COSTILLA ENERGY INC
S-1/A, 1996-09-24
CRUDE PETROLEUM & NATURAL GAS
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<PAGE>
   
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 24, 1996
    
 
                                                      REGISTRATION NO. 333-08909
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                            ------------------------
 
   
                                AMENDMENT NO. 2
                                       TO
    
                                    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.  / /
 
                            ------------------------
 
    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>
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 SEPTEMBER 24, 1996
    
 
PRELIMINARY PROSPECTUS
                                  $100,000,000
 
                             COSTILLA ENERGY, INC.
 
   
                             % SENIOR NOTES DUE 2006
    
                               -----------------
 
   
    The   % Senior  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 senior obligations  of the Company and
will rank equally  in right of  payment with all  other Senior Indebtedness  (as
defined  herein) of the Company, which  will include borrowings under the Credit
Facility (as  defined  herein), but  will  be effectively  subordinated  to  any
existing  or future secured Senior Indebtedness. The Credit Facility is expected
to be secured by substantially all of the assets of the Company. As of June  30,
1996,  on a pro forma basis after giving effect to the Corporate Reorganization,
the Offerings and the application of the proceeds therefrom, as described  under
"Use  of Proceeds", the  Company would have  had $0.4 million  of secured Senior
Indebtedness. No indebtedness of  the Company is  expressly subordinated to  the
Notes.  Initially, both  the Notes and  the Credit Facility  will be effectively
subordinated to liabilities of the Company's subsidiaries. On a pro forma basis,
the total liabilities of  the Company's subsidiaries were  $6.5 million at  June
30,  1996,  all  of  which  were  operating  liabilities.  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 transfers 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 has  been
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  10 FOR A  DISCUSSION OF 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  has 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 $600,000.
 
    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>
                            PRIMARY OPERATING AREAS
 
              [A GEOGRAPHICAL MAP INDICATING WHERE THE COMPANY HAS
                      OIL AND GAS PROPERTIES AND OFFICES]
 
    IN  CONNECTION WITH THIS NOTES 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.
<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."  "ADJUSTED  EBITDA,"  AS  USED
HEREIN,  MEANS  NET INCOME  (LOSS), PLUS  INTEREST, INCOME  TAXES, DEPRECIATION,
DEPLETION AND AMORTIZATION, EXPLORATION AND ABANDONMENT COSTS AND  EXTRAORDINARY
LOSS FROM EXTINGUISHMENT OF DEBT.
 
                                  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 area of Texas and New Mexico, 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 an entity  which has 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 April 1, 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  April 1, 1996. The Company also
has a  substantial  undeveloped acreage  position  consisting of  180,704  gross
(165,166  net) acres at June  30, 1996. The Company  has identified in excess of
185 drilling locations of which 64 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 37 wells based on these
3-D surveys,  31  of  which  have been  productive.  The  Company  has  recently
completed  two additional 3-D surveys and intends to commence drilling on one of
these acreage blocks in the second half of 1996. The Company currently plans  to
drill 63 wells through 1997 based on its 3-D surveys.
    
 
   
    Since   1993,  Costilla  has  generated   significant  growth  in  reserves,
production and  Adjusted  EBITDA. The  Company  increased its  estimated  proved
reserves from 6.0 MMBOE at December 31, 1993 to 35.3 MMBOE at April 1, 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
$3.60 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 10,231 BOE for
the three months  ended March  31, 1996 (pro  forma for  the 1996  Acquisition),
representing a compound annual growth rate of 190%. Adjusted 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 geographically diverse
portfolio of properties,  the reserves attributable  to which are  approximately
balanced  between oil and gas. 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  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 24 exploratory wells during the last half of 1996 and 36 exploratory
    wells in 1997. Capital budgeted for exploration activities is $8.1 million
    for the last six 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 $8.4 million
    for the last six months of 1996 and $9.2 million for 1997, which  includes
    the  drilling of 12 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 April 1, 1996, the Company  operated
    wells  constituting approximately 72% 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 7.1 Mmbbls of oil and 44.1 Bcf of gas, aggregating
14.4 MMBOE.  From the  date of  acquisition until  March 31,  1996, the  Company
produced  1.5  MMBOE from  the acquired  properties  and sold  a portion  of the
acquired properties for approximately  $3.6 million. At April  1, 1996, the  net
proved  reserves  of  the remaining  properties  were 13.4  MMBOE.  The acquired
properties also included 103,010 gross (93,787 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  April 1,  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
(16,646 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 eight
wells located on  the Company's  Edwards/McElroy Ranch Prospect  in the  Permian
Basin.  While one of such wells is being drilled, the remaining seven wells have
been completed as  producers. Three  of the  productive wells  have resulted  in
separate   field  discoveries   which  have  confirmed   the  Company's  seismic
interpretation of  a  significant  trend. Since  beginning  operations  on  this
prospect,  the Company  has drilled 11  producing wells  and one dry  hole. As a
result, the Company has identified up to 68 additional drilling locations,  none
of which are included in the Company's proved reserves.
    
 
   
    The  Company  has also  continued drilling  in  the McGyver-Green  Acres 3-D
Prospect. Since commencing activity  in this prospect in  July 1994 the  Company
has  drilled 17 wells, of  which 14 have been  successful. During June 1996, the
average  daily  capacity  from  the   producing  wells  in  this  prospect   was
approximately 83 BOE per well. The Company has identified 34 additional drilling
locations in the McGyver-Green Acres Prospect, nine of which are included in the
Company's proved reserves.
    
 
   
    The  Company has also  drilled and completed seven  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 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 senior
                                              obligations of  the  Company,  and  will  rank
                                              equally  in  right of  payment with  all other
                                              Senior Indebtedness of the Company  (including
                                              the  Credit Facility)  and senior  in right of
                                              payment   to   all    existing   and    future
                                              Subordinated   Indebtedness  of  the  Company.
                                              Borrowings  under  the  Credit  Facility   are
                                              expected to be secured by substantially all of
                                              the  assets of the  Company and any subsidiary
                                              of   the   Company   that   guarantees    such
                                              borrowings.  Initially, no subsidiaries of the
                                              Company will guarantee the obligations of  the
                                              Company  under  the  Credit  Facility.  To the
                                              extent of pledged collateral, such
                                              Indebtedness  will  have  priority  over   the
                                              Notes.  At June 30, 1996, on a pro forma basis
                                              after   giving   effect   to   the   Corporate
                                              Reorganization,    the   Offerings   and   the
                                              application of the net proceeds therefrom, the
                                              Company would have had $0.4 million of secured
                                              Senior Indebtedness  and  no  other  unsecured
                                              Senior  Indebtedness. The  Notes also  will be
                                              effectively subordinated  to all  indebtedness
                                              and   other   liabilities  of   the  Company's
                                              subsidiaries  until  such  subsidiaries   (the
                                              'Subsidiaries  Guarantors") deliver Subsidiary
                                              Guarantees  to   fully   and   unconditionally
                                              guarantee  the  Notes on  a senior  basis (the
                                              "Subsidiary   Guarantees").   At   June    30,
</TABLE>
    
 
                                       6
<PAGE>
 
   
<TABLE>
<S>                                           <C>
                                              1996, the subsidiaries' total liabilities were
                                              $6.5  million,  all  of  which  were operating
                                              liabilities. The Indenture  pursuant to  which
                                              the  Notes  will be  issued  (the "Indenture")
                                              requires  each   Subsidiary   to   deliver   a
                                              Subsidiary  Guarantee  as a  condition  to its
                                              incurrence   of   Indebtedness   (other   than
                                              intercompany Indebtedness). At the date of the
                                              Indenture,   there   will  be   no  Subsidiary
                                              Guarantees.  See  "Description  of  Notes   --
                                              Ranking" and "-- Subsidiary Guarantees."
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  will  restrict,  among  other
                                              things,  the   Company's  ability   to   incur
                                              additional indebtedness, pay dividends or make
                                              certain   other  restricted   payments,  incur
                                              liens,  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,   or    enter   into   certain
                                              transactions with affiliates.
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  information 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>
                                                                 YEAR ENDED DECEMBER 31,               SIX MONTHS ENDED JUNE 30,
                                                        ------------------------------------------  -------------------------------
                                                                  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  $   5,573  $  19,525  $  28,748
  Expenses:
    Oil and gas production............................      1,688      2,351     10,355     26,937      2,413      8,278     13,295
    General and administrative........................        952      1,184      3,571      4,850      1,008      2,809      3,010
    Exploration and abandonments......................        218        793      1,650      2,761      1,007        308        555
    Depreciation, depletion and amortization..........        884      1,847      5,958     14,176      1,367      4,620      6,981
    Interest..........................................        605      1,458      4,591     11,635      1,046      4,156      5,817
    Other.............................................         --         --          2          2         --         --         --
  Net income (loss) before income taxes and
   extraordinary item.................................         50        203     (4,311)    (7,724)    (1,268)      (646)      (910)
  Net income (loss)...................................         73        163     (4,314)    (7,727)    (1,268)    (2,286)      (910)
  Pro forma earnings (loss) per common share..........         --         --         --      (0.78)        --         --      (0.09)
  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         --  $  (3,040) $    (122)        --
    Investing activities..............................     (6,731)   (12,146)   (62,467)        --    (57,773)   (49,723)        --
    Financing activities..............................      6,315     10,618     58,830         --     62,094     48,143         --
OTHER FINANCIAL DATA:
  Capital expenditures................................  $   6,862  $  11,868  $  62,220         --  $  57,773  $  49,723         --
  Adjusted EBITDA (2).................................      1,757      4,301      7,888  $  20,848      2,152      8,438  $  12,443
  Adjusted EBITDA/interest expense (2)................        2.9x       2.9x       1.7x       1.8x       2.1x       2.0x       2.1x
  Ratio of earnings to fixed charges (3)..............        1.0        1.1         --         --         --         --         --
BALANCE SHEET DATA (AS OF PERIOD END):
  Working capital.....................................  $   1,612  $   1,081  $   2,496         --         --  $   4,266  $  13,757
  Total assets........................................     13,290     24,904     87,367         --         --    135,047    146,434
  Total debt..........................................     12,034     23,613     71,494         --         --    122,365    100,365
  Redeemable members' capital.........................         --         --     12,278         --         --     13,557         --
  Members' capital....................................         51       (747)    (8,147)        --         --    (11,712)        --
  Pro forma stockholders' equity......................         --         --         --         --         --         --     35,232
  ACNTA (4)...........................................                                                                      200,923
  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
     June  30, 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)  Adjusted  EBITDA and the  ratio of Adjusted EBITDA  to interest expense are
     presented because of  their wide  acceptance as financial  indicators of  a
     company's  ability  to  service or  incur  debt. Adjusted  EBITDA  (as used
     herein) is  calculated  by  adding interest,  income  taxes,  depreciation,
     depletion   and  amortization,   exploration  and   abandonment  costs  and
     extraordinary loss  resulting from  extinguishment of  debt to  net  income
     (loss).  The ratio of Adjusted EBITDA  to interest expense is calculated by
     dividing Adjusted EBITDA  by interest. Interest  includes interest  expense
     accrued  and amortization of deferred  financing costs. Adjusted EBITDA and
     the ratio of Adjusted EBITDA to  interest expense should not be  considered
     as  alternatives  to  earnings  (loss), or  operating  earnings  (loss), as
     defined by generally accepted accounting  principles, as indicators of  the
     Company's financial performance or to cash flow as a measure of liquidity.
(3)  For  purposes  of  calculating  the ratio  of  earnings  to  fixed charges,
     "earnings" are net income (loss)  before extraordinary loss resulting  from
     extinguishment  of debt, 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, $1,268,000 and $646,000
     for the historical periods ended December 31, 1995, June 30, 1995 and  June
     30,  1996,  respectively, and  $7,724,000 and  $910,000  for the  pro forma
     periods ended December 31, 1995 and June 30, 1996, respectively.
(4)  ACNTA means Adjusted  Consolidated Net  Tangible Assets as  defined in  the
     Indenture. See "Description of Notes-- Certain Definitions."
 
                                       8
<PAGE>
                              SUMMARY RESERVE DATA
 
   
<TABLE>
<CAPTION>
                                                                 AS OF DECEMBER 31,           AS OF APRIL 1, 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        16,477
  Gas (Mmcf).............................................     21,619     27,512     78,152     79,420       112,921
  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)......................       19.8       14.4       13.6         --            --
RESERVE REPLACEMENT DATA:
  Production replacement ratio (4).......................        513%       540%       969%        --            --
  All-in finding costs per BOE (5).......................  $    4.31  $    3.67  $    3.43  $    2.84   $      3.72
</TABLE>
    
 
- ------------------------------
 
(1)  Gives effect to the 1996 Acquisition as if such transaction had occurred as
    of April 1, 1996.
 
(2) Estimates of net proved oil and gas  reserves at April 1, 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 $3.60 per BOE.
 
                             SUMMARY OPERATING DATA
 
   
<TABLE>
<CAPTION>
                                                             YEAR ENDED DECEMBER 31,
                                                  ----------------------------------------------
                                                                                                  SIX MONTHS ENDED JUNE 30,
                                                            HISTORICAL             PRO FORMA(1)              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          709           990
  Gas (Mmcf)....................................        865      1,600      4,806       11,984        3,504         5,345
  MBOE..........................................        302        597      1,751        4,083        1,293         1,881
AVERAGE SALES PRICE PER UNIT:
  Oil (per Bbl).................................  $   16.93  $   15.25  $   15.53    $   15.75    $   18.93     $   18.26
  Gas (per Mcf).................................       1.82       1.63       1.45         1.59         1.91          1.87
COSTS PER BOE:
  Production costs, including severance taxes
   (2)..........................................  $    5.59  $    3.94  $    5.91    $    6.60    $    6.40     $    7.07
  Depreciation, depletion and amortization......       2.93       3.09       3.40         3.47         3.57          3.71
</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 six months ended June 30,  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. Additionally,  the
    Company's 1995 production costs were adversely affected by expenses incurred
    in  connection  with plugging  wells  to comply  with  applicable regulatory
    requirements.
 
                                       9
<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  June 30,  1996, as  adjusted for  the Corporate  Reorganization, the
Offerings and the application of the net proceeds therefrom, the Company's total
debt and stockholders' equity would have been $100.4 million and $35.2  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  Credit  Facility  will  afford  the  Company  $50.0  million  of
available  borrowing  capacity, none  of which  is expected  to be  necessary to
finance the Company's existing business  plan. See "Management's Discussion  and
Analysis  of  Financial Condition  and Results  of  Operations --  Liquidity and
Capital Resources" and "Description of Other Indebtedness."
 
    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.  See  "Management's  Discussion  and  Analysis  of  Financial
Condition and Results of Operations -- Liquidity and Capital Resources."
 
    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. Earnings  were insufficient to cover  fixed charges by $4.3
million and $0.6 million  for the year  ended December 31,  1995 and six  months
ended June 30, 1996, respectively, and $7.7 million and $0.9 million for the pro
forma  year  ended  December  31,  1995 and  six  months  ended  June  30, 1996,
respectively. Based upon the  current and anticipated  level of operations,  the
Company  believes, however,  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.  The inability  to  obtain additional
financing could have a  material adverse effect on  the Company. For example,  a
default  by  the Company  under the  terms of  the Indenture  could result  in a
default under the terms of the Credit Facility.
 
   
EFFECTIVE SUBORDINATION OF NOTES
    
 
   
    The obligations  of the  Company  and any  subsidiary  of the  Company  that
guarantees the obligations of the Company under the Credit Facility are expected
to  be  secured by  substantially  all of  the assets  of  the Company  and such
subsidiary. Holders of secured Indebtedness of the Company and its subsidiaries,
including the lenders under the Credit Facility, have claims with respect to the
assets constituting  collateral for  such  Indebtedness that  are prior  to  the
claims  of holders of the Notes. In the event of a default on such Indebtedness,
or  a  bankruptcy,  liquidation  or  reorganization  of  the  Company  and   its
subsidiaries,  such assets will be available to satisfy obligations with respect
to the
    
 
                                       10
<PAGE>
   
Indebtedness secured thereby before any payment  therefrom could be made on  the
Notes.  Accordingly, the  Notes will  be effectively  subordinated to  claims of
secured creditors of  the Company  and its subsidiaries  to the  extent of  such
pledged  collateral. As of June  30, 1996, after giving  pro forma effect to the
Corporate Reorganization, the Offerings and the application of the net  proceeds
therefrom,   the  Company  would  have  had   $0.4  million  of  secured  Senior
Indebtedness outstanding and will have $50.0 million available under the  Credit
Facility. See "Description of Notes -- Ranking."
    
 
   
    The  Indenture does not require the Subsidiaries to guarantee the payment of
the Notes unless  the Subsidiaries incur  Indebtedness (other than  intercompany
Indebtedness).  The  Indenture prohibits  Subsidiaries  that are  not Subsidiary
Guarantors  from  incurring   Indebtedness.  The  Notes   will  be   effectively
subordinated to claims of creditors (other than the Company) of the Subsidiaries
that   are  not   Subsidiary  Guarantors,  including   trade  creditors,  taxing
authorities and tort claimants. Such  creditors generally will have priority  as
to  the assets of such Subsidiaries over  the claims and equity interests of the
Company and, thereby  indirectly, the  holders of indebtedness  of the  Company,
including  the Notes.  At June  30, 1996,  on a  pro forma  basis, the Company's
Subsidiaries had  $6.5  million of  liabilities,  all of  which  were  operating
liabilities. Any Subsidiary Guarantees will be effectively subordinated in right
of  payment  to  all existing  and  future  secured Senior  Indebtedness  of the
Subsidiary Guarantors. On the date of the Indenture there will be no  Subsidiary
Guarantees.  See "Description of  Notes -- Ranking,"  "-- Subsidiary Guarantees"
and "-- Incurrence of Indebtedness and Preferred Stock."
    
 
SUBSIDIARY GUARANTEES MAY TERMINATE; FRAUDULENT CONVEYANCE CONSIDERATIONS
RELATING TO SUBSIDIARY GUARANTEES
 
    The Indenture does not require any Subsidiary to guarantee the Notes  unless
such  Subsidiary incurs Indebtedness (other  than intercompany Indebtedness). On
the date  of the  Indenture  there will  be  no Subsidiary  Guarantees.  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 that may be delivered. To  the extent that a court were  to
find  that (x) a  Subsidiary Guarantee was  incurred with the  intent to hinder,
delay or  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
 
                                       11
<PAGE>
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.
 
   
POTENTIAL INABILITY TO FUND A CHANGE OF CONTROL OFFER AND ASSET SALE OFFER
    
   
    The  Company must offer to purchase the Notes upon the occurrence of certain
events. The Indenture 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.
In  the event of certain asset dispositions,  the Company will be required under
certain circumstances  to use  the  Excess Proceeds  (as  defined) to  offer  to
purchase  the Notes at  100% of the  principal amount thereof,  plus accrued and
unpaid interest to the date of purchase. See "Description of Notes -- Repurchase
at the Option of Holders."
    
 
   
    The  Credit  Facility  prohibits  the  Company  from  prepaying  the  Notes,
including  prepayments pursuant to a  Change of Control or  Asset Sale. Prior to
commencing such an offer to purchase, the  Company may be required to (i)  repay
in  full all indebtedness of  the Company that would  prohibit the repurchase of
the Notes including that under the Credit Facility, or (ii) obtain any requisite
consent to permit the repurchase. If the Company is unable to repay all of  such
indebtedness  or is  unable to obtain  the necessary consents,  then the Company
will be unable to offer to purchase the Notes, and such failure will  constitute
an  Event of Default under the Indenture.  It is unlikely that the Company would
have sufficient internally generated funds available  at the time of any  Change
of Control or Asset Sale Offer to satisfy all of its debt obligations (including
repurchases  of the  Notes and  payment of  the Credit  Facility) simultaneously
without refinancing the indebtedness.
    
 
   
    The events that  constitute a  Change of Control  or require  an Asset  Sale
Offer  under  the Indenture  may  also be  events  of default  under  the Credit
Facility or other senior indebtedness of the Company and the Subsidiaries.  Such
events may permit the lenders under such debt instruments to accelerate the debt
and, if the debt is not paid, to enforce security interests on substantially all
the  assets of the Company and  the Subsidiaries, thereby limiting the Company's
ability to  raise cash  to  repurchase the  Notes,  and reducing  the  practical
benefit  of the  offer to purchase  provisions to  the holders of  the Notes. In
addition, the Change of Control covenant in the Indenture could have the  effect
of  discouraging a takeover of the Company by making such an attempt potentially
more expensive.
    
 
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.  Although  the
Company  believes  such  estimates  to  be  reasonable,  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
 
                                       12
<PAGE>
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 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. A&P also owes the Company $247,000, which is represented by a
promissory note payable upon demand. See "Certain Transactions."
 
                                       13
<PAGE>
    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  within  the initial  three-year term  of  each employment  agreement. 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.
 
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.
 
                                       14
<PAGE>
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."
 
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".  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
 
                                       15
<PAGE>
"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.
 
                                  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  an entity which has 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"). Costilla has been formed solely for the purpose of
conducting the Offerings, and has not commenced operations. 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  $15.5 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,  Inc.,  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  Corporation,  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 40.5%  interest in a Delaware 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
 
    Concurrent with the 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.
 
                                       16
<PAGE>
                                USE OF PROCEEDS
 
    The net  proceeds of  the  Offerings are  estimated  to be  $151.5  million,
assuming  an initial public offering price of  $15 per share in the Common Stock
Offering ($159.8 million if the underwriters' over-allotment option with respect
to the Common Stock Offering is exercised). Approximately $125.8 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
$30.0 million of the Existing Debt  currently bears interest at 14.0% per  annum
(increasing  to 14.5%  on September  13, 1996)  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, $20.5  million of  the  net
proceeds  will be used  to pay certain  amounts incurred in  connection with the
Corporate Reorganization, including $15.5  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 $5.1 million will be used by the Company for
general corporate purposes. Pending such  uses, the remaining net proceeds  will
be invested in short-term, investment grade, interest-bearing securities.
 
    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..........................................  $   125.8
  Redeem membership interests......................................       15.5
  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..................................................        5.1
  Estimated fees, commissions, underwriting discounts and expenses
   related to the Offerings........................................        8.6
                                                                     ---------
                                                                     $   160.0
                                                                     ---------
                                                                     ---------
</TABLE>
 
                                       17
<PAGE>
                                 CAPITALIZATION
 
    The  following table sets forth the  unaudited capitalization of the Company
as of June  30, 1996, on  an historical basis  and on a  pro forma basis  giving
effect  to the Corporate Reorganization and the Offerings and the application of
the net proceeds therefrom, as if  such transactions had been consummated as  of
June  30, 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>
                                                                                               JUNE 30, 1996
                                                                                          ------------------------
                                                                                          HISTORICAL    PRO FORMA
                                                                                          -----------  -----------
                                                                                               (IN THOUSANDS)
<S>                                                                                       <C>          <C>
Long-term debt:
  Existing debt.........................................................................  $   122,365  $       365
  Credit Facility.......................................................................           --           --
     % Senior Notes due 2006............................................................           --      100,000
                                                                                          -----------  -----------
Total long-term debt....................................................................      122,365      100,365
                                                                                          -----------  -----------
Redeemable members' capital.............................................................       13,557           --
                                                                                          -----------  -----------
Members' capital and stockholders' equity:
  Members' capital......................................................................      (11,712)          --
  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.......................................................................           --       34,232
                                                                                          -----------  -----------
Total members' capital and stockholders' equity.........................................      (11,712)      35,232
                                                                                          -----------  -----------
Total capitalization....................................................................  $   124,210  $   135,597
                                                                                          -----------  -----------
                                                                                          -----------  -----------
</TABLE>
    
 
                                       18
<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  June 30,  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.
 
                                       19
<PAGE>
                             COSTILLA ENERGY, INC.
 
                 PRO FORMA CONDENSED BALANCE SHEET -- UNAUDITED
 
                                 JUNE 30, 1996
 
                                 (IN THOUSANDS)
   
<TABLE>
<CAPTION>
                                                                                                       PRO FORMA
                                                                                         PRO FORMA     COSTILLA
                                                                           COSTILLA       OFFERING      ENERGY,
                                ASSETS                                      L.L.C.      ADJUSTMENTS      INC.
- -----------------------------------------------------------------------  -------------  ------------  -----------
<S>                                                                      <C>            <C>           <C>
Current assets:
  Cash and cash equivalents............................................    $   1,164    $     (700)(1)  $  10,655
                                                                                           151,450(3)
                                                                                          (141,259)(4)
  Accounts receivable..................................................        8,785                       8,785
  Prepaid and other current assets.....................................        2,629                       2,629
                                                                         -------------                -----------
      Total current assets.............................................       12,578                      22,069
Oil and gas properties, using the successful efforts method of
 accounting:
  Proved properties....................................................      126,809                     126,809
  Unproved properties..................................................        4,615                       4,615
  Accumulated depreciation, depletion and amortization.................      (13,933)                    (13,933)
                                                                         -------------                -----------
                                                                             117,491                     117,491
Other property and equipment, net......................................        1,640           700(1)      2,340
Deferred charges (Note 2)..............................................        2,654         3,850(3)      3,850
                                                                                            (2,654)(4)
Note receivable -- affiliate...........................................          684                         684
                                                                         -------------                -----------
                                                                           $ 135,047                   $ 146,434
                                                                         -------------                -----------
                                                                         -------------                -----------
 
<CAPTION>
          LIABILITIES, REDEEMABLE MEMBERS' CAPITAL AND EQUITY
- -----------------------------------------------------------------------
<S>                                                                      <C>            <C>           <C>
Current liabilities:
  Current maturities of long-term debt.................................    $      98                   $      98
  Trade accounts payable...............................................        4,587                       4,587
  Undistributed revenue................................................        1,524                       1,524
  Other current liabilities............................................        2,103                       2,103
                                                                         -------------                -----------
      Total current liabilities........................................        8,312                       8,312
Long-term debt, less current maturities................................      122,267       100,000(3)    100,267
                                                                                          (122,000)(4)
Deferred income........................................................        2,623                       2,623
                                                                         -------------                -----------
      Total liabilities................................................      133,202                     111,202
Redeemable members' capital............................................       13,557       (13,557)(4)         --
Members' capital and stockholders' equity:
  Members' capital.....................................................      (11,712)       11,712(2)         --
  Preferred stock, $.10 par value (3,000,000 shares authorized; no
   shares outstanding).................................................           --                          --
  Common Stock, $.10 par value (20,000,000 shares authorized; no shares
   outstanding historical, 10,000,000 shares outstanding pro forma)....           --         1,000(3)      1,000
  Paid-in capital......................................................           --        (2,654)(4)     34,232
                                                                                            (1,443)(4)
                                                                                            (4,259)(4)
                                                                                            54,300(3)
                                                                                           (11,712)(2)
                                                                         -------------                -----------
  Total members' capital and stockholders' equity......................      (11,712)                     35,232
                                                                         -------------                -----------
                                                                           $ 135,047                   $ 146,434
                                                                         -------------                -----------
                                                                         -------------                -----------
</TABLE>
    
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                       20
<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)(1)      26,937
  General and administrative............        3,571            --           --         (172)(1)       4,850
                                                                                        1,451(5)
  Exploration and abandonments..........        1,650           109        1,002                        2,761
  Depreciation, depletion and
   amortization.........................        5,958            --           --          100(1)       14,176
                                                                                        8,118(6)
  Interest..............................        4,591            --           --       10,046(7)       14,637    $  14,637(8)
                                                                                                                    11,635(8)
  Other.................................            2            --           --                            2
                                          -------------  -----------  -----------                 -------------
                                               26,127         5,582       12,411                       63,363
                                          -------------  -----------  -----------                 -------------
Net income (loss) before federal income
 taxes..................................       (4,311)        5,348        7,480                      (10,726)
Provision for federal income taxes......            3            --           --                            3
                                          -------------  -----------  -----------                 -------------
Net income (loss).......................    $  (4,314)    $   5,348    $   7,480                    $ (10,729)
                                          -------------  -----------  -----------                 -------------
                                          -------------  -----------  -----------                 -------------
Net 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 abandonments..........       2,761
  Depreciation, depletion and
   amortization.........................      14,176
 
  Interest..............................      11,635
 
  Other.................................           2
                                          -----------
                                              60,361
                                          -----------
Net income (loss) before federal income
 taxes..................................      (7,724)
Provision for federal income taxes......           3
                                          -----------
Net income (loss).......................   $  (7,727)
                                          -----------
                                          -----------
Net loss per share......................   $   (0.78)
                                          -----------
                                          -----------
</TABLE>
    
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                       21
<PAGE>
                             COSTILLA ENERGY, INC.
 
            PRO FORMA CONDENSED STATEMENT OF OPERATIONS -- UNAUDITED
 
                         SIX MONTHS ENDED JUNE 30, 1996
 
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
   
<TABLE>
<CAPTION>
                                                                                                                     PRO FORMA
                                                                                       PRE OFFERING    PRO FORMA     COSTILLA
                                             COSTILLA        1996        PRO FORMA       COSTILLA       OFFERING      ENERGY,
                                              L.L.C.      ACQUISITION   ADJUSTMENTS       L.L.C.      ADJUSTMENTS      INC.
                                           -------------  -----------  --------------  -------------  ------------  -----------
<S>                                        <C>            <C>          <C>             <C>            <C>           <C>
Revenues.................................    $  19,525     $   9,223                     $  28,748                   $  28,748
Expenses:
  Oil and gas production.................        8,278         5,167    $    (150)(1)       13,295                      13,295
  General and administrative.............        2,809                        (86)(1)        3,010                       3,010
                                                                              287(5)
  Exploration and abandonments...........          308           247                           555                         555
  Depreciation, depletion and
   amortization..........................        4,620                         50(1)         6,981                       6,981
                                                                            2,311(6)
  Interest...............................        4,156                      2,832(7)         6,988     $  (6,988)(8)      5,817
                                                                                                           5,817(8)
                                           -------------  -----------                  -------------                -----------
                                                20,171         5,414                        30,829                      29,658
                                           -------------  -----------                  -------------                -----------
Net income (loss) before federal income
 taxes...................................         (646)        3,809                        (2,081)                       (910)
                                           -------------  -----------                  -------------                -----------
Net income (loss)........................    $    (646)    $   3,809                     $  (2,081)                  $    (910)
                                           -------------  -----------                  -------------                -----------
                                           -------------  -----------                  -------------                -----------
Net income (loss) per share..............                                                                            $   (0.09)
                                                                                                                    -----------
                                                                                                                    -----------
</TABLE>
    
 
 See accompanying notes to unaudited pro forma condensed financial statements.
 
                                       22
<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 June 30, 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 June 30,  1996 and  the
    related  consolidated  statements  of  operations  for  the  year  ended
    December 31, 1995 and the six months ended June 30, 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
    period  from  January  1,  1995  to June  14,  1996  (date  of  the 1996
    Acquisition).
 
NOTE 2. -- PRO FORMA ENTRIES
 
    (1) 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.
 
    (2) To  reflect  the  Corporate Reorganization  including  the  transfer  of
members' capital to stockholders' equity.
 
    (3)  To  reflect the  issuance of  4,000,000  shares of  Common Stock  at an
estimated price of $15.00 per share  for estimated proceeds of $55,300,000,  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
$3,850,000.
 
    (4) To  record the  repayment of  the  Existing Debt  and the  write-off  of
related  debt issuance costs,  the distribution of cash  to certain members, and
the repurchase of redeemable members capital for approximately $15,000,000  from
proceeds of the Offerings.
 
    The redemption amount is composed of the following:
 
<TABLE>
<S>                                                             <C>
Redeemable members' interest subject to preferred return......  $11,000,000
Redeemable members' interest not subject to preferred
 return.......................................................    1,500,000
Accrued 15% preferred return including associated 10%
 redemption premium...........................................    2,500,000
                                                                -----------
                                                                $15,000,000
                                                                -----------
                                                                -----------
</TABLE>
 
    (5)  Estimated incremental general and  administrative expenses necessary to
administer the  properties  acquired  in  the 1995  and  1996  acquisitions  and
increased  public reporting and administration costs include salary and benefits
for one executive level employee  and revised compensation arrangements for  the
remaining  executives, approximately 29 additional administrative personnel (the
majority of  which were  added prior  to December  31, 1995),  directors'  fees,
insurance coverage and estimated costs to administer shareholder communications.
 
                                       23
<PAGE>
                             COSTILLA ENERGY, INC.
    NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS (CONTINUED)
 
NOTE 2. -- PRO FORMA ENTRIES (CONTINUED)
    (6)  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  June 14,  1996  (date of  the  1996
Acquisition).
 
    (7)  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  from  January  1,  1995  to  June  14,  1996  (date  of  the   1996
Acquisition).  The adjustment also reflects adjusted interest expense due to the
Existing Debt.  Also included  is the  amortization of  estimated debt  issuance
costs of $2,728,000 over a three-year period.
 
    Incremental interest expense includes the following components:
 
<TABLE>
<CAPTION>
                                                             YEAR ENDED      SIX MONTHS ENDED
                                                          DECEMBER 31, 1995    JUNE 30, 1996
                                                          -----------------  -----------------
<S>                                                       <C>                <C>
Additional interest on borrowings associated with the
 1995 Acquisition for the period of January 1 to June
 12, 1995 (Average rate 10.0%)..........................     $     2,350         $      --
Additional interest on borrowings for the 1996
 Acquisition through June 14, 1996 (including Tranche B
 interest ranging from 14% to 16.5%)....................           6,750             2,300
Adjustment of average interest rate on previously
 existing debt and amortization of loan fees............             946               532
                                                                --------           -------
                                                             $    10,046         $   2,832
                                                                --------           -------
                                                                --------           -------
</TABLE>
 
   
    (8)  To reverse interest on the Existing Debt and to adjust interest expense
to reflect issuance of  the Notes at 11.25%  plus the amortization of  estimated
debt issuance costs over 10 years ($385,000 annually).
    
 
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 June  30,
1996,  the pro forma tax basis of  the Company's assets and liabilities exceeded
the pro forma book  basis by approximately $5,000,000.  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 LOSS PER SHARE
    Net 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 April 1, 1996.
 
                                       24
<PAGE>
                             COSTILLA ENERGY, INC.
    NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS (CONTINUED)
 
NOTE 5. -- SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (CONTINUED)
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 April 1, 1996.
The pro forma information  assumes that both the  1995 Acquisition and the  1996
Acquisition took place on January 1, 1995.
 
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.....................................              437           2,615
  Extensions and discoveries..........................................              592             296
  Production..........................................................             (492)         (2,634)
                                                                                -------      -----------
Balance, April 1, 1996................................................           16,477         112,921
                                                                                -------      -----------
                                                                                -------      -----------
Proved Developed Reserves:
  December 31, 1995...................................................           13,235          87,345
  April 1, 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.
 
    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
 
                                       25
<PAGE>
                             COSTILLA ENERGY, INC.
    NOTES TO UNAUDITED PRO FORMA CONDENSED FINANCIAL STATEMENTS (CONTINUED)
 
NOTE 5. -- SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (CONTINUED)
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........................................................   $  516,515    $    572,426
Future costs:
  Production.............................................................     (239,388)       (253,348)
  Development............................................................      (20,907)        (22,076)
                                                                           ------------  --------------
Future net cash flows before income taxes (a)............................      256,220         297,002
Future income taxes......................................................      (48,735)        (63,418)
                                                                           ------------  --------------
Future net cash flows....................................................      207,485         233,584
10% annual discount for estimated timing of cash flows...................      (66,851)        (76,359)
                                                                           ------------  --------------
Standardized measure of discounted net cash flows........................   $  140,634    $    157,225
                                                                           ------------  --------------
                                                                           ------------  --------------
</TABLE>
    
 
- ------------------------
   
(a) Present value of estimated future net cash flows, before income taxes  would
    be  $155,984  and $179,527  as  of December  31,  1995 and  March  31, 1996,
    respectively.
    
 
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>
 
                                       26
<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>
                                                                                                     SIX MONTHS ENDED
                                                           YEAR ENDED DECEMBER 31,                       JUNE 30,
                                            -----------------------------------------------------  --------------------
                                              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  $   2,362  $   4,231  $   7,637  $  21,693  $   5,568  $  19,445
  Total revenues..........................      2,134      2,887      4,397      7,836     21,816      5,573     19,525
  Expenses:
    Oil and gas production................        769      1,340      1,688      2,351     10,355      2,413      8,278
    General and administrative............        354        388        952      1,184      3,571      1,008      2,809
    Exploration and abandonments..........        106          4        218        793      1,650      1,007        308
    Depreciation, depletion and
     amortization.........................        494        404        884      1,847      5,958      1,367      4,620
    Interest..............................        179        365        605      1,458      4,591      1,046      4,156
    Other.................................         --         --         --         --          2         --         --
                                            ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Income (loss) before income taxes and
   extraordinary item.....................        232        386         50        203     (4,311)    (1,268)      (646)
  Net income (loss).......................        234        368         73        163     (4,314)    (1,268)    (2,286)
STATEMENT OF CASH FLOWS DATA:
  Net cash provided by (used in):
    Operating activities..................  $     276  $     140  $     322  $   1,527  $   6,366  $  (3,040) $    (122)
    Investing activities..................     (2,659)    (1,432)    (6,731)   (12,146)   (62,467)   (57,773)   (49,723)
    Financing activities..................      2,440      1,450      6,315     10,618     58,830     62,094     48,143
OTHER FINANCIAL DATA:
  Capital expenditures....................  $   3,092  $   3,720  $   6,862  $  11,868  $  62,220  $  57,773  $  49,723
  Distributions to members................         --         --        456        961         55         55         --
  Adjusted EBITDA (1).....................      1,011      1,159      1,757      4,301      7,888      2,152      8,438
  Adjusted EBITDA/interest expense (1)....        5.6x       3.2x       2.9x       2.9x       1.7x       2.1x       2.0x
  Ratio of earnings to fixed charges
   (2)....................................        1.3        1.5        1.0        1.1         --         --         --
BALANCE SHEET DATA (AS OF PERIOD END):
  Working capital.........................  $    (580) $     185  $   1,612  $   1,081  $   2,496         --  $   4,266
  Total assets............................      4,602      6,675     13,290     24,904     87,367         --    135,047
  Total debt..............................      3,610      5,352     12,034     23,613     71,494         --    122,365
  Redeemable members' capital.............         --         --         --         --     12,278         --     13,557
  Members' capital........................        504        434         51       (747)    (8,147)        --    (11,712)
</TABLE>
    
 
- ------------------------------
(1) Adjusted EBITDA  and the ratio  of Adjusted EBITDA  to interest expense  are
    presented  because of  their wide  acceptance as  financial indicators  of a
    company's ability to service or incur debt. Adjusted EBITDA (as used herein)
    is calculated by adding interest, income taxes, depreciation, depletion  and
    amortization,  exploration  and  abandonment  costs  and  extraordinary loss
    resulting from extinguishment  of debt to  net income (loss).  The ratio  of
    Adjusted  EBITDA  to interest  expense  is calculated  by  dividing Adjusted
    EBITDA  by  interest.  Interest   includes  interest  expense  accrual   and
    amortization  of deferred financing costs. Adjusted  EBITDA and the ratio of
    Adjusted EBITDA to interest expense should not be considered as alternatives
    to earnings (loss), or  operating earnings (loss),  as defined by  generally
    accepted  accounting principles,  as indicators  of the  Company's financial
    performance or to cash flow as a measure of liquidity.
 
(2) For  purposes  of  calculating  the ratio  of  earnings  to  fixed  charges,
    "earnings"  are net income  (loss) before extraordinary  loss resulting from
    extinguishment of debt, 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,  $1,268,000  and  $646,000  for  the
    historical periods ended December 31, 1995, June 30, 1995 and June 30, 1996,
    respectively.
 
                                       27
<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 Adjusted 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>
                                                                                         SIX MONTHS ENDED
                                                          YEAR ENDED DECEMBER 31,            JUNE 30,
                                                      -------------------------------  --------------------
                                                        1993       1994       1995       1995       1996
                                                      ---------  ---------  ---------  ---------  ---------
<S>                                                   <C>        <C>        <C>        <C>        <C>
OIL AND GAS PRODUCTION:
  Oil (MBbls).......................................        158        330        950        233        709
  Gas (Mmcf)........................................        865      1,600      4,806      1,233      3,504
  MBOE..............................................        302        597      1,751        438      1,293
AVERAGE SALES PRICES (1):
  Oil (per Bbl).....................................  $   16.93  $   15.25  $   15.53  $   16.12  $   18.93
  Gas (per Mcf).....................................       1.82       1.63       1.45       1.46       1.91
PRODUCTION COST (2):
  Per BOE (3).......................................  $    5.59  $    3.94  $    5.91  $    5.51  $    6.40
  Per dollar of sales...............................       0.40       0.31       0.48       0.43       0.43
DEPRECIATION, DEPLETION AND AMORTIZATION:
  Per BOE...........................................  $    2.93  $    3.09  $    3.40  $    3.12  $    3.57
  Per dollar of sales...............................       0.21       0.24       0.27       0.25       0.24
</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.
 
(3)  Production costs per BOE in 1995 and for the six months ended June 30, 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.
     Additionally, the Company's 1995  production costs were adversely  affected
     by  expenses  incurred in  connection with  plugging  wells to  comply with
     applicable regulatory requirements.
 
                                       28
<PAGE>
    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. If market prices of oil and gas exceed the strike price of
put options,  the  options  will expire  unexercised,  therefore,  reducing  the
effective  price  received for  oil and  gas sales  by the  cost of  the related
option. Conversely, if  market prices of  oil and gas  decline below the  strike
price  of put options, the options  will be exercised, therefore, increasing the
effective price received for oil and gas sale by the proceeds received from  the
related  option. The  net effect of  the Company's  commodity hedging activities
reduced  oil  and  gas  revenues  by  $9,000,  $80,000,  $80,000  and  $854,000,
respectively, for the years ended December 31, 1994 and 1995, and the six months
ended  June 30, 1995 and 1996 and increased  oil and gas revenues by $71,000 for
the year  ended  December  31,  1993.  See  "Business  and  Properties  --  Risk
Management."
 
    The  Company utilizes interest rate swap  agreements to reduce the potential
impact of  increases in  interest rates  on floating-rate,  long term  debt.  If
market  rates of interest experienced during  the applicable swap term are below
the rate  of interest  effectively fixed  by  the swap  agreement, the  rate  of
interest  incurred by  the Company  will exceed  the rate  that would  have been
experienced under the Credit Agreement. The net effect of the Company's interest
rate hedging activities increased interest expense by $8,000 for the year  ended
December 31, 1995 and $359,000 for the six months ended June 30, 1996.
 
    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
 
  SIX MONTHS ENDED JUNE 30, 1996 COMPARED TO SIX MONTHS ENDED JUNE 30, 1995
 
    The Company's total oil and gas revenues  for the six months ended June  30,
1996  were  $19,445,000, representing  an  increase of  $13,877,000  (249%) over
revenues of $5,568,000  for the  comparable period  in 1995.  This increase  was
primarily  due  to  the  1995  Acquisition  which  accounted  for  approximately
$12,300,000 of the revenue increase. Prior  to accounting for the impact of  the
1995  Acquisition  and the  1996 Acquisition,  the Company's  total oil  and gas
revenues for the six months ended June 30, 1996 increased by $658,000 (12%) over
the same period in 1995.
 
    Oil and gas production  was 1,293 MBOE  in the 1996  period compared to  438
MBOE  in the 1995 period.  Of the 855 MBOE  increase, approximately 800 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 $40,000  for the six months ended June  30,
1996  compared  to $5,000  for the  comparable period  in 1995,  representing an
increase of $35,000, which was primarily
 
                                       29
<PAGE>
comprised of an increase in interest income of $33,000 in 1996 due to  increased
funds  earning interest. Also in the 1996  period, the Company realized gains of
$40,000 on various transactions for which there were no comparable  transactions
for the six months ended June 30, 1995.
 
    Oil  and gas production costs in the  1996 period were $8,278,000 ($6.40 per
BOE), compared to $2,413,000 in 1995  ($5.51 per BOE), representing an  increase
of  $5,865,000 (243%),  due principally  to the 1995  Acquisition. On  a per BOE
basis, production  costs increased  $0.89  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.
 
    General and administrative expense  for the six months  ended June 30,  1996
was   $2,809,000,  representing  an  increase  of  $1,801,000  (179%)  from  the
comparable period in  1995 of $1,008,000.  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 $308,000 in the 1996 period
compared to $1,007,000 in 1995. The Company incurred $4,000 of seismic costs for
the six months ended June 30, 1996, compared to $514,000 which were incurred for
the comparable  period  in 1995.  Dry  hole  costs decreased  from  $493,000  to
$304,000 for the comparable periods in 1995 and 1996, respectively.
    
 
    Depreciation,  depletion and  amortization expense  for the  1996 period was
$4,620,000 compared to $1,367,000 for the 1995 period, representing an  increase
of  $3,253,000 (238%). During 1996,  depreciation, depletion and amortization on
oil and gas production was provided at an average rate of $3.57 per BOE compared
to $3.12  per  BOE  for  1995.  The increase  was  due  primarily  to  the  1995
Acquisition.
 
    Interest  expense was $4,156,000 in the  1996 period, compared to $1,046,000
for  the  comparable  period  in  1995.  The  $3,110,000  (297%)  increase   was
attributable  primarily 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  $77,646,000  and
$25,145,000, respectively.
 
   
    Results  of operations  for the  six months ended  June 30,  1996 include an
extraordinary charge of $1,640,000  related to the  early extinguishment of  the
Company's   previous  credit  agreement.  The  charge  consisted  of  previously
capitalized debt issuance costs. The  previous credit agreement was replaced  by
the Existing Debt.
    
 
  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 $13,373,000 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  in
connection with properties acquired in late 1994.
 
                                       30
<PAGE>
    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 $5,958,000
compared to $1,847,000 for 1994, representing an increase of $4,111,000  (233%).
During  1995, depreciation, depletion and amortization on oil and gas production
was provided at an average rate of $3.40  per BOE compared to $3.09 per BOE  for
1994. The increase was due primarily to the 1995 Acquisition.
 
    Interest  expense was $4,591,000 in 1995 compared to $1,458,000 in 1994. The
$3,133,000 (215%) 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
 
  NET CASH USED IN OPERATING ACTIVITIES
 
    For  the  six  months  ended  June 30,  1996,  net  cash  used  in operating
activities decreased to $0.1 million from $3.0 million for the comparable period
in 1995. Cash provided by operations, before
 
                                       31
<PAGE>
changes in operating assets and liabilities, increased to $4.2 million from $0.1
million for the comparable period in 1995 due primarily to the 1995  Acquisition
and the increase in results of operations therefrom.
 
  NET CASH USED IN INVESTING ACTIVITIES
 
   
    Net cash used in investing activities for the six months ended June 30, 1996
was   $49.7  million.  Approximately  $42.5  million   was  used  for  the  1996
Acquisition, $5.2 million was used for  other oil and gas expenditures and  $2.0
million  was used for other property and  equipment. For the year ended December
31, 1995, net cash used in investing activities was $62.5 million. Approximately
$46.6 million was used  for the 1995 Acquisition,  $14.9 million for  additional
acquisitions of producing oil and gas properties and exploration and development
activities and $1.0 million primarily for other property and equipment.
    
 
NET CASH PROVIDED BY FINANCING ACTIVITIES
 
    The  Company entered into  a $125.0 million senior  credit agreement in June
1996, against which  $122.0 million  was initially  funded. Approximately  $74.5
million  was for the extension and refinancing  of prior debt, $42.5 million was
used for  the 1996  Acquisition  and approximately  $5.0  million was  used  for
general corporate purposes.
 
  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  $10.0  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.
    
 
    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 believes that cash flow  from operations 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. The Company's historical and pro forma  earnings
for the year ended December 31, 1995 and the six months ended June 30, 1996 were
insufficient  to  cover  fixed  charges. Although  the  Company's  earnings were
insufficient to cover fixed charges for these periods, the Company does not have
covenants in  the Indenture  or the  Credit Facility  requiring the  Company  to
maintain  a specific ratio of earnings to fixed charges. However, if the Company
is unable to generate sufficient cash flow from operations to service its  debt,
it  may be  required to refinance  all or a  portion of its  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. See "Risk Factors -- Significant Leverage and Debt Service."
 
   
    The Company has received a commitment  from NationsBank of Texas, N.A.  (the
"Bank")  to provide the Credit Facility  to the Company following the Offerings.
The Credit  Facility  will provide  for  a revolving  line  of credit  with  the
availability  of funds and letters  of credit being subject  to a borrowing base
determination at  least semiannually.  The  borrowing base  will provide  for  a
maximum  availability of $50.0 million (which amount  is also expected to be the
initial borrowing base), none of which is expected to be outstanding immediately
following the  Offerings. Availability  under the  borrowing base  is  initially
limited  to $20.0 million for working capital and $30.0 million for acquisitions
of oil and
    
 
                                       32
<PAGE>
   
gas properties  meeting certain  criteria established  by the  Bank.  Borrowings
under  the  Credit Facility  will bear  interest  at the  Company's option  at a
floating rate which is at or above the NationsBank, N.A. prime rate or the LIBOR
rate, depending on the percentage of  committed funds which have been  borrowed.
Interest  will be  payable quarterly and  principal will be  amortized in twelve
equal installments commencing  two years following  the execution of  definitive
loan  documents. Under the Credit Facility, the Company will be obligated to pay
certain fees to the Bank, including a commitment fee based on the unused portion
of the  commitment.  The  Credit Facility  will  contain  customary  restrictive
covenants (including restrictions on the payment of dividends and the incurrence
of  additional indebtedness) and will require  the Company to maintain a current
ratio of  not less  than 1.0  to 1.0,  a ratio  of Adjusted  EBITDA to  interest
expense  of not less than 2.0  to 1.0 and a minimum  tangible net worth. At June
30, 1996, on a pro forma basis, the Company's current ratio would have been  2.7
to  1.0, the ratio of Adjusted EBITDA to interest expense would have been 2.1 to
1.0 and the  Company would have  exceeded the  tangible net worth  test by  $1.4
million.  The Company believes it  will be in compliance  with such covenants on
the date of closing of the Offerings. Borrowings under the Credit Facility  will
be  secured by substantially all of the assets of the Company and any subsidiary
of the  Company  that guarantees  the  Company's obligations  under  the  Credit
Facility. Initially, no subsidiaries of the Company will guarantee the Company's
obligations  under  the Credit  Facility. The  Bank's  commitment is  subject to
certain conditions,  including completion  of the  Offerings and  the  Corporate
Reorganization  and  application  of the  net  proceeds therefrom  to  repay the
Company's prior secured indebtedness. See "Use of Proceeds."
    
 
    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.
 
<TABLE>
<CAPTION>
                                                                                           SIX MONTHS
                                                            YEARS ENDED DECEMBER 31,          ENDED
                                                         -------------------------------    JUNE 30,
                                                           1993       1994       1995         1996
                                                         ---------  ---------  ---------  -------------
                                                                       (IN THOUSANDS)
<S>                                                      <C>        <C>        <C>        <C>
Development costs......................................  $      --  $      --  $     158   $       607
Exploration costs......................................      2,017      2,167      5,627         3,881
Acquisition costs:
  Unproved properties..................................        829      1,232      1,742         1,712
  Proved properties....................................      4,665      9,649     52,470        41,791
                                                         ---------  ---------  ---------  -------------
Total..................................................  $   7,511  $  13,048  $  59,997   $    47,991
                                                         ---------  ---------  ---------  -------------
                                                         ---------  ---------  ---------  -------------
</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  $5.2 million  was expended  for exploration  and
development activities during the six months ended June 30, 1996.
 
  DELIVERY COMMITMENT
 
    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.
 
                                       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 area of Texas and New Mexico, 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 an  entity  which has  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 April 1, 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 April 1,  1996.
The  Company also has  a substantial undeveloped  acreage position consisting of
180,704 gross (165,166 net) acres at  June 30, 1996. The Company has  identified
in  excess of  185 drilling  locations of  which 64  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 37 wells based on these
3-D surveys,  31  of  which  have been  productive.  The  Company  has  recently
completed  two additional 3-D surveys and intends to commence drilling on one of
these acreage blocks in the second half of 1996. The Company currently plans  to
drill 63 wells through 1997 based on its 3-D surveys.
    
 
   
    Since   1993,  Costilla  has  generated   significant  growth  in  reserves,
production and  Adjusted  EBITDA. The  Company  increased its  estimated  proved
reserves from 6.0 MMBOE at December 31, 1993 to 35.3 MMBOE at April 1, 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
$3.60 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 10,231 BOE for
the three months  ended March  31, 1996 (pro  forma for  the 1996  Acquisition),
representing a compound annual growth rate of 190%. Adjusted 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 geographically diverse
portfolio of properties,  the reserves attributable  to which are  approximately
balanced  between oil and gas. 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  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
 
                                       34
<PAGE>
  known  producing regions.  The Company plans  to drill  24 exploratory wells
  during the  last half  of 1996  and 36  exploratory wells  in 1997.  Capital
  budgeted  for exploration activities is $8.1 million for the last six 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 $8.4 million
  for the last six months  of 1996 and $9.2  million for 1997, which  includes
  the  drilling of 12  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 April  1,  1996, the  Company  operated wells
  constituting approximately 72% 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 7.1 Mmbbls of oil and 44.1 Bcf of gas,  aggregating
14.4  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 April  1, 1996, the net
proved reserves  of  the remaining  properties  were 13.4  MMBOE.  The  acquired
properties also included 103,010 gross (93,787 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  April 1, 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
(16,646  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 April 1, 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
REGION                                                        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        697      6,395       1,762          5.0
                                                            ---------  ---------  ---------  -----------       -----
Total.....................................................      3,522     16,477    112,921      35,297        100.0%
                                                            ---------  ---------  ---------  -----------       -----
                                                            ---------  ---------  ---------  -----------       -----
</TABLE>
    
 
    PERMIAN  BASIN.  At  April 1, 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 68 drilling locations on  the Company's 11,513 gross (5,066  net)
acres  in this prospect  based on 3-D  seismic data. Since  January 1, 1996, the
Company has drilled seven successful wells on this prospect, three of which have
resulted in  three separate  field discoveries.  In addition,  these wells  have
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 Production Inc. ("Texaco"). One additional well is being drilled
on  seismic delineated  features. The  Company plans to  drill 21  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 producing  wells  drilled
through June 30, 1996 are producing an aggregate of approximately 80 Bbls of oil
per  day and  the Company  has participated  in the  drilling of  two additional
productive wells subsequent to June 30,  1996. Drilling of six additional  Queen
Sand  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 34 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. From completion  to June  30, 1996, the  well produced  61
MBbls of oil and 238 Mmcf of gas, and had average capacity of 71 Bbls of oil per
day  and 278 Mcf of gas per day  during June 1996. Subsequent to the first well,
16 additional  wells  have  been  drilled  on this  prospect  of  which  13  are
productive.  The Company is  drilling or intends to  drill five additional wells
during the balance of 1996 on its  9,801 gross (7,057 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:
 
    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
 
                                       36
<PAGE>
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  up  to  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 completed
another 3-D seismic project 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. An exploratory well is scheduled on this prospect
for the first quarter of 1997.
 
    Two examples of the  Company's current exploitation  efforts in the  Permian
Basin include:
 
   
    EAST  GOLDSMITH FIELD  C02 PROJECT, ECTOR  COUNTY, TEXAS.   The Company owns
3,053 gross  (2,656 net)  acres in  this  field located  20 miles  northwest  of
Midland,  Texas. Since  its discovery,  the field has  produced in  excess of 20
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
approximately 68 Bbls of oil per  day and 225 Mcf of  gas per day in July  1996.
With  only two workovers and the new  horizontal well, the Company has increased
Susan Peak production from approximately 31 Bbls  of oil per day and 760 Mcf  of
gas  per day in  the last half of  1995 to an average  rate of approximately 126
Bbls of oil per  day and 1,330  Mcf of gas  per day in  July 1996. 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 is 50%.
    
 
    GULF  COAST.  At April 1, 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 and 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%.  The Company is currently
attempting to acquire additional acreage in this prospect prior to initiating  a
3-D survey in late 1996 or 1997.
    
 
   
    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 122 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 are to conduct a 3-D survey in the Speaks area in late  1996
or 1997. The Company's working interest in this prospect is approximately 50%.
    
 
                                       37
<PAGE>
   
    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 providing  opportunity for further
development. The Company's lease in the Borchers Field area has produced a total
of 21.2 Bcf of gas from two  Wilcox sands. Costilla has a 100% working  interest
in  this field  consisting of 1,322  gross and  net acres. The  Company plans to
conduct a 3-D survey in the Borchers Field in 1997.
    
 
    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
capacity, 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 10,900  foot test well on the
Josey Ranch lease to test the Wilcox formation. The well was completed in  April
1996  and has consistently produced approximately 1,000  Mcf of gas per day. The
Josey Ranch lease covers 1,661 gross (650 net) acres, and the Company's  working
interest in this prospect is approximately 39%.
    
 
   
    PERSONVILLE, LIMESTONE COUNTY, TEXAS.  The Company has recently completed an
11,000  foot Cotton Valley well, which is producing 2.8 Mmcf of gas per day. The
Company is  currently drilling  an additional  well on  this prospect.  Costilla
leases  411  gross (119  net) acres  in  this prospect,  and has  identified one
additional drilling location. The Company is  the operator of this prospect  and
its working interest is approximately 29%.
    
 
    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  April 1, 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.
 
    The Company  has a  number of  opportunities in  the Rocky  Mountain  region
involving 3-D seismic surveys, exploratory drilling and exploitation activities.
Examples of each of these opportunities are:
 
   
    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 179 Bbls of oil
per day since its acquisition in  June 1995 to 368 Bbls  of oil per day in  June
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 October 1996 that will be drilled
to 10,500  feet,  a  depth  sufficient to  test  several  different  formations.
Costilla  leases 5,169 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 4,640 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 reserves to  any undeveloped acres.  As gas prices  improve, the  Company
plans to drill additional wells on the prospect.
    
 
                                       38
<PAGE>
    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  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
1,778 Bbls of oil per day for June 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. While these arrangements have the
effect of increasing the net price the Company receives for its crude oil,  such
arrangements  do  not have  the  effect of  limiting  the Company's  exposure to
movements in crude  oil prices. The  Company markets its  gas production at  the
lease  level  pursuant to  month-to-month contracts.  Phibro Energy  USA, Inc.'s
purchases of the Company's oil production  for the year ended December 31,  1995
accounted  for 17.7% of the Company's 1995 consolidated revenues. Because of the
number of crude oil purchasers, the  Company does not anticipate any  difficulty
in replacing Phibro Energy USA, Inc.
    
 
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  1996  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  52%
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 84% 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 April 1, 1996 were as
follows:
 
   
<TABLE>
<CAPTION>
                                                       AS OF DECEMBER 31,
                               ------------------------------------------------------------------       PRO FORMA
                                                                                                         APRIL 1,
                                        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        430      7,930
Proved undeveloped...........         580       8,351      1,377     11,172      2,222     20,759      2,925     28,552
                                    -----   ---------  ---------  ---------  ---------  ---------  ---------  ---------
  Total proved...............       2,365      21,619      4,009     27,512     10,788     78,152     16,477    112,921
                                    -----   ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                    -----   ---------  ---------  ---------  ---------  ---------  ---------  ---------
</TABLE>
    
 
- ------------------------------
(1)  Assumes that the 1996 Acquisition had been consummated at April 1, 1996.
 
    The following table sets forth the future net cash flows from the  Company's
estimated proved reserves:
 
<TABLE>
<CAPTION>
                                                                            DECEMBER 31,              PRO FORMA
                                                                  ---------------------------------   APRIL 1,
                                                                    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 April 1, 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 of the Company's engineering analysis covering approximately 54.0%
of the Company's proved reserves at such date. The pro forma estimates for April
1, 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
 
                                       40
<PAGE>
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.
 
    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 June 30, 1996, the Company was
in the process of drilling two gross (0.49 net) wells and was in the process  of
completing  three gross (1.22 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>
 
                                                     SIX MONTHS ENDED JUNE
                                                            30, 1996
                                                     ----------------------
                                                        GROSS        NET
                                                     -----------  ---------
<S>                                                  <C>          <C>
Exploratory:
  Productive.......................................           3        1.74
  Dry..............................................           1        0.72
                                                            ---         ---
    Total..........................................           4        2.46
                                                            ---         ---
                                                            ---         ---
Development:
  Productive.......................................           4        1.98
  Dry..............................................          --          --
                                                            ---         ---
    Total..........................................           4        1.98
                                                            ---         ---
                                                            ---         ---
Total:
  Productive.......................................           7        3.72
  Dry..............................................           1        0.72
                                                            ---         ---
    Total..........................................           8        4.44
                                                            ---         ---
                                                            ---         ---
</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......................................................................................      2,248     678.54
Gas wells......................................................................................      1,278     231.11
                                                                                                 ---------  ---------
    Total......................................................................................      3,526     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  June 30,  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
                                             --------------------  --------------------  --------------------
REGION                                         GROSS       NET       GROSS       NET       GROSS       NET
- -------------------------------------------  ---------  ---------  ---------  ---------  ---------  ---------
<S>                                          <C>        <C>        <C>        <C>        <C>        <C>
Permian Basin..............................    126,091     50,151     65,741     59,669    191,832    109,820
Gulf Coast.................................    197,650     65,547     46,040     39,713    243,690    105,260
Rocky Mountain.............................      8,534      6,126     24,757     24,650     33,291     30,776
Other......................................     43,651     26,108     44,166     41,134     87,817     67,242
                                             ---------  ---------  ---------  ---------  ---------  ---------
    Total..................................    375,926    147,932    180,704    165,166    556,630    313,098
                                             ---------  ---------  ---------  ---------  ---------  ---------
                                             ---------  ---------  ---------  ---------  ---------  ---------
</TABLE>
    
 
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 ($1.2 million of which had
been expended through June 30, 1996) in  return for a 50.0% interest in  Redeco.
After the initial $2.0 million expenditure, the Company and the other members of
Redeco are each responsible for bearing 50.0% of future expenses. 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,  Redeco's exclusive  rights continue  for 20  years.  Redeco's
exclusive period to explore throughout the remainder of Moldova expires in 2005,
but  Redeco 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 material  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  June 30,  1996,
Statewide   expended  approximately  $3.3  million  in  acquiring  interests  in
approximately 1,400 properties.  Through June 30,  1996, Statewide had  received
revenues  from such interests aggregating approximately $1.4 million, as well as
proceeds from sales of such interests of approximately $102,000.
    
 
   
    GAS GATHERING AND  TRANSMISSION.   In 1996,  the Company  purchased a  40.5%
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
Delaware  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 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.
 
                                       42
<PAGE>
    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 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,
 
                                       43
<PAGE>
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, the 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
personal injury and property damage allegedly caused by the hazardous substances
released  into  the environment.  The Company  is able  to control  directly the
operation of  only those  wells with  respect  to which  its acts  as  operator.
Notwithstanding the Company's lack of
 
                                       44
<PAGE>
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 $21 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). 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,
the  Independent  Producer's  Association  of  America,  the  Texas  Independent
Producers   and  Royalty  Owners  Association  and  the  Permian  Basin  Landman
Association. 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 former 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
 
                                       46
<PAGE>
companies, financial  institutions and  law  firms on  a variety  of  technical,
commercial  and regulatory 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.
 
                                       47
<PAGE>
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.
 
    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  and  that  the  Common  Stock  Offering  is  consummated  without  the
underwriters' over-allotment option being exercised.
 
<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)  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, assuming that the Common Stock Offering
is consummated without the underwriters' over-allotment option being exercised.
 
<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)..........................          5,554,992(3)          52.2%
</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 an option  granted under  the
     Company's   1996  Stock  Option  Plan  which  option  will  be  immediately
     exercisable upon closing of the Offerings  at a price equal to the  initial
     public offering price of the Common Stock.
 
(3)  Includes  635,000  shares issuable  pursuant to  options granted  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. 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 employment other than for cause. If such
person were to voluntarily leave his employment with the
 
                                       50
<PAGE>
Company prior to  the second anniversary  of the Agreement  no further  payments
would  be required. If  a voluntary termination  were to occur  after the second
anniversary of the Agreement, such person would be entitled to one year's salary
from the date of termination.  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, in either case if such event occurs within the initial three-year term of
the Agreement. 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  50,000 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  1,000 shares of Common Stock will be
granted to each person who qualifies as an outside director each year 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, shares  of Common Stock  or a  broker-assisted
cashless  transaction.  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, such participant may  exercise an outstanding option under the
plan within six months 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 any
amendment which requires stockholder
    
 
                                       51
<PAGE>
approval by  law  and may  only  modify  an outstanding  option,  including  the
repricing  of such options, with  the consent of the  option holder. The Company
currently has five  directors, two of  whom are eligible  to participate in  the
plan.
 
   
    1996  STOCK OPTION PLAN.  The 1996  Stock Option Plan provides for the grant
of both incentive  stock options and  non-qualifying stock options,  as well  as
limited  stock appreciation rights and supplemental bonuses, to the employees of
the Company  and its  subsidiaries,  including officers  and directors  who  are
salaried  employees.  A  total  of  850,000  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 Board  of
Directors.  The Board of Directors 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 (and  for incentive  stock options,  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,  by  surrendering
previously  owned shares of Common Stock upon the exercise of the option or by a
promissory note or broker-assisted  cashless exercise approved  by the Board  of
Directors,  (c) the  term of  the option may  not exceed  ten years,  and (d) no
option is transferrable other than by will, the laws of descent and distribution
or pursuant to  a qualified  domestic relations  order. Upon  termination of  an
optionee's  employment (other than  by death or  disability), an incentive stock
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,  while the  rights of  the holder  of a  non-qualifying  stock
option  will  be  set  forth in  each  option  agreement. In  the  event  of the
disability of an optionee,  the option may  be exercised by  such person or  his
personal  representative at any time within one  year of the termination of such
person's employment,  but only  to the  extent  the optionee  had the  right  to
exercise  the option as of the date of  his disability. In the event of death of
the optionee, the  option may  be exercised  by his  personal representative  or
successor  in interest  at any  time until  the later  of the  expiration of the
option or one  year after the  optionee's death,  to the extent  the option  was
exercisable at the time of the optionee's death. Incentive stock 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. Limited stock appreciation rights may be granted under the plan
with respect to  specified options, allowing  the option holder  to receive,  in
cash,  the difference  between the  exercise price and  the market  value in the
event of a change  of control of  the Company. The Board  of Directors may  also
grant  supplemental bonuses under the plan which  are cash bonuses not to exceed
the amount  of income  tax liability  incurred by  a plan  participant upon  the
exercise  of a non-qualifying stock option or a limited stock appreciation right
with respect to  which the bonus  was granted. Incentive  stock 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 an incentive stock  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 non-qualifying stock
options granted under the plan should  be taxable when the option is  exercised,
at  which  time  the optionee  would  recognize ordinary  income  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 will be treated as compensation
by the Company for federal income tax purposes. The Board of Directors may amend
    
 
                                       52
<PAGE>
the  plan, without stockholder approval, in any respect other than any amendment
that requires stockholder approval by law, and may modify an outstanding option,
including the  repricing of  non-qualifying  options, with  the consent  of  the
option holder. There are currently approximately 100 persons who are eligible to
participate under the plan.
 
   
    BONUS  INCENTIVE PLAN.  The Company has  adopted the Bonus Incentive Plan to
become effective upon the  completion of the Offerings.  The plan provides  that
the  Board of Directors  each year may  award bonuses in  cash, Common Stock, or
some combination thereof, to those  officers, directors, employees and  advisors
of  the  Company or  a subsidiary  of the  Company, who  the Board  of Directors
determines have contributed to  the success of the  Company. A total of  100,000
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. All officers,
directors, employees and advisors of the Company or a subsidiary of the  Company
who have completed a minimum of 180 days of service and are employed or retained
by  the Company or such subsidiary on the  last day of the plan year, other than
such persons who own  ten percent or  more of the  outstanding shares of  Common
Stock  during that year  are eligible to  participate in the  plan. Bonus awards
will be  determined based  on a  number of  factors, including  performance  and
salary level of the participant and the financial performance of the Company and
its  subsidiaries. Bonuses will be awarded after review and upon approval of the
Board of Directors, subject to the terms and conditions of 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 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 1995 the Company paid $440,884 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
 
                                       53
<PAGE>
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.
 
   
    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 tax advisors,
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
$0.8 million, 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. In addition, Messrs.
Liedtke, Grella and Musselman  and NBCC will receive  an aggregate of  6,000,000
shares of Common Stock in the Merger in exchange for their interests in the LLC.
    
 
                                       54
<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  general unsecured  senior  obligations of  the Company,
limited in  aggregate principal  amount to  $100.0 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.
    
 
   
RANKING
    
 
   
    The  Notes will be  general unsecured senior obligations  of the Company and
will rank  equally in  right of  payment  with all  existing and  future  Senior
Indebtedness  of the Company, and senior in right of payment to all existing and
future subordinated indebtedness  of the  Company. The Notes,  however, will  be
effectively  subordinated to secured Senior Indebtedness  of the Company and its
subsidiaries with respect  to the assets  securing such Indebtedness,  including
indebtedness  under the Credit  Facility, which is  expected to be  secured by a
lien on substantially all of the assets of the Company and any subsidiary of the
Company that guarantees the Company's obligations under the Credit Facility. See
"Description of Other Indebtedness  -- Credit Facility." On  a pro forma  basis,
after  giving  effect to  the Corporate  Reorganization,  the Offerings  and the
application of  proceeds  therefrom,  the  Company  would  have  had  no  senior
unsecured  indebtedness,  other  than the  Notes  and trade  payables,  and $0.4
million  of  secured  Senior  Indebtedness.  On  such  a  pro  forma  basis,  no
Indebtedness  was  junior  to the  Notes.  The  Notes will  also  be effectively
subordinated   to    liabilities   of    the   Company's    subsidiaries    that
    
 
                                       55
<PAGE>
   
are  not Subsidiary Guarantors. On  a pro forma basis,  the total liabilities of
the Company's Subsidiaries were $6.5 million at June 30, 1996, all of which were
operating liabilities. The  Indenture will limit,  subject to certain  financial
tests,   the  amount  of  additional  Indebtedness  that  the  Company  and  its
Subsidiaries can incur. See "Certain Covenants -- Incurrence of Indebtedness and
Issuance of Preferred Stock." The Indenture  will also limit the amount of  such
Indebtedness that can be secured. See "Certain Covenants -- Liens."
    
 
SUBSIDIARY GUARANTEES
 
   
    The  Indenture does not  require any Subsidiary to  guarantee the payment of
the Notes  unless  each such  Subsidiary  incurs Indebtedness  (other  than  its
Indebtedness  existing on  the date  of the  Indenture and  certain intercompany
Indebtedness). The Indenture requires  the Company to  cause such Subsidiary  to
fully  and  unconditionally, jointly  and  severally guarantee  (the "Subsidiary
Guarantees") the  Company's payment  obligations under  the Notes  prior to  the
incurrence  of  such  Indebtedness.  See  "Certain  Covenants  --  Incurrence of
Indebtedness and Issuance  of Preferred Stock."  On the date  of the  Indenture,
there  will be no 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." As a result, claims of creditors against the Subsidiaries and the
Unrestricted  Subsidiaries, including their trade  creditors and tort claimants,
will effectively have priority to the property and earnings of such subsidiaries
over claims of creditors of the Company, including the Holders. 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 Person 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) becomes a Subsidiary Guarantor pursuant to a  supplemental
indenture  or other agreement  in form and  substance reasonably satisfactory to
the Trustee, 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."
    
 
                                       56
<PAGE>
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.
 
    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
 
                                       57
<PAGE>
   
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.
    
 
    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.
 
   
    If  a Change of  Control Offer is made,  there can be  no assurance that the
Company will  have available  funds  sufficient to  pay  the Change  of  Control
Purchase  Price for all of the Notes  that might be delivered by Holders seeking
to accept the Change of Control Offer.  If on a Change of Control Purchase  Date
the  Company  does not  have available  funds  sufficient to  pay the  Change of
Control Purchase Price or is prohibited  from purchasing the Notes, an Event  of
Default  would occur  under the Indenture.  The definition of  Change of Control
includes an event by which the  Company sells, conveys, transfers or leases  all
or  substantially  all of  its  properties to  any  Person. The  phrase  "all or
substantially all" is subject to applicable  legal precedent and as a result  in
the  future  there may  be uncertainty  as to  whether a  Change of  Control has
occurred. The  existence of  a Holder's  right to  require, subject  to  certain
conditions,  the Company to  repurchase the Notes  upon a Change  of Control may
deter  a  third  party  from  acquiring  the  Company  in  a  transaction   that
constitutes, or results in, a Change of Control.
    
 
   
    The  Credit Facility  provides that  certain change  of control  events with
respect to the Company would constitute  a default thereunder and prohibits  the
Company  from making a Change  of Control Offer or  Asset Sale Offer. Any future
credit agreements or other agreements  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. Even  if such consents to  an offer to purchase  were
obtained  or the lenders did not declare a default under the Credit Facility and
other credit facilities, the Company's ability to pay cash to the holders of the
Notes upon a repurchase may be limited by the Company's then existing  financial
resources.
    
 
  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
 
                                       58
<PAGE>
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.
 
   
    The  Credit Facility prohibits the Company  from making an Asset Sale Offer.
The Indenture prohibits the Company from  directly or indirectly engaging in  an
Asset Sale of any Principal Properties to any Subsidiary other than a Subsidiary
Guarantor.
    
 
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, and will  not permit any
Subsidiary of the Company to issue Capital Stock (except to the Company or to  a
Wholly  Owned Subsidiary) 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  "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
 
                                       59
<PAGE>
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  Subsidiary  Guarantee,  supplemental
indenture  or  other  agreement 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.
 
  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  the Company or 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 Subordinated
Indebtedness of the  Company or  any Subsidiary of  the Company,  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
 
                                       60
<PAGE>
    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  day of the fiscal  month during which the  Indenture
    was  executed and delivered 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
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
Subordinated 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 Subordinated 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
 
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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 pursuant to this paragraph.
 
    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 the
    greater of (a) $50 million and (b) 15% of Adjusted Consolidated Net Tangible
    Assets, in each case, 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
 
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<PAGE>
    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;
 
       (vii)  The incurrence by the Subsidiaries of Indebtedness in existence on
    the date of the Indenture; and
 
      (viii) 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:
 
provided  that no Subsidiary may incur  any Indebtedness other than Indebtedness
described in the foregoing  clauses (iv) or (vii)  unless such Subsidiary  shall
have executed and delivered a Subsidiary Guarantee and such Subsidiary Guarantee
remains  in  full force  and effect  (unless terminated  in accordance  with the
provisions of the Indenture).
 
   
    Further, the Company will  not, directly or indirectly,  in any event  incur
any  Indebtedness which by its terms (or by the terms of any agreement governing
such Indebtedness)  is subordinated  to any  other Indebtedness  of the  Company
unless  such Indebtedness is also by its terms (or by the terms of any agreement
governing such Indebtedness)  expressly subordinated  to the Notes  to the  same
extent  and in the same manner as  such Indebtedness is subordinated pursuant to
subordination provisions that  are most favorable  to the holders  of any  other
Indebtedness of the Company.
    
 
  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) on any of their respective
assets,  now owned or  hereafter acquired, securing  any Indebtedness unless the
Notes, in  the case  of such  Indebtedness of  the Company,  and the  Subsidiary
Guarantee  of such Subsidiary Guarantor,  in the case of  such Indebtedness of a
Subsidiary  Guarantor,  are  secured  equally   and  ratably  with  such   other
Indebtedness;  PROVIDED that,  if such  Indebtedness is  by its  terms expressly
subordinate to the Notes  or the Subsidiary Guarantees,  the Lien securing  such
subordinate  or junior Indebtedness shall be  subordinate and junior to the Lien
securing the Notes or the Subsidiary Guarantees with the same relative  priority
as such subordinated or junior Indebtedness shall have with respect to the Notes
or the Subsidiary Guarantees, as the case may be.
    
 
  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
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
 
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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."
 
  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
 
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<PAGE>
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,  (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  and (c) such Net Proceeds
are applied in the same  manner and to the same  extent as Net Proceeds from  an
Asset Sale pursuant to the "-- Asset Sales" covenant.
    
 
  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  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
 
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Subsidiary  Guarantor attempts to revoke its Subsidiary Guarantee or contest its
validity or  any Subsidiary  Guarantee shall  not be  in full  force and  effect
(other than in accordance with the terms of the Indenture).
 
    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 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.
 
                                       66
<PAGE>
    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
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, the
Subsidiary Guarantees  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, the Subsidiary Guarantees 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).
 
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<PAGE>
    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, or the Subsidiary Guarantees 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,  the
Subsidiary   Guarantees  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.
 
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
 
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<PAGE>
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. 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,
 
                                       69
<PAGE>
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.
 
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
 
                                       70
<PAGE>
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 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.
 
                                       71
<PAGE>
    "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  (other than any Principal
Properties to any Wholly  Owned Subsidiary not a  Subsidiary Guarantor) 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.
 
    "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),  (iv)  in the  case  of  a limited  liability  company,  membership
interests,  and (v) 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
 
                                       72
<PAGE>
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
 
        (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 or write-off 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
    
 
                                       73
<PAGE>
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 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  or write-off  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.
 
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<PAGE>
    "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  (which shall  initially be  a credit
facility among the Company, NationsBank of Texas, N.A. or one of its affiliates,
as agent, and the other 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,  extended,
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.
    
 
    "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.
 
                                       75
<PAGE>
    "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.
 
   
    "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.
    
 
    "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
 
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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.
 
    "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, except as provided in (b) below), 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,  other than  any loss arising  out of  the extinguishment  of
Indebtedness  refinanced with  the proceeds  of the  Notes and  other securities
issued contemporaneously with the Notes  or Indebtedness that was refinanced  in
June   1996  by  such   refinanced  Indebtedness,  (ii)   any  extraordinary  or
nonrecurring   gain   (but    not   loss,    except   as    provided   in    (i)
    
 
                                       77
<PAGE>
above),  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.
 
    "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.
 
                                       78
<PAGE>
   
    "PERMITTED LIENS" means (a) Liens existing on the date of the Indenture; (b)
Liens under the Credit Facility  securing Indebtedness permitted to be  incurred
in  accordance with  clause (i)  of the second  paragraph under  the caption "--
Incurrence of Indebtedness and  Issuance of Preferred Stock";  (c) Liens now  or
hereafter  securing any Hedging Obligations so  long as the related Indebtedness
is permitted under clauses (v) or (vi) of the second paragraph under the caption
"-- Incurrence  of Indebtedness  and  Issuance of  Preferred Stock";  (d)  Liens
securing Permitted Refinancing Indebtedness; PROVIDED, that such Liens extend to
or  cover only the property or  assets currently securing the Indebtedness being
refinanced; (e) 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; (f)
statutory   landlords',   carriers',   mechanics',   workmen's,   materialman's,
operator's  or similar Liens arising in the ordinary course of business for sums
not delinquent  or 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; (g) easements, rights  of
way, restrictions and other similar encumbrances or minor imperfections in title
that,  in the  case of  any of the  foregoing, were  not incurred  or created to
secure the payment of borrowed money or the deferred purchase price of  property
or  services, and in  the aggregate do  not materially and  adversely affect the
value of such properties or materially impair use for the purposes of which such
properties are held by the Company or any Subsidiaries; (h) Liens on, or related
to, properties to  secure all  or part of  the costs  (other than  Indebtedness)
incurred   in  the  ordinary  course   of  business  of  exploration,  drilling,
development or operation thereof; (i)  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; (j) Liens
on deposits made  in the  ordinary course  of business;  (k) Liens  in favor  of
collecting  or  payor banks  having a  right of  set-off, 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; (l) Liens on pipeline or pipeline
facilities which arise out of operation of law; (m) 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;  (n) liens  reserved in  oil and  gas
leases  for bonus or rental  payments and for compliance  with the terms of such
leases; (o)  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  and that do not secure Indebtedness;  (p)
(i)  Liens upon any property  of any Person existing  at the time of acquisition
thereof by the Company or a Subsidiary, (ii) Liens upon any property of a Person
existing at the time such Person is  merged or consolidated with the Company  or
any  Subsidiary or  existing at  the time of  the sale  or transfer  of any such
property of such Person to  the Company or any  Subsidiary, or (iii) Liens  upon
any  property of a Person existing at the time such Person becomes a Subsidiary;
PROVIDED, that in each case such Lien  has not been created in contemplation  of
such  sale, merger, consolidation, transfer or acquisition, and PROVIDED that in
each such case no such Lien shall extend to or cover any property of the Company
or any  Subsidiary  other than  the  property being  acquired  and  improvements
thereon;  (q) purchase money Liens granted in connection with the acquisition of
assets, PROVIDED, that (i) such Liens attach only to the assets so acquired with
the purchase money  indebtedness secured  thereby, (ii) such  Liens secure  only
Indebtedness that is not in excess of 100% of the purchase price of such assets,
and (iii) such Liens attach no later than 180 days after the acquisition of such
assets;  and (r) Liens securing Indebtedness incurred as a result of extensions,
renewals or replacements of Indebtedness  secured by Liens permitted by  clauses
(p)  or (q),  PROVIDED, that  (i) the  principal amount  of the  Indebtedness so
issued and secured by  such Lien shall  not exceed the  principal amount of  the
Indebtedness  so extended, renewed,  replaced, exchanged or  refinanced and (ii)
the Indebtedness so
    
 
                                       79
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issued and secured by such Lien shall  not be secured by any property or  assets
of  the Company or any  Subsidiary other than the  property or assets subject to
the Liens securing such Indebtedness being exchanged or refinanced.
    
 
    "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 any  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 any 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.
 
    "PRINCIPAL PROPERTIES" means the oil  and gas properties and other  tangible
assets   and  properties  owned  by  Company   on  the  date  of  the  Indenture
(collectively, the "Original Principal Properties") and assets and properties of
the Company obtained in exchange for any of the Original Principal Properties.
 
    "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.
 
   
    "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 or 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.
    
 
    "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  or any  of  its
Subsidiaries 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.
    
 
    "SENIOR  REVOLVING  INDEBTEDNESS"  means  revolving  credit  borrowings  and
letters  of credit  under the Credit  Facility and/or any  successor facility or
facilities.
 
   
    "SUBORDINATED INDEBTEDNESS" means any Indebtedness of the Company or any  of
its Subsidiaries (whether outstanding on the date of the Indenture or thereafter
incurred)  that is contractually  subordinated or junior in  right of payment of
principal, premium and interest to the Notes or the Subsidiary Guarantees.
    
 
    "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
 
                                       80
<PAGE>
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.
 
    "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.
 
                                       81
<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 13, 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 Credit Facility will provide the Company with a revolving facility based
on the borrowing base of its oil and  gas assets which will initially be set  at
$50.0 million, 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 assets of the Company and any subsidiary of the Company that guarantees  the
Company's  obligations under the Credit  Facility. Initially, no subsidiaries of
the Company  will guarantee  the obligations  of the  Company under  the  Credit
Facility.  See "Mangement's Discussion  and Analysis of  Financial Condition and
Results of  Operations  --  Liquidity  and  Capital  Resources"  for  a  further
description of the Credit Facility.
    
 
                          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.
 
                                       82
<PAGE>
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
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."
 
                                       83
<PAGE>
                                  UNDERWRITING
 
    Upon  the terms and subject to  the conditions of the Underwriting Agreement
(the "Underwriting Agreement") among  the Company, 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  has  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.
 
    The Underwriters  have informed  the  Company that  they  do not  expect  to
confirm  sales of Notes offered hereby to  any accounts over which they exercise
discretionary authority.
 
    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,  an affiliate  of Prudential
Securities Incorporated, 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  $16.3
million  of the  proceeds of  the Offerings  in redemption  of a  portion of the
membership interests owned by it  and in a distribution  to 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
 
                                       84
<PAGE>
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 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. The members  of the  LLC made the
decision to change the LLC's principal accountants.
 
    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
 
                                       85
<PAGE>
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  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.
 
                                       86
<PAGE>
                                    GLOSSARY
 
    The terms defined in this section are used throughout this Prospectus.
 
    ADJUSTED EBITDA.  Calculated by adding interest, income taxes, depreciation,
depletion  and amortization, exploration and abandonment costs and extraordinary
loss resulting from extinguishment of debt to net income (loss).
 
    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.
 
    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
 
                                       87
<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.
 
                                       88
<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 June 30, 1996
   (unaudited).......................................................................        F-4
  Consolidated Statements of Operations for the years ended December 31, 1993, 1994,
   and 1995, and the six months ended June 30, 1995 and 1996 (unaudited).............        F-5
  Consolidated Statements of Members' Capital for the years ended December 31, 1993,
   1994, and 1995, and the six months ended June 30, 1995 (unaudited)................        F-6
  Consolidated Statements of Cash Flows for the years ended December 31, 1993, 1994,
   and 1995, and the six months ended June 30, 1995 and 1996 (unaudited).............        F-7
  Notes to Consolidated Financial Statements.........................................        F-8
 
Financial Statements of the 1995 Acquisition:
  Independent Auditors' Report.......................................................       F-22
  Statements of Revenues and Direct Operating Expenses for the years ended December
   31, 1993 and 1994 and the period ended June 12, 1995..............................       F-23
  Notes to the Statements of Revenues and Direct Operating Expenses..................       F-24
 
Financial Statements of the 1996 Acquisition:
  Independent Auditors' Report.......................................................       F-27
  Statements of Revenues and Direct Operating Expenses for the years ended December
   31, 1993, 1994 and 1995, and the periods ended June 14, 1995 and 1996
   (unaudited).......................................................................       F-28
  Notes to the Statements of Revenues and Direct Operating Expenses..................       F-29
</TABLE>
 
   
Note:  The  financial statements of Costilla  Energy, Inc. (incorporated in June
       1996) are not presented, as Costilla Energy, Inc. has no material assets,
       liabilities or equity,  and has  not generated any  material revenues  or
       incurred any material expenses.
    
 
                                      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 June 14, 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,
                                                                                            ----------------   JUNE 30,
                                                                                             1994     1995       1996
                                                                                            -------  -------  -----------
                                                                                                              (UNAUDITED)
<S>                                                                                         <C>      <C>      <C>
Current assets:
  Cash and cash equivalents...............................................................  $   137  $ 2,866    $ 1,164
  Accounts receivable:
    Trade, net............................................................................    1,042    3,154      2,521
    Affiliates............................................................................       --      507        927
    Oil and gas sales.....................................................................    1,715    3,915      5,337
  Prepaid and other current assets........................................................      223      439      2,629
                                                                                            -------  -------  -----------
        Total current assets..............................................................    3,117   10,881     12,578
                                                                                            -------  -------  -----------
Property, plant and equipment, at cost:
  Oil and gas properties, using the successful efforts method of accounting:
    Proved properties.....................................................................   22,794   79,897    126,809
    Unproved properties...................................................................    2,060    2,903      4,615
  Accumulated depletion, depreciation and amortization....................................   (3,562)  (9,413)   (13,933)
                                                                                            -------  -------  -----------
                                                                                             21,292   73,387    117,491
                                                                                            -------  -------  -----------
Other property and equipment, net.........................................................       76      679      1,640
Deferred charges (Note 2).................................................................       29    1,736      2,654
Note receivable -- affiliate..............................................................      390      684        684
                                                                                            -------  -------  -----------
                                                                                            $24,904  $87,367    $135,047
                                                                                            -------  -------  -----------
                                                                                            -------  -------  -----------
 
<CAPTION>
 
                              LIABILITIES, REDEEMABLE MEMBERS' CAPITAL AND MEMBERS' CAPITAL
<S>                                                                                         <C>      <C>      <C>
Current liabilities:
  Current maturities of long-term debt....................................................  $    22  $    --    $    98
  Trade accounts payable..................................................................    1,712    5,467      4,587
  Undistributed revenue...................................................................      110    1,227      1,524
  Other current liabilities...............................................................      192    1,691      2,103
                                                                                            -------  -------  -----------
        Total current liabilities.........................................................    2,036    8,385      8,312
                                                                                            -------  -------  -----------
Long-term debt, less current maturities (Note 7)..........................................   23,591   71,494    122,267
Deferred income (Note 2)..................................................................       24    3,319      2,623
Other noncurrent liabilities..............................................................       --       38         --
                                                                                            -------  -------  -----------
        Total liabilities.................................................................   25,651   83,236    133,202
                                                                                            -------  -------  -----------
Redeemable members' capital (Note 10).....................................................       --   12,278     13,557
                                                                                            -------  -------  -----------
Members' capital (Note 10)................................................................     (747)  (8,147)   (11,712)
Commitments and contingencies (Note 8)....................................................       --       --         --
                                                                                            -------  -------  -----------
                                                                                            $24,904  $87,367    $135,047
                                                                                            -------  -------  -----------
                                                                                            -------  -------  -----------
</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>
                                                                                                SIX MONTHS ENDED
                                                                YEARS ENDED DECEMBER 31,            JUNE 30,
                                                             -------------------------------  --------------------
                                                               1993       1994       1995       1995       1996
                                                             ---------  ---------  ---------  ---------  ---------
                                                                                                  (UNAUDITED)
<S>                                                          <C>        <C>        <C>        <C>        <C>
Revenues:
  Oil and gas sales........................................  $   4,231  $   7,637  $  21,693  $   5,568  $  19,445
  Interest and other.......................................         56         87        123          5         40
  Gain on sale of assets...................................        110        112         --         --         40
                                                             ---------  ---------  ---------  ---------  ---------
                                                                 4,397      7,836     21,816      5,573     19,525
                                                             ---------  ---------  ---------  ---------  ---------
Expenses:
  Oil and gas production...................................      1,688      2,349     10,024      2,268      8,093
  Oil and gas production -- affiliates.....................         --          2        331        145        185
  General and administrative...............................        639        634      2,910        678      2,439
  General and administrative -- affiliates.................        313        550        661        330        370
  Exploration and abandonments.............................        218        793      1,650      1,007        308
  Depreciation, depletion and amortization.................        884      1,847      5,958      1,367      4,620
  Interest.................................................        605      1,458      4,591      1,046      4,156
  Other....................................................         --         --          2         --         --
                                                             ---------  ---------  ---------  ---------  ---------
                                                                 4,347      7,633     26,127      6,841     20,171
                                                             ---------  ---------  ---------  ---------  ---------
    Income (loss) before federal income taxes and
     extraordinary item....................................  $      50  $     203  $  (4,311) $  (1,268)      (646)
Provision for federal income taxes
  Current..................................................        (25)         8          3         --         --
  Deferred.................................................          2         32         --         --         --
                                                             ---------  ---------  ---------  ---------  ---------
    Income (loss) before extraordinary item................  $      73  $     163  $  (4,314) $  (1,268) $    (646)
    Extraordinary loss resulting from extinguishment of
     debt (Note 7).........................................         --         --         --         --     (1,640)
                                                             ---------  ---------  ---------  ---------  ---------
    Net income (loss)......................................  $      73  $     163  $  (4,314) $  (1,268) $  (2,286)
                                                             ---------  ---------  ---------  ---------  ---------
                                                             ---------  ---------  ---------  ---------  ---------
</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 and accretion of redeemable members' capital.......................................      (2,278)
                                                                                                        ----------
Balance at December 31, 1995..........................................................................      (8,147)
  Net loss (unaudited)................................................................................      (2,286)
  Preferred return and accretion of redeemable members' capital (unaudited)...........................      (1,279)
                                                                                                        ----------
Balance at June 30, 1996 (unaudited)..................................................................  $  (11,712)
                                                                                                        ----------
                                                                                                        ----------
</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>
                                                                                                                SIX MONTHS ENDED
                                                                                   YEARS ENDED DECEMBER 31,         JUNE 30,
                                                                                  ---------------------------  ------------------
                                                                                   1993      1994      1995      1995      1996
                                                                                  -------  --------  --------  --------  --------
                                                                                                                  (UNAUDITED)
<S>                                                                               <C>      <C>       <C>       <C>       <C>
Cash flows from operating activities:
  Net income (loss).............................................................  $    73  $    163  $ (4,314) $ (1,268) $ (2,286)
  Adjustments to reconcile net income (loss) to net cash provided by operating
   activities:
    Depreciation, depletion and amortization....................................      884     1,847     5,958     1,367     4,620
    Amortization of deferred charges............................................       --        --       137        --       169
    Other noncash...............................................................      (21)       35       (75)      (28)       79
    Gain on sale of oil and gas properties......................................     (110)     (112)       --        --       (40)
    Extraordinary loss resulting from extinguishment of debt....................       --        --        --        --     1,640
    Change in operating assets and liabilities:
      Increase in accounts receivable...........................................     (837)   (1,535)   (4,818)   (3,568)   (1,209)
      Decrease (increase) in other assets.......................................       20       301      (216)     (107)   (2,190)
      Increase (decrease) in accounts payable...................................      262       723     4,863     2,188      (880)
      Increase (decrease) in other liabilities..................................       59       102     1,537    (1,624)      671
      Increase (decrease) in deferred income....................................       (8)        3     3,294        --      (696)
                                                                                  -------  --------  --------  --------  --------
        Total adjustments.......................................................      249     1,364    10,680    (1,772)    2,164
                                                                                  -------  --------  --------  --------  --------
        Net cash provided by (used in) operating activities.....................      322     1,527     6,366    (3,040)     (122)
                                                                                  -------  --------  --------  --------  --------
Cash flows from investing activities:
  Capital expenditures for oil and gas properties...............................   (6,634)  (11,819)  (61,500)  (57,261)  (47,727)
  Proceeds from sale of oil and gas properties..................................      131       112        --        --        --
  Additions to other property and equipment.....................................     (228)      (49)     (720)     (512)   (1,996)
  Advances on affiliate notes receivable........................................       --      (390)     (247)       --        --
                                                                                  -------  --------  --------  --------  --------
        Net cash used in investing activities...................................   (6,731)  (12,146)  (62,467)  (57,773)  (49,723)
                                                                                  -------  --------  --------  --------  --------
Cash flows from financing activities:
  Borrowings under long-term debt...............................................    6,770    11,579    62,704    62,680   125,390
  Payments of long-term debt....................................................       --        --   (11,232)   (7,902)  (74,519)
  Deferred loan and financing costs.............................................       --        --    (2,587)   (2,587)   (2,728)
  Proceeds from redeemable members' capital.....................................       --        --    10,000    10,000        --
  Contributions.................................................................        1        --        --        --        --
  Withdrawals...................................................................     (456)     (961)      (55)      (97)       --
                                                                                  -------  --------  --------  --------  --------
        Net cash provided by financing activities...............................    6,315    10,618    58,830    62,094    48,143
                                                                                  -------  --------  --------  --------  --------
Net increase (decrease) in cash and cash equivalents............................      (94)       (1)    2,729     1,281    (1,702)
Cash and cash equivalents, beginning of period..................................      232       138       137       137     2,866
                                                                                  -------  --------  --------  --------  --------
Cash and cash equivalents, end of period........................................  $   138  $    137  $  2,866  $  1,418  $  1,164
                                                                                  -------  --------  --------  --------  --------
                                                                                  -------  --------  --------  --------  --------
</TABLE>
    
 
          See accompanying notes to consolidated financial statements.
 
                                      F-7
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
                   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.  The   Company
proportionately  consolidates less-than-100%-owned oil  and gas partnerships and
joint ventures in  accordance with industry  practice. 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. Prior  to February 14,  1995, the combining companies
were owned by individuals who own 70% of the Company, in approximately the  same
proportion  relative to one  another as is  their current ownership. 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.
During  the year ended December 31, 1995,  the Company had sales to one customer
which accounted for 17.7% of total revenues.
    
 
    TRADE RECEIVABLES
 
    Trade receivables  generally consist  of amounts  due from  outside  working
interest  owners for their  proportionate share of  drilling and operating costs
incurred by the Company, as operator of the related properties.
 
    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.
 
                                      F-8
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(2) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    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  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 on  a
straight-line  basis over the estimated useful  lives of the assets, which range
from 5 to 7 years.
 
    Prior to the adoption of FAS 121 on January 1, 1995, the Company's aggregate
oil and gas properties were  carried at cost, not  in excess of total  estimated
undiscounted future net revenues, on a worldwide basis.
 
    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.
 
                                      F-9
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(2) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    REVENUE RECOGNITION
 
    The  Company uses  the sales  method of  accounting for  crude oil revenues.
Under this method, revenues are recognized  based on actual volumes of oil  sold
to purchasers.
 
    The  Company  uses the  entitlements method  of  accounting for  natural gas
revenues. Under this method, revenues are recognized based on actual  production
of  natural gas. Natural gas revenues  would not have been significantly altered
in any period  had the  sales method of  recognizing natural  gas revenues  been
utilized.
 
    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  June 30,  1996, and  for the  six
months  ended June 30, 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 transaction was  accounted
for  using  the  purchase method.  The  results  of operations  of  the acquired
properties are included in the  Consolidated Statements of Operations  beginning
June  12, 1995.  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.
    
 
    PRO FORMA RESULTS OF OPERATIONS (UNAUDITED)
 
    The  following table reflects the pro  forma results of operations as though
the acquisition, net of the related properties sold, had occurred on January  1,
1994.  The pro forma amounts are not  necessarily indicative of the results that
may be reported in the future.
 
<TABLE>
<CAPTION>
                                                                           YEARS ENDED DECEMBER
                                                                                   31,
                                                                             1994       1995
                                                                           ---------  ---------
                                                                              (IN THOUSANDS)
<S>                                                                        <C>        <C>
Revenues.................................................................     35,460     32,746
Net income (loss)........................................................      1,563     (3,999)
</TABLE>
 
                                      F-10
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(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.
 
(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. If market prices of oil and
gas exceed the strike price of put options, the options will expire unexercised,
therefore reducing the  effective price received  for oil and  gas sales by  the
cost  of the related option.  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.  If market rates  of interest experienced  during
the  applicable swap term are  below the rates of  interest effectively fixed by
the swap agreement, the rate of interest experienced by the Company will  exceed
the  rate  that  would have  been  experienced  under the  Credit  Agreement. At
December 31, 1995, the Company was a
 
                                      F-11
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(5) DERIVATIVE FINANCIAL INSTRUMENTS (CONTINUED)
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>
 
(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.
 
                                      F-12
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(6) FAIR VALUE OF FINANCIAL INSTRUMENTS (CONTINUED)
    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.
 
(7) LONG-TERM DEBT
    Long-term debt consists of the following:
 
<TABLE>
<CAPTION>
                                                                             DECEMBER 31,
                                                                         --------------------
                                                                           1994       1995
                                                                         ---------  ---------
                                                                            (IN THOUSANDS)
<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.
 
                                      F-13
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(7) LONG-TERM DEBT (CONTINUED)
    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.
 
    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 demonstrated its
intent and  ability  to  refinance  the  current  maturities  under  the  Credit
Agreement  by entering into a new loan agreement, proceeds of which were used to
repay the existing notes. Concurrently, the deferred charges associated with the
Credit Agreement were expensed as an extraordinary loss.
 
(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
 
                                      F-14
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(8) COMMITMENTS AND CONTINGENCIES (CONTINUED)
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
 
    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 ($214,178 of  which had been  expended through December 31,
1995) in return for a 50.0% interest  in Redeco. After the initial $2.0  million
expenditure,  Redeco and the  Company are responsible for  bearing 50.0% each of
future expenses. 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,  Redeco's  exclusive  rights
continue  for  20 years.  Redeco's exclusive  period  to explore  throughout the
remainder of  Moldova  expires  in  2005, but  Redeco  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  material
fixed financial commitments with respect to the Concession.
 
    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,  NationsBanc  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  includes  $10,000,000 that  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
 
                                      F-15
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(10) REDEEMABLE MEMBERS' CAPITAL AND MEMBERS' CAPITAL (CONTINUED)
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>
 
    In addition, a portion of NBCC's interest not subject to preferential return
is  classified as redeemable members' capital as  the Company may be required to
repurchase such interest upon the occurrence of certain events similar to  those
events  requiring redemption of the  redeemable members' capital described above
and, in any  event, on or  after February 17,  2000. Such interest  may, at  the
Company's  option, be  repurchased to the  extent the Company  has exercised its
right to redeem all or a portion of the redeemable members' interest subject  to
the  preferential return. The  redemption price the Company  would pay in either
instance 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>
 
    The ultimate redemption price  of $5,500,000 is  being accrued ratably  over
the  period from February 17, 1995 through February 17, 2000 and is treated as a
reduction of members' capital.
 
    NBCC would  retain an  18% interest  in the  Company after  the  redemptions
described above occur. Such interest is not subject to redemption.
 
    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
 
                                      F-16
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(11) RELATED PARTY TRANSACTIONS (CONTINUED)
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  $42.5 million. The
properties are located primarily  in south and west  Texas. The transaction  was
accounted  for  using the  purchase  method. The  results  of operations  of the
acquired properties are included in the Consolidated Statements of Operations as
of the closing date, June 14, 1996.
 
    PRO FORMA RESULTS OF OPERATIONS (UNAUDITED)
 
    The following table  reflects the pro  forma results of  operations for  the
six-months  ended June  30, 1995  and 1996,  as though  both acquisitions, which
closed on June 12, 1995 and June 14,  1996, had occurred as of January 1,  1995.
The  pro forma amounts are not necessarily indicative of the results that may be
reported in the future.
 
   
<TABLE>
<CAPTION>
                                                                           SIX MONTHS ENDED
                                                                               JUNE 30,
                                                                         --------------------
                                                                           1995       1996
                                                                         ---------  ---------
                                                                            (IN THOUSANDS)
<S>                                                                      <C>        <C>
Revenues...............................................................  $  25,706  $  28,748
Net loss...............................................................     (3,779)    (2,081)
</TABLE>
    
 
    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 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.
 
                                      F-17
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(12) SUBSEQUENT EVENTS (CONTINUED)
    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.  If  such  additional  fees are
incurred, they will be  amortized over the remaining  period that the Loans  are
expected to be outstanding.
 
(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
                                                                  ---------  ---------  ---------  ---------------
                                                                          (IN THOUSANDS)             (UNAUDITED)
<S>                                                               <C>        <C>        <C>        <C>
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-18
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
        (THE INFORMATION AND AMOUNTS FOR INTERIM PERIODS ARE UNAUDITED.)
 
(14) SUPPLEMENTAL OIL AND GAS RESERVE INFORMATION (UNAUDITED) (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 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-19
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
        (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-20
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                      (A TEXAS LIMITED LIABILITY COMPANY)
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
        (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-21
<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-22
<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-23
<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. Under this  method, revenues  are
recognized  based on actual  volumes of oil  and gas sold  to purchasers. 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-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)
    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:
 
<TABLE>
<CAPTION>
                                                                       DECEMBER 31,
                                                                 ------------------------
                                                                    1993         1994      JUNE 12, 1995
                                                                 -----------  -----------  -------------
                                                                             (IN THOUSANDS)
<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-25
<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:
 
<TABLE>
<CAPTION>
                                                                YEARS ENDED DECEMBER
                                                                        31,
                                                               ----------------------  PERIOD ENDED
                                                                  1993        1994     JUNE 12, 1995
                                                               ----------  ----------  -------------
                                                                          (IN THOUSANDS)
<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-26
<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-27
<PAGE>
                            COSTILLA ENERGY, L.L.C.
                                1996 ACQUISITION
              STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES
 
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                      YEARS ENDED                  PERIODS
                                                                     DECEMBER 31,               ENDED JUNE 14,
                                                            -------------------------------  --------------------
                                                              1993       1994       1995       1995       1996
                                                            ---------  ---------  ---------  ---------  ---------
<S>                                                         <C>        <C>        <C>        <C>        <C>
                                                                                                 (UNAUDITED)
Revenues:
  Oil and condensate......................................  $  11,467  $  10,170  $  10,564  $   5,140  $   5,205
  Natural gas.............................................     11,294     10,105      8,645      3,763      3,434
  Gas plant...............................................         57         57        126         47         42
  Transportation..........................................         39        379        556        253        542
                                                            ---------  ---------  ---------  ---------  ---------
                                                               22,857     20,711     19,891      9,203      9,223
 
Direct operating expenses:
  Lease operating.........................................     10,977      9,053      9,232      3,965      4,020
  Workovers and dry hole costs............................        675        869      1,002        256        450
  Production taxes........................................      1,166      1,089        992        458        453
  Gas plant...............................................        131        350        598        393        269
  Transportation..........................................         10        394        587        268        222
                                                            ---------  ---------  ---------  ---------  ---------
                                                               12,959     11,755     12,411      5,340      5,414
                                                            ---------  ---------  ---------  ---------  ---------
Revenues in excess of direct operating expenses...........  $   9,898  $   8,956  $   7,480  $   3,863  $   3,809
                                                            ---------  ---------  ---------  ---------  ---------
                                                            ---------  ---------  ---------  ---------  ---------
</TABLE>
 
                See the accompanying notes to these statements.
 
                                      F-28
<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. Under this  method, revenues  are
recognized  based on actual  volumes of oil  and gas sold  to purchasers. Direct
operating expenses are recognized on the accrual method.
 
    INTERIM STATEMENTS OF REVENUES AND DIRECT OPERATING EXPENSES
 
    The interim financial information  for the periods ended  June 14, 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
 
                                      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)
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.
 
    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.
 
                                      F-30
<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 Company's estimated standardized measure of discounted
future net cash flows from proved reserves attributable to the 1996 Acquisition:
 
<TABLE>
<CAPTION>
                                                                           DECEMBER 31,
                                                              ---------------------------------------   MARCH 31,
                                                                  1993          1994         1995         1996
                                                              ------------  ------------  -----------  -----------
                                                                          (IN THOUSANDS)
<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>
 
    The following are  the sources  of changes  in the  standardized measure  of
discounted net cash flows:
 
<TABLE>
<CAPTION>
                                                                                                   THREE MONTH
                                                                     YEARS ENDED DECEMBER 31,      PERIOD ENDED
                                                                  -------------------------------   MARCH 31,
                                                                    1993       1994       1995         1996
                                                                  ---------  ---------  ---------  ------------
                                                                          (IN THOUSANDS)
<S>                                                               <C>        <C>        <C>        <C>
Standardized measure, beginning of period.......................  $  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 period.............................  $  38,230  $  29,566  $  42,688   $   50,436
                                                                  ---------  ---------  ---------  ------------
                                                                  ---------  ---------  ---------  ------------
</TABLE>
 
                                      F-31
<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.
 
    No  opinion is expressed  by Williamson as  to the fair  market value of the
evaluated properties.
 
                                      A-6
<PAGE>
Costilla Energy, Inc.
Mr. Michael J. Grella
July 23, 1996
Page 7
 
    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.
 
    UNTIL                  , 1996,  ALL DEALERS  EFFECTING TRANSACTIONS  IN  THE
REGISTERED SECURITIES, WHETHER OR NOT PARTICIPATING IN THIS DISTRIBUTION, MAY BE
REQUIRED  TO DELIVER  A PROSPECTUS.  THIS IS  IN ADDITION  TO THE  OBLIGATION OF
DEALERS TO DELIVER
A PROSPECTUS WHEN ACTING AS UNDERWRITERS AND
WITH RESPECT TO THEIR UNSOLD ALLOTMENTS OR SUBSCRIPTIONS.
                            ------------------------
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                    PAGE
                                                    -----
<S>                                              <C>
Prospectus Summary.............................           3
Risk Factors...................................          10
The Company....................................          16
Common Stock Offering..........................          16
Use of Proceeds................................          17
Capitalization.................................          18
Pro Forma Condensed Financial Statements.......          19
Selected Financial Information.................          27
Management's Discussion and Analysis of
 Financial Condition and Results of
 Operations....................................          28
Business and Properties........................          34
Management.....................................          46
Security Ownership of Certain Beneficial Owners
 and Management................................          49
Executive Compensation and Other Information...          50
Certain Transactions...........................          53
Description of Notes...........................          55
Description of Other Indebtedness..............          82
Description of Capital Stock...................          82
Underwriting...................................          84
Legal Matters..................................          85
Experts........................................          85
Available Information..........................          85
Glossary.......................................          87
Index to Financial Statements..................         F-1
Summary Reserve Report.........................         A-1
</TABLE>
 
                                     [LOGO]
 
                             COSTILLA ENERGY, INC.
 
   
                           $100,000,000     % SENIOR
                                 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.....................................    109,375
Engineering fees and expenses....................................    113,750
Trustee fees and expenses........................................      7,500
Legal fees and expenses..........................................    156,250
Printing and mailing expenses....................................    122,000
Miscellaneous....................................................     36,142
                                                                   ---------
      TOTAL......................................................    600,000
                                                                   ---------
                                                                   ---------
</TABLE>
 
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 director's 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 3 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
  **10.1   Commitment Letter dated September 20, 1996 by NationsBank of Texas, N.A. to the Company
   *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   Form of 1996 Stock Option Plan
   *10.7   Form of 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
   *10.14  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
   *10.15  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
   *10.16  Supplemental Agreement to Purchase and Joint Exploration Agreement dated August 7, 1996 among
            the Company, Costilla Redeco Energy, L.L.C. and Resource Development Company Limited, L.L.C.
            (DE)
   *10.17  Form of Bonus Incentive Plan
   *12.1   Computation of Ratio of Adjusted EBITDA to Interest Expense
</TABLE>
    
 
                                      II-2
<PAGE>
   
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                       DESCRIPTION OF EXHIBIT
- ---------  ---------------------------------------------------------------------------------------------
<C>        <S>
   *12.2   Computation of Ratio of Earnings to Fixed Charges
   *12.3   Pro Forma Computation of Ratio of ACNTA to Total Debt
   *16.1   Letter Regarding Change of Accountants
   *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>
    
 
- ------------------------
*  Previously filed
** Filed herewith
 
    (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,  thereunto duly authorized in the  City of Midland, State of Texas,
on September 24, 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.
 
   
             SIGNATURE                      TITLE                 DATE
- -----------------------------------  --------------------  ------------------
 
                                     Chairman of the
                 *                    Board, Chief
- -----------------------------------   Executive Officer    September 24, 1996
         Cadell S. Liedtke            and Director
 
                 *                   President, Chief
- -----------------------------------   Operating Officer    September 24, 1996
         Michael J. Grella            and Director
 
                 *                   Executive Vice
- -----------------------------------   President and        September 24, 1996
        Henry G. Musselman            Director
 
         /s/ BOBBY W. PAGE           Senior Vice Present,
- -----------------------------------   Treasurer and Chief  September 24, 1996
           Bobby W. Page              Financial Officer
 
                 *
- -----------------------------------  Director              September 24, 1996
         Jerry J. Langdon
 
                 *
- -----------------------------------  Director              September 24, 1996
           W.D. Kennedy
 
*By:          /s/ BOBBY W. PAGE
- -----------------------------------
           Bobby W. Page
         ATTORNEY-IN-FACT
 
    
 
                                      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
  **10.1   Commitment Letter dated September 20, 1996 by NationsBank of Texas, N.A. to the Company
   *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   Form of 1996 Stock Option Plan
   *10.7   Form of 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
   *10.14  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
   *10.15  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
   *10.16  Supplemental Agreement to Purchase and Joint Exploration Agreement dated August 7, 1996 among
            the Company, Costilla Redeco Energy, L.L.C. and Resource Development Company Limited, L.L.C.
            (DE)
   *10.17  Form of Bonus Incentive Plan
   *12.1   Computation of Ratio of Adjusted 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
   *16.1   Letter Regarding Change of Accountants
</TABLE>
    
<PAGE>
   
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                       DESCRIPTION OF EXHIBIT
- ---------  ---------------------------------------------------------------------------------------------
<C>        <S>
   *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>
    
 
- ------------------------
*  Previously filed
** Filed herewith

<PAGE>


                                COSTILLA ENERGY, INC.,
                                      as Issuer,

                         Subsidiary Guarantors parties hereto

                                     $100,000,000

                              ___% SENIOR 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).......................................................4.16; 4.18
         (b)................................................................N.A.
         (c)(1)............................................................11.03
         (c)(2)............................................................11.03
         (c)(3).............................................................N.A.
         (d)................................................................N.A.
         (e)...............................................................11.04
         (f)................................................................4.18
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.........21
    SECTION 1.03.  RULES OF CONSTRUCTION.....................................21
    SECTION 1.04.  FORM OF DOCUMENTS DELIVERED TO TRUSTEE....................22
    SECTION 1.05.  ACTS OF HOLDERS...........................................22
    SECTION 1.06.  SATISFACTION AND DISCHARGE................................23

                                      ARTICLE II

THE NOTES....................................................................24
    SECTION 2.01.  FORM AND DATING...........................................24
    SECTION 2.02.  EXECUTION AND AUTHENTICATION..............................25
    SECTION 2.03.  REGISTRAR AND PAYING AGENT................................26
    SECTION 2.04.  PAYING AGENT TO HOLD MONEY IN TRUST.......................27
    SECTION 2.05.  GLOBAL NOTES..............................................27
    SECTION 2.06.  TRANSFER AND EXCHANGE.....................................28
    SECTION 2.07.  REPLACEMENT NOTES.........................................29
    SECTION 2.08.  OUTSTANDING NOTES.........................................30
    SECTION 2.09.  TEMPORARY NOTES...........................................30
    SECTION 2.10.  CANCELLATION..............................................31
    SECTION 2.11.  PAYMENT OF INTEREST; INTEREST RIGHTS PRESERVED............31
    SECTION 2.12.  AUTHORIZED DENOMINATIONS..................................32
    SECTION 2.13.  COMPUTATION OF INTEREST...................................32
    SECTION 2.14.  PERSONS DEEMED OWNERS.....................................32
    SECTION 2.15.  CUSIP NUMBERS.............................................32

                                     ARTICLE III

REDEMPTION...................................................................32
    SECTION 3.01.  NOTICE TO TRUSTEE.........................................32
    SECTION 3.02.  SELECTION OF NOTES TO BE REDEEMED.........................33
    SECTION 3.03.  NOTICE OF REDEMPTION......................................33
    SECTION 3.04.  EFFECT OF NOTICE OF REDEMPTION............................34
    SECTION 3.05.  DEPOSIT OF REDEMPTION PRICE...............................34
    SECTION 3.06.  NOTES REDEEMED IN PART....................................35


                                         -ii-

<PAGE>

                                      ARTICLE IV

COVENANTS....................................................................35
    SECTION 4.01.  PAYMENT OF NOTES..........................................35
    SECTION 4.02.  MAINTENANCE OF OFFICE OR AGENCY...........................35
    SECTION 4.03.  MONEY FOR THE NOTE PAYMENTS TO BE HELD IN TRUST...........36
    SECTION 4.04.  CORPORATE EXISTENCE.......................................36
    SECTION 4.05.  MAINTENANCE OF PROPERTY...................................36
    SECTION 4.06.  PAYMENT OF TAXES AND OTHER CLAIMS.........................37
    SECTION 4.07.  REPURCHASE AT THE OPTION OF HOLDERS UPON A
                   CHANGE OF CONTROL.........................................37
    SECTION 4.08.  LIMITATION ON ASSET SALES.................................39
    SECTION 4.09.  OWNERSHIP OF CAPITAL STOCK................................42
    SECTION 4.10.  UNRESTRICTED SUBSIDIARIES.................................42
    SECTION 4.11.  RESTRICTED PAYMENTS.......................................43
    SECTION 4.12.  INCURRENCE OF INDEBTEDNESS AND ISSUANCE OF PREFERRED
                   STOCK.....................................................45
    SECTION 4.13.  LIENS.....................................................47
    SECTION 4.14.  DIVIDENDS AND OTHER PAYMENT RESTRICTIONS
                   AFFECTING SUBSIDIARIES....................................47
    SECTION 4.15.  TRANSACTIONS WITH AFFILIATES..............................48
    SECTION 4.16.  REPORTS...................................................48
    SECTION 4.17.  WAIVER OF STAY, EXTENSION OR USURY LAWS...................49
    SECTION 4.18.  COMPLIANCE CERTIFICATE; NOTICE OF DEFAULT OR EVENT OF
                   DEFAULT...................................................49
    SECTION 4.19.  INVESTMENT COMPANY ACT....................................50
    SECTION 4.20.  SALE AND LEASEBACK........................................50
    SECTION 4.21.  FURTHER INSTRUMENTS AND ACTS..............................50

                                      ARTICLE V

CONSOLIDATION, MERGER,
CONVEYANCE, LEASE OR TRANSFER................................................50
    SECTION 5.01.  MERGER, CONSOLIDATION OR SALE OF ASSETS...................50
    SECTION 5.02.  SUCCESSOR CORPORATION SUBSTITUTED.........................51

                                      ARTICLE VI

DEFAULTS AND REMEDIES........................................................51
    SECTION 6.01.  EVENTS OF DEFAULT.........................................51
    SECTION 6.02.  ACCELERATION..............................................53
    SECTION 6.03.  OTHER REMEDIES............................................54
    SECTION 6.04.  WAIVER OF PAST DEFAULTS...................................54
    SECTION 6.05.  CONTROL BY MAJORITY.......................................54
    SECTION 6.06.  LIMITATION ON SUITS.......................................55


                                        -iii-

<PAGE>

    SECTION 6.07.  RIGHTS OF HOLDERS TO RECEIVE PAYMENT......................55
    SECTION 6.08.  TRUSTEE MAY FILE PROOFS OF CLAIM..........................56
    SECTION 6.09.  PRIORITIES................................................56
    SECTION 6.10.  UNDERTAKING FOR COSTS.....................................57
    SECTION 6.11.  WAIVER OF STAY OR EXTENSION LAWS..........................57
    SECTION 6.12.  TRUSTEE MAY ENFORCE CLAIMS WITHOUT
                   POSSESSION OF THE NOTES...................................57
    SECTION 6.13.  RESTORATION OF RIGHTS AND REMEDIES........................57
    SECTION 6.14.  RIGHTS AND REMEDIES CUMULATIVE............................58
    SECTION 6.15.  DELAY OR OMISSION NOT WAIVER..............................58

                                     ARTICLE VII

TRUSTEE......................................................................58
    SECTION 7.01.  DUTIES OF TRUSTEE.........................................58
    SECTION 7.02.  RIGHTS OF TRUSTEE.........................................59
    SECTION 7.03.  INDIVIDUAL RIGHTS OF TRUSTEE..............................60
    SECTION 7.04.  TRUSTEE'S DISCLAIMER......................................60
    SECTION 7.05.  NOTICE OF DEFAULTS........................................60
    SECTION 7.06.  PRESERVATION OF INFORMATION; REPORTS BY TRUSTEE TO
                   HOLDERS...................................................60
    SECTION 7.07.  COMPENSATION AND INDEMNITY................................61
    SECTION 7.08.  REPLACEMENT OF TRUSTEE....................................62
    SECTION 7.09.  SUCCESSOR TRUSTEE BY MERGER...............................64
    SECTION 7.10.  ELIGIBILITY; DISQUALIFICATION.............................65
    SECTION 7.11.  PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY.........65

                                     ARTICLE VIII

DEFEASANCE...................................................................66
    SECTION 8.01.  COMPANY'S OPTION TO EFFECT LEGAL DEFEASANCE
                   OR COVENANT DEFEASANCE....................................66
    SECTION 8.02.  LEGAL DEFEASANCE AND DISCHARGE............................66
    SECTION 8.03.  COVENANT DEFEASANCE.......................................67
    SECTION 8.04.  CONDITIONS TO DEFEASANCE OR COVENANT DEFEASANCE...........67
    SECTION 8.05.  DEPOSITED MONEY AND U.S. GOVERNMENT OBLIGATIONS
                   TO BE HELD IN TRUST; MISCELLANEOUS PROVISIONS.............69
    SECTION 8.06.  REINSTATEMENT.............................................69

                                      ARTICLE IX

AMENDMENTS...................................................................70
    SECTION 9.01.  WITHOUT CONSENT OF HOLDERS................................70
    SECTION 9.02.  WITH CONSENT OF HOLDERS...................................71
    SECTION 9.03.  EFFECT OF SUPPLEMENTAL INDENTURES.........................72


                                         -iv-

<PAGE>

    SECTION 9.04.  COMPLIANCE WITH TRUST INDENTURE ACT.......................72
    SECTION 9.05.  REVOCATION AND EFFECT OF CONSENTS AND WAIVERS.............72
    SECTION 9.06.  NOTATION ON OR EXCHANGE OF NOTES..........................72
    SECTION 9.07.  TRUSTEE TO EXECUTE SUPPLEMENTAL INDENTURES................73

                                      ARTICLE X

SUBSIDIARY GUARANTEES........................................................74
    SECTION 10.01. ADDITION OF SUBSIDIARY GUARANTORS.........................74
    SECTION 10.02. RELEASE OF A SUBSIDIARY GUARANTOR.........................74
    SECTION 10.03. SUBSIDIARY GUARANTORS MAY CONSOLIDATE, ETC., ON
                   CERTAIN TERMS.............................................75

                                      ARTICLE XI

MISCELLANEOUS................................................................76
    SECTION 11.01. TRUST INDENTURE ACT CONTROLS..............................76
    SECTION 11.02. NOTICES...................................................76
    SECTION 11.03. CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT........76
    SECTION 11.04. STATEMENTS REQUIRED IN CERTIFICATE OR OPINION.............77
    SECTION 11.05. RULES BY TRUSTEE, PAYING AGENT AND REGISTRAR..............77
    SECTION 11.06. PAYMENTS ON BUSINESS DAYS.................................77
    SECTION 11.07. GOVERNING LAW.............................................77
    SECTION 11.08. NO RECOURSE AGAINST OTHERS................................77
    SECTION 11.09. SUCCESSORS................................................77
    SECTION 11.10. COUNTERPARTS..............................................77
    SECTION 11.11. TABLE OF CONTENTS; HEADINGS...............................78
    SECTION 11.12. SEVERABILITY..............................................78
    SECTION 11.13. FURTHER INSTRUMENTS AND ACTS..............................78

EXHIBIT A     FORM OF GLOBAL NOTE
EXHIBIT B     FORM OF CERTIFICATED NOTE
EXHIBIT C     FORM OF SUBSIDIARY GUARANTEE


                                         -v-

<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, 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 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.

         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 to make this Indenture a valid
instrument of the Company 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.

         "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.


                                         -1-

<PAGE>

         "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 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,


                                         -2-

<PAGE>

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 4.15
hereof.

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

         "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


                                         -3-

<PAGE>

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 (other than any Principal Properties to
any Wholly Owned Subsidiary not a Subsidiary Guarantor) 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(d)
hereof.

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

         "ASSET SALE PURCHASE PRICE" has the meaning set forth in Section
    4.08(d) 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.

         "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.


                                         -4-

<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
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), (iv) in the case of a limited liability company,
membership interests, and (v) 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) 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


                                         -5-

<PAGE>

    "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 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); 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 or write-off 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


                                         -7-

<PAGE>

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 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 or write-off 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 (which shall initially be a
credit facility among the Company, NationsBank of Texas, N.A. or one of its
affiliates, as agent, and the other 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, extended, 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.

         "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.


                                         -9-


<PAGE>
         "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(c) 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 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 3 of the
Subsidiary Guarantees.

         "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.


                                         -10-

<PAGE>

         "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.

         "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 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


                                         -11-

<PAGE>

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 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


                                         -12-

<PAGE>



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.

         "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 except as provided in (b) below), 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, other than such losses arising out of the extinguishment of
Indebtedness refinanced from the proceeds of the Notes and other securities
issued contemporaneously with the Notes or Indebtedness that was refinanced in
June 1996 by such refinanced Indebtedness, (ii) any extraordinary or
nonrecurring gain (but not loss except as provided in (i) above), 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.


                                         -13-

<PAGE>

         "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 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 4.18 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


                                         -14-

<PAGE>

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.

         "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(b)(ii);
(d) Investments outstanding as of the date of this Indenture; (e) Investments in
Wholly Owned Subsidiaries that are 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.

         "PERMITTED LIENS" means (a) Liens existing on the date of the
Indenture; (b) Liens under the Credit Facility securing Indebtedness permitted
to be incurred in accordance with Section 4.12(b)(i); (c) Liens now or hereafter
securing any Hedging Obligations so long as the related Indebtedness is
permitted under Section 4.12(v) or (vi); (d) Liens securing Permitted
Refinancing Indebtedness; PROVIDED, that such Liens extend to or cover only the
property or assets currently securing the Indebtedness being refinanced;
(e) 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; (f) statutory landlords',
carriers', mechanics', workmen's, materialman's, operator's or similar Liens
arising in the ordinary course of business for sums not delinquent or 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; (g) easements, rights of way, restrictions and
other similar encumbrances or minor imperfections in title that, in the case of
any of the foregoing, were not incurred or created to secure the payment of


                                         -15-

<PAGE>

borrowed money or the deferred purchase price of property or services, and in
the aggregate do not materially and adversely affect the value of such
properties or materially impair use for the purposes of which such properties
are held by the Company or any Subsidiaries; (h) Liens on, or related to,
properties to secure all or part of the costs (other than Indebtedness) incurred
in the ordinary course of business of exploration, drilling, development or
operation thereof; (i) 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; (j) Liens on
deposits made in the ordinary course of business; (k) Liens in favor of
collecting or payor banks having a right of set-off, 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; (l) Liens on pipeline or pipeline
facilities which arise out of operation of law; (m) 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; (n) liens reserved in oil and gas
leases for bonus or rental payments and for compliance with the terms of such
leases; (o) 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 and that do not secure Indebtedness,
(p) (i) Liens upon any property of any Person existing at the time of
acquisition thereof by the Company or a Subsidiary, (ii) Liens upon any property
of a Person existing at the time such Person is merged or consolidated with the
Company or any Subsidiary or existing at the time of the sale or transfer of any
such property of such Person to the Company or any Subsidiary, or (iii) Liens
upon any property of a Person existing at the time such Person becomes a
Subsidiary; PROVIDED, that in each case such Lien has not been created in
contemplation of such sale, merger, consolidation, transfer or acquisition, and
PROVIDED that in each such case no such Lien shall extend to or cover any
property of the Company or any Subsidiary other than the property being acquired
and improvements thereon; (q) purchase money Liens granted in connection with
the acquisition of assets, PROVIDED, that (i) such Liens attach only to the
assets so acquired with the purchase money indebtedness secured thereby,
(ii) such Liens secure only Indebtedness that is not in excess of 100% of the
purchase price of such assets, and (iii) such Liens attach no later than 180
days after the acquisition of such assets; and (r)  Liens securing Indebtedness
incurred as a result of extensions, renewals or replacements of Indebtedness
secured by Liens permitted by clauses (p) or (q) provided that (i) the principal
amount of the Indebtedness so issued and secured by such Lien shall not exceed
the principal amount of the Indebtedness so extended, renewed, replaced,
exchanged or refinanced and (ii) the Indebtedness so issued and secured by such
Lien shall not be secured by any property or assets of the Company or any
Subsidiary other than the property or assets subject to the Liens securing such
Indebtedness being exchanged or refinanced.

         "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


                                         -16-

<PAGE>

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.

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

         "PRINCIPAL PROPERTIES" means the oil and gas properties and other
tangible assets and properties owned by Company on the date of this Indenture
(collectively, the "Original Principal Properties") and assets and properties of
the Company obtained in exchange for any of the Original Principal Properties.

         "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.

         "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.


                                         -17-

<PAGE>

         "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.

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

         "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.


                                         -18-

<PAGE>

         "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.

         "SUBORDINATED INDEBTEDNESS" means any Indebtedness of the Company or
any of its Subsidiaries (whether outstanding on the date of the Indenture or
thereafter incurred) that is contractually subordinate or junior in right of
payment of principal, premium and interest to the Notes or the Subsidiary
Guarantees.

         "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 this Indenture.

         "SUBSIDIARY GUARANTEE" means the guarantee of the Notes by a
Subsidiary Guarantor pursuant to Exhibit C and Article X under which such
Subsidiary Guarantor guarantees the Notes.

         "SUBSIDIARY GUARANTOR" means each of the Subsidiaries that agrees to
guarantee the Notes.

         "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 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.


                                         -19-

<PAGE>

         "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.

         "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


                                         -20-


<PAGE>

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 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.

         "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;


                                         -21-

<PAGE>

         (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 of the Company 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 of the Company stating that the information with
respect to such factual matters is in the possession of the Company or such
Subsidiary, 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.

         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 Subsidiaries of the Company.  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 Subsidiaries of the Company, if made in the manner provided
in this Section.


                                         -22-

<PAGE>

         (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 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, the Notes and the Subsidiary Guarantees 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


                                         -23-

<PAGE>

on any Notes or any Subsidiary Guarantee 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.  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


                                         -24-


<PAGE>

         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.  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.

         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 preceding
paragraphs of this Section 2.02, 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.


                                         -25-

<PAGE>

         Upon the occurrence of any event specified in Section 2.06(a) hereof
and compliance by the Company with the provisions of the paragraphs preceding
this 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 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


                                         -26-

<PAGE>

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 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


                                         -27-

<PAGE>

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.

         (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.


                                         -28-

<PAGE>

         (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.

         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.


                                         -29-

<PAGE>

         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 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


                                         -30-

<PAGE>

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 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


                                         -31-


<PAGE>

    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 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


                                         -32-

<PAGE>

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

         (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;


                                         -33-

<PAGE>

         (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.

         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


                                         -34-

<PAGE>

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 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.


                                         -35-

<PAGE>

         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 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.


                                         -36-

<PAGE>

         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;

         (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


                                         -37-

<PAGE>

    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 (i)
accept for payment all Notes or portions thereof properly tendered pursuant to
the Change of Control Offer, (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 Change of Control 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 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 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


                                         -38-

<PAGE>

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.

         SECTION 4.08.  LIMITATION ON ASSET SALES. (a)  The Company shall not
directly or indirectly engage in an Asset Sale of any Principal Properties to
any Subsidiary other than a Subsidiary Guarantor.

         (b)  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.

         (c)  The Company may apply Net Proceeds of an Asset Sale, at its
option, (i) to permanently reduce Senior Indebtedness other than Senior
Revolving Indebtedness, (ii) to permanently reduce Senior Revolving Indebtedness
(and to correspondingly reduce commitments with respect thereto), or (iii) 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.


                                         -39-

<PAGE>

         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."

         (d)  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(e) 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.

         (e)  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 all 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 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,


                                         -40-

<PAGE>

    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.

         (f)  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(e) 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.

         (g)  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(f) 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 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.

         (h)  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


                                         -41-

<PAGE>

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.

         (i)  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.

         (j)  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 4.09.  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 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) 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.

         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


                                         -42-

<PAGE>

the Company or such Subsidiary with an unrelated Person and as otherwise
permitted under Section 4.11.  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 Subsidiary Guarantee,
supplemental indenture or other agreement 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 Subsidiary
Guarantee, supplemental indenture or other agreement 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.

         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 the Company or 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 Subordinated
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


                                         -43-

<PAGE>

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 day of the fiscal month which this Indenture was
    executed and delivered 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 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


                                         -44-

<PAGE>

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 Subordinated 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 Subordinated 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 of the
Company set forth in an Officers' Certificate of the Company 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, subject to Section 4.12(c), 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 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



                                         -45-

<PAGE>

may be incurred pursuant to this paragraph, unless the guaranteed Indebtedness
is incurred by the Company pursuant to this paragraph.

         (b)  The foregoing provisions, subject to Section 4.12(c), 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 the greater of (x) $50 million and (y) 15% of Adjusted Consolidated
    Net Tangible Assets, in each case, 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 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;


                                         -46-

<PAGE>

              (vii)     the incurrence by the Subsidiaries of Indebtedness in
    existence on the date of this Indenture listed on Schedule 4.12(b)(viii)
    attached to this Indenture; and

              (viii)    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;

PROVIDED that no Subsidiary may incur any Indebtedness other than Indebtedness
described in Section 4.12(b)(iv) or (vii) unless such Subsidiary shall have
executed and delivered a Subsidiary Guarantee and such Subsidiary Guarantee
shall be in full force and effect (except to the extent Section 10.02 hereof
would result in the release thereof) so long as such Indebtedness remains
outstanding.

              (c)   The Company will not, directly or indirectly, in any event
incur any Indebtedness which by its terms (or by the terms of any agreement
governing such Indebtedness) is subordinated to any other Indebtedness of the
Company unless such Indebtedness is also by its terms (or by the terms of any
agreement governing such Indebtedness) made expressly subordinate to the Notes
to the same extent and in the same manner as such Indebtedness is subordinated
pursuant to subordination provisions that are most favorable to the holders of
any other Indebtedness of the Company.

         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 on any of their respective assets,
now owned or hereafter acquired, securing any Indebtedness of the Company or any
of its Subsidiaries, unless the Notes in the case of such Indebtedness of the
Company, the Subsidiary Guarantee of such Subsidiary Guarantor, in the case of
such Indebtedness of a Subsidiary Guarantor, are secured equally and ratably
with such other Indebtedness; PROVIDED that, if such Indebtedness is by its
terms expressly subordinate to the Notes or the Subsidiary Guarantees, the Lien
securing such subordinate or junior Indebtedness shall be subordinate and junior
to the Lien securing the Notes or the Subsidiary Guarantees with the same
relative priority as such subordinated or junior Indebtedness shall have with
respect to the Notes or the Subsidiary Guarantees, as the case may be.

         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,


                                         -47-

<PAGE>

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.

         SECTION 4.15.  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 $1.0 million, a resolution of the Board of
Directors of the Company 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 of the Company 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 4.16.  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.


                                         -48-

<PAGE>

         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).

         SECTION 4.17.  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 4.18.  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 4.18(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 4.16 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.


                                         -49-

<PAGE>

         SECTION 4.19.  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.

         SECTION 4.20.  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, (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,
and (c) such Net Proceeds are applied in accordance with Section 4.08.

         SECTION 4.21.  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 5.01.  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



                                         -50-

<PAGE>

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.

         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 5.02.  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 6.01.  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; 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; or


                                         -51-

<PAGE>

         (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

         (d)  the Company or any Subsidiary fails to comply with any of its
    other agreements or covenants in, or provisions of, the Notes, this
    Indenture or any Subsidiary Guarantee 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


                                         -52-

    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 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 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 (other
    than pursuant to Section 10.02 hereof), 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 6.02.  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.


                                         -53-

<PAGE>

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

         SECTION 6.03.  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, the Subsidiary Guarantors 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, the Subsidiary Guarantors 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 6.04.  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 6.05.  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


                                         -54-

<PAGE>

conducting any proceeding for any remedy available to the Trustee or exercising
any trust or power conferred on the Trustee; PROVIDED that:

         (a)  such direction shall not be in conflict with any rule of law or
    with this Indenture of the Subsidiary Guarantees 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 6.06.  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 of the Subsidiary Guarantees, except in the manner herein provided and
for the equal and ratable benefit of all Holders of Notes.

         SECTION 6.07.  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


                                         -55-

<PAGE>

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.

         SECTION 6.08.  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 or other obligor 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 6.09.  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


                                         -56-

<PAGE>


         (c)  THIRD: To the Company.

         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 or the Subsidiary Guarantees; 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 or in the Subsidiary
Guarantees 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 or the Subsidiary Guarantees 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


                                         -57-

<PAGE>

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.

         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 7.01.  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


                                         -58-

<PAGE>

it takes or omits to take in good faith in accordance with a direction received
by it pursuant to Section 6.05 hereof.

         (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 7.02.  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 11.02 hereof from the Company or any Holder of Notes.


                                         -59-

<PAGE>

         (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, 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 7.03.  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 7.04.  TRUSTEE'S DISCLAIMER.  The Trustee shall not be
responsible for and makes no representation as to the validity or adequacy of
this Indenture, the Subsidiary Guarantees 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 or the Subsidiary Guarantors
in this Indenture or the Subsidiary Guarantees, 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 7.05.  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 7.06.  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


                                         -60-

<PAGE>

              (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 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 7.07.  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.


                                         -61-

<PAGE>

         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.

         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.


                                         -62-

<PAGE>

         (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 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


                                         -63-

<PAGE>

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.

         (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


                                         -64-

<PAGE>

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

              (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.



                                         -65-

<PAGE>

                                     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 of the Company
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 and each Subsidiary Guarantor from its obligations with respect to its
Subsidiary Guarantee as provided in this Section 8.02 on and after the date the
conditions set forth 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, the
Subsidiary Guarantees 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 the Subsidiary Guarantees.

         (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.


                                         -66-

<PAGE>

         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 4.16, 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 4.16,
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 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


                                         -67-

<PAGE>

    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.

         (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.


                                         -68-

<PAGE>

         (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 8.05.  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.

         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 8.06.  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, the Subsidiary Guarantee and such Notes
from which the Company and the Subsidiary Guarantors have 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.


                                         -69-

<PAGE>

                                      ARTICLE IX

                                      AMENDMENTS

         SECTION 9.01.  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 or execute and deliver any Subsidiary Guarantee
or amendment or supplement thereto, 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 or its Subsidiaries, for
    the benefit of the Holders of all of the Notes, or to surrender any right
    or power herein conferred upon the Company or its Subsidiaries; 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 the Subsidiary Guarantees; or

         (g)   to cure any ambiguity herein, or to correct or supplement any
    provision hereof or the Subsidiary Guarantees 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 10.02; or

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


                                         -70-

<PAGE>

         SECTION 9.02.  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 or amendments or supplements to the Subsidiary Guarantees
for the purpose of adding any provisions to or changing in any manner or
eliminating any of the provisions of this Indenture or the Subsidiary Guarantees
or of modifying in any manner the rights of the Holders (including Section 4.07
and Section 4.08 hereof); PROVIDED that no such supplement or amendment 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;

         (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 or the Subsidiary
    Guarantees relating to the relative ranking of the Notes or the Subsidiary
    Guarantees in a manner adverse to the Holders thereof.



                                         -71-

<PAGE>

         It shall not be necessary for any Act of Holders under this Section
9.02 to approve the particular form of any proposed supplement or amendment, 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 or other amendment under this Article IX, this
Indenture or the Subsidiary Guarantees, as the case may be, shall be modified in
accordance therewith, and such supplemental indenture or other amendment shall
form a part of this Indenture or the Subsidiary Guarantees, as the case may be,
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, the Subsidiary Guarantees 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 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


                                         -72-

<PAGE>

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 or other amendment 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 or other amendment.  In executing any supplemental indenture or other
amendment, 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 or other amendment 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 or any Subsidiary Guarantor, as the case may be, has
    all necessary corporate power and authority to execute and deliver the
    supplemental indenture or other amendment and that the execution, delivery
    and performance of such supplemental indenture or other amendment has been
    duly authorized by all necessary corporate action of the Company or such
    Subsidiary Guarantor;

         (c)  the execution, delivery and performance of the supplemental
    indenture or other amendment 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 such Subsidiary Guarantor, or (iii) any material agreement or
    instrument to which the Company or such Subsidiary Guarantor 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 or other amendment 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 such Subsidiary Guarantor, or
    (ii) any material order, writ, injunction or decree of any court or
    governmental instrumentality applicable to the Company or such Subsidiary
    Guarantor;

         (e)  such supplemental indenture or other agreement has been duly and
    validly executed and delivered by the Company or such Subsidiary Guarantor,
    and this Indenture or Subsidiary Guarantee, as the case may be, together
    with such supplemental indenture or other agreement constitutes a legal,
    valid and binding obligation of the Company or such Subsidiary Guarantor
    enforceable against such Person in accordance with its terms, except as
    such enforceability may


                                         -73-

<PAGE>

be limited by applicable bankruptcy, insolvency or similar laws affecting the
enforcement of creditors' rights generally and general equitable principles; and

         (f)  this Indenture or Subsidiary Guarantee, as the case may be,
    together with such amendment or supplement complies with the Trust
    Indenture Act.

                                      ARTICLE X

                                SUBSIDIARY GUARANTEES

         SECTION 10.01. ADDITION OF SUBSIDIARY GUARANTORS.

         (a)  The Company agrees to cause each Subsidiary to execute and
deliver a Subsidiary Guarantee in the form of Exhibit C attached hereto pursuant
to which such Subsidiary guarantees the payment of the Notes at or before such
Subsidiary incurs any Indebtedness other than Indebtedness described in Section
4.12(b)(iv) or (vii).

         (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 Subsidiary Guarantee in the form of Exhibit C attached hereto
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 be acceptable to the Trustee in its discretion and provided
that no opinion need be rendered concerning the enforceability of the Subsidiary
Guarantee).

         SECTION 10.02. 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 10.03 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.


                                         -74-

<PAGE>

         (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 X.

         (d)  Any Subsidiary Guarantor not released in accordance with this
Section 10.02 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
X and the Subsidiary Guarantees.

         SECTION 10.03. 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 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 10.02 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, 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, Subsidiary
Guarantee or other instrument 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 Section
10.02 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, Subsidiary Guarantee or other instrument and
shall not have to assume such Subsidiary Guarantor's Subsidiary Guarantee).  In
the case of any such consolidation, merger, sale,


                                         -75-

<PAGE>

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.

                                      ARTICLE XI

                                    MISCELLANEOUS

         SECTION 11.01. 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 11.02. 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 11.03. 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 (b) an Opinion of Counsel stating
that, in the opinion of such counsel, all such conditions precedent have been
complied with.


                                         -76-

<PAGE>

         SECTION 11.04. 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 4.18 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 11.05. 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 11.06. 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 11.07. 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 11.08. 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, the Subsidiary Guarantees 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 11.09. 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.

         SECTION 11.10. 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


                                         -77-

<PAGE>

shall be deemed to be an original and all of which taken together shall
constitute one and the same agreement.

         SECTION 11.11. 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 11.12. 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 11.13. 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 COMPANY,
                                       as Trustee


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


                                         -78-

<PAGE>

STATE OF TEXAS          )
                        )              SS.:
COUNTY OF HARRIS        )

         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 Texas
                                       My commission expires
                                                            -------------

[Seal]


STATE OF TEXAS          )
                        )              SS.:
COUNTY OF HARRIS        )

         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 Texas
                                       My commission expires
                                                            --------------
[Seal]


                                         -79-

<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. AND THE TRUSTEE
     NAMED THEREIN, PURSUANT TO WHICH THIS NOTE WAS ISSUED.

<PAGE>

                                     GLOBAL NOTE

                       REPRESENTING ____% SENIOR 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 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 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 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, subsidiaries of the Company that have guaranteed the payment of the
Notes (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, pay dividends or make certain other restricted payments,
apply net proceeds from certain asset sales, enter into certain transactions
with affiliates, incur indebtedness, 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


                                         A-3

<PAGE>

most 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 4.16 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, the Subsidiary Guarantees 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 and the Subsidiary Guarantees, without the consent of any Holder of
Notes, the Company, the Subsidiary Guarantors and the Trustee may amend the
Indenture, the Subsidiary Guarantees 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 contained in its Subsidiary Guarantee; (ii) to add
additional covenants or to


                                         A-8

<PAGE>

surrender rights and powers conferred on the Company or any Subsidiary; (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 or the Subsidiary Guarantees; (vii) to cure any
ambiguity in the Indenture or the Subsidiary Guarantees, to correct or
supplement any provision in the Indenture or the Subsidiary Guarantees 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.  SUBSIDIARY GUARANTEE.

          Subject to the limitations set forth in the Indenture and the
Subsidiary Guarantees, the payment of principal of, premium, if any, and
interest on the Notes will be guaranteed by each Subsidiary Guarantor.

     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.


                                         A-9

<PAGE>

     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, the
Subsidiary Guarantees 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


                                         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           Notation
               Decrease in    Increase in    Maturity            Made by
Date of        Principal      Principal      Following such      or on
Decrease/      Amount at      Amount at      Decrease/           Behalf of
Increase       Maturity       Maturity       Increase            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>

                          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 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 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 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
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 subsidiaries of
the Company that have guaranteed the payment of the Notes (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, pay dividends or make certain other restricted payments,
apply net proceeds from certain asset sales, enter into certain transactions
with affiliates, incur indebtedness, 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


                                         B-3

<PAGE>

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.


                                         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 4.16 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, the Subsidiary Guarantees 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 and the Subsidiary Guarantees, without the consent of any Holder of
Notes, the Company, the Subsidiary Guarantors and the Trustee may amend the
Indenture, the Subsidiary Guarantees or the Notes (i) to evidence the succession
of another Person to (A) the Company and the assumption by


                                         B-7

<PAGE>

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; (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 or the Subsidiary Guarantees; (vii) to cure any ambiguity in
the Indenture or the Subsidiary Guarantees, to correct or supplement any
provision in the Indenture or the Subsidiary Guarantees 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.  SUBSIDIARY GUARANTEE.

          Subject to the limitations set forth in the Indenture and the
Subsidiary Guarantees, 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.

     16.  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


                                         B-8

<PAGE>

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.

     17.  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, the
Subsidiary Guarantees 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.

     18.  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 C

                                 SUBSIDIARY GUARANTEE

          This Subsidiary Guarantee, dated as of ___________________, (this
"Subsidiary Guarantee" and together with all such guarantees delivered from time
to time under Article X of the Indenture referred to below being referred to
herein as the "Subsidiary Guarantees") is made by ____ and ______________ (each
a "Subsidiary Guarantor" and collectively, the "Subsidiary Guarantors") in favor
of STATE STREET BANK AND TRUST COMPANY as Trustee (together with its successors
and assigns in such capacity, the "Trustee") under the Indenture (as amended or
modified from time to time, the "Indenture") dated as of _____, 1996 made by
Costilla Energy, Inc., a Delaware corporation (the "Company"), pursuant to which
the Company issued its __% Senior Notes due 2006 (the "Notes"). Unless otherwise
defined herein, capitalized terms used herein have the meanings assigned to such
terms in the Indenture.

          WHEREAS, pursuant to Section 4.12(b) of the Indenture, each Subsidiary
Guarantor is prohibited from incurring certain Indebtedness without executing
and delivering a Subsidiary Guarantee; and

          WHEREAS, the Subsidiary Guarantor wishes to incur such Indebtedness;

          NOW THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the Subsidiary Guarantor agrees as follows:

          SECTION 1.  UNCONDITIONAL GUARANTEE.

          Each Subsidiary Guarantor hereby, jointly and severally,
unconditionally 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 the Indenture and the Notes by the
Company, whether at maturity, by acceleration, redemption, repurchase or
otherwise, including, without limitation, interest on the 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 2.

          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 Guarantor hereby agrees that its
obligations hereunder shall be unconditional irrespective of the validity,
regularity or enforceability of the Notes, the Indenture or any other Subsidiary
Guarantee, 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 or any other Subsidiary Guarantor,
any action to enforce the same or any other circumstance which might otherwise
constitute a legal or equitable discharge or defense of any


                                         C-1

<PAGE>

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 or any other Subsidiary Guarantor, 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 VI of the Indenture 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 VI of the Indenture 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 2.  LIMITATION OF SUBSIDIARY GUARANTOR'S LIABILITY.

          Each Subsidiary Guarantor and, by its acceptance of its Note, 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
Guarantees shall be limited to the maximum amount as will, after giving effect
to all other contingent and fixed liabilities of such Subsidiary Guarantors 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 Guarantees or pursuant to Section 3,
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 2 is for the benefit of the
creditors of each Subsidiary Guarantor.

          SECTION 3.  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 Guarantees,
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



                                         C-2

<PAGE>

the Funding Guarantor in discharging the Company's obligations with respect to
the Notes or, subject to this Section 3, any other Subsidiary Guarantor's
obligations with respect to the Subsidiary Guarantees.

          SECTION 4.  AMENDMENTS.  The provisions of this Subsidiary Guarantee
shall not be amended or modified except in accordance with Article IX of the
Indenture.

          SECTION 5.  REPRESENTATIONS AND WARRANTIES.  Each Subsidiary Guarantor
hereby represents and warrants as follows:

          (a)  Such Subsidiary Guarantor is (i) a duly organized, validly
existing and in good standing under the laws of the jurisdiction of its
organization, (ii) has all requisite power and authority to own or lease and
operate its properties and to carry on its business as now conducted and as
proposed to be conducted; and (iii) is duly qualified or licensed to do business
as a foreign [corporation] and is in good standing in all jurisdictions in which
it owns or leases assets and property or in which the conduct of its business
requires it to so qualify or be licensed except where the failure to so qualify
or be licensed would not have a material adverse effect on the operations,
business, prospects, assets, properties or condition (financial or other) of the
Company and its Subsidiaries, including such Guarantor, considered as one
enterprise.

          (b)  The execution, delivery and performance by such Subsidiary
Guarantor of this Subsidiary Guarantee, have been duly authorized by all
necessary corporate or other action on the part of such Subsidiary Guarantor and
do not and will not violate any provision of the articles or certificate of
incorporation or by-laws or other charter documents of such Subsidiary Guarantor
and do not and will not violate, or be in conflict with, or constitute a default
under, or permit the termination of, or result in the creation of any Lien
(other than a Permitted Lien) upon any property of such Subsidiary Guarantor
under (x) any statute or law or any judgment, decree, order, regulation or rule
of any court or governmental authority to which such Subsidiary Guarantor or any
of its properties may be subject, or (y) any contract, indenture, mortgage, loan
agreement, note, lease or other agreement or instrument to which such Subsidiary
Guarantor is a party or by which it may be bound, or to which any of its
properties may be subject, which conflict, default, termination or Lien would
have a material adverse effect upon the operations, business, prospects, assets,
properties or condition (financial or other) of the Company and its
Subsidiaries, including such Subsidiary Guarantor, considered as one enterprise.
This Subsidiary Guarantee is the legal, valid and binding obligation of such
Subsidiary Guarantor, enforceable against such Subsidiary Guarantor in
accordance with its terms, except as enforcement thereof may be limited by
bankruptcy, insolvency, reorganization or other similar laws affecting
enforcement of creditors rights generally and except as enforcement thereof is
subject to general principles of equity (regardless of whether enforcement is
considered in a proceeding in equity or at law).

          (c)  No authorization, consent, approval or other action by, and no
notice to or filing with, any court, governmental, administrative or judicial
authority or regulatory body


                                         C-3

<PAGE>


(domestic or foreign) is required for the due execution, delivery or performance
by such Subsidiary Guarantor of this Subsidiary Guarantee.

          SECTION 6.  ADDRESSES FOR NOTICES.  All notices, requests, demands and
other communications provided for or permitted hereunder shall be in writing
(including telegraphic communication) and, if to any Subsidiary Guarantor,
mailed or telegraphed or delivered to it, addressed to it at the address of the
Company specified in the Indenture, if to Trustee, addressed to it at the
address specified in the Indenture, or as to each party at such other address as
shall be designated by such party in a written notice to each other party
complying as to delivery with the terms of this Section 17.

          SECTION 7.  NO WAIVER; REMEDIES.  No failure on the part of the
Trustee or any Holder, to exercise, and no delay in exercising, an right
hereunder shall operate as a waiver thereof; nor shall any single or partial
exercise of any right hereunder preclude any other or further exercise thereof
or the exercise of any other right. The remedies herein provided are cumulative
and not exclusive of any remedies provided by law or any other agreement.

          SECTION 8.  CONTINUING GUARANTY; TRANSFER OF NOTES; TERMINATION OF
GUARANTY.

          (a)  This Subsidiary Guarantee is a continuing guaranty and, subject
to the provisions of subsection (b) below, shall (i) remain in full force and
effect until payment in full of the Notes and all other amounts payable under
this Subsidiary Guarantee, (ii) be binding upon each Subsidiary Guarantor, its
successors and assigns, and (iii) inure to the benefit of and be enforceable by
the Trustee and its successors, transferees and assigns.

          (b)  All obligations of a particular Subsidiary Guarantor hereunder
shall automatically terminate as set forth in Section 10.02 of the Indenture
enforceable in such jurisdiction and such illegal, invalid or unenforceable
provision shall be legal, valid and enforceable in all other jurisdictions.

          SECTION 9.  INDENTURE OBLIGATIONS.  Each Subsidiary Guarantor agrees
to perform the obligations of a Subsidiary Guarantor under the Indenture.

          SECTION 10.  GOVERNING LAW.  THIS SUBSIDIARY GUARANTEE SHALL BE
GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK,
UNITED STATES.

          SECTION 10.  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.


                                         C-4

<PAGE>

          IN WITNESS WHEREOF, each Subsidiary Guarantor has caused this
Subsidiary Guarantee to be duly executed and delivered by its officer thereunto
duly authorized as of the date first above written.

                                             [LIST OF SUBSIDIARY GUARANTORS]

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


<PAGE>
                                                                  EXHIBIT 5.1

                     COTTON, BLEDSOE, TIGHE & DAWSON
                       A PROFESSIONAL CORPORATION
                            ATTORNEYS AT LAW
                                SUITE 300
                           500 WEST ILLINOIS
                        MIDLAND, TEXAS 79701-4337
                       P.O. BOX 2776 ZIP 79702-2776
                         TELEPHONE (915) 684-5782
                            FAX (915) 682-3672


                            September 24, 1996



Costilla Energy, Inc.
400 West Illinois, Suite 1000
Midland, Texas 79701

Re: Registration Statement on Form S-1
    (Registration No. 333-08909)

Gentlemen:

   
   We have acted as counsel for Costilla Energy, Inc., a Delaware corporation 
(the "Company") in connection with the registration under the Securities Act 
of 1933, as amended (the "Act"), of $100,000,000 of ____% Senior Notes due 
2006 (the "Notes") of the Company to be sold to the several Underwriters to 
be named in Schedule 1 (collectively, the "Underwriters") attached to the 
Underwriting Agreement (the "Underwriting Agreement") to be entered into by 
and between the Underwriters, for whom NationsBanc Capital Markets, Inc. and 
Prudential Securities Incorporated are acting as representatives, the 
Company, and Costilla Energy, L.L.C.  A Registration Statement on Form S-1 
(Registration No. 333-08909) covering the sale of the Notes was filed under 
the Act with the Securities and Exchange Commission (the "Commission") on 
July 26, 1996, as amended by Amendment No. 1 filed with the Commission 
on August 30, 1996 and Amendment No. 2 to be filed with the Commission
on September 24, 1996, and as further amended (the "Registration Statement").
    

   In reaching the conclusions expressed in this opinion, we have examined 
signed copies of the Registration Statement and all exhibits thereto.  We 
have also examined and relied upon originals, or copies certified to our 
satisfaction, of (i) the Certificate of Incorporation

<PAGE>

Costilla Energy, Inc.
September 24, 1996
Page 2



and Bylaws of the Company, (ii) minutes and records of the corporate 
proceedings of the Company with respect to the issuance of the Notes and 
related matters, (iii) the form of Underwriting Agreement, and (iv) such other 
agreements and instruments relating to the Company as we have deemed necessary 
or appropriate for the purposes of the opinions hereinafter expressed.  In 
rendering such opinions, we have relied, to the extent we deemed reasonable, 
on certificates and certain other information provided to us by officers of the
Company and public officials as to matters of fact of which the maker of such 
certificates or the person providing such information had knowledge, without 
investigation into or verification of such information.  Furthermore, in 
rendering such opinions we have assumed that the signatures on all documents 
examined by us are genuine, that all documents and corporate record books 
submitted to us as originals are authentic, accurate and complete, and that all
documents submitted to use as copies are true, correct and complete copies of 
the originals thereof.  We have also assumed that the Underwriting Agreement 
will be executed in substantially the same form as presented to us.

   Based solely upon the foregoing, subject to the assumptions, limitations 
and qualifications set forth herein, and specifically limited in all respects 
to the laws of the State of Texas, of the United States of America and the 
General Corporation Law of the State of Delaware, we are of the opinion that 
the Notes registered pursuant to the Registration Statement have been duly 
and validly authorized by the Company and, when paid for, issued or sold and 
delivered in accordance with the terms of the Underwriting Agreement and the 
Registration Statement, will be binding obligations of the Company, subject 
to applicable bankruptcy, insolvency, reorganization, fraudulent transfer, 
moratorium or similar laws affecting creditors' rights severally and to 
general principles of equity and the availability of equitable remedies.  
Please note in this regard that we are not licensed to practice law in the 
State of Delaware, but have reviewed Delaware law in connection with the 
opinions expressed herein.

   We hereby consent to the use of this opinion as an exhibit to the 
Registration Statement and to the reference to this Firm under the caption 
"Legal Matters" in the Prospectus forming a part of the Registration 
Statement.  In giving this consent we do not thereby admit that we come 
within the category of persons whose consent is required under the Act or the 
rules and regulations of the Commission promulgated thereunder.

   
   This opinion is rendered only to the Company and solely for the benefit of 
the Company, its stockholders and the Commission in connection with the 
registration and the issuance of the Notes pursuant to the Registration 
Statement.  This opinion may not be otherwise used,
    

<PAGE>

Costilla Energy, Inc.
September 24, 1996
Page 3



circulated, quoted, relied upon, or referred to by you or the Commission for 
any other purpose or by any other person, firm or corporation for any 
purpose, without our prior written consent.


                                           Yours very truly,

                                   COTTON, BLEDSOE, TIGHE & DAWSON


                                   By:    /s/ Richard T. McMillan
                                      ------------------------------
                                           Richard T. McMillan



<PAGE>


September 20, 1996


Costilla Energy, Inc.
400 West Illinois Avenue, 10th Floor
Midland, Texas  79701
Attn: Michael J. Grella

Dear Mike:

We are pleased to advise you that NationsBank of Texas, N.A. ("NATIONSBANK")
hereby commits (the "COMMITMENT"), subject to the terms and conditions outlined
in this letter and in the Summary of Terms and Conditions attached hereto,
incorporated herein and made a part hereof (collectively, this "COMMITMENT
LETTER") that it will make available to you a credit facility in an amount up to
$50,000,000 (the "CREDIT FACILITY").  Proceeds of the Credit Facility will be
used as provided in the Summary of Terms and Conditions.

The Commitment is conditioned upon the preparation, execution and delivery of
such documents in form and substance satisfactory to us and our counsel (the
"DEFINITIVE DOCUMENTS"), upon the resolution to our satisfaction of any legal or
structural issues in connection with the Credit Facility, and upon the absence
of a material adverse change in Costilla's financial condition, operations,
prospects or properties from that reflected in the information delivered to
NationsBank or any of its affiliates in connection with the transaction
contemplated by this Commitment Letter.  The Commitment is also subject to (i)
the completion of such legal and financial review as we determine to be
necessary, (ii) the absence of any factors which we determine from such review
to adversely affect our ability to offer the Credit Facility as set forth in the
attached Summary of Terms and Conditions, and (iii) the satisfaction of all
conditions set forth in this Commitment Letter.

Neither this Commitment Letter nor the Commitment is assignable by you.  Nothing
in this Commitment Letter, express or implied, shall give any person, other than
the parties hereto, any benefit or any legal or equitable right, remedy or claim
under this Commitment Letter.  Furthermore, this Commitment Letter is
confidential and may not be disclosed to any person or entity except Costilla's
officers, directors, employees and professional advisors.


<PAGE>

Mr. Michael J. Grella
September 20, 1996
Page 2

Costilla agrees to pay NationsBank the fees and expenses as set forth in the
attached Summary of Terms and Conditions.  In addition, Costilla agrees to
indemnify and hold NationsBank and its affiliates harmless from and against any
and all liabilities, claims, losses, damages, penalties, costs, or expenses
(including without limitation, reasonable fees and expenses of counsel)  of any
kind or nature whatsoever which in any way or to any extent may be imposed on,
incurred by, or asserted against us in connection with this Commitment Letter,
the Definitive Documents, or any of the negotiations, transactions and events at
any time associated therewith or contemplated therein except for any of the
foregoing arising from the gross negligence or willful misconduct of NationsBank
or its affiliates, and upon demand from time to time, to reimburse NationsBank
and its affiliates for all reasonable out-of-pocket costs, expenses and other
payments, including but not limited to, reasonable legal fees and disbursements
incurred or made in connection with the Commitment and the preparation,
execution and delivery of the Definitive Documents, regardless of whether or not
the Definitive Documents are executed.

Additionally, Costilla agrees to allow NationsBank or any of its affiliates to
reference this Commitment for the benefit of promoting NationsBank or such
affiliate.

This Commitment Letter (including the attached Summary of Terms and Conditions)
sets forth the entire understanding of the parties as to the scope of the
Commitment and the obligation of NationsBank with respect thereto.  The
Commitment will expire at 5:00 PM Midland, Texas time on September 23, 1996
unless accepted prior to such time.  The Commitment will also expire on October
15, 1996 if by such date you have not executed and delivered Definitive
Documents acceptable to us as contemplated in the attached Summary of Terms and
Conditions.

This Commitment Letter shall be governed by, and construed in accordance with,
the laws of the State of Texas as applied to contracts made and performed within
such state, without giving effect to the principles of conflicts of laws
thereof.  To the fullest extent permitted by applicable law, each of NationsBank
and Costilla hereby irrevocably submit to the jurisdiction of any Texas court or
Federal court sitting in Texas, in respect of any suit, action or proceeding
arising out of or relating to the Commitment, this Commitment Letter or the
Definitive Documents and agree that any such suit, action or proceeding may be
heard and determined in any such court.  Each of NationsBank and Costilla waive,
to the fullest extent permitted by applicable law, any objection which it may
now or hereafter have to the laying of the venue of any such suit, action or
proceedings brought in any such court, and any claim that any such suit, action
or proceeding brought in any such court has been brought in an inconvenient
forum.


<PAGE>

Mr. Michael J. Grella
September 20, 1996
Page 3

This Commitment Letter (including the summary of Terms and Conditions) replaces
in its entirety the original Commitment Letter dated as of August 27, 1996
between you and NationsBank, which original Commitment Letter shall hereafter be
null and void.  The $50,000 payment made under the original Commitment Letter
will be applied to the $50,000 payment required under this Commitment Letter.

Please indicate your acceptance of the Commitment and your agreement to the
matters contained in this Commitment Letter by executing this document and
returning it to us at or before 5:00 PM September 23, 1996, together with 
one-fifth of the underwriting fee ($50,000) due upon your execution of this
Commitment Letter with the remainder payable at closing.

Sincerely,

NATIONSBANK OF TEXAS, N.A.



By:  /s/ Frank K. Stowers       
     ---------------------------
     Name:  Frank K. Stowers
     Title: Vice President




ACCEPTED AND AGREED TO
as of the date first written above

COSTILLA ENERGY, INC.



By:  /s/ Michael J. Grella      
     ---------------------------
     Name:  Michael J. Grella
     Title: President

<PAGE>

                      SUMMARY OF TERMS AND CONDITIONS

                            SEPTEMBER 20, 1996


BORROWER:                    Costilla Energy, Inc., a Delaware corporation.

AGENT:                       NationsBank of Texas, N.A. ("NATIONSBANK").

ARRANGER:                    NationsBanc Capital Markets, Inc. ("NCMI").

LENDERS:                     NationsBank and other financial institutions 
                             acceptable to Agent, NCMI and Borrower.

ISSUING LENDER:              NationsBank.

AMOUNT AND TYPE              Revolving Line of Credit consisting of Working 
CREDIT FACILITY:             Capital Advances and Acquisition Advances (as 
                             described below) in an amount not to exceed the
                             Borrowing Base, subject to the sublimits set 
                             forth below.  Prior to the second anniversary 
                             date of the Credit Facility, the Borrowing Base
                             will be redetermined periodically and increased
                             or decreased in the manner described below, but
                             in no event will the Borrowing Base ever exceed
                             $50,000,000.

                             Beginning on the second anniversary of the date
                             of the Credit Facility, the Borrowing Base will 
                             be redetermined periodically and MAY BE DECREASED,
                             BUT WILL NOT BE INCREASED above the amount of 
                             the Borrowing Base in effect immediately prior 
                             to such redetermination.  In addition, the 
                             Borrowing Base WILL BE FURTHER REDUCED EACH 
                             QUARTER by an amount equal to one-twelfth of 
                             the Borrowing Base in effect on such second 
                             anniversary date.

WORKING CAPITAL              Limited to maximum of $20,000,000 and used for:
ADVANCES:                    (i) general corporate purposes and (ii) issuance
                             of letters of credit (sub-limit on letter of 
                             credit issuance of $1,000,000).

- -----------------------------------------------------------------------------
Costilla Energy, Inc.                    Page 1                   NationsBank
<PAGE>

ACQUISITION ADVANCES:        Limited to maximum of $30,000,000 and used for 
                             the acquisition of oil and gas reserves that 
                             meet all of the following criteria:

                                (a) at least ninety percent (90%) of the 
                             value attributable to such reserves (calculated
                             by Borrower using pricing guidelines established
                             by Agent from time to time in its sole 
                             discretion) is characterized as proved 
                             developed producing reserves under standards 
                             recognized by the oil and gas industry.

                                (b) no more than sixty percent (60%) of the
                             value attributable to such reserves is funded 
                             with Acquisition Advances.

                                (c) all such reserves are located in the 
                             United States of America or in off-shore areas 
                             under the jurisdiction of any State or the 
                             continental United States of America.

                                (d) the interest to be acquired by Borrower 
                             in such reserves is a direct working interest 
                             or royalty interest.

                                (e) Borrower has delivered to Agent title 
                             opinions covering a substantial part of the 
                             reserves (as designated by Agent) in accordance 
                             with guidelines established by Agent from time 
                             to time in its sole discretion.

                                (f) Borrower has performed environmental due 
                             diligence on the associated properties in 
                             accordance with standards established by Agent 
                             from time to time in its sole discretion.

                               (g) Upon the purchase of such reserves by 
                             Borrower, they shall become subject to a 
                             first-priority perfected Lien in favor of Agent 
                             for the benefit of Lenders.

- -----------------------------------------------------------------------------
Costilla Energy, Inc.                    Page 2                   NationsBank
<PAGE>

INTEREST RATE:               Agent's fluctuating "Base Rate" (defined as the 
                             higher of Agent's Prime Rate and the Federal 
                             Funds Rate plus 1/2%) plus the Applicable Base 
                             Rate Margin, based on a 360-day year, payable 
                             monthly.

                             Agent's reserve adjusted eurodollar rate for 
                             periods of 1, 2, 3, or 6 months, plus the 
                             Applicable Eurodollar Rate Margin, based on a 
                             360 day year, payable quarterly and at the end 
                             of each interest period.

                             Interest on past due principal and interest 
                             shall be payable at the highest lawful rate.
                             
                             The Applicable Margins shall be based upon the 
                             outstanding balances of the Credit Facility, 
                             including Letter of Credit Obligations, divided 
                             by the Borrowing Base then in effect (expressed 
                             in basis points):

<TABLE>
<CAPTION>
                                                Less-than  Greater-than  Less-than   Greater-than
                                                    50%         50%         75%           75%
                             <S>                    <C>               <C>                <C>               
                             Base Rate Margin        0                 25                 50
                             Eurodollar Rate 
                              Margin             137.5              162.5                 200
</TABLE>

FEES:                        A commitment fee payable quarterly in arrears 
                             on the unutilized portion of the Borrowing 
                             Base, and calculated based on a 360-day year 
                             (expressed in basis points).
                             
<TABLE>
<CAPTION>
                                                Less-than  Greater-than  Less-than   Greater-than
                                                    50%         50%         75%           75%
                             <S>                    <C>               <C>                <C>               

                             Commitment Fee           30              35                 40
</TABLE>

                             Underwriting fee of 50 bp; 20% due upon 
                             acceptance of the commitment and 80% due at 
                             closing of the Credit Facility.
                             
                             A fee of 1/4% on any increase in the Borrowing 
                             Base.

                             Letter of Credit Fees: (i) issuance fee for the 
                             account of the Issuing Lender in the amount of 
                             0.125% of the face amount of each letter of 
                             credit issued, and (ii) letter of 

- -----------------------------------------------------------------------------
Costilla Energy, Inc.                    Page 3                   NationsBank
<PAGE>

                             credit fee for the pro rata accounts of the 
                             Lenders equal to the greater of (a) the 
                             Applicable Eurodollar Rate Margin per annum of 
                             the face amount of each letter of credit and 
                             (b) $500, payable at the time of issuance.

                             Agent's fee of $50,000 per year.

AMORTIZATION/MATURITY:       Beginning on the second anniversary of the date 
                             of the Credit Facility, quarterly payments of 
                             principal in the amount necessary to cause the 
                             outstanding balance of the Credit Facility to 
                             equal the reduced Borrowing Base.  Due in full 
                             on the fifth anniversary of the Credit Facility.

OPTIONAL PREPAYMENTS:        Permitted at any time without penalty, so long 
                             as no principal bearing interest at a 
                             eurodollar rate is paid before the end of the 
                             applicable interest period.
                             
BORROWING BASE REDUCTIONS:   Prior to the second anniversary date of the 
                             Credit Facility, Borrower may reduce the 
                             Borrowing Base within fifteen days after the 
                             date on which the Borrowing Base is 
                             redetermined.

REQUIRED PREPAYMENTS:        See requirements under Borrowing Base.

SECURITY AND SUPPORTING      First priority liens and assignments of 
AGREEMENTS:                  production covering substantially all of 
                             Borrower's oil and gas properties and all 
                             related contracts.
 
                             First priority security interest in and pledge 
                             of Borrower's stock in all of its subsidiaries.
 
                             Negative Pledge on all other properties of 
                             Borrower and its subsidiaries, and Agreement to 
                             Pledge such properties or stock upon request.
                              
                             All security documentation will be prepared by 
                             Agent's counsel and must be satisfactory to 
                             Agent and Lenders in form and substance.
                             
TITLE ASSURANCES:            Legal opinions or other title assurances 
                             satisfactory to Agent covering certain oil and
                             gas properties to be mortgaged and assurances 
                             from Borrower that title matters have not 
                             materially changed since the title 

- -----------------------------------------------------------------------------
Costilla Energy, Inc.                    Page 4                   NationsBank
<PAGE>

                             review which occurred in connection with the 
                             NationsBridge facility.

ENVIRONMENTAL REVIEW:        An environmental report on the oil and gas 
                             properties owned by Borrower, in form and 
                             substance and authorship satisfactory to Agent 
                             and assurances from Borrower that environmental 
                             matters have not materially changed since the 
                             environmental due diligence which occurred in 
                             connection with the NationsBridge facility.

BORROWING BASE:              The aggregate outstanding principal balance 
                             under the Credit Facility (including any 
                             letters of credit) may at no time exceed the 
                             Borrowing Base, which will be set semi-annually 
                             by Agent and Lenders in their sole discretion 
                             (Agent and Borrower shall each have the right 
                             to request additional Borrowing Base 
                             redeterminations but not more than once during 
                             any six month period).  All Borrowing Base 
                             redeterminations will be set by Majority 
                             Lenders provided that agreement of 100% of the 
                             Lenders will be required to increase the 
                             Borrowing Base.  INCREASES IN THE BORROWING 
                             BASE WILL NOT OCCUR AFTER THE SECOND 
                             ANNIVERSARY DATE.
                             
                             To assist Agent and Lenders in setting the 
                             Borrowing Base, Borrower will furnish by 
                             February 28 of each year an annual engineering 
                             report on proved oil and gas properties of 
                             Borrower and its subsidiaries, dated as of 
                             January 1 of such year, and prepared by 
                             Williamson Petroleum Consultants, Inc. or other 
                             independent petroleum engineers acceptable to 
                             Agent, and Borrower will furnish by July 31 of 
                             each year a supplemental in-house engineering 
                             report effective as of July 1.

                             Borrower will furnish to Agent and Lenders with 
                             these engineering reports a report of 
                             production and associated operating statements 
                             for the oil and gas properties of Borrower.  
                             Borrower will also furnish to Agent and Lenders 
                             a quarterly report of production and associated 
                             operating statements for the oil and gas 
                             properties of Borrower.

                             If the Borrowing Base ever falls below the 
                             outstanding balance of the Credit Facility (the 
                             amount by which the 
                             
- -----------------------------------------------------------------------------
Costilla Energy, Inc.                    Page 5                   NationsBank
<PAGE>

                             outstanding balance exceeds the Borrowing Base 
                             is herein called the "BORROWING BASE 
                             DEFICIENCY"), Borrower must either (i) prepay 
                             the Credit Facility in the amount of the 
                             deficit within 10 days after notice thereof by 
                             Agent, or elect within such period to repay the 
                             Borrowing Base Deficiency in 6 equal 
                             consecutive monthly installments which shall be 
                             in addition to other principal payments due 
                             under the Credit Facility or (ii) mortgage to 
                             Agent additional oil and gas properties 
                             sufficient to cause an increase in the 
                             Borrowing Base by the amount of such Borrowing 
                             Base Deficiency; however, if a Borrowing Base 
                             Deficiency exists as the result of a quarterly 
                             reduction occurring after the second 
                             anniversary date, Borrower must immediately 
                             prepay the Credit Facility in an amount at 
                             least equal to the Borrowing Base Deficiency.  
                             If Borrower does not (x) elect to cure a 
                             Borrowing Base Deficiency within 10 days after 
                             notice thereof or (y) immediately eliminate a 
                             Borrowing Base Deficiency occurring as a result 
                             of a quarterly reduction, Agent may require any 
                             of Borrower's subsidiaries to unconditionally 
                             guarantee the Credit Facility and grant to 
                             Agent first perfected liens and security 
                             interests in all of its properties to secure 
                             the Credit Facility.

CONDITIONS OF LENDING:       1.  Borrower shall have successfully completed 
                             (i) the merger of Costilla Energy, L.L.C. into 
                             Costilla Energy, Inc. (the "MERGER"), (ii) the 
                             public issuance of ten-year unsecured debt in 
                             the net amount of at least $100,000,000 and 
                             (iii) equity in the gross amount of at least 
                             $60,000,000 upon terms and conditions outlined 
                             in the Form S-1 Registration Statements filed 
                             with Securities and Exchange Commission on 
                             August 30, 1996.

                             2.  All documents governing the Credit Facility 
                             (including without limitation a Credit 
                             Agreement, Promissory Note, and documents 
                             establishing the security rights listed above) 
                             must be executed and delivered in forms 
                             acceptable to Agent and Lenders.

                             3.  The Credit Facility and the loan documents 
                             must comply with all applicable laws, 
                             contracts, instruments and governmental 
                             policies.

- -----------------------------------------------------------------------------
Costilla Energy, Inc.                    Page 6                   NationsBank

<PAGE>                        4. There must be no default at closing or any 
                              funding, and all representations and warranties 
                              must then be true.

                              5. Receipt by Agent of:

                                 (a) Closing certificates of senior officers of 
                              Borrower, confirming that all representations 
                              and warranties are true, that all closing 
                              conditions have been satisfied, and such other 
                              matters as Agent may specify.

                                 (b) Certificates of public officials as to 
                              Borrower's existence and good standing.

                                 (c) Such legal opinions of counsel for 
                              Borrower and Costilla Petroleum Corporation (as 
                              to certain transfers of assets only) and 
                              satisfaction or resolution of such other legal 
                              requirements or risks, as Agent and its counsel 
                              may specify including but not limited to 
                              opinions regarding the Merger and the 
                              associated transfer of assets in connection 
                              therewith.

                                 (d) Title assurances as described above.

                                 (e) Environmental review as described above.

                              6. There must be no material adverse change in 
                              the financial condition, operations, prospects 
                              or properties of Borrower or its subsidiaries 
                              from that presented to Agent in connection 
                              herewith, and no pending or threatened 
                              challenge thereto by governmental officials or 
                              third parties.

REPRESENTATIONS AND           The Credit Agreement and other loan documents 
WARRANTIES:                   shall contain such representations and warranties 
                              that Agent deems appropriate for this 
                              transaction, including without limitation 
                              confirmation of various factors which Agent and 
                              Lenders have considered in making their 
                              decision to enter into the Credit Facility.

AFFIRMATIVE COVENANTS:        The Credit Agreement and other loan documents 
                              shall contain such affirmative covenants of 
                              Borrower and its subsidiaries as are usual and 
                              customary for transactions 

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<PAGE>
                              of this kind, including without limitation the 
                              following affirmative covenants:

                              1. Borrower will deliver the following 
                              financial statements and reports:

                                 (a) Annual audited consolidated (and 
                              consolidating upon the request of Agent) 
                              financial statements of Borrower and its 
                              subsidiaries (with accountants' certificate of 
                              no default and officer's certificate of no 
                              default) within 105 days after each fiscal year.

                                 (b) Quarterly unaudited consolidated (and 
                              consolidating upon the request of Agent) 
                              financial statements of Borrower and its 
                              subsidiaries (with officer's certificate of no 
                              default) within 60 days after each fiscal 
                              quarter.

                                 (c) Reports outlined under "BORROWING BASE" 
                              above.

                              2. Agent and Lenders will have general access 
                              to information about Borrower and its 
                              subsidiaries.

                              3. Borrower will pay Agent's and Arranger's 
                              expenses, including legal fees, in negotiating, 
                              syndicating, administering, enforcing, and 
                              defending the various loan documents and rights 
                              of Agent and Lenders thereunder, together with 
                              interest on amounts not timely paid to the 
                              extent permitted by law.  Borrower will pay 
                              Lenders' expenses, including legal fees, in 
                              enforcing and defending the various loan 
                              documents and Lenders' rights thereunder, 
                              together with interest on amounts not timely 
                              paid to the extent permitted by law.

                              4. Borrower and its subsidiaries will maintain 
                              insurance as is customary in industry and 
                              satisfactory to Agent.

                              5. All transactions among Borrower, its 
                              subsidiaries and their affiliates shall be on 
                              terms no more favorable 

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Costilla Energy, Inc.                     Page 8                     NationsBank
<PAGE>
                              than could be obtained from third parties in an 
                              arm's length transaction.

                              6. Each of Borrower's subsidiaries that 
                              guarantees any Debt of Borrower will also 
                              unconditionally guarantee the Credit Facility 
                              and grant to Agent first perfected liens and 
                              security interests in all of its properties to 
                              secure the Credit Facility.

NEGATIVE COVENANTS:           The Credit Agreement and other loan documents 
                              shall contain such negative covenants of 
                              Borrower and Subsidiaries as are usual and 
                              customary for transactions of this type, 
                              including without limitation the following 
                              negative covenants:

                              1. Debt (other than trade debt, taxes and other 
                              current liabilities according to GAAP, but 
                              including guaranties) of Borrower and its 
                              subsidiaries will be limited to the Credit 
                              Facility, public unsecured debt contemplated 
                              hereby, and other debt of Borrower not to 
                              exceed $750,000.  Any intercompany debt will be 
                              limited to customary intercompany accounts in 
                              an amount to be determined.

                              2. Liens by Borrower and its subsidiaries will 
                              be limited to those securing the Credit 
                              Facility, and to customary statutory and 
                              inchoate liens.

                              3. Mergers by Borrower and its subsidiaries 
                              will be prohibited unless Borrower is the 
                              surviving entity and no Default or Event of 
                              Default exists or occurs as a result of such 
                              merger.

                              4. Sales of interests in Borrower's 
                              subsidiaries will be prohibited.  Sales of 
                              property by Borrower and its subsidiaries will 
                              be generally prohibited, EXCEPT THAT assets 
                              having an aggregate value of $750,000 may be 
                              sold during the six-month period following each 
                              redetermination of the Borrowing Base without 
                              consent of Lenders.  Borrower shall notify 
                              Agent of each such sale and Agent shall release 
                              such property at Borrower's expense.  All other 
                              sales of property must be approved by Agent and 
                              Majority Lenders and the Borrowing Base 

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Costilla Energy, Inc.                     Page 9                     NationsBank
<PAGE>
                              will be reduced by the value assigned by 
                              Lenders to such property.

                              5. Dividends and other payments to equity 
                              owners by Borrower will not be permitted.  
                              Prepayments, purchases and defeasance of 
                              Borrower's public unsecured debt will not be 
                              permitted.

                              6. Investments (or acquisitions) by Borrower 
                              and its subsidiaries will be limited to (i) 
                              high-grade cash equivalents, (ii) investments 
                              in the Moldovan operation in amount not to 
                              exceed $2,500,000 per year, (iii) oil and gas 
                              reserves to which proved reserves are 
                              attributable, (iv) Republic Gas Partners, 
                              L.L.C., in an amount not to exceed $1,000,000, 
                              (v) existing Promissory Notes from A & P Meter 
                              Service and Supply, Inc., and (vi) oil and gas 
                              leases to which no proved reserves are 
                              attributable in an amount not to exceed 
                              $2,500,000 per year.  Investments by Borrower 
                              in its subsidiaries (and loans by Borrower to 
                              its subsidiaries) will generally be prohibited 
                              unless the subsidiary has unconditionally 
                              guaranteed the Credit Facility and granted to 
                              Agent first perfected liens and security 
                              interests in all of its properties to secure 
                              the Credit Facility.  Should a Borrowing Base 
                              Deficiency or an Event of Default occur, the 
                              Agent shall have the right to require that each 
                              subsidiary of Borrower unconditionally guaranty 
                              the Credit Facility and grant to Agent first 
                              perfected liens and security interests in all 
                              of its assets to secure the Credit Facility.  
                              In the ordinary course of business, cash 
                              transfers to and from Borrower's subsidiaries 
                              for customary intercompany accounts will be 
                              allowed in an amount to be determined.  Loans 
                              and new lines of business will be generally 
                              prohibited.

                              7. Borrower's consolidated current ratio will 
                              not be less than 1.0 to 1.0.  Current 
                              maturities of long term debt will be excluded 
                              as current liabilities and up to $10,000,000 of 
                              borrowing availability can be included as a 
                              current asset.

                              8. After the transactions contemplated hereby, 
                              Borrower's consolidated tangible net worth will 
                              not be less than the sum of (i) $30,000,000 
                              plus (ii) 50% of Borrower's consolidated net 
                              income earned after June 

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Costilla Energy, Inc.                     Page 10                    NationsBank

<PAGE>

                             30, 1996, plus (iii) 75% of net proceeds 
                             from the sale of equity interests in Borrower 
                             after the making of the first advance under the 
                             Credit Facility.

                             9. Payments due under leases (other than oil and 
                             gas leases) by Borrower and its subsidiaries shall
                             not exceed $1,000,000 in any fiscal year.
                             
                             10. Commodity hedging shall be limited in any 
                             month, without duplication, to: (i) 100% of proved
                             production for puts and (ii) 75% of proved 
                             production for all other derivative products.
                             
                             11. Beginning December 31, 1996, Borrower's 
                             ratio of EBITDA to interest expense shall never 
                             be less than 2.0 to 1. The calculation of 
                             EBITDA and interest expense will be based upon: 
                             (i) for the period ending December 31, 1996 the 
                             immediately preceding two fiscal quarters 
                             annualized, (ii) for the period ending March 
                             31, 1997 the immediately preceding three fiscal 
                             quarters annualized, and (iii) for the period 
                             ending June 30, 1997 and for each fiscal 
                             quarter thereafter, the last four fiscal 
                             quarters.
 
                             12. Neither Borrower nor any of its 
                             subsidiaries will, directly or indirectly, 
                             enter into, create, or otherwise allow to exist 
                             any contract or other consensual restriction on 
                             the ability of any subsidiary of Borrower: (i) 
                             to pay dividends or make other distributions to 
                             Borrower, (ii) to redeem equity interests held 
                             in it by Borrower, (iii) to repay loans and 
                             other indebtedness owing by it to Borrower, or 
                             (iv) to transfer any of its assets to Borrower.
                             
EVENTS OF DEFAULT:           The Credit Agreement and other loan 
                             documents will contain such events 
                             of default as are usual and customary for 
                             transactions of this kind, including without 
                             limitation defaults in payment or performance 
                             under the Credit Facility, misrepresentations, 
                             cross-defaults to other debt instruments or 
                             material obligations, events of default related 
                             to ERISA and insolvency, change of ownership, 
                             change in management and any material 


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Costilla Energy, Inc.                  Page 11                  NationsBank
                             
<PAGE>
                             adverse change affecting Borrower or any of its 
                             subsidiaries.

                             Upon the occurrence of an event of default, 
                             Agent may require any of Borrower's 
                             subsidiaries to unconditionally guarantee the 
                             Credit Facility and grant to Agent first 
                             perfected liens and security interests in all 
                             of its properties to secure the Credit Facility.

INDEMNIFICATION:             Borrower will generally indemnify Agent, NCMI, 
                             their affiliates and all Lenders under the 
                             Credit Facility against losses in connection 
                             with the Credit Facility and the rights 
                             provided to Agent and Lenders in connection 
                             therewith, including without limitation 
                             indemnification against costs and taxes related 
                             to the making, commitment to make, failure to 
                             take down or prepayment of loans thereunder or 
                             the reservation of capital in connection 
                             therewith.

GENERAL:                     1. The loan documents will generally be governed by
                             Texas law.

                             2. The loan documents as ultimately executed 
                             will constitute the complete agreement of the 
                             parties thereto, without modification by this 
                             summary of terms and conditions or any 
                             discussions among representatives of Borrower, 
                             Agent, Lenders, or any other parties.
                             
                             3. The loan documents will provide that the 
                             parties thereto will waive, to the maximum 
                             extent not prohibited by law, any right to a 
                             trial by jury or to claim or recover special, 
                             exemplary, punitive or consequential damages, 
                             under or in connection with the loan documents 
                             as ultimately executed, or any negotiations, 
                             transactions or events associated herewith or 
                             therewith or contemplated hereby or thereby.
                             
                             4. Each Lender will have the right to assign 
                             all or part of its interest in the Credit 
                             Facility at its discretion, subject to 
                             Borrower's consent which shall not be 
                             unreasonably withheld or required if an Event 
                             of Default exists, provided that the amount of 
                             each such assignment is not less than 
                             $10,000,000.  A processing fee in the 

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Costilla Energy, Inc.                  Page 12                  NationsBank
                             
<PAGE>

                             amount of $2,500 shall be due and payable to 
                             Agent upon any assignment of all or part of any 
                             Lender's interest in the Credit Facility.  In 
                             addition, each Lender shall have the right to 
                             sell participations in its interest in the 
                             Credit Facility, provided that the amount 
                             thereof shall be at least $1,000,000 and that 
                             no participant shall have the right to (i) 
                             participate in setting the Borrowing Base or 
                             (ii) approve any amendment to or waiver of the 
                             loan documents except for material changes in 
                             the amount and term of the Credit Facility.
                             
                             5. Agent and Lenders shall have the right to 
                             disclose any and all information they have 
                             concerning Borrower, Subsidiaries, their 
                             properties and the Credit Facility to NCMI and 
                             any financial institution that may participate 
                             in the syndication of the Credit Facility.
                             
                             
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Costilla Energy, Inc.                  Page 13                  NationsBank




<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
   
September 24, 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
   
September 24, 1996
    


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