by REDECO.  It is 
recognized that only SPAF has the required expertise to represent the State's 
oil interests, and MOLDOVAGAS to represent the State's gas interests.

     3.3 MANAGEMENT.  REDECO will establish an operations office in Chisinau. 
REDECO management will be on-site at all field activities, and its designated 
manager will exercise final approval authority for all field management, 
operational and technical activities to include drilling, completion, well 
workover, site preparation and evacuation, safety, security and related oil 
field support and engineering activities.

     3.4  MONETARY CONVERSION.  The Government guarantees full exchange of 
Moldovan Lei for United States Dollars, to occur within {F10}thirty (30) days 
of claimancy by REDECO to the Government for redemption, only for payments 
related to this Agreement.

     3.5  INSURANCE.  REDECO will provide insurance to cover accidents due to 
its own negligence.  This insurance will cover the costs of environmental 
cleanup, losses of private property, and oil well firefighting.

     4.  LAND PAYMENT OBLIGATIONS.  During the normal course of conducting 
its business operations, it is recognized that REDECO will require access to 
and use of both private and public properties.  To this end, REDECO will pay 
for the use of surface rights as hereby agreed to wit:

     4.1.  LEASE FEES.  REDECO will pay lease fees as defined in existing 
land lease prices and tariffs provided by Moldovan legislation.

     4.2.  GUARANTEES.  The Government will take appropriate steps to 
identify and guarantee the legal ownership of surface rights effected by the 
exploration and drilling activities granted by this Agreement.  Where private 
ownership is unclear, or lands are publically held, the Government guarantees 
the right for REDECO to lease the property as defined in paragraph 4.1 above. 
 The Government will ensure the availability of, and access to, surface 
rights within the Concession Area and therefore undertakes to perform any 
necessary expropriations, requisitions, or compulsory purchases in respect of 
privately owned properties, of which the 

<PAGE>

Concessionaire otherwise reasonably considers to be necessary to enable it to 
carry out the Concession Project and otherwise fulfill its obligations under 
this Agreement, and that the Government will be responsible for paying all 
costs associated with the acquisition of such property.

     ARTICLE D  FORCE MAJEURE

     REDECO shall not be liable for any failure or delay by it in complying 
with any obligation under this Agreement as the Concessionaire, to the extent 
that such failure or delay has been caused by any event or circumstance 
presenting the characteristics of Force Majeure, such as: ware (whether 
declared or undeclared); invasion, armed conflict or act of foreign enemy; 
revolution, riot, insurrection, act of terrorism, sabotage, criminal damage 
or threat of such acts; nuclear explosion, radioactive or chemical 
contamination or ionizing radiation; earthquake; any effect of the natural 
elements including geological conditions which it was not reasonably 
practicable to allow for; the occurrence of any of the perils insured 
against; strikes, other labor disputes, disturbances, or material economic 
dislocations; any act or omission by the State affecting this Agreement such 
as restrictions on the importation of any materials or machinery, any legal 
directions or other disruptions caused by the encounter with antiquities and 
other archeological sites, or the failure of existing or to-be-provided 
necessary utilities.

     ARTICLE E  DISPUTES

     The Government will establish a management oversight board, to with 
REDECO will be permitted to have a sitting member present at all discussions 
and points of decision.  Points of contention will first be addressed by the 
board, and where this fails to reach agreement, by mutual meeting between 
Moldova's Vice Prime Minister and the President of REDECO Ltd.  In the event 
that a mutually agreeable solution to a situation is not reached then both 
parties agree to submit to international arbitration pursuant to mutually 
agreed upon rules and proceedures in accordance with international law.  In 
this regard, the Government of Moldova waives sovereign immunity and agrees 
to submit to international arbitration.  In turn, REDECO agrees to comply 
with Moldovan Law in all of its activities conducted on Moldovan territory.  
Furthermore, the State agrees to represent and protect REDECO and its assigns 
from any and all civil and tort litigation that may occur in Moldova.

     ARTICLE F  GOOD FAITH

     Both parties agree to operate in good faith, and to this end, to ensure 
that effective communications are continuously maintained.  To this end, 
technical and administrative files regarding oil and gas exploration and 
development activities will be fully open to and accessible by both parties, 
in both Moldova and in the United States.

     ARTICLE G  AGREEMENT

     This Concession is hereby awarded to REDECO by the Government of the 
Republic of Moldova.  Both parties agree to the conditions defined in this 
document, which was drawn up 

<PAGE>

in Moldovan, Russian, and English with three originals of this document 
prepared in each language and all language versions are equal.  A timetable 
for this agreement is attached.

On behalf of the Government                  Of behalf of REDECO, Ltd.
of the Republic of Moldova

     /s/  A. BANGLELIO                            /s/  WILLIAM J. COX         
- -----------------------------------       ----------------------------------- 
A. Banglelio                                 William J. Cox
Prime Minister of the                        President of REDECO, Ltd.
Republic of Moldova











<PAGE>

                                                                 EXHIBIT 10.4


                                  PURCHASE AND
                           JOINT EXPLORATION AGREEMENT


     This Joint Exploration Agreement (the "Agreement") is entered into this
21st day of February, 1996 by and between COSTILLA ENERGY, L.L.C., a Texas
limited liability company ("Costilla") and RESOURCE DEVELOPMENT COMPANY LIMITED,
L.L.C. (DE), a Delaware limited liability company ("Redeco").

                                 R E C I T A L S

     (a)  Redeco has entered into a Concession Agreement (the "Concession"),
dated July 6, 1995, with the Republic of Moldova ("Moldova") under the terms of
which Redeco has acquired rights to explore, develop and produce oil, gas and
other minerals within the geographic boundaries of Moldova, together with other
rights related to said production.  The Concession is incorporated herein and
made a part hereof by reference.

     (b)  By Option Agreement dated October 17, 1995, as extended by Extension
of Option Agreement dated November 21, 1995 (collectively, the "Option"), for
the consideration of $25,000 paid to Redeco, Costilla has acquired from Redeco
an option to acquire an undivided 50% interest in the Concession.  The Option is
incorporated herein and made a part hereof by reference.

     (c)  By this Agreement, Costilla is exercising its option and Redeco and
Costilla are agreeing to their respective rights and obligations under the
Concession.


                                       I.
                               EXERCISE OF OPTION

     1.1  EXERCISE OF OPTION.  Contemporaneously with the execution of this
Agreement, Costilla has paid Redeco the sum of $90,000 and has agreed to bear
the first $750,000 of joint activities expenses, including but not limited to
direct and indirect drilling costs, travel, and related overhead expenses for
office operations and technical analysis, in Direct Oil and Gas Projects.  By
such payment and agreement, Costilla has exercised its option under the Option.
In the event any provision of this Agreement conflicts with any provision of the
Option, this Agreement shall prevail.

     1.2  ASSIGNMENT OF RIGHTS UNDER CONCESSION.  Immediately upon execution of
this Agreement, Redeco shall execute and deliver to Costilla a conditional
assignment of an undivided 50% of Redeco's rights and obligations under the
Concession.  Redeco and Costilla understand that the assignment by Redeco to
Costilla is subject to Moldova granting its written consent to the assignment
and, possibly, its consent to this Agreement and all other subsequent agreements
between  Redeco and Costilla  and  satisfaction  of  the conditions  precedent
recited

<PAGE>

above.  In the event Moldova refuses to grant such written consent, Costilla's
exercise of the Option shall be void and Redeco shall be obligated to
immediately refund to Costilla all sums of money heretofore and hereafter paid
by Costilla to Redeco in connection with its exercise of the Option, as well as
all funds expended by Costilla, or its affiliates, relating to Concession
activities, in Moldova.


                                       II.
                             NATURE OF RELATIONSHIP

     2.1  DISCLAIMER OF PARTNERSHIP.  This Agreement is not intended to create,
and shall not construed to create, a partnership, mining partnership, joint
venture, or other type of relationship pursuant to which a party hereto shall
have liability for the actions of the other (except as specified in Article III
hereof) in connection with the Concession Agreement, or otherwise.  The
relationship of the parties hereto shall be as co-owners of the rights granted
to Redeco pursuant to the Concession Agreement, and such rights shall be
governed solely by the terms of this Agreement; provided however, as between
Redeco and Costilla, there shall be a fiduciary duty owed one to the other in
connection with all their dealings involving their business activities within
Moldova.

     2.2  NAMING OF OPERATOR AND CONCESSIONAIRE.  Costilla, or its designee,
shall be designated the Operator under this Agreement.  Redeco, or its designee,
shall be designated the Concessionaire under this Agreement.  The duties and
responsibilities of Costilla and Redeco in their respective roles shall be set
forth in Article III hereof.

     2.3  ESTABLISHMENT OF ADDITIONAL ENTITIES.  Costilla and Redeco acknowledge
and agree that each of them may form one or more domestic or foreign
subsidiaries to carry out the activities contemplated by the Moldovan
Agreements.  Each of Costilla and Redeco consent to the formation of such
additional entities (domestic or foreign) as may be recommended by their
advisors; provided however, that any agreements between such entities will
either incorporate this Agreement by reference or restate the terms and
conditions of this Agreement.  Costilla has caused to be formed Costilla Redeco
Energy, L.L.C. to succeed to all its rights (other than its rights as Operator)
under this Agreement, and the parties hereto, by their signatures below (as well
as the signature of Costilla Redeco Energy, L.L.C.) recognize that the Costilla
Redeco Energy, L.L.C. has succeeded to all such rights.  Costilla additionally
intends to cause to be formed a subsidiary or affiliate which will succeed to
its rights as operator hereunder.

     2.4  COVERAGE OF THIS AGREEMENT.  The parties intend that this Agreement
cover their rights and responsibilities with respect to the Concession
Agreement, and such projects as may be ancillary thereto.  Specifically, the
parties intend that this Agreement shall cover the following activities:

     (a)  Development of the abandoned field of Valeni.

                                        2

<PAGE>


     (b)  Development of the Victorophka gas fields.

     (c)  Exploration or development of other oil and gas properties.

     (d)  Geophysical, geological or geochemical studies for exploration and
          development of hydrocarbons.

     (e)  General and administrative expenses associated with the activities
          described in (a) through (d) above, including but not limited to
          travel and lodging expenses, as well as the payments made pursuant to
          Article VI hereof.

     (f)  Costs and expenses associated with any attempts made by Costilla to
          obtain third party financing for the activities described in (a)
          through (d) above.

     (g)  Refineries.

     (h)  Distribution and transportation pipelines (excluding gathering lines
          or gathering line systems which shall be considered part of the
          facilities relating to the exploratory or development wells to which
          they pertain.)

     (i)  Liquified natural gas facilities.

     (j)  Wholesale and retail oil terminals and gas and gasoline stations.

     (k)  Development of any other mineral resources, including geophysical,
          geological or geochemical studies, subject to the time limitations
          imposed in the Concession for the development of said resources.

     The matters covered by subsection (a) through (k) of this Section 2.4 are
referred to herein as "Direct Projects" and the matters covered by subsections
(a) through (f) are also referred to as "Direct Oil and Gas Projects".  In
addition, this Agreement may cover certain projects and opportunities which
shall be referred to herein as "Indirect Projects".  Indirect Projects are those
projects and opportunities that, although not specifically mentioned in the
Concession, arise by virtue of or "spin-off" from, the Concession.  Unlike
Direct Projects which are initially proposed by the Operator, Indirect Projects
may also be proposed by any non-operator.  Indirect Projects must relate to the
Direct Projects in some manner.  It is recognized that Indirect Projects may
impact Direct Projects and Direct Projects shall take precedence unless jointly
agreed otherwise.  The proposal of an Indirect Project and scope thereof will be
subject to review by the Operator for potential conflict with Direct Projects.
Assuming that the Operator does not find that a proposed Indirect Project
conflicts with a Direct Project, the Indirect Project, at the option of the
party proposing same, shall be conducted  under such terms as the parties
participating in the Indirect Project may agree.

                                        3

<PAGE>


     In addition to Direct and Indirect Projects, either Redeco or Costilla may
propose "Miscellaneous Projects", being projects unrelated to the Concession
either directly or indirectly but which were acquired or envisioned as a result
of the parties' contacts in Moldova and which directly relate to doing business
either with Moldova or with citizens of Moldova.  If either Redeco or Costilla
has a Miscellaneous Project it will be obligated to disclose same and offer it
to the other party on a right of first refusal basis.  Bona fide disputes as to
whether a project is a Miscellaneous Project or an Indirect Project shall be
resolved in favor of its being an Indirect Project.  Costilla and Redeco
recognize that a Miscellaneous Project may impact Direct or Indirect Projects
and the parties recognize that Direct or Indirect Projects shall take precedence
unless jointly agreed otherwise.  Prior to proposing a Miscellaneous Project,
the form and scope of the project will be brought before the Operator for
discussion of potential conflicts with existing or proposed Direct and Indirect
Projects.  Opportunities in the nature of personal service shall not give rise
to this right of first refusal and shall not be considered a Miscellaneous
Project.

     2.5  CREATION OF OPERATING COMMITTEE.  An Operating Committee shall be
formed which shall consist of the principals of Costilla and Redeco.  Meetings
of the Operating Committee may be held as frequently as desired by Costilla and
Redeco, but not less than frequently than quarterly.  At meetings of the
Operating Committee, other invited persons may attend and participate, if such
attendance and participation is agreed upon by both parties.  The role of the
Operating Committee shall be advisory only; it being acknowledged and understood
that Costilla, in its capacity as Operator and Redeco, in its capacity as
Concessionaire, shall exercise the rights and duties granted to them under
Article III of this Agreement, but that the Operating Committee shall be free to
advise either Costilla or Redeco with respect to any matter covered by this
Agreement.

                                      III.
                               DUTIES OF OPERATOR

     3.1  POWER AND AUTHORITY OF OPERATOR.  The Operator shall conduct, direct
and exercise full control over all activities to be conducted pursuant to the
Concession Agreement.  Except as otherwise expressly provided in Sections 3.2
and 3.3 and elsewhere in this Agreement (including the advisory role of the
Operating Committee described in Section 2.5), all management powers over the
business and affairs of the activities to be conducted pursuant to the
Concession Agreement shall be exclusively vested in the Operator.  The parties
recognize that Redeco is best poised to offer expert opinions regarding the
cultural and political aspects of the Concessions, as well as the Concession
inherent obligations and requirements, and Operator agrees to give serious
consideration to this counsel, giving it fair weight in all strategic decisions.
The Operator shall have full power and authority to do all things deemed
necessary or desirable by it to conduct the activities to be conducted pursuant
to the Concession Agreement without limitation (except as aforesaid), including
the right and power to:

          (a)  propose and adopt a budget for expenditures pursuant to
     activities to be conducted pursuant to Direct Projects and Indirect
     Projects, and cause a copy of said

                                        4

<PAGE>

     budget to be delivered to Redeco not later than December 1 of the year
     preceding the year for which expenditures have been budgeted, except as to
     calendar year 1996 as to which the budget will be delivered not later than
     _________, 1996.  Costilla will update the budget quarterly throughout a
     calendar year and furnish all such updated revisions to Redeco.  The rights
     and obligations of Redeco with respect to its participation in such
     activities are set forth in Article IV hereof;

          (b)  conduct and/or supervise all field operations, including drilling
     and reworking of wells, and ordering equipment and all other ancillary
     matters related thereto:

          (c)  purchase or otherwise acquire other real or personal property of
     every nature considered necessary or appropriate to carry on and conduct
     the activities contemplated by the Concession Agreement.

          (d)  contract with third parties for such purposes and to do any and
     all other things necessary or appropriate to carry out the activities
     contemplated by the Concession Agreement which could or might be done by a
     normal and prudent operator in the development, operation and management of
     its own property;

          (e)  purchase, lease, rent or otherwise acquire or obtain the use of
     facilities, machinery, equipment, tools, materials and all other kinds and
     types of real or personal property that may in anyway be deemed necessary,
     convenient, or advisable in connection with carrying on the activities
     contemplated by the Concession Agreement;

          (f)  make and enter into such agreements and contracts with such
     parties and to give such receipts, releases and discharges with respect to
     any and all of the foregoing and any matters incident thereto as the
     Operator may deem advisable or appropriate;

          (g)  procure and maintain in force such insurance as the Operator
     shall deem prudent to serve as protection against liability for loss and
     damage as required by the Concession Agreement or which may be occasioned
     by the activities contemplated by the Concession Agreement on behalf of
     Costilla and Redeco or their assigns;

          (h)  prepay in whole or in part, refinance, recast, increase, modify
     or extend any liabilities affecting the activities to be conducted pursuant
     to the Concession Agreement and in connection therewith execute any
     extensions or renewals of encumbrances on any or all of the property or
     interest pledged to secure same;

          (i)  contract on behalf of Costilla and Redeco for the employment and
     services of employees and/or independent contractors, such as independent
     legal counsel and accountants; provided, however, that on disputed matters
     with third parties involving more than $50,000, Redeco may elect to supply
     its own legal counsel at its own expense;

                                        5

<PAGE>


          (j)  take, or refrain from taking, all actions, not expressly reserved
     or limited by this Agreement, as may be necessary or appropriate to
     accomplish the activities to be conducted pursuant to the Concession
     Agreement;

          (k)  institute, prosecute, defend, mediate, arbitrate and settle
     lawsuits or other judicial or administrative proceedings brought on or in
     behalf of, or against Costilla or Redeco in connection with joint
     activities to be conducted pursuant to the Concession Agreement, and to
     engage counsel or others in connection therewith;

          (l)  take such other acts as may be incidental to the acts and things
     expressly authorized by this Agreement; and

          (m)  take such other actions as may be permitted by the Operator under
     the Operating Agreement, to the extent not inconsistent with the terms of
     this Agreement.

     In accomplishing all of the foregoing and in fulfilling its obligations
pursuant to this Agreement, the Operator may, in its sole discretion, retain or
use any affiliates' personnel, properties and equipment or the Operator may hire
or rent those of third parties and may employ on a temporary or continuing basis
outside accountant, attorneys, consultants and others on such terms as the
Operator deems advisable.  No person, firm or corporation dealing with the
Operator shall be required to inquire into the authority of the Operator to take
any action or make any decision.

     3.2  CERTAIN RESTRICTIONS ON OPERATOR'S POWER AND AUTHORITY.
Notwithstanding anything else expressed or implied to the contrary to this
Agreement, the Operator shall not have the power or authority to and shall not
perform or authorize any of the following acts without having previously
obtained the consent of Redeco:

          (a)  do any act in contravention of this Agreement;

          (b)  confess a judgment which could affect the rights of the parties
     pursuant to the Concession Agreement;

          (c)  possess property interests arising from the Concession Agreement,
     or assign rights in specific property interest arising from the Concession
     Agreement, for other than the joint and mutual benefit of the parties
     hereto or their assigns;

          (d)  use the property interests arising from the Concession Agreement
     for other than the joint and mutual benefit of the parties hereto or their
     assigns; and

          (e)  except as expressly provided herein, take any action with respect
     to the property interests arising from the Concession Agreement which
     benefits the Operator or an Affiliate thereof to the detriment of Redeco.

                                        6

<PAGE>


     3.3  POWER AND AUTHORITY OF CONCESSIONAIRE; LIMITATIONS.

          (a)  The Concessionaire shall be responsible for relations with the
     Republic of Moldova and its duly authorized representatives, as well as the
     administration of matters covered by the Concession within the Republic of
     Moldova.  In addition, the Concessionaire shall be primarily responsible
     for related research with respect to the Concession; non-oil and gas
     logistical matters such as the obtaining of housing, transportation, food
     and the like; and the acquisition of leasehold interests or other similar
     interests necessary to carry out the purposes of the Concession.

          (b)  In carrying out its duties as Concessionaire, Redeco agrees to
     consult with Costilla, either through the Operating Committee, or
     otherwise, but in the event of any disagreement with respect to the powers
     to be exercised by the Concessionaire under Section 3.3(a), Redeco's
     judgment shall be conclusive unless: (i) the action proposed to be taken by
     Redeco would increase the financial commitment otherwise required pursuant
     to the terms of the Concession; or (ii) would otherwise have a material
     adverse effect on the Concession, or the transactions to be conducted
     pursuant thereto.

     3.4  LIABILITY OF PARTIES AND INDEMNIFICATION.

          (a)  Costilla, Redeco and their affiliates, members, managers,
     officers, employees and agents, shall not be liable, responsible or
     accountable in damages or otherwise to the other party hereto for any acts
     or omissions that do not constitute gross negligence, willful misconduct,
     or a breach of the express terms of this Agreement, and each party to this
     Agreement shall indemnify and save harmless the other parties hereto and
     their affiliates, members, managers, officers, employees and agents
     (individually, "Indemnitee") from all liabilities relating to the
     Concession Agreement or the activities conducted pursuant thereto.  Any act
     or omission performed or omitted by an Indemnitee on advice of legal
     counsel or an independent consultant who has been employed or retained by
     the Operator in accordance with Section 3.1 shall be presumed to have been
     performed or omitted in good faith without gross negligence or willful
     misconduct.  THE PARTIES RECOGNIZE THAT THIS PROVISION SHALL RELIEVE ANY
     SUCH INDEMNITEE FROM ANY AND ALL LIABILITIES, OBLIGATIONS, DUTIES, CLAIMS,
     ACCOUNTS AND CAUSES OF ACTION WHATSOEVER ARISING OR TO ARISE OUT OF ANY
     ORDINARY NEGLIGENCE BY ANY SUCH INDEMNITEE, AND SUCH INDEMNITEE SHALL BE
     ENTITLED TO INDEMNIFICATION FROM ACTS OR OMISSIONS THAT MAY CONSTITUTE
     ORDINARY NEGLIGENCE.

          (b)  An Indemnitee shall not be denied indemnification in whole or in
     part under this Section 3.4 because the Indemnitee had an interest in the
     transaction with respect to which the indemnification applies if the
     transaction was otherwise permitted by the terms of this Agreement.

                                        7

<PAGE>


     3.5  TAX ELECTIONS.  The Operator shall make such tax elections as agreed
by the parties on behalf of Costilla and Redeco relating to the joint activities
to be conducted pursuant to the Concession Agreement.

                                       IV.
                    PAYMENT OF COSTS AND DIVISION OF REVENUES

     4.1  INITIAL ALLOCATION.  Except as provided in this Section 4.1 and the
remainder of this Article IV, Costilla and Redeco shall each pay 50% of all
costs associated with activities conducted pursuant to the Concession Agreement
including the fees and expenses of advisors retained pursuant to Section 3.1(i)
of this Agreement.  However, Costilla agrees that it shall be solely responsible
for and shall pay the initial sum of $2,000,000 (the "Initial Tranche"), which
shall include the $750,000 expenditure contemplated by Section 1.1 for the joint
account of Costilla and Redeco in Direct Oil and Gas Projects.  Costilla and
Redeco acknowledge and agree that as of the date of this Agreement, $450,000  of
the Initial Tranche has been expended by Costilla.

     4.2  UTILIZATION OF REVENUES TO PAY EXPENSES.  Although no partnership is
intended to be created pursuant to this Agreement, Costilla and Redeco each
agree that all revenues which accrue to their respective interests shall be
initially paid to Costilla in its capacity as Operator.  At such time that
Redeco has participated under alternative 4.4 (a) or (b) below and Costilla has
been paid all Reimbursable Amounts, Redeco may elect to either receive its
revenue directly or take its share of production in kind, provided, however that
Operator shall have continuing rights to market Redeco's share of production
should Redeco fail to timely make such arrangements.  The Operator shall utilize
such revenues initially to pay budgeted expenses and to maintain a prudent cash
reserve, provided that such cash reserve is not anticipated to exceed 20% of the
authorized budget.  Only when all budgeted expenses have been paid and adequate
reserves established will the Operator disburse any remaining funds.

     4.3  PROJECT FINANCING.   Recognizing that initial income to the parties as
a result of their operations to the Concession may be insufficient to meet
current financial obligations incurred as a result of the operations, both
Redeco and Costilla shall make a concerted effort to raise additional capital
either for the two of them, jointly, or, at least, for the benefit of Redeco.
Such funding may occur either in the form of debt financing or in the form of
equity funding from third parties, the latter being an acknowledged goal of
Redeco, either on its own or in concert with Costilla.  At any time during the
expenditure of the Initial Tranche, and specifically at such time as the Initial
Tranche has been expended, Costilla may (prior to the expenditure of the Initial
Tranche) and shall (for a period of up to six months following the expenditure
of the Initial Tranche) use best efforts to secure project financing primarily
for the joint account of Costilla and Redeco, but at least for the benefit of
Redeco.  Such funding may occur either in the form of debt financing or in the
form of equity funding from third parties.  Such funding necessary to meet all
financial obligations relating to the parties' operations involving the
Concession shall herein, collectively, be referred to as "Project Financing."

                                        8

<PAGE>


     4.4  RIGHTS OF REDECO AFTER EXPENDITURE OF INITIAL TRANCHE.  Once the
Initial Tranche has been expended, if Operator has a good faith belief that
revenues from the Concession will not be sufficient to fund anticipated
expenditures for Direct or Indirect Projects, it shall promptly provide a
written notice to such effect to Redeco.  Redeco shall have a period of 180 days
from receipt of the notice (the "Notice Period") to elect one of the
alternatives set forth in this Section 4.4.  Notwithstanding any existing
budgets or anything else to the contrary herein, Costilla agrees that during the
Notice Period, the total sums expended by Costilla for the joint account in
Direct Oil and Gas Projects shall not exceed $2,500,000, including expenditures
made by Costilla during the Notice Period.  To the extent  Redeco does not
provide notice of election by the conclusion of the Notice Period, it will be
deemed to have elected the alternative set forth in Section 4.4(c).  The
alternatives available to Redeco during the Notice Period are:

          (a)  Accept the Project Financing obtained for the account of both
     parties.  In this connection, Redeco agrees to execute any documents, in
     the same form as executed by Costilla, necessary to accomplish this
     purpose; provided however, that should Costilla fail to execute such
     documents, Redeco may satisfy this alternative by accepting and executing
     the Project Financing as to its interest.

          (b)  Pay Costilla the sum of the following (the "Reimbursable
     Amount"):

               (i)  50% of all amounts spent by Costilla with respect to Direct
          Oil and Gas Projects under the Concession, subject to a maximum amount
          of $2,500,000, less $750,000; and

               (ii) interest computed on the amount specified in Section
          4.4(b)(i) from the date of each such expenditure until repayment
          thereof at a floating rate equal to Nations Bank of Texas, N.A. prime
          rate, plus .75%.

          In the event Redeco pays the Reimbursable Amount, it will retain its
     50% interest in the Direct Oil and Gas Projects under the Concession;
     provided, however, that should Redeco subsequently fail to pay its share of
     a budgeted expenditure, it shall forfeit its entire interest in the Direct
     Oil and Gas Projects under the Concession in accordance with the terms of
     the Operating Agreement; or

          (c)  Convert its interest in the Direct Oil and Gas Projects under the
     Concession  to a 7.5% Non-Participating Revenue Interest and not be
     required to bear any of the Reimbursable Amount, or future costs, with
     respect to the Direct Oil and Gas Projects under the Concession. Such Non-
     Participating Revenue Interest shall be equal to 7.5% of the gross proceeds
     attributable to the sales of oil, gas and other hydrocarbons from the lands
     covered by the Concession and shall be owned by Redeco free and clear of
     all costs and expense, except that it shall bear and pay its 7.5% share of
     all royalties, taxes on production and any other levies imposed by the
     Republic of Moldova not separately due and payable by  Redeco on its Non-
     Participating Revenue Interest.

                                        9

<PAGE>

     Amounts due and payable to Redeco will be paid in the same currency and at
     the same exchange rate as payments are made to Costilla.

          At any time during the Initial Tranche up until the end of the Notice
     Period, Redeco may elect to proceed under alternative 4.4(b) above by
     paying the Reimbursable amount as of that date.

     4.5  NON OIL AND GAS PROJECTS.  Notwithstanding the obligation of Costilla
and Redeco to pay 50% of all costs associated with activities conducted pursuant
to the Concession Agreement,  either party may elect not to participate in the
costs of either a Direct Project (other than a Direct Oil and Gas Project) or an
Indirect Project at the time that such project is proposed, and may convert its
interest in such project to a non-cost-bearing interest functionally equivalent
to the Non-Participating Revenue Interest defined above in Section 4.4(c),
adjusted for the risks and cost structure of the business contemplated by such
project.

     4.6  EARLY WITHDRAWAL BY COSTILLA.  Should Costilla elect at any time to
cease participation under the Concession Agreement and withdraw from activities
conducted thereunder,  it shall cede its interest in the Concession back to
Redeco, subject to a right to  convert its interest in the Concession to a non-
cost-bearing interest functionally equivalent to the Non-Participating Revenue
Interest defined above in Section 4.4(c), adjusted for the risks and cost
structure of the business contemplated by such project.

                                       V.
                      ASSIGNABILITY; RIGHT OF FIRST REFUSAL

     5.1  ASSIGNABILITY.  Either party may sell, assign, transfer, pledge,
hypothecate or otherwise dispose of its interest in the Concession, or its
rights or obligations thereunder or under any specific Direct or Indirect
Project, subject only to the provisions of Section 5.2.

     5.2  RIGHT OF FIRST REFUSAL.  In the event that any party shall receive a
bona fide offer for the purchase of such parties interest under the Concession
Agreement or one or more Direct or Indirect Projects, the terms of which it
desires to accept, it shall not sell any such interest without first complying
with this Section 5.2.  First, it shall immediately send a notice in writing of
all of the terms and conditions of such offer, including, but not limited to,
the following:

          (a)  the name and address of the offeror;

          (b)  nature of the interest in the Concession Agreement or the Direct
               or Indirect Projects proposed to be purchased;

          (c)  the price which the offeror proposes to pay;

          (d)  the financial arrangements for the payment of the purchase price;
               and

                                       10

<PAGE>


          (e)  all other material terms of the proposed transaction.

     to the other party, and, in connection therewith, shall certify that such
     offer is bona fide and genuine and that it intends to accept it according
     to its terms.  Such notice and certification shall be mailed to the other
     party at its address as specified herein by registered or certified United
     States mail, return receipt requested, with postage thereon prepaid.  The
     other party shall thereupon have the irrevocable right and option to
     purchase and acquire the interest subject to such offer giving such notice
     on the same terms and for the same purchase price as set forth in the
     written notice.  The other party shall be entitled to exercise its right
     and option until the expiration of thirty (30) calendar days from the date
     the notice was received by the other party; but shall not contact or
     negotiate with the offeror during that thirty (30) day period.


                                       VI.
                            MONTHLY PAYMENT TO REDECO

     Commencing 1 January 1996 and through 31 December 1997, Costilla will pay
to Redeco (or to its assigns) the sum of $12,500 per month, with payments to be
made on the 1st day of each month.  This payment amount will be renegotiated
upwards if and when total production exceeds 1,000 barrels per day equivalent
(oil or gas), assuming that the oil or gas is selling at a fair market price.
Costilla will also compensate Redeco for up to sixteen round-trip tickets per
year, and will pay term life insurance premiums for Mr. and Mrs. William J. Cox
up to a total face value of $1 million, with beneficiaries to be designated by
William J. Cox.

                                      VII.
                                  MISCELLANEOUS

     7.1  ENTIRE AGREEMENT.  Subject to the provisions of Section 2.3, this
Agreement constitutes the entire agreement of the parties with regard to the
subject matter of this Agreement and replaces and supersedes all other written
and oral agreements and statements of the parties relating to the subject matter
of this Agreement.

     7.2  WAIVER.  The failure of a party to insist in any one or more instances
on the performance of any term or condition of this Agreement shall not operate
as a waiver of any future performance of that term or condition.

     7.3  HEADINGS.  The headings used in this Agreement appear strictly for the
parties' convenience in identifying the provisions of this Agreement and shall
not affect the construction or interpretation of the provisions of this
Agreement.

     7.4  BINDING EFFECT.  This Agreement binds and inures to the benefit of the
parties and their respect successors, legal representatives and permitted
assigns.

                                       11

<PAGE>


     7.5  AMENDMENTS.  No amendments to this Agreement shall become effective or
binding on the parties, unless agreed to in writing by all of the parties.

     7.6  TIME.  Time constitutes an essential part of each and every part of
this Agreement.

     7.7  NOTICE.  Except as otherwise provided in this Agreement, when this
Agreement makes provision for notice or concurrence of any kind, the sending
party shall deliver or address the notice to the other party by certified mail,
telecopy or nationally-recognized overnight delivery service to the following
address or telecopy number:

          Costilla:           Costilla Energy, LLC
                              511 West Texas
                              Midland, Texas 79701
                              (fax) (915) 686-6080

          Redeco:             Resource Development Company
                                Limited, LLC (DE)
                              2700 Liberty Tower
                              Oklahoma City, Oklahoma 73102
                              (fax) (405) 239-7337

     7.8  GOVERNING LAW.  The law of Texas shall govern this Agreement.

     7.9  FOREIGN CORRUPT TRADE PRACTICES ACT AND OTHER FEDERAL LAWS.  Each
party pledges and commits to the other that it will fully comply with the
Foreign Corrupt Trade Practices Act, as well as any other federal laws relating
to its activities in and with Moldova, its governmental representatives and
citizens and each party pledges immediate disclosure to the other of any
incident that may give rise to a potential complaint under the Foreign Corrupt
Trade Practices Act or any other federal law relating to their activities under
this Agreement.

     7.10 MULTIPLE COUNTERPARTS.  This Agreement may be executed in a number of
identical separate counterparts, each of which for all purposes is to be deemed
an original, but all of which shall constitute, collectively, one agreement.  No
party to this Agreement shall be bound hereby until a counterpart of this
Agreement has been executed by all parties hereto.

     7.11 DISPUTE RESOLUTION. The terms of the Dispute Resolution Procedure
attached as Exhibit A dealing with the resolution of disputed matters shall be
specifically incorporated into and made a part of this Agreement.

                                       12

<PAGE>


     EXECUTED as of the day and year first set forth above.

                              COSTILLA ENERGY, LLC



                              By:       /S/ MICHAEL J. GRELLA
                                     --------------------------------
                              Name:     MIKE GRELLA
                                     --------------------------------
                              Title:    President
                                     --------------------------------


                              RESOURCE DEVELOPMENT COMPANY
                                LIMITED, L.L.C. (DE)



                              By:       /S/ WILLIAM J. COX
                                     --------------------------------
                              Name:     WILLIAM J. COX
                                     --------------------------------
                              Title:    President
                                     --------------------------------


                              COSTILLA REDECO ENERGY, L.L.C.



                              By:       /S/ MICHAEL J. GRELLA
                                     --------------------------------
                              Name:     MIKE GRELLA
                                     --------------------------------
                              Title:    President
                                     --------------------------------


                                       13


<PAGE>



                                                                    EXHIBIT 10.8

                                 EMPLOYMENT AGREEMENT

    AGREEMENT made as of the 30th day of June, 1996, between COSTILLA PETROLEUM
CORPORATION and COSTILLA ENERGY, L.L.C. (the "Companies") and BOBBY W. PAGE
("Page").

    In consideration of the mutual agreements herein contained, the parties
hereto agree as follows:

    1.   This Agreement shall be effective as of June 30, 1996, and shall
continue in effect for a three-year term ending June 30, 1999, provided however,
this Agreement will automatically renew for a period of one year, and successive
one-year periods thereafter, unless Page is notified of its termination in
writing by placing such notice in United States certified mail, return receipt
requested, postage prepaid at the address shown below, at least 90 days prior to
June 30, 1999, or 90 days prior to any successive anniversary date (being June
30th of each year) thereafter.  This Agreement may also be terminated by the
Companies because of Page's willful misconduct, negligence, inability to perform
the services required, dishonesty, breach of a fiduciary duty, willful violation
of any law, rule, regulation (other than a law, rule or regulation relating to a
traffic violation or similar offense), or a material breach of any provision of
this Agreement, which remains uncured after 30 days' written notice to Page.

    2.   The Companies may terminate Page's employment hereunder without cause,
effective on the date written notice of such termination is placed in United
States certified mail, return receipt requested, postage prepaid, addressed to
Page at the address shown below.  Termination without cause shall be deemed to
have occurred if the Companies significantly reduce Page's duties and
responsibilities in a manner inconsistent with his experience, training and
background; provided, however, that upon any termination without cause, Page
shall be paid the greater of the Base Salary then in effect for the remaining
term of the Agreement or one year's salary at the then Base Salary rate.  Any
vested benefits of Page under any plan or agreement shall not be affected.

    3.   Page may terminate his employment hereunder upon at least one month's
written notice to the Companies placed in United States certified mail, return
receipt requested, postage prepaid to the address shown below, provided however,
if Page terminates his employment, the Companies' obligations under this
Agreement shall cease immediately except as provided below upon receipt of such
notice of termination by the Companies.  If Page terminates his employment, he
will be paid his Base Salary on a pro rata basis through the last day worked.

    4.   Page's title during his term of employment shall be Senior Vice
President and Chief Financial Officer of both of the Companies.  During the term
of this Agreement, and subject to the other provisions of this Agreement, Page
shall diligently provide services to the Companies by supervising the activities
of the Controller and coordinating the generation of financial statements and
information with the needs of management and agency and lender requirements; be
responsible for the working relationships with outside accountants, attorneys,



<PAGE>

commercial banks, investment bankers; plan and budget financial activities; and
supervise the administrative functions of the Companies, including human
resources.

    5.   Page agrees that this contract is one for full time employment, that
he will spend no less than 40 hours per week (subject to legal holidays and
vacations as set forth below) at this employment and that he will not engage in
the oil and gas business, including but not limited to, exploration, production,
purchase of commercial quantities of oil or gas, or oil or gas production
brokering, for his own account or that of any person or entity other than the
Companies while employed by the Companies.

    6.   As compensation for the services to be rendered by Page, the Companies
or one of them shall pay Page a Base Salary at the annual rate of $150,000
beginning June 30, 1996.  The Base Salary beginning January 1, 1997, shall be at
the annual rate of $175,000; the Base Salary beginning January 1, 1998, shall be
at the annual rate of $185,000.  Notwithstanding the quotation of the Base
Salary at an annual rate, Page will only be paid on a pro rata basis only for
the actual days worked if his employment is terminated.

    7.   In addition to the other compensation provided for herein, in the
event Costilla Energy, L.L.C. is merged into Costilla Energy, Inc. (the
"Corporate Successor") and, subsequent or contemporaneously therewith, the
Corporate Successor accomplishes an initial public offering of its equity
securities, Page shall be entitled to an option to purchase 75,000 shares of the
$.10 par value Common Stock of the Corporate Successor.  The exercise price with
respect to such initial stock option shall be the initial public offering price,
and such option shall be immediately exercisable by Page, without restriction.

    8.   As an incentive bonus for execution of this Agreement, Page will
receive $25,000 on or before July 15, 1996, which is to include the cost of his
household move from Denver to Midland.  Any other bonuses or incentive pay will
be determined and paid by the Companies from time to time, or not at all, at
their sole discretion.

    9.   As a perquisite, Page shall be entitled to receive payment of, or the
Companies shall purchase on his behalf, the initial membership fee to the
Midland Country Club.  Other fringe benefits will be given to Page, such as
participation in the group health insurance plan, dental insurance plan, life
insurance plan, and 401K plan in accordance with the Companies' standard benefit
program, provided however, Page will receive a life insurance policy to be
effective for the term of this Agreement in an amount no less than $200,000 and
long-term disability insurance of 60% of monthly Base Salary up to $10,000 per
month.

    10.  Page shall be entitled to 15 days paid vacation in each calendar year,
earned pro rata each month.  Page shall be entitled to all paid holidays given
by the Companies to its senior executive officers.

    11.  The Companies shall reimburse Page for any direct, reasonable and
necessary expenses incurred directly at the request of the Companies in the
performance of this


                                         -2-

<PAGE>


Agreement, such expenses to generally include, but not be limited to, travel,
lodging and meals incurred while away from Midland and any other directly
attributable expenses to carrying out Page's obligations under this Agreement.

    12.  If, as a result of Page's inability to perform the essential functions
of the duties set out herein, with or without accommodation,  due to physical or
mental illness or injury, and if Page shall have been absent from his duties
hereunder for more than 180 days within any 365-day period, the Companies shall
be entitled to deliver written notice of termination to Page and if within 30
days after any such written notice of termination is given, Page shall not have
returned to the performance of his duties in accordance with the terms of this
Agreement, the Companies may terminate his employment hereunder upon written
notice placed in United States certified mail, return receipt requested, postage
prepaid to the address shown below.  Upon the death of Page during the term of
this Agreement, the Companies shall continue to pay to Page's estate the Base
Salary for a period of 180 days following Page's death, following which the
obligations of the Companies under this Agreement shall terminate in their
entirety.  Termination of Page's employment under this paragraph shall not
affect Page's entitlement to any vested benefits provided herein.

    13.  If any action at law or equity is necessary to enforce or interpret
the terms of this Agreement, the prevailing party shall be entitled to
reasonable attorney's fees, as may be awarded by the court, costs and necessary
disbursements in addition to any other relief to which it may be entitled.  This
provision shall be binding on the parties without regard to whether attorney's
fees would be due under statute or common law.

    14.  All notices authorized or required by the parties hereunder shall be
given in writing by United States certified mail, return receipt requested,
postage prepaid, and addressed to the party to whom the notice is given at the
addresses shown on the signature page.  Notices shall be deemed given when
deposited in the United States mail.  Each party shall have the right to change
its addresses at any time and from time to time by giving written notice thereof
to the other.

    15.  This Agreement shall be construed under and in accordance with the
laws of the State of Texas.

    16.  This Agreement shall be binding upon and inure to the benefit of the
parties hereto and their respective heirs, executors, administrators, legal
representatives, successors and assigns where permitted by this Agreement.
However, the services to be provided by Page are personal and not performable in
satisfaction of this Agreement by any other person.

    17.  In case any one or more of the provisions contained in this Agreement
shall for any reason be held to be invalid, illegal or unenforceable in any
respect, such invalidity, illegality or unenforceability shall not affect any
other provisions hereof, and this Agreement shall be construed as if such
invalid, illegal or unenforceable provision had never been contained herein.


                                         -3-

<PAGE>


    18.  This Agreement constitutes the sole and only agreement of the parties
hereto and supersedes any prior understandings or written or oral agreement
between the parties respecting the within subject matter.  The parties agree
this contract can be modified only in writing and that Page will not rely on any
oral representations of any sort or character regarding his employment status,
salary, bonuses or benefits.

    19.  For purposes of this Agreement, notices and all other communications
provided for in this Agreement shall be in writing and shall be deemed to have
been duly given when placed in United States certified mail, return receipt
requested, postage prepaid, addressed as follows:

         If to Page:

              Bobby W. Page
              5100 North A Street, Apartment 457
              Midland, Texas 79705

         If to the Companies:

              Costilla Petroleum Corporation/Costilla Energy, L.L.C.
              P. O. Box 10369
              Midland, Texas  79702

              Attention:  President

or to such other address as either party may have furnished to the other in
writing in accordance herewith, except that notices of change of address shall
be effective only upon receipt.

    20.  The obligations and liabilities of the Companies hereunder shall be
joint and several in nature.

                                     /s/ Bobby W. Page
                                   ------------------------------------------
                                  BOBBY W. PAGE


                                  COSTILLA PETROLEUM CORPORATION

                                  By:      /s/ Michael J. Grella
                                       --------------------------------------
                                       Michael J. Grella, President


                                  COSTILLA ENERGY, L.L.C.

                                  By:       /s/ Michael J. Grella
                                        -------------------------------------
                                       Michael J. Grella, President

<PAGE>


                                                                   EXHIBIT 10.12
KOCH
- --------------------------------------------------------------------------------

KOCH OIL COMPANY



                                       Contract No:  18541
EXCHANGED WITH:    EXCHANGE AGREEMENT       Page:        1
                                            Date:  1/05/96
COSTILLA PETROLEUM CORPORATION         Confirming Agreement between
ATTN:  SAL PAGANO                           Blaine Parrott
P. O. BOX 10369                             and
MIDLAND, TX  79702                          Sal Pagano
                                       CUSTOMER CONTRACT: MT-SHE-1-EXC



- --------------------------------------------------------------------------------


                            KOCH OIL COMPANY WILL DELIVER

CRUDE TYPE:   1.   Domestic Sweet

QUANTITY:     A volume equal to the applicable percentage of the volume
              purchased by Koch Oil Company from the leases listed in Exhibit
              'A' attached.

TERM:         1.   Effective 1/01/96 to 7/01/96 and continuing month to month
                   thereafter until cancelled by either party with 30 days
                   advance written notice.

DELIVERY:     1.   By transfer in the facilities of Arco Pipe Line Company at
                   Cushing Terminal.

TITLE:        1.   Shall pass from Seller to Buyer at the completion of the
                   transfer.

PRICE:        1.   Koch Oil Company's posted price for West Texas Intermediate
                   crude oil deemed 40.0 degrees gravity plus $1.4500 per
                   barrel gathering and handling charges


                            KOCH OIL COMPANY WILL RECEIVE

CRUDE TYPE:   2.   North Dakota Sweet

              3.   Wyoming Sweet

QUANTITY:     The applicable percentage of the volume purchased by Koch Oil
              Company from the leases listed in Exhibit 'A' attached.

                                                          CONTINUED ON NEXT PAGE


<PAGE>


                                            Contract No:  18541
EXCHANGED WITH:         EXCHANGE AGREEMENT       Page:        2
                                                 Date:  1/05/96
COSTILLA ENERGY LLC                         Confirming Agreement between
ATTN:  SAL PAGANO                                Blaine Parrott
P. O. BOX 10369                                  and
MIDLAND, TX  79702                               Sal Pagano
                                            CUSTOMER CONTRACT: MT-SHE-1-EXC



- --------------------------------------------------------------------------------


TERM:    2.   Effective 1/01/96 to 7/01/96 and continuing month to month
              thereafter until cancelled by either party with 30 days advance
              written notice.

         3.   Effective 1/01/96 to 7/01/96 and continuing month to month
              thereafter until cancelled by either party with 30 days advance
              written notice.

DELIVERY: 2.  From tankage and/or through mutually acceptable meters located at
              the facilities of Seller at the leases in exhibit "A"

         3.   From tankage and/or through mutually acceptable meters located at
              the facilities of Seller at the leases in exhibit "A"

TITLE:   2.   Shall pass from Seller to Buyer as the crude oil passes the
              outlet flange of the lease tankage or meter.

         3.   Shall pass from Seller to Buyer as the crude oil passes the
              outlet flange of the lease tankage or meter.

PRICE:   2.   Koch Oil Company's posted price for North Dakota Southern
              Swtcrude oil deemed 40.0 degrees gravity plus $.9000 per barrel
              Bonus at the lease level.

         3.   Koch Oil Company's posted price for Wyoming Sweet crude oil
              deemed 40.0 degrees gravity plus $.9000 per barrel bonus at the
              lease level.

SPECIAL
PROVISIONS
         Payment due by wire transfer on or before the 20th of the month
         following the month of delivery. Pricing will be on an E.D.Q. pricing
         basis on both sides of the contract.
         Koch will pay Costilla 100% including taxes.
         *Please sign the attached Exhibit "B" Conditions of Payment at Lease
         Level".  Exhibit "B" will become a part of the contract and will allow
         us to eliminate the signing of Indemnifying Division Orders on future
         leases assigned to this contract.

                                                          CONTINUED ON NEXT PAGE



<PAGE>


                                            Contract No:  18541
EXCHANGED WITH:         EXCHANGE AGREEMENT       Page:        3
                                                 Date:  1/05/96
COSTILLA ENERGY LLC                         Confirming Agreement between
ATTN:  SAL PAGANO                                Blaine Parrott
P. O. BOX 10369                                  and
MIDLAND, TX  79702                               Sal Pagano
                                            CUSTOMER CONTRACT: MT-SHE-1-EXC

- --------------------------------------------------------------------------------


This agreement and the attached General Provisions represent the entire
agreement between the parties and where the General Provisions are inconsistent
with the specific provisions of the contract, the contract shall control.

If the foregoing conforms to your understanding of our agreement, please sign
and return one copy to signify your acceptance

ACCEPTED AND AGREED:              ACCEPTED AND AGREED:

KOCH OIL COMPANY                  COSTILLA ENERGY LLC

BY   /S/ ERIC P. MORK                  BY    /S/ SAL J. PAGANO
  -------------------                     ---------------------
Eric Mork
Vice President - Rocky Mt              TITLE   MGR - ENGR & OPERS
                                            ---------------------
                                       DATE    1/22/96
                                           -----------


<PAGE>
                                            Contract No:  18541
EXCHANGED WITH:       EXCHANGE AGREEMENT         Page:        1
                                                 Date:  1/05/96
COSTILLA ENERGY LLC                         Confirming Agreement between
ATTN:  SAL PAGANO                                Blaine Parrott
P. O. BOX 10369                                  and
MIDLAND, TX  79702                               Sal Pagano
                                            CUSTOMER CONTRACT: MT-SHE-1-EXC

- --------------------------------------------------------------------------------

              EXHIBIT "A"

<TABLE>
<CAPTION>
LEASE     NAME                    OPERATOR                COUNTY     ST     APPLICABLE PERCENT    EFFECTIVE DATE
<C>      <S>                     <C>                     <C>        <C>    <C>                   <C>
0062674    STRINGER #1 14-1B      COSTILLA ENERGY LLC     SHERIDAN   MT        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062675    TANGE #2               COSTILLA ENERGY LLC     SHERIDAN   MT        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062676    MADSEN #2 RE-ENTRY     COSTILLA ENERGY LLC     SHERIDAN   MT        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062677    MADSEN #1              COSTILLA ENERGY LLC     SHERIDAN   MT        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062678    M NORAGER #1           COSTILLA ENERGY LLC     SHERIDAN   MT        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062679    STRINGER #2 14-1B      COSTILLA ENERGY LLC     SHERIDAN   MT        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062680    WOODROW STAR #1-A      COSTILLA ENERGY LLC      MCKENZIE  ND        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+   DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                           gravity

0062681    ELLA MANY RIBS #2A     COSTILLA ENERGY LLC      MCKENZIE  ND        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+   DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                           gravity

0062682    KATE HOPKINS #2        COSTILLA ENERGY LLC      MCKENZIE  ND        1.0000000                1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+   DESC -Koch Oil Company's,North Dakota Southern Sweet deemed 40 degrees
                                                           gravity

</TABLE>

                   CONTINUED ON NEXT PAGE



<PAGE>

                                            Contract No:  18541
EXCHANGED WITH:       EXCHANGE AGREEMENT         Page:       2.
                                                 Date:  1/05/96
COSTILLA ENERGY LLC                         Confirming Agreement between
ATTN:  SAL PAGANO                                Blaine Parrott
P. O. BOX 10369                                  and
MIDLAND, TX  79702                               Sal Pagano
                                            CUSTOMER CONTRACT: MT-SHE-1-EXC


- --------------------------------------------------------------------------------

         EXHIBIT "A"

<TABLE>
<CAPTION>
LEASE     NAME                    OPERATOR                COUNTY     ST     APPLICABLE PERCENT    EFFECTIVE DATE
<C>      <S>                     <C>                     <C>        <C>    <C>                   <C>
0062683    ELLA MANY RIBS # 1A    COSTILLA ENERGY LLC     MCKENZIE   ND         1.0000000              1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062684    RAYMOND NISKU UT       COSTILLA ENERGY LLC     SHERIDAN   MT         1.0000000              1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062685    RAYMOND STATE N 16     COSTILLA ENERGY LLC     SHERIDAN   MT         1.0000000              1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, North Dakota Southern Sweet deemed 40 degrees
                                                          gravity

0062686    PRAIRIE CRK MUDDY SD   COSTILLA ENERGY LLC     CROOK      WY         1.0000000              1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, Wyoming Sweet deemed 40 degrees gravity

0062687    LEWARK 6-1             COSTILLA ENERGY LLC     CROOK      WY         1.0000000              1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, Wyoming Sweet deemed 40 degrees gravity

0062688    L H ROBINSON G #3      COSTILLA ENERGY LLC     CROOK      WY         1.0000000              1/96
         PRICE: EDQ, ADJUSTMENTS               0.9000 P+  DESC -Koch Oil Company's, Wyoming Sweet deemed 40 degrees gravity
</TABLE>

<PAGE>

KOCH CONTRACT #18541



                                     Exhibit "B"


                         Conditions of Payment at Lease Level



     (Purchaser)                   (Seller)
To:  Koch Oil Company              From:       Costilla Energy LLC
     P. O. Box 2236                            P. O. Box 10369
     Wichita, KS 67201                         Midland, TX 79702



     Seller guarantees and warrants that it is the legal owner of, and/or has
the right to sell and deliver, all the oil (which, for the purposes hereof,
includes all liquid hydrocarbons purchased hereunder) produced from the lease
(s) listed on Exhibit "A".

     Purchaser is authorized to receive for purchase, on the terms herein
     stated, oil from such leases to the extent of your requirements, as
     directed below:

One: PROCEEDS.  The proceeds of said oil, after deducting any taxes imposed on
said oil which are required to be deducted by Purchaser and any trucking or
handling charges or other deductions agreed upon by Purchaser and Seller, shall
be paid to Seller monthly for oil received and purchased during the preceding
month by Purchaser.  In the event of any adverse claim, assertion of lien, or
any dispute concerning title to the property described in this agreement or to
the mineral proceeds from such property, Purchaser may withhold payments for the
oil until the claim, lien assertion, or dispute is settled, without liability
for interest unless otherwise required by applicable statute.  If requested,
Seller agrees to furnish evidence of title satisfactory to Purchaser.  Should
Purchaser resell the oil to another purchaser who accepts delivery at the point
at which Purchaser takes title, settlements to Seller may be based on the
grades, measurements, volume computations. and/or deductions of that purchaser.



Two: INDEMNITY BY SELLER. In consideration of Purchaser buying the oil
hereunder, Seller agrees to indemnify Purchaser, its agents, successors,
assigns, and related entities, against any and all claims, liabilities, losses
damages, costs, expenses, and attorneys' fees relating to or otherwise arising
from the oil purchases under this agreement.  Seller further agrees to make
settlement with all parties in interest, including settlement with the proper
authorities for taxes, interest, and penalties, if any, due upon said oil when
such taxes, interest and penalties are not deducted as authorized in Section One
hereof.

Koch Oil Company is required to withhold 31% in Federal Income Tax from payments
to owners who have not provided us with a taxpayer identification number.  To
avoid the 31% withholding, please fill in your tax identification number in the
space provided below.


Tax ID #     75-2262668                        Signature   /s/ Sal J. Pagano
        ---------------------------------                --------------------
Owner #


<PAGE>

                       EXCHANGE AND BUY/SELL GENERAL PROVISIONS

1.  MEASUREMENT AND TESTS:  All measurements hereunder shall represent one
hundred percent (100%) volume, consisting of United States barrels of forty-two
(42) gallons, the quantity and gravity of which will be adjusted to sixty
degrees (60 DEGREES) Fahrenheit temperature.  Procedures for measuring and
testing, except for delivery through positive displacement type meters shall be
computed in accordance with the latest ASTM published methods then in effect.
Procedures for such meter type deliveries shall be in accordance with the latest
ASME-API (Petroleum PD Meter Code) published methods then in effect.  The crude
oil and/or condensate delivered hereunder shall be merchantable and acceptable
to the carriers involved but not to exceed on percent (1%) BS&W and full
deduction shall be made for all BS&W content according to the ASTM Standard
Method then in effect.  Should either party hereto fail to have a representative
present during such measuring and testing, the measurement and tests of the 
other party shall be accepted.

2.  PAYMENT:  Unless specifically stated otherwise on the reverse side of this
agreement, Buyer agrees to make payment to Seller for the crude oil and/or
condensate purchased hereunder not later than the 20th of the month following
delivery.  Should the financial responsibility of Buyer at any time become
impaired, unsatisfactory, or unacceptable to Seller, or if sales to Buyer should
exceed approved credit lines, then Buyer shall secure and deliver to Seller such
advance payments or other security, including in appropriate instances an
acceptable letter of credit, as shall be required by Seller, and deliveries of
oil and/or condensate hereunder may be withheld until such security is received.
If such security is not received within the time specified by Seller, then
Seller shall have the right to cancel this agreement.

3.  WARRANTY:  The Seller warrants title to all crude oil and/or condensate sold
and delivered hereunder and warrants that same shall be free from all royalties,
liens, and encumbrances, and that all taxes applicable prior to delivery,
including but not limited to any production, extraction or other state, federal
or local lease level tax as well as any taxes for which the "First Purchaser" is
responsible for paying or collecting, have been or will be paid.  There are no
other representations, guarantees, or warranties, expressed or implied,
including particularly any implied warranty of fitness for a particular purpose,
or otherwise, which extend beyond the descriptions set forth explicitly in this
agreement.  The parties agree that this transaction is in the ordinary course of
their respective business activities.

4.  RULES AND REGULATIONS:  All of the terms and provisions of this agreement
shall be subject to the applicable orders, rules and regulations (hereinafter
generically referred to as "Regulations") of all governmental authorities having
or purporting to have jurisdiction in the premises.  If at any time or from time
to time such regulations should be amended or should new regulations be adopted
and the effect of such amended or new regulation (a) is not covered by any other
provision of this agreement and (b) has an adverse economic effect upon either
party hereto or its supplies or customers, the party affected shall have the
option to request renegotiation of the prices and other pertinent terms provided
for in this agreement.  Said option may be exercised by such party at any time
after such amended or new regulation is promulgated by giving written notice of
the desire to renegotiate prior to the time of delivery of the oil, such notice
to contain the new prices and terms desired by the affected party.  If the
parties do not agree upon new prices and terms satisfactory to both within
thirty (30) days after such notice is given, the affected party shall have the
right to terminate this agreement at the end of said thirty (30) day period,
except as provided in Paragraph 8 below.

5.  FORCE MAJEURE:  Either party hereto shall be relieved from liability for
failure to deliver or receive crude oil and/or condensate hereunder for the time
and to the extent such failure is occasioned by war, fire, explosion, riot,
strike or other industrial disturbances or concerned action of workmen, acts of
God, government regulations, disruption or breakdown of production or
transportation facilities, delays of pipeline carrier in receiving and
delivering crude oil and/or condensate tendered, by any decline in field
production, or by any other cause, whether similar or not to those heretofore
enumerated, reasonably beyond the control of such party.

6.  EQUAL DAILY DELIVERIES:  It is agreed that Buyer will pay for said crude oil
and/or condensate purchased hereunder on the basis of the posted price in effect
each day for the average number of barrels delivered each day during each month
hereunder.  Such average shall be determined by dividing the total number of
barrels delivered hereunder during each month by the total number of days in
such month.  The parties agree, conclusively, that delivery shall be presumed to
be made in equal daily quantities on the respective dates as determined
hereinabove and not on any other date.

7.  CLAIMS:  Claims for loss, damage or delay with respect to pipeline transfers
of title to crude oil and/or condensate hereunder must be filed by the claimant
in writing with the concerned carrier within the time specified in the
applicable tariff filed by such carrier.  A copy of the claim as filed is to be
submitted to the other party hereto as soon as practicable.  Failure of the
claimant to timely file such claim with the concerned carrier shall release the
other party hereto from all liability in respect of such claim.

All other claims as to shortage in quantity, to defects in quality, or any
other, except for demurrage, shall be made by written notice to the other party
within sixty (60) days after the delivery in question; claims for demurrage
shall be made within one (1) year after the delivery in question; otherwise, any
such claims shall be deemed to have been waived.  No claims whatever shall be
made under this agreement for special, indirect, or consequential damages.

8.  EXCHANGES:  If these General Provisions apply to an exchange or a matching
purchase and sale arrangement, the second party shall be obligated to return the
volume of crude oil and/or condensate specified hereby if the party which is
first in time to perform delivers the crude oil and/or condensate as specified
herein.  Except for differentials, if any are set forth on the reverse side of
this agreement, and other adjustments set forth in this agreement, this exchange
shall be on a barrel for barrel basis.  If any reason should intervene to
obstruct return delivery on the agreed date, the parties will agree upon the
type, grade, and place of such a substitute delivery, and price differentials,
if any, to be made at the earliest reasonable date.

In the event an exchange imbalance arises as a result of this agreement as a
result of one party delivering prior to or more than the other party, subsequent
deliveries shall be applied first to such exchange imbalance and then to any
further deliver obligations, consistent with the pricing and delivery terms of
this agreement set forth above.

Any crude imbalances under this agreement upon termination will be settled by
either the sale of the crude imbalance by one party to the other at a mutually
agreeable price or by other mutually agreeable methods.

9.  ASSIGNMENT:  Neither party shall assign this agreement or any rights
hereunder without first obtaining the written consent of the other party hereto.

10.  SAFETY:  Each party agrees that its agents and employees will comply with
all safety regulations of the other when such agents or employees are upon the
premises of the other in connection with the performance of this contract.

11.  RIGHTS OF SETOFF:  In the event that either party shall default in any
payment or other performance under this or any other agreement existing by and
between the parties hereto, or if any suit, claim, demand, action or cause of
action shall be instituted involving any sums due under this or any other such
agreement, then and in any of those events the other party, at its option, shall
have the right to withhold any payment or any deliveries of crude oil and/or
condensate due under this or any other such agreement, or offset and deduct from
any payments or deliveries due under this or any other such agreement.


<PAGE>

12.  BUSINESS PRACTICES:  Each party hereto agrees to comply with all laws and
regulations applicable to activities carried out in the name of or on the behalf
of the other party under provisions of this agreement.

Each party hereto agrees that all financial settlements, billings and reports
rendered to the other party as provided for in this agreement will, to the best
of its knowledge, reflect properly the facts about all activities and
transactions related to this agreement.

Each party agrees to notify the other party promptly upon discovery of any
instance where the notifying party fails to comply with either provision above
or whose conduct by the notified party is considered, by the notifying party, to
be in breach of this agreement.

13.  ADDITIONAL TERMS:  No waiver by either party hereto of a breach of an
obligation owed hereunder by the other party shall be construed as a waiver of
any other breach, whether of the same or a different nature.

Any provision hereof which is legally unenforceable shall be ineffective only to
the extent of such unenforceability without thereby invalidating the remaining
provisions hereof or affecting the validity of enforceability of this agreement
as a whole.

This agreement contains the entire agreement between the Seller and Buyer with
respect to the subject matter hereof, and there are no other promises,
representations, or warranties affecting it.

The specific provisions contained in this agreement govern the general
provisions of this agreement in the event of any conflict between the two.

This agreement shall not be modified or amended except by written instrument
duly executed by officers or other duly authorized representative of the
respective parties.

<PAGE>

                                                                EXHIBIT 10.13


January 2, 1996


Costilla Petroleum Corporation
PO Box 10369
Midland, TX 79702
ATTN:     Mr. Michael Grella

RE:  FRONTIER CONTRACT NO. 9601-001B 
     COSTILLA CONTRACT NO. WY-CAM-1-LTR
     CONTRACT DATE: January 2, 1996

Gentlemen:

This Agreement is made between FRONTIER OIL AND REFINING COMPANY, herein
referred to as Frontier, and COSTILLA PETROLEUM CORPORATION, herein referred to
as Costilla, whereby Seller agrees to sell and deliver and Buyer agrees to
purchase and receive crude oil or condensate under the terms and conditions set
forth below and in the General Provisions and Exhibit "A", attached hereto and
made a part hereof.

COSTILLA DELIVERS:

QUALITY:  Wyoming General Sour type crude oil.

QUANTITY: Volume equal to production (approximately 650 barrels per day) from
          the leases listed on attached exhibit.  These leases are located in
          Campbell and Crook Counties, Wyoming.

DELIVERY: Title shall pass from Seller to Buyer as it leaves Seller's tankage at
          the various lease locations into Frontier's designated carriers.

PRICE:    Texaco's posted price for Wyoming General Sour type crude oil, gravity
          adjusted, plus $3.30 per barrel gathering and handling (equal daily
          quantities).

PAYMENT:  Made on the 20th of the month following the month of delivery.  Buyer
          will pay Seller as per signed Division Orders.

TERM:     Effective January 1, 1996 for six (6) months and continuing month to
          month thereafter unless terminated by either party upon giving thirty
          (30) days advance written notice of such termination or cancellation
          to the other party.  Termination shall not affect rights or
          obligations of either party accrued prior to the date of termination.

<PAGE>

Costilla Petroleum Corporation
Page Two
January 2, 1996


FRONTIER DELIVERS:

QUALITY:  West Texas Intermediate type crude oil.

QUANTITY: Approximately 650 barrels per day.

DELIVERY: Via in-line transfer with the facilities of Arco Pipeline at Cushing,
          Oklahoma terminal.

PRICE:    Koch's posted price for West Texas Intermediate type crude oil, deemed
          40 DEG., plus $1.35 per barrel gathering and handling (equal daily
          quantities).

PAYMENT:  Made on the 20th of the month following the month of delivery.

TERM:     Effective January 1, 1996 for six (6) months and continuing month to
          month thereafter unless terminated by either party upon giving thirty
          (30) days advance written notice of such termination or cancellation
          to the other party.  Termination shall not affect rights or
          obligations of either party accrued prior to the date of termination.

INVOICES AND NOTICES:

All invoices and notices given pursuant to this agreement shall be in writing or
by fax and shall be deemed delivered when received by the other party at the
addresses specified below.

Invoices to Frontier shall be mailed or faxed as follows:

     Frontier Oil and Refining Company
     ATTN:     Mary Carpenter
               Crude Oil Accounting
     5340 South Quebec Street, Suite 20ON
     Englewood, CO 80111-1911
     FAX: (303) 714-0163
     PHONE:    (303) 714-0189

Notices and all other correspondence to either Buyer or Seller shall be mailed
or faxed as follows:

     Frontier Oil and Refining Company
     5340 South Quebec Street, Suite 20ON
     Englewood, CO 80111-1911
     ATTN:     Crude Oil Supply & Trading


<PAGE>

     PHONE: (303) 714-0144
     FAX: (303) 714-0163
Costilla Petroleum Corporation
PO Box 10369
Midland, TX 79702
ATTN:  Loretta B. Brown/Valley Gathering Company
PHONE:  (915) 683-3092


<PAGE>

Costilla Petroleum Corporation
Page Three
January 2, 1996

Please return one fully executed copy of this Agreement to the attention of
Contract Administrator.  If you do not respond within twenty (20) days from the
date of receipt of this letter, each term and condition set forth in this
Agreement will be considered accepted and therefore binding.

FRONTIER OIL AND REFINING COMPANY

     /S/ MICHAEL R. NOVAK
- -------------------------------------
BY:  Michael R. Novak
     Manager, Lease Crude Acquisitions



AGREED TO AND ACCEPTED THIS 17TH DAY OF JANUARY, 1996.

COSTILLA ENERGY L.L.C.

BY:   /S/ MICHAEL J. GRELLA 
   ----------------------------------
     Michael J. Grella
Title:  President

Attachments
costilla.con


<PAGE>

                        FRONTIER OIL AND REFINING COMPANY
                                     AND
                         COSTILLA PETROLEUM CORPORATION

                        FRONTIER CONTRACT NO. 9601-001B
                   COSTILLA ENERGY CONTRACT NO. WY-CAM-1-LTR

                                  EXHIBIT "A"

                         LEASE
WELL NAME                NUMBER            LOCATION
- ---------                ------            --------
Candy Draw Unit          WY-079            53N-69W
                                           Campbell County, WY

Schwartz Draw W.I.F.     WY-080            Sec. 34-57N-74W
                                           Campbell County, WY

USA Hoffine B #1         WY-081            NE SE Sec. 5-49N-67W
                                           Campbell County, WY

L.H. Robinson F #1       WY-082            SE SE Sec. 5-49N-67W
                                           Crook County, WY

<PAGE>

                         FRONTIER OIL & REFINING COMPANY
                               GENERAL PROVISIONS

WARRANTY:  The party selling and/or delivering warrants title to all crude oil
sold and/or delivered hereunder and warrants that all such oil shall be free
from all liens and encumbrances and that all royalties applicable prior to
delivery shall have been or will be paid.  Seller warrants that all crude oil
and, if applicable, lease condensate purchased is virgin material of marketable
quality.  The crude oil and lease condensate purchased hereunder shall not
include refined products, natural gasoline, butane, propane, or any combination
thereunder, or any other substances or chemicals not normally associated with
virgin crude oil.  Such party further warrants that said crude oil has been
produced, handled and transported to the delivery point hereunder in accordance
with all applicable laws, rules and regulations of all local, state and federal
authorities.

TITLE AND RISK OF LOSS:  Title and risk of loss will pass to the party taking
delivery as the crude oil or condensate passes from equipment owned or
controlled by the party making delivery, or owned or controlled by a party
designated to make delivery on behalf of the party making delivery, into
equipment owned or controlled by the party taking delivery, or owned or
controlled by a party designated to take delivery on behalf of the party taking
delivery.

MEASUREMENTS AND TESTS:  All measurements hereunder shall represent one 
hundred percent (100%) volume, such volume and gravity adjusted to sixty 
degrees (60 DEG.) Fahrenheit temperature.  Procedures for measuring and 
testing, except for deliveries through positive displacement type liquid 
meters, shall be according to latest ASTM published methods then in effect.  
Procedures for such metered type deliveries shall be according to latest 
ASME-API published methods then in effect.  The crude oil delivered hereunder 
shall be merchantable and acceptable to the carriers involved and full 
deduction shall be made for all BS&W content according to the latest ASTM 
standard method then in effect.  Should either party hereto fail to have a 
representative present during such measuring and testing, the measurement and 
tests of the other party will be accepted.

CONFIRMATION OF DELIVERY:  Confirmation of delivery shall be based on run
tickets evidencing such delivery or allocation statements issued by the carriers
involved.

EQUAL DELIVERIES:  For pricing purposes, crude oil or condensate delivered
during any given month hereunder shall be deemed to have been delivered in equal
daily quantities during such month except for deliveries made pursuant to meter
tickets, in which case deliveries shall be deemed to have been delivered in
equal daily quantities during the period covered by such meter ticket, and
deliveries made at lease locations, in which case the date recorded on the run
tickets issued by the carrier shall be used in determining the price.

BALANCING:  In the case of exchanges, the parties agree to use their best
efforts to keep exchange quantities in balance pursuant to the terms of this
Agreement.  Periodically, and at the end of the term of this Agreement,
imbalances shall be corrected.  In case of an underdelivery, the underdelivering
party shall make up his/its underdeliveries, unless another method is mutually
agreed upon.

AUDIT:  Each party and its duly authorized representatives shall have access to
the accounting records and other documents maintained by the other party which
relate to materials being delivered to the other party under this Agreement, and
shall have the right to audit such records at any reasonable time or times
within three years after termination of this Agreement.

DIVISION ORDERS:  In the event either party signs a division order in favor of
the other party pertaining to the object of this Agreement, the terms of this
Agreement shall supersede the terms of such division order to the extent that
there may be a conflict between the two.

RULES AND REGULATIONS:  All the terms and provisions of this Agreement shall be
subject to the applicable orders, rules and regulations of all governmental
authorities.

FINANCIAL RESPONSIBILITY:  If either party's payments or deliveries to the other
party shall be in arrears, or the financial responsibility of either party
becomes impaired or unsatisfactory in the opinion of the other party, advance
cash payment or satisfactory security shall be given upon demand, and shipments
may be withheld by said other party until such payment or security is received. 
If such payment or security is not received within 15 days from demand therefor,
the said other party demanding such payment or security may terminate this
Agreement.  In the event either party makes an assignment or any general
arrangement for the benefit of creditors, or if there are instituted by or
against either party proceedings in bankruptcy or under any insolvency law or
law for reorganization, receivership or dissolution, the other party may
withhold shipments or terminate this Agreement without notice.  Either party
shall have the option to terminate this Agreement by providing 10 days written
notice to the other party if a determination affecting this Agreement is made by
any governmental authority which creates a material adverse change in the basic
economics of this Agreement.  The exercise by either party of any right reserved
under this section shall be without prejudice to any claim for damages or any
other right under this Agreement or applicable law.

TERMINATION AGREEMENT:  The parties agree that any quantity of crude oil or
condensate, due and owing or to become due from one party to the other pursuant
to this Agreement, may be waived or otherwise settled by mutual agreement of the
parties in writing, without further consideration other than that which is set
forth in this Agreement.


<PAGE>

ASSIGNMENT:  Neither party shall assign this contract without consent of the
other.

FORCE MAJEURE:  Neither party shall be liable to the other for failure or delay
in making or accepting delivery hereunder to the extent that such failure or
delay may be due to compliance with acts, orders, regulation or requests of any
federal, state or local civilian or military authority or any other persons
purporting to act therefor; riots; strikes; labor difficulties; action of the
elements; transportation difficulties; or any other cause reasonably beyond the
control of such party, whether similar or not.

WAIVER CLAUSE:  No waiver by either party of any breach of any of the covenants
or conditions herein contained to be performed by the other party shall be
construed as a waiver of any succeeding breach of the same or of any other
covenant or condition hereof.

TIMING:  References to calendar dates set forth in this Agreement and any
amendments hereto, shall mean 7:00 a.m. of the dates indicated.

<TABLE>
<S>                                                    <C>
ADDRESSES:
- ----------
Exchange Statements, Contracts & Correspondence to:    Invoices to:
  FRONTIER OIL & REFINING COMPANY                        FRONTIER OIL & REFINING COMPANY
  5340 South Quebec Street, Suite 200N                   5340 South Quebec Street.  Suite 200N
  Englewood, CO 80111-1911                               Englewood, CO 80111-1911
  ATTN: Crude Oil                                        ATTN: Crude Oil Payables
</TABLE>





<PAGE>

<TABLE>

                                                                                                                     EXHIBIT 12.1


                                                    COSTILLA ENERGY, INC.
                                                   EBITDA/INTEREST EXPENSE
                                                      (in thousands)

<CAPTION>
                                                                                                           Three Months Ended
                                                              Year Ended December 31,                           March 31,
                                           -------------------------------------------------------   ---------------------------
                                                                                            Pro                            Pro
                                                             Historical                    Forma         Historical       Forma
                                           --------------------------------------------   --------   -----------------   -------
                                            1991     1992     1993     1994      1995       1995       1995      1996      1996
                                           ------   ------   ------   ------   --------   --------   --------   ------   -------
<S>                                         <C>       <C>      <C>      <C>       <C>       <C>        <C>       <C>       <C>
Net income (loss)                          $  234   $  368   $   73   $  163   $(4,314)   $(7,860)   $(1,051)   $   12   $ (299)

  Interest expense                            179      365      605    1,458     4,454     11,631        407     1,704    2,908
  Income taxes                                 (2)      18      (23)      40         3          3          -         -        -
  Exploration and abandonment                 106        4      218      793     1,650      2,761      1,007       228      475
  Depreciation, depletion and amortization    494      404      884    1,847     6,095     14,313        462     1,986    3,166
                                           ------   ------   ------   ------   -------    -------    -------    ------   ------
EBITDA                                     $1,011   $1,159   $1,757   $4,301   $ 7,888    $20,848    $   825    $3,930   $6,250
                                           ------   ------   ------   ------   -------    -------    -------    ------   ------
EBITDA/Interest expense                       5.6x     3.2x     2.9x     2.9x      1.8x       1.8x       2.0x      2.3x     2.1x
                                           ------   ------   ------   ------   -------    -------    -------    ------   ------
</TABLE>


<PAGE>

<TABLE>
                                                                                                                     EXHIBIT 12.2

                                              COSTILLA ENERGY, INC.

                                      RATIO OF EARNINGS TO FIXED CHANGES
                                                 (in thousands)

<CAPTION>
                                                                                                          Three Months Ended
                                                               Year Ended December 31,                         March 31,
                                                 ---------------------------------------------------   -------------------------
                                                                                               Pro                         Pro
                                                                Historical                    Forma       Historical      Forma
                                                 -----------------------------------------   -------   ----------------   ------
                                                 1991    1992     1993     1994      1995      1995      1995     1996     1996
                                                 ----   ------   ------   ------   -------   -------   -------   ------   ------
<S>                                              <C>    <C>      <C>      <C>      <C>       <C>       <C>       <C>      <C>
Net income (loss) before income taxes            $232   $  386   $   50   $  203   $(4,311)  $(7,857)  $(1,051)  $   12   $ (299)
Fixed charges                                     683      780    1,599    3,503    10,860    26,255       893    3,725    6,109
                                                 ----   ------   ------   ------   -------   -------   -------   ------   ------
    Earnings                                     $915   $1,166   $1,649   $3,706   $ 6,549   $18,398   $  (158)  $3,737   $5,810
                                                 ----   ------   ------   ------   -------   -------   -------   ------   ------
Fixed charges:
  Interest expense                               $179   $  365   $  605   $1,458   $ 4,454   $11,631   $   407   $1,704   $2,908
  Interest portion of operating lease payments     10       11      110      198       311       311        24       35       35
  Depreciation, depletion and amortization        494      404      884    1,847     6,095    14,313       462    1,986    3,166
                                                 ----   ------   ------   ------   -------   -------   -------   ------   ------
    Fixed charges                                $683   $  780   $1,599   $3,503   $10,860   $26,255   $   893   $3,725   $6,109
                                                 ----   ------   ------   ------   -------   -------   -------   ------   ------
Ratio of earnings to fixed charges                1.3      1.5      1.0      1.1       n/a       n/a       n/a      1.0      n/a
                                                 ----   ------   ------   ------   -------   -------   -------   ------   ------
Amount that earnings are insufficient to
 cover fixed charges                              n/a      n/a      n/a      n/a   $(4,311)  $(7,857)  $(1,051)     n/a   $ (299)
                                                 ----   ------   ------   ------   -------   -------   -------   ------   ------
</TABLE>



<PAGE>

                                                                  EXHIBIT 12.3




                            COSTILLA ENERGY, INC.
                   Pro Forma Ratio of ACTNA to Total Debt
                            As of March 31, 1996
                               (in thousands)


Discounted future net revenues from
 proved oil and gas reserves                              $179,527
Capitalized costs of unproved properties                     3,580
Net working capital                                         15,955
Other property and equipment, net (at cost)                  1,724
Note receivable - affiliate                                    684
                                                          --------
Adjusted Consolidated Net Tangible Assets (ACTNA)         $201,470
                                                          --------
Total debt                                                $103,097
                                                          --------
Ratio of ACTNA to Total Debt                                   2.0x
                                                          --------





<PAGE>

                                                                 EXHIBIT 21.1 

                         SUBSIDIARIES OF THE REGISTRANT




     Costilla Energy, Inc. has the following subsidiaries (as defined in Rule
405 of the Rules and Regulations promulgated under the Securities Act of 1993,
as amended):


     1.   Costilla Petroleum Corporation, a Texas corporation;

     2.   Statewide Minerals, Inc., a Texas corporation;

     3.   Costilla Pipeline Corporation, a Texas corporation; and 

     4.   Valley Gathering Company, a Texas corporation.





<PAGE>
                                                                    EXHIBIT 23.1
 
                        CONSENT OF INDEPENDENT AUDITORS
 
The Members
Costilla Energy, L.L.C.
 
    We consent to the use of our reports included herein and to the reference to
our firm under the heading "Experts" in the Prospectus.
 
                                          KPMG PEAT MARWICK LLP
 
Midland, Texas
July 26, 1996

<PAGE>
                                                                    EXHIBIT 23.2
 
                        CONSENT OF INDEPENDENT ENGINEERS
 
    As  independent engineering consultants, we hereby consent to the use of our
Summary Reserve Report entitled "Summary  Letter (for Inclusion in a  Prospectus
Included  in a  Registration Statement  for Costilla  Energy, Inc.  on Form S-1)
Combining  Specific  Data  from  Two  Williamson  Petroleum  Consultants,   Inc.
Evaluations  (1) to the  Interests of Costilla  Petroleum Corporation in Various
Properties and (2) to the Interests of  Parker & Parsley Petroleum USA, Inc.  in
Various Properties Included in Their First Quarter 1996 Sales Package, Effective
April  1,  1996, Williamson  Project 6.8393"  dated July  23, 1996  prepared for
Costilla Energy, Inc., and data extracted  therefrom (and all references to  our
Firm,  including any  references as  Experts) included  in or  made part  of the
Prospectus included in this Registration Statement on Form S-1.
 
                                     WILLIAMSON PETROLEUM CONSULTANTS, INC.
 
Houston, Texas
July 23, 1996

<PAGE>
                                                                    EXHIBIT 23.3
 
                        CONSENT OF INDEPENDENT AUDITORS
 
The Members
Costilla Energy, L.L.C.
 
    We consent to the use of our reports included herein and to the reference to
our firm under the heading "Experts" in the Prospectus.
 
                                          ELMS, FARIS & CO., P.C.
 
Midland, Texas
July 26, 1996

<PAGE>
                                                                 EXHIBIT 24.1 

                                POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS, the undersigned, being certain of the 
Officers and all of the Directors of Costilla Energy, Inc., a Delaware 
Corporation, do hereby constitute and appoint Michael J. Grella and Bobby W. 
Page, or either of them, with full power of substitution, our true and lawful 
attorneys and agents, to do any and all acts and things in our names in the 
capacities indicated which Michael J. Grella and Bobby W. Page, or either of 
them, may deem necessary or advisable to enable the Company to comply with 
the Securities Act of 1933, as amended, any state securities laws and any 
rules, regulations and requirements of the Securities and Exchange Commission 
in connection with the Registration Statement seeking to register 
$100,000,000 of _____% Senior Subordinated Notes due 2006 of Costilla Energy, 
Inc., including specifically, but not limited to, the power and authority to 
sign such Registration Statement, any and all amendments (including 
post-effective amendments) to such Registration Statement and any other forms 
or documents related to such Registration Statement which are required under 
federal or state securities laws for us, or any of us, in our names in the 
capacities indicated; and we do hereby ratify and confirm all that Michael J. 
Grella and Bobby W. Page, or either of them, shall do or cause to be done by 
virtue hereof.  This Power of Attorney may be signed in any number of 
counterparts, and each such counterpart shall be considered an original 
hereof.

     IN WITNESS WHEREOF I have hereunto set my hand this 12th day of July, 
1996.

                                  /s/  CADELL S. LIEDTKE                     
                              ---------------------------------------------- 
                              CADELL S. LIEDTKE, Chairman of the Board,
                              Chief Executive Officer and Director

                                  /s/  MICHAEL J. GRELLA                     
                              ---------------------------------------------- 
                              MICHAEL J. GRELLA, President, Chief
                              Operating Officer and Director

                                  /s/  HENRY G. MUSSELMAN                    
                              ---------------------------------------------- 
                              HENRY G. MUSSELMAN, Executive Vice
                              President and Director

                                  /s/  BOBBY W. PAGE                         
                              ---------------------------------------------- 
                              BOBBY W. PAGE, Senior Vice President,
                              Treasurer and Chief Financial Officer


                                   /s/  JERRY LANGDON                        
                              ---------------------------------------------- 
                              JERRY LANGDON, Director


                                  /s/  W.D. KENNEDY                          
                              ---------------------------------------------- 
                              W. D. KENNEDY, Director


<PAGE>


                                                                    EXHIBIT 24.2



                               CERTIFICATE OF RESOLUTION



    I, CLIFFORD N. HAIR, JR., Secretary of Costilla Energy, Inc., a Delaware
corporation, do hereby certify that the Board of Directors of Costilla Energy,
Inc., acting by unanimous written consent, duly adopted the following
resolutions as of July 1, 1996:

         RESOLVED, that the directors and officers of the Corporation are
    hereby authorized and directed to execute and deliver a Power of Attorney
    to Michael J. Grella and Bobby W. Page in the following form:

              KNOW ALL MEN BY THESE PRESENTS, the undersigned, being certain of
         the Officers and all of the Directors of Costilla Energy, Inc., a
         Delaware Corporation, do hereby constitute and appoint MICHAEL J.
         GRELLA and BOBBY W. PAGE, or either of them, with fully power of
         substitution, our true and lawful attorneys and agents, to do any and
         all acts and things in our names and in the capacities indicated which
         MICHAEL J. GRELLA and BOBBY W. PAGE, or either of them, may deem
         necessary or advisable to enable the Company to comply with the
         Securities Act of 1933, as amended, any state securities laws, and any
         rules, regulations, and requirements of the Securities and Exchange
         Commission in connection with the Registration Statement seeking to
         register shares of Common Stock, $.10 par value of Costilla Energy,
         Inc., including specifically, but not limited to, the power and
         authority to sign such Registration Statement, any and all amendments
         (including post-effective amendments) to such Registration Statement,
         and any other forms or documents related to such Registration
         Statement which are required under federal or state securities laws
         for us, or any of us, in our names in the capacities indicated; and we
         do hereby ratify and confirm all that MICHAEL J. GRELLA and BOBBY W.
         PAGE, or either of them, shall do or cause to be done by virtue
         hereof.  This Power of Attorney may be signed in any number of
         counterparts, and each such counterpart shall be considered an
         original hereof.

         RESOLVED, that the Officers of the Corporation are hereby authorized
    and directed to take all such further action as they may deem advisable in
    order to carry out the intent and purposes of the foregoing resolutions.


    IN WITNESS WHEREOF, I have hereunto set my hand on behalf of this
Corporation on this 15th day of July, 1996.


                                 /s/ Clifford N. Hair, Jr.
                             --------------------------------
                             CLIFFORD N. HAIR, JR., Secretary


<PAGE>

                    SECURITIES AND EXCHANGE COMMISSION
                          WASHINGTON, D.C.  20549



                           _____________________

                   STATEMENT OF ELIGIBILITY UNDER THE 
                    TRUST INDENTURE ACT OF 1939 OF A 
                CORPORATION DESIGNATED TO ACT AS TRUSTEE

            CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY
              OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) __


                  STATE STREET BANK AND TRUST COMPANY
           (EXACT NAME OF TRUSTEE AS SPECIFIED IN ITS CHARTER)

            Massachusetts                               04-1867445
   (JURISDICTION OF INCORPORATION OR                 (I.R.S. EMPLOYER   
ORGANIZATION IF NOT A U.S. NATIONAL BANK)           IDENTIFICATION NO.) 


225 Franklin Street, Boston, Massachusetts                  02110
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)                  (ZIP CODE)

    John R. Towers, Esq.  Senior Vice President and Corporate Secretary
            225 Franklin Street, Boston, Massachusetts  02110
                               (617)654-3253
        (NAME, ADDRESS AND TELEPHONE NUMBER OF AGENT FOR SERVICE)
                           _____________________

                           COSTILLA ENERGY, INC.
             (EXACT NAME OF OBLIGOR AS SPECIFIED IN ITS CHARTER)

            DELAWARE                                 75-2658940
(STATE OR OTHER JURISDICTION OF                     (I.R.S. EMPLOYER  
INCORPORATION OR ORGANIZATION)                     IDENTIFICATION NO.)

                       400 WEST ILLINOIS, SUITE 1000
                           MIDLAND, TEXAS 79701
            (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)  (ZIP CODE)
                           _____________________

                        (SENIOR SUBORDINATED NOTES)
                      (TITLE OF INDENTURE SECURITIES)

<PAGE>

                                  GENERAL 

ITEM 1.  GENERAL INFORMATION.

         FURNISH THE FOLLOWING INFORMATION AS TO THE TRUSTEE:

         (a)  NAME AND ADDRESS OF EACH EXAMINING OR SUPERVISORY AUTHORITY TO 
              WHICH IT IS SUBJECT.

                 Department of Banking and Insurance of The Commonwealth of 
                 Massachusetts, 100 Cambridge Street, Boston, Massachusetts.

                 Board of Governors of the Federal Reserve System, Washington,
                 D.C., Federal Deposit Insurance Corporation, Washington, D.C.

ITEM 2.  AFFILIATIONS WITH OBLIGOR.

         IF THE OBLIGOR IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH SUCH 
         AFFILIATION.

                 The obligor is not an affiliate of the trustee or of its 
                 parent, State Street Boston Corporation.

                 (See note on page 6.)

ITEM 3. THROUGH ITEM 15.  NOT APPLICABLE.

ITEM 16. LIST OF EXHIBITS.

         LIST BELOW ALL EXHIBITS FILED AS PART OF THIS STATEMENT OF ELIGIBILITY.

         1. A COPY OF THE ARTICLES OF ASSOCIATION OF THE TRUSTEE AS NOW IN 
            EFFECT.

                A copy of the Articles of Association of the trustee, as now in
                effect, is on file with the Securities and Exchange Commission 
                as Exhibit 1 to Amendment No. 1 to the Statement of Eligibility 
                and Qualification of Trustee (Form T-1) filed with the 
                Registration Statement of Morse Shoe, Inc. (File No. 22-17940) 
                and is incorporated herein by reference thereto.

         2. A COPY OF THE CERTIFICATE OF AUTHORITY OF THE TRUSTEE TO COMMENCE 
            BUSINESS, IF NOT CONTAINED IN THE ARTICLES OF ASSOCIATION.

                A copy of a Statement from the Commissioner of Banks of 
                Massachusetts that no certificate of authority for the trustee
                to commence business was necessary or issued is on file with the
                Securities and Exchange Commission as Exhibit 2 to Amendment No.
                1 to the Statement of Eligibility and Qualification of Trustee 
                (Form T-1) filed with the Registration Statement of Morse Shoe,
                Inc. (File No. 22-17940) and is incorporated herein by reference
                thereto.

         3. A COPY OF THE AUTHORIZATION OF THE TRUSTEE TO EXERCISE CORPORATE 
            TRUST POWERS, IF SUCH AUTHORIZATION IS NOT CONTAINED IN THE 
            DOCUMENTS SPECIFIED IN PARAGRAPH (1) OR (2), ABOVE.

                A copy of the authorization of the trustee to exercise corporate
                trust powers is on file with the Securities and Exchange 
                Commission as Exhibit 3 to Amendment No. 1 to the Statement of 
                Eligibility and Qualification of Trustee (Form T-1) filed with 
                the Registration Statement of Morse Shoe, Inc. (File No. 
                22-17940) and is incorporated herein by reference thereto.

         4. A COPY OF THE EXISTING BY-LAWS OF THE TRUSTEE, OR INSTRUMENTS 
            CORRESPONDING THERETO.

                A copy of the by-laws of the trustee, as now in effect, is on 
                file with the Securities and Exchange Commission as Exhibit 4 
                to the Statement of Eligibility and Qualification of Trustee 
                (Form T-1) filed with the Registration Statement of Eastern 
                Edison Company (File No. 33-37823) and is incorporated herein by
                reference thereto.

                                      1 
<PAGE>


         5.   A COPY OF EACH INDENTURE REFERRED TO IN ITEM 4 IF THE OBLIGOR 
              IS IN DEFAULT.

                 Not applicable.

         6.   THE CONSENTS OF UNITED STATES INSTITUTIONAL TRUSTEES REQUIRED BY
              SECTION 321(b) OF THE ACT.

                 The consent of the trustee required by Section 321(b) of the 
                 Act is annexed hereto as Exhibit 6 and made a part hereof.

         7.   A COPY OF THE LATEST REPORT OF CONDITION OF THE TRUSTEE PUBLISHED
              PURSUANT TO LAW OR THE REQUIREMENTS OF ITS SUPERVISING OR 
              EXAMINING AUTHORITY.

                 A copy of the latest report of condition of the trustee 
                 published pursuant to law or the requirements of its 
                 supervising or examining authority is annexed hereto as 
                 Exhibit 7 and made a part hereof.


                                   NOTES

     In answering any item of this Statement of Eligibility and Qualification 
which relates to matters peculiarly within the knowledge of the obligor or 
any underwriter for the obligor, the trustee has relied upon information 
furnished to it by the obligor and the underwriters, and the trustee 
disclaims responsibility for the accuracy or completeness of such information.

     The answer furnished to Item 2. of this statement will be amended, if 
necessary, to reflect any facts which differ from those stated and which 
would have been required to be stated if known at the date hereof.

                                 SIGNATURE

     Pursuant to the requirements of the Trust Indenture Act of 1939, as 
amended, the trustee, State Street Bank and Trust Company, a corporation 
organized and existing under the laws of The Commonwealth of Massachusetts, 
has duly caused this statement of eligibility and qualification to be signed 
on its behalf by the undersigned, thereunto duly authorized, all in the City 
of Boston and The Commonwealth of Massachusetts, on the 23RD DAY OF JULY, 
1996.

                                      STATE STREET BANK AND TRUST COMPANY 


                                      By:        /s/  Donald E. Smith        
                                         ----------------------------------- 
                                                    DONALD E. SMITH          
                                                    VICE PRESIDENT           
















                                     2 
<PAGE>

                                EXHIBIT 6


                          CONSENT OF THE TRUSTEE

     Pursuant to the requirements of Section 321(b) of the Trust Indenture 
Act of 1939, as amended, in connection with the proposed issuance by COSTILLA 
ENERGY, INC.. of its Senior Subordinated Notes, we hereby consent that 
reports of examination by Federal, State, Territorial or District authorities 
may be furnished by such authorities to the Securities and Exchange 
Commission upon request therefor.

                                      STATE STREET BANK AND TRUST COMPANY 


                                      By:        /s/  Donald E. Smith        
                                         ----------------------------------- 
                                                    DONALD E. SMITH          
                                                    VICE PRESIDENT           

DATED:  JULY 23, 1996


















                                    3 

<PAGE>

                                EXHIBIT 7

Consolidated Report of Condition of State Street Bank and Trust Company of 
Boston, Massachusetts and foreign and domestic subsidiaries, a state banking 
institution organized and operating under the banking laws of this 
commonwealth and a member of the Federal Reserve System, at the close of 
business DECEMBER 31, 1995, published in accordance with a call made by the 
Federal Reserve Bank of this District pursuant to the provisions of the 
Federal Reserve Act and in accordance with a call made by the Commissioner of 
Banks under General Laws, Chapter 172, Section 22(a).

                                                                  Thousands of
ASSETS                                                               Dollars 

Cash and balances due from depository institutions:
  Noninterest-bearing balances and currency and coin.............   1,331,827 
  Interest-bearing balances......................................   5,971,326 
Securities.......................................................   6,325,054 
Federal funds sold and securities purchased under agreements 
 to resell in domestic offices of the bank and its Edge 
 subsidiary......................................................   5,436,994 
Loans and lease financing receivables:
  Loans and leases, net of unearned 
   income.................................   4,308,339 
  Allowance for loan and lease losses.....      63,491 
  Loans and leases, net of unearned income and allowances........   4,244,848 
Assets held in trading accounts..................................   1,042,846 
Premises and fixed assets........................................     374,362 
Other real estate owned..........................................       3,223 
Investments in unconsolidated subsidiaries.......................      31,624 
Customers' liability to this bank on acceptances outstanding.....      57,472 
Intangible assets................................................      68,384 
Other assets.....................................................     670,058 
                                                                   ---------- 
Total assets.....................................................  25,558,018 
                                                                   ---------- 
                                                                   ---------- 

LIABILITIES

Deposits:
  In domestic offices............................................   6,880,231 
    Noninterest-bearing...................   4,728,115 
    Interest-bearing......................   2,152,116 
  In foreign offices and Edge subsidiary.........................   9,607,427 
    Noninterest-bearing...................      28,265 
    Interest-bearing......................   9,579,162 
Federal funds purchased and securities sold under agreements 
 to repurchase in domestic offices of the bank and of its Edge 
 subsidiary......................................................   5,913,969 
Demand notes issued to the U.S. Treasury and Trading 
 Liabilities.....................................................     530,406 
Other borrowed money.............................................     493,191 
Bank's liability on acceptances executed and outstanding.........      57,387 
Other liabilities................................................     620,287 
                                                                   ---------- 
Total liabilities................................................  24,102,898 
                                                                   ---------- 

EQUITY CAPITAL
Common stock.....................................................      29,176 
Surplus..........................................................     228,448 
Undivided profits................................................   1,197,496 
                                                                   ---------- 
Total equity capital.............................................   1,455,120 
                                                                   ---------- 

Total liabilities and equity capital.............................  25,558,018 
                                                                   ---------- 
                                                                   ---------- 


                                    4 
<PAGE>

I, Rex S. Schuette, Senior Vice President and Comptroller of the above named 
bank do hereby declare that this Report of Condition has been prepared in 
conformance with the instructions issued by the Board of Governors of the 
Federal Reserve System and is true to the best of my knowledge and belief.

                                      Rex S. Schuette


We, the undersigned directors, attest to the correctness of this Report of 
Condition and declare that it has been examined by us and to the best of our 
knowledge and belief has been prepared in conformance with the instructions 
issued by the Board of Governors of the Federal Reserve System and is true 
and correct.

                                       David A. Spina
                                       Marshall N. Carter
                                       Charles F. Kaye













                                       5 

<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
FINANCIAL STATEMENTS OF COSTILLA ENERGY, L.L.C. FOR YEARS ENDED DECEMBER 31,
1993, 1994, AND 1995 AND THE UNAUDITED PERIODS MARCH 31, 1995 AND 1996, AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   YEAR                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1995             DEC-31-1996
<PERIOD-START>                             JAN-01-1995             JAN-01-1996
<PERIOD-END>                               DEC-31-1995             MAR-31-1996
<CASH>                                           2,616                   2,760
<SECURITIES>                                         0                       0
<RECEIVABLES>                                    7,576                   7,584
<ALLOWANCES>                                         0                       0
<INVENTORY>                                          0                       0
<CURRENT-ASSETS>                                10,881                  11,394
<PP&E>                                          83,479                  88,569
<DEPRECIATION>                                 (9,413)                (11,281)
<TOTAL-ASSETS>                                  87,367                  91,024
<CURRENT-LIABILITIES>                            8,385                   9,290
<BONDS>                                         71,494                  74,494
                           11,320                  11,678
                                          0                       0
<COMMON>                                             0                       0
<OTHER-SE>                                     (7,189)                 (7,535)
<TOTAL-LIABILITY-AND-EQUITY>                    87,367                  91,024
<SALES>                                         21,693                   8,833
<TOTAL-REVENUES>                                21,816                   8,951
<CGS>                                           10,355                   3,659
<TOTAL-COSTS>                                   12,005                   3,887
<OTHER-EXPENSES>                                 6,097                   1,986
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                               4,454                   1,704
<INCOME-PRETAX>                                (4,311)                      12
<INCOME-TAX>                                         3                       0
<INCOME-CONTINUING>                            (4,314)                      12
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                   (4,314)                      12
<EPS-PRIMARY>                                        0                       0
<EPS-DILUTED>                                        0                       0
        

</TABLE>


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