ENEX RESOURCES CORP
SC 14D1, 1998-02-19
CRUDE PETROLEUM & NATURAL GAS
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<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                 SCHEDULE 14D-1
                             TENDER OFFER STATEMENT
       PURSUANT TO SECTION 14(D)(1) OF THE SECURITIES EXCHANGE ACT OF 1934


                           ENEX RESOURCES CORPORATION
                            (Name of Subject Company)


                          MIDDLE BAY OIL COMPANY, INC.
                                   (Purchaser)


                          COMMON STOCK, $.05 PAR VALUE
                         (Title of Class of Securities)

                                    292744208
                      (CUSIP Number of Class of Securities)

                           JOHN J. BASSETT, PRESIDENT
                          MIDDLE BAY OIL COMPANY, INC.
                             1221 LAMAR, SUITE 1020
                              HOUSTON, TEXAS 77010
                                 (713) 759-6808
          (Name, Address and Telephone Number of Persons Authorized to
           Receive Notices and Communications on Behalf of Purchaser)

                                   Copies to:

                          H. Grady Thrasher, III, Esq.
                       Thrasher, Whitley, Hampton & Morgan
                       Five Concourse Parkway, Suite 2150
                             Atlanta, Georgia 30328
                            Telephone: (770) 804-8000


                            CALCULATION OF FILING FEE

<TABLE>
<CAPTION>
      Transaction Valuation*                 Amount of Filing Fee**
      ----------------------                 ----------------------
      <S>                                    <C>   
           $20,152,780                               $4,030
</TABLE>

*   For purposes of calculating the filing fee only. This calculation assumes
    the purchase of 1,343,352 shares of Common Stock, par value $.05 per share,
    of Enex Resources Corporation for $15.00 net per share in cash.
**  1/50th of 1% of Transaction Valuation.

[ ]  Check box if any part of the fee is offset as provided by Rule 0-11(a)(2)
     and identify the filing with which the offsetting fee was previously paid.
     Identify the previous filing by registration statement number or the form
     or schedule and the date of its filing.

      AMOUNT PREVIOUSLY PAID:    Not applicable     FILING PARTY: Not applicable
      FORM OR REGISTRATION NO.:  Not applicable     DATE FILED:   Not applicable


<PAGE>   2



         This Tender Offer Statement on Schedule 14D-1 (the "Schedule 14D-1")
relates to the offer by Middle Bay Oil Company, Inc., an Alabama corporation
("Purchaser" or "Middle Bay"), to purchase all shares of Common Stock, par value
$0.05 per share (the "Shares"), of Enex Resources Corporation, a Delaware
corporation ("Enex"), presently outstanding or such lesser number of Shares as
equals a majority of the Shares outstanding on a fully-diluted basis at a price
of $15.00 per Share net to the seller in cash, without interest thereon (the
"Offer Price"), upon the terms and subject to the conditions set forth in the
Offer to Purchase dated February 19, 1998 (the "Offer to Purchase") and the
related Letter of Transmittal (which, together with any amendments or
supplements thereto, collectively constitute the "Offer"), which are annexed to
and filed with this Schedule 14D-1 as Exhibits (a)(1) and (2), respectively.
According to information furnished to Middle Bay by Enex, as of February 10,
1998, 1,343,352 Shares were outstanding.


ITEM 1.   SECURITY AND SUBJECT COMPANY

       (a)    The name of the subject company is Enex Resources Corporation, a
              Delaware corporation. According to the most recent Enex 10-QSB,
              the address of Enex's principal executive office is 800 Rockmead
              Drive, Three Kingwood Place, Suite 200, Kingwood, Texas 77339.

       (b)    The information set forth in the Introduction of the Offer to
              Purchase annexed hereto as Exhibit (a)(1) is incorporated herein
              by reference. The class of securities to which this Statement
              relates is the common stock, par value $0.05 per share, of Enex.
              The information set forth in the Introduction and Section 1 of the
              Offer to Purchase is incorporated herein by reference.

       (c)    The information set forth in Section 6 ("Price Range of the
              Shares; Dividends on the Shares") of the Offer to Purchase is
              incorporated herein by reference.


ITEM 2.   IDENTITY AND BACKGROUND

       (a)-(d); (g)  This statement is being filed by Middle Bay Oil Company,
                     Inc., an Alabama corporation. Information regarding
                     Purchaser's principal business and address of principal
                     business office is set forth in Section 8 ("Certain
                     Information Concerning Purchaser") of the Offer to Purchase
                     and is incorporated herein by reference. The name, business
                     address, present principal occupation or employment, the
                     material occupations, positions, offices or employments for
                     the past five years and the citizenship of each director
                     and executive officer of Purchaser, and the name, principal
                     business and address of any corporation or other
                     organization in which such occupations, positions, offices
                     and employments are or were carried on are set forth in
                     Schedule I of the Offer to Purchase and are incorporated
                     herein by reference.

       (e)-(f)       Neither Purchaser nor, to the best knowledge of Purchaser,
                     any of the directors or executive officers of Purchaser,
                     has during the last five years (i) been convicted in a
                     criminal proceeding (excluding traffic violations or
                     similar misdemeanors) or (ii) been a party to a civil
                     proceeding of a judicial or administrative body of
                     competent jurisdiction and as a result of such proceeding
                     was or is subject to a judgment, decree or final order
                     enjoining future violations of, or prohibiting activities
                     subject to, federal or state securities laws or finding any
                     violation of such laws.



<PAGE>   3




ITEM 3.   PAST CONTACTS, TRANSACTIONS OR NEGOTIATIONS WITH THE SUBJECT
          COMPANY

         (a)-(b)  The information set forth in the Introduction, Section 8
                  ("Certain Information Concerning Purchaser"), Section 10
                  ("Background of the Offer; Contacts with Enex") and Section 11
                  ("Purpose of the Offer; Plans for Enex") of the Offer to
                  Purchase is incorporated herein by reference.

ITEM 4.   SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION

         (a)-(c)  The information set forth in Section 9 ('Source and Amount of
                  Funds') of the Offer to Purchase is incorporated herein by
                  reference.


ITEM 5.   PURPOSE OF THE TENDER OFFER AND PLANS OR PROPOSALS OF PURCHASER

         (a)-(e)  The information set forth in the Introduction and Sections 10
                  ("Background of the Offer; Contacts with Enex") and 11
                  ("Purpose of the Offer; Plans for Enex") of the Offer to
                  Purchase is incorporated herein by reference.

         (f)-(g)  The information set forth in Section 13 ("Effect of the Offer
                  on the Market for the Shares; NASDAQ Listing; Exchange Act
                  Registration; Margin Regulations") of the Offer to Purchase is
                  incorporated herein by reference.


ITEM 6.   INTEREST IN SECURITIES OF THE SUBJECT COMPANY

         (a)      The information set forth in the Introduction and Section 8
                  ("Certain Information Concerning Purchaser") of the Offer to
                  Purchase is incorporated herein by reference.

         (b)      There were no transactions in Enex Shares during the 60 days
                  preceding the date hereof by Purchaser, its executive
                  officers, directors, subsidiaries and affiliates.


ITEM 7.   CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH
          RESPECT TO THE SUBJECT COMPANY'S SECURITIES

         The information set forth in the Introduction and Sections 8 ("Certain
Information Concerning Purchaser"), 10 ("Background of the Offer; Contacts with
Enex") and 11 ("Purpose of the Offer; Plans for Enex") of the Offer to Purchase
is incorporated herein by reference.


ITEM 8.   PERSONS RETAINED, EMPLOYED OR TO BE COMPENSATED

         The information set forth in the Introduction and Section 16 ("Fees and
Expenses") of the Offer to Purchase is incorporated herein by reference.



<PAGE>   4

ITEM 9.   FINANCIAL STATEMENTS OF CERTAIN PURCHASERS

         The information set forth in Section 8 ("Certain Information Concerning
Purchaser") of the Offer to Purchase is incorporated herein by reference.


ITEM 10.   ADDITIONAL INFORMATION

         (a)      Not applicable.

         (b)-(c)  The information set forth in the Introduction and Sections 11
                  ("Purpose of the Offer; Plans for Enex") and 15 ("Certain
                  Legal Matters") of the Offer to Purchase is incorporated
                  herein by reference.

         (d)      The information set forth in Sections 13 ("Effect of the Offer
                  on the Market for Shares; NASDAQ Listing; Exchange Act
                  Registration; Margin Regulations") and 15 ("Certain Legal
                  Matters") of the Offer to Purchase is incorporated herein by
                  reference.

         (e)      The information set forth in Section 15 ("Certain Legal
                  Matters") of the Offer to Purchase is incorporated herein by
                  reference.

         (f)      The information set forth in the Offer to Purchase and the
                  Letter of Transmittal, to the extent not otherwise
                  incorporated herein by reference, copies of which are attached
                  hereto as Exhibits (a)(1) and (a)(2), is incorporated herein
                  by reference.


ITEM 11.   MATERIAL TO BE FILED AS EXHIBITS

         (a)  (1) Offer to Purchase, dated February 19, 1998.

              (2) Letter of Transmittal with respect to the Shares, together
                  with the Guidelines for Certification of Taxpayer
                  Identification Number on Substitute Form W-9.

              (3) Notice of Guaranteed Delivery (included in (a)(2) above).

              (4) Letter, dated February 19, 1998, from Purchaser to brokers,
                  dealers, banks, trust companies and other nominees.

              (5) Form of letters to be sent by brokers, dealers, banks, trust
                  companies and other nominees.

              (6) Press Release, dated February 19, 1998 relating to the
                  commencement of the Offer.

              (7) Form of summary advertisement, dated February 19, 1998.

         (b)      Second Restated Revolving Credit and Term Loan Agreement dated
                  August 25, 1997 among Purchaser, its subsidiaries and Bank of
                  Oklahoma, N.A.

         (c)      Letter of Intent from Purchaser to Enex dated January 29, 
                  1998.


<PAGE>   5

             

         (d)      Opinion of Thrasher, Whitley, Hampton & Morgan.

         (e)      Not applicable.

         (f)      None.



                                   SIGNATURES

         After due inquiry and to the best of our knowledge and belief, we
certify that the information set forth in this statement is true, complete and
correct.

         Dated:  February 19, 1998

                                              MIDDLE BAY OIL COMPANY, INC.


                                              By: /s/ John J. Bassett
                                                 ------------------------------
                                                 John J. Bassett, President



<PAGE>   1
                           OFFER TO PURCHASE FOR CASH
                                      UP TO
                        1,343,352 SHARES OF COMMON STOCK
                                       OF
                       ENEX RESOURCES CORPORATION ("ENEX")
                                       AT
                              $15.00 NET PER SHARE
                                       BY
                   MIDDLE BAY OIL COMPANY, INC. ("PURCHASER")




         THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, HOUSTON,
TEXAS TIME, ON MONDAY, MARCH 16, 1998, UNLESS THE OFFER IS EXTENDED TO A LATER
DATE AND TIME (THE "EXPIRATION DATE"). SHARES WHICH ARE TENDERED PURSUANT TO THE
OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE EXPIRATION DATE.

         THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, THE SATISFACTION OR,
WHERE APPLICABLE, WAIVER OF THE FOLLOWING CONDITIONS: (1) THERE BEING VALIDLY
TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION DATE A NUMBER OF SHARES
WHICH, TOGETHER WITH SHARES OWNED BY MIDDLE BAY OIL COMPANY, INC. ('PURCHASER')
AND ITS AFFILIATES, WILL CONSTITUTE AT LEAST A MAJORITY OF THE TOTAL NUMBER OF
OUTSTANDING SHARES ON A FULLY DILUTED BASIS AS OF THE DATE THE SHARES ARE
ACCEPTED FOR PAYMENT BY PURCHASER PURSUANT TO THE OFFER, AND (2) PURCHASER BEING
SATISFIED IN ITS SOLE DISCRETION THAT THE BOARD OF DIRECTORS OF ENEX HAS
IRREVOCABLY TAKEN ALL SUCH ACTION SO THAT (A) THE ACQUISITION OF SHARES PURSUANT
TO THE OFFER DESCRIBED HEREIN HAS BEEN APPROVED PURSUANT TO SECTION 203 OF THE
DELAWARE GENERAL CORPORATION LAW OR THE PROVISIONS OF SECTION 203 ARE OTHERWISE
INAPPLICABLE TO THE ACQUISITION OF SHARES PURSUANT TO THE OFFER, (B) THE
ACQUISITION OF SHARES PURSUANT TO THE OFFER HAS BEEN APPROVED PURSUANT TO
ARTICLE NINETEEN OF ENEX'S CERTIFICATE OF INCORPORATION, (C) THE STOCK PURCHASE
RIGHTS ISSUED BY ENEX HAVE BEEN REDEEMED OR PURCHASER IS SATISFIED IN ITS SOLE
DISCRETION THAT THE RIGHTS ARE OTHERWISE INAPPLICABLE TO THE OFFER, AND (D)
PURCHASER'S DESIGNEES HAVE BEEN ELECTED TO THE BOARD OF DIRECTORS OF ENEX IN
ANTICIPATION OF THE REPLACEMENT OF THE EXISTING DIRECTORS SO THAT AFTER THE
RESIGNATION OF THE EXISTING DIRECTORS SUCH DESIGNEES SHALL CONSTITUTE THE BOARD
OF DIRECTORS OF ENEX OR SHALL BE ABLE TO ELECT ADDITIONAL DIRECTORS TO
RECONSTITUTE THE BOARD. THE OFFER IS ALSO SUBJECT TO OTHER TERMS AND CONDITIONS
CONTAINED IN THIS OFFER TO PURCHASE. (SEE SECTION 14.)

         THE OFFER IS NOT CONDITIONED ON PURCHASER OBTAINING FINANCING.




                                     - 1 -

<PAGE>   2



                                    IMPORTANT

         PURCHASER RESERVES THE RIGHT TO AMEND THE OFFER (INCLUDING AMENDING THE
NUMBER OF SHARES TO BE PURCHASED AND THE PURCHASE PRICE) AND/OR TO ENTER INTO A
SUBSEQUENT MERGER AGREEMENT WITH ENEX OR TO NEGOTIATE A MERGER AGREEMENT WITH
ENEX NOT INVOLVING A TENDER OFFER PURSUANT TO WHICH PURCHASER WOULD TERMINATE
THE OFFER AND THE SHARES WOULD, UPON CONSUMMATION OF SUCH MERGER, BE CONVERTED
INTO CASH, MIDDLE BAY COMMON STOCK AND/OR OTHER SECURITIES IN SUCH AMOUNTS AS
ARE NEGOTIATED BY PURCHASER AND ENEX.

         Any Enex stockholder desiring to tender all or any portion of such
stockholder's Shares should either (i) complete and sign the Letter of
Transmittal (or a facsimile thereof) in accordance with the instructions in the
Letter of Transmittal, have such stockholder's signature thereon guaranteed if
required by Instruction 1 to the Letter of Transmittal, mail or deliver the
Letter of Transmittal (or such facsimile), an Agent's Message (as defined
herein), and any other required documents to the Depositary (as defined herein)
and either deliver the certificates for such Shares, along with the Letter of
Transmittal (or facsimile), or (ii) request such stockholder's broker, dealer,
bank, trust company or other nominee to effect the transaction for such
stockholder. An Enex stockholder having Shares registered in the name of a
broker, dealer, bank, trust company or other nominee must contact such broker,
dealer, bank, trust company or other nominee if such stockholder desires to
tender such Shares.

         If an Enex stockholder desires to tender Shares and such stockholder's
certificates for Shares are not immediately available or time will not permit
all required documents to reach the Depositary prior to the Expiration Date,
such stockholder's tender may be effected by following the procedure for
guaranteed delivery set forth in Section 2 of this Offer to Purchase.

         Questions and requests for assistance or for additional copies of this
Offer to Purchase, the Letter of Transmittal and the Notice of Guaranteed
Delivery may be directed to Purchaser or to Enex at their respective addresses
and telephone numbers set forth below. An Enex stockholder may also contact
brokers, dealers, commercial banks, trust companies or other nominees for
assistance concerning the Offer.

February 19, 1998


MIDDLE BAY OIL COMPANY, INC.                ENEX RESOURCES CORPORATION
1221 Lamar, Suite 1020                      800 Rockmead Drive
Houston, Texas 77010                        Three Kingwood Place, Suite 200
Telephone: (713) 759-6808                   Kingwood, Texas 77339
Fax: (713) 650-0352                         Telephone: (281) 358-8401
                                            Fax: (281) 358-7895





                                      - 2 -

<PAGE>   3



                                TABLE OF CONTENTS




<TABLE>
<S>                                                                         <C>
INTRODUCTION.................................................................4

THE TENDER OFFER.............................................................7
     Terms of the Offer......................................................7
     Procedure for Tendering Shares..........................................9
     Withdrawal Rights......................................................12
     Acceptance for Payment and Payment for Shares..........................13
     Certain Federal Income Tax Consequences................................14
     Price Range of the Shares; Dividends on the Shares.....................15
     Certain Information Concerning Enex....................................16
     Certain Information Concerning Purchaser...............................17
     Source and Amount of Funds.............................................18
     Background of the Offer; Contacts With Enex............................19
     Purpose of the Offer; Plans for Enex...................................19
     Dividends and Distributions............................................21
     Effect of the Offer on the Market for the 
            Shares; Exchange Listing; Exchange Act
            Registration; Margin Regulations................................22
     Certain Conditions of the Offer........................................23
     Certain Legal Matters..................................................26
     Fees and Expenses......................................................26
     Miscellaneous..........................................................27


DIRECTORS AND EXECUTIVE OFFICERS OF PURCHASER.......................Schedule I

LETTER OF TRANSMITTAL...............................................Attachment
</TABLE>





                                      - 3 -

<PAGE>   4



To the Holders of Common Stock of Enex Resources Corporation:

                                  INTRODUCTION

         Middle Bay Oil Company, Inc., an Alabama corporation ("Purchaser") with
principal offices in Houston, Texas, hereby offers to purchase all of the
presently outstanding shares of Common Stock, par value $0.05 per share (the
"Shares"), of Enex Resources Corporation, a Delaware corporation ("Enex"), such
number of Shares is estimated to be 1,343,352 as of the date hereof, at a price
of $15.00 per Share net to the seller in cash, without interest thereon (the
"Offer Price"), upon the terms and subject to the conditions set forth in this
Offer to Purchase and in the related Letter of Transmittal attached hereto
(which, together with any amendments or supplements hereto or thereto,
collectively constitute the "Offer").

         Tendering stockholders will not be obligated to pay brokerage fees or
commissions or, except as set forth in Instruction 6 of the Letter of
Transmittal, transfer taxes in connection with the tender of Shares pursuant to
the Offer. Purchaser will pay all fees and expenses of Bank of Oklahoma, N.A.,
which is acting as the Depositary (the "Depositary"), incurred in connection
with the Offer. (See Section 16.)

         The purpose of the Offer is to acquire up to the entire equity interest
in Enex, but not less than a majority of the Shares outstanding on a
fully-diluted basis. The Offer is conditioned on, among other things,
Purchaser's designees constituting a majority of the Enex Board of Directors so
that Purchaser will be able to control Enex following consummation of the Offer.
(See Section 14.)

         Certain federal income tax consequences of the sale of Shares pursuant
to the Offer are described in Section 5.

         The Offer is subject to the fulfillment of a number of conditions,
including, without limitation, the following:

       (A)    MINIMUM TENDER CONDITION. THE OFFER IS CONDITIONED UPON THERE
BEING VALIDLY TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION DATE (AS
DEFINED IN SECTION 1) AT LEAST THAT NUMBER OF SHARES (THE "MINIMUM NUMBER OF
SHARES") WHICH CONSTITUTE A MAJORITY OF THE TOTAL NUMBER OF ALL OUTSTANDING
SHARES ON A FULLY DILUTED BASIS (AS THOUGH ALL OPTIONS OR OTHER SECURITIES
CONVERTIBLE INTO OR EXERCISABLE OR EXCHANGEABLE FOR SHARES HAD BEEN SO
CONVERTED, EXERCISED OR EXCHANGED) ON THE DATE SHARES ARE ACCEPTED FOR PAYMENT
(THE "MINIMUM TENDER CONDITION"). Purchaser reserves the right (subject to the
applicable rules and regulations of the Securities and Exchange Commission (the
"Commission")), which it presently has no intention of exercising, to waive or
reduce the Minimum Tender Condition and to elect to purchase, pursuant to the
Offer, fewer than the Minimum Number of Shares. (See Sections 1 and 14.)

         According to information provided to Purchaser by Enex, as of February
10, 1998, there were 1,343,352 Shares issued and outstanding. In addition,
according to information provided to Purchaser by Enex, as of February 10, 1998,
there were 143,000 Shares subject to options outstanding under Enex's stock
option plans. Neither Purchaser nor any affiliate of Purchaser owns any Shares,
and Purchaser does not presently intend to acquire Shares. Based on the
foregoing and assuming that no options were granted or



                                     - 4 -

<PAGE>   5



expired after February 10, 1998 and no options were exercised after February 10,
1998, there would be 1,486,352 Shares outstanding on a fully diluted basis, and
the Minimum Number of Shares would be 743,177. However, the actual Minimum
Number of Shares will depend on the facts as they exist on the date of purchase.

         (B)    BOARD ACTION CONDITION. THE OFFER IS CONDITIONED UPON PURCHASER
BEING SATISFIED IN ITS SOLE DISCRETION THAT THE ENEX BOARD HAS IRREVOCABLY TAKEN
ALL SUCH ACTION SO THAT (A) THE ACQUISITION OF SHARES PURSUANT TO THE OFFER HAVE
BEEN APPROVED PURSUANT TO SECTION 203 ("SECTION 203") OF THE DELAWARE GENERAL
CORPORATION LAW (THE "DELAWARE LAW") OR THE PROVISIONS OF SECTION 203 ARE
OTHERWISE INAPPLICABLE TO THE ACQUISITION OF SHARES PURSUANT TO THE OFFER, (B)
THE ACQUISITION OF SHARES PURSUANT TO THE OFFER HAS BEEN APPROVED PURSUANT TO
ARTICLE NINETEEN OF ENEX'S CERTIFICATE OF INCORPORATION, (C) THE STOCK PURCHASE
RIGHTS ISSUED BY ENEX HAVE BEEN REDEEMED OR PURCHASER IS SATISFIED IN ITS SOLE
DISCRETION THAT THE RIGHTS HAVE BEEN INVALIDATED OR ARE OTHERWISE INAPPLICABLE
TO THE OFFER, AND (D) PURCHASER'S DESIGNEES HAVE BEEN ELECTED TO THE ENEX BOARD
IN ANTICIPATION OF REPLACEMENT OF EXISTING DIRECTORS SO THAT AFTER THE
RESIGNATION OF THE EXISTING DIRECTORS SUCH DESIGNEES SHALL CONSTITUTE THE ENEX
BOARD OR SHALL BE ABLE TO ELECT ADDITIONAL DIRECTORS TO RECONSTITUTE THE BOARD
(COLLECTIVELY, THE "BOARD ACTION CONDITION").

         Section 203, in general, prohibits a Delaware corporation such as Enex
from engaging in a "Business Combination" (defined as a variety of transactions,
including mergers, as set forth below) with an "Interested Stockholder" (defined
generally as a person that is the beneficial owner of 15% or more of a
corporation's outstanding voting stock) for a period of three years following
the date that such person became an Interested Stockholder unless (a) prior to
the date such person became an Interested Stockholder, the Board of Directors of
the corporation approved either the Business Combination or the transaction that
resulted in the stockholder becoming an Interested Stockholder, (b) upon
consummation of the transaction that resulted in the stockholder becoming an
Interested Stockholder, the Interested Stockholder owned at least 85% of the
voting stock of the corporation outstanding at the time the transaction
commenced, excluding stock held by directors who are also officers of the
corporation and employee stock ownership plans that do not provide employees
with the right to determine confidentially whether shares held subject to the
plan will be tendered in a tender or exchange offer or (c) on or subsequent to
the date such person became an Interested Stockholder, the Business Combination
is approved by the Board of Directors of the corporation and authorized at a
meeting of stockholders, and not by written consent, by the affirmative vote of
the holders of at least 66-2/3% of the outstanding voting stock of the
corporation not owned by the Interested Stockholder. (See Section 15.)

         Under Article Nineteen of Enex's Certificate of Incorporation, a
committee consisting of the independent directors of Enex (the "Fairness
Committee") shall vote upon the fairness to the minority shareholders of a
merger or consolidation of Enex with or into another corporation, a sale or
lease of all or substantially all the assets of Enex to another corporation,
person or entity and, under certain conditions, a sale or lease to Enex or any
subsidiary of Enex of assets in exchange for voting securities of Enex, in each
case where the other party to the transaction is a beneficial owner, directly or
indirectly, of 20% or more of the outstanding shares of any class or series of
voting stock of Enex. If the Fairness Committee does not recommend such proposed
transaction, the vote of holders of 66 2/3% of the voting securities of Enex is
required for approval. In addition, for any transaction to be effected for which
the foregoing 66-2/3% vote is required, it is also required that such
transaction be approved by a majority of the outstanding securities of each


                                     - 5 -

<PAGE>   6



ownership in Enex give rise to the requirement of the 66-2/3% vote. Any
amendments to Enex's Certificate of Incorporation which would amend the
foregoing requirements require the same affirmative votes.

         A Rights Agreement was entered into between Enex and American
Securities Transfer, Incorporated on September 4, 1990, as amended April 12,
1994, and the Rights Agreement was filed with and the Rights are described in
Enex's Current Report on Form 8-K dated September 4, 1990 and Form 8-K dated
April 12, 1994 (the "Enex Rights 8-K"). The Board Action Condition requires, in
part, that Purchaser be satisfied that the Enex Board has taken action to redeem
the Rights issued thereunder or that the Rights are otherwise inapplicable to
the Offer.

         Article Eight of the Certificate of Incorporation of Enex provides that
the number of directors of Enex shall be not less than six nor more than 15. The
Certificate of Incorporation provides that the Board shall be divided into three
classes of directors, with the classes to be as nearly equal in number of
directors as possible. One class of directors is elected each year for a
three-year term by the stockholders representing a plurality of the total Shares
voting in the election of directors. The Certificate of Incorporation and Enex's
Bylaws provide that no director shall be removed from office by vote or other
action of the stockholders except for cause and only upon the vote of two-thirds
of the Shares then entitled to vote at an election of directors. Enex's
Certificate of Incorporation also provides that no action required or permitted
to be taken at any annual or special meeting of stockholders of Enex may be
taken without a meeting, and the power of stockholders to act by written consent
is specifically denied. Enex's Bylaws provide that special meetings of
stockholders may be called only by the Enex Board or the President of Enex. As a
result of the classified Board and related provisions, Purchaser may be unable
to elect a majority of directors to the Enex Board until the second annual
meeting of stockholders of Enex following consummation of the Offer, even if
Purchaser acquires a majority of the outstanding Shares in the Offer. The Board
Action Condition requires, in part, that, prior to consummation of the Offer,
the Enex Board elect the designees of Purchaser in anticipation of the
replacement of existing directors so that after the resignation of the existing
directors, such designees shall constitute the Enex Board of Directors or shall
be able to elect additional directors to reconstitute the Board. (See Sections
1, 10 and 11.)

         Purchaser has entered into a Letter of Intent with Enex with respect to
the Offer (see Section 10), and Enex management has agreed in principle to
recommend to Enex's Board of Directors that it satisfy the Board Action
Condition and recommend acceptance of the Offer by Enex stockholders. Purchaser
believes that the Enex Board has taken or will take such action as is necessary
to satisfy the Board Action Condition in order to give Enex stockholders the
opportunity to decide whether they wish to take advantage of the Offer by
tendering their Shares pursuant to the Offer; however, Purchaser presently
intends to extend the Offer from time to time (if required) until the Board
Action Condition is fully satisfied or Purchaser determines, in its sole
discretion, that such condition is not reasonably likely to be satisfied under
then current circumstances.

         Certain other conditions to the Offer are described in Section 14.
Purchaser reserves the right (but shall not be obligated) to waive any or all
such conditions. (See Sections 1, 10, 11, 14 and 15.)

       THIS OFFER TO PURCHASE AND THE LETTER OF TRANSMITTAL CONTAIN IMPORTANT
INFORMATION WHICH SHOULD BE READ CAREFULLY BEFORE ANY DECISION IS MADE WITH
RESPECT TO THE OFFER.






                                     - 6 -

<PAGE>   7
                                                                 


                                THE TENDER OFFER

1.       TERMS OF THE OFFER

         Upon the terms and subject to the conditions of the Offer (including,
if the Offer is extended or amended, the terms and conditions of any extension
or amendment), Purchaser will accept for payment and pay for all Shares validly
tendered prior to the Expiration Date and not theretofore withdrawn in
accordance with Section 3. The term "Expiration Date" means 12:00 Midnight,
Houston, Texas time, on March 16, 1998, unless and until Purchaser, in its sole
discretion, shall have extended the period of time during which the Offer is
open, in which event the term "Expiration Date" shall mean the latest time and
date at which the Offer, as so extended by Purchaser, will expire.

         Consummation of the Offer is conditioned upon, among other things,
satisfaction of the Minimum Tender Condition and the Board Action Condition. If
any or all of such conditions are not satisfied or any or all of the other
events set forth in Section 14 shall have occurred or shall be determined by
Purchaser to have occurred prior to the Expiration Date, Purchaser reserves the
right (but shall not be obligated) to (i) decline to purchase any or all of the
Shares tendered and terminate the Offer, and return all tendered Shares to
tendering stockholders, (ii) waive or reduce the Minimum Tender Condition or
waive or reduce any or all other conditions and, subject to complying with
applicable rules and regulations of the Commission, purchase all Shares validly
tendered, or (iii) extend the Offer and, subject to the right of stockholders to
withdraw Shares until the Expiration Date, retain the Shares which have been
tendered during the period or periods for which the Offer is extended.

         UPON THE TERMS AND SUBJECT TO THE CONDITIONS OF THE OFFER, IF THE
MINIMUM TENDER CONDITION HAS BEEN MET, ALL SHARES VALIDLY TENDERED AND NOT
WITHDRAWN PRIOR TO THE EXPIRATION DATE WILL BE PURCHASED BY PURCHASER UPON THE
TERMS AND SUBJECT TO THE CONDITIONS OF THE OFFER.

         Purchaser expressly reserves the right, in its sole discretion, at any
time and from time to time, to extend for any reason the period of time during
which the Offer is open, including the occurrence of any of the events specified
in Section 14, by giving oral or written notice of such extension to the
Depositary. During any such extension, all Shares previously tendered and not
withdrawn will remain subject to the Offer, subject to the rights of a tendering
stockholder to withdraw its Shares. (See Section 3.) Under no circumstances will
interest be paid on the purchase price for tendered Shares, whether or not
Purchaser exercises its right to extend the Offer.

         Subject to the applicable regulations of the Commission, Purchaser also
expressly reserves the right, in its sole discretion at any time and from time
to time, (i) to delay acceptance for payment of or, regardless of whether such
Shares were theretofore accepted for payment, payment for any Shares in order to
comply in whole or in part with any applicable law, (ii) to terminate the Offer
and not accept for payment any Shares if any of the conditions referred to in
Section 14 has not been satisfied or upon the occurrence of any of the events
specified in Section 14 and (iii) to waive any condition or otherwise amend the
Offer in any



                                      - 7 -

<PAGE>   8



respect by giving oral or written notice of such delay, termination, waiver or
amendment to the Depositary and by making a public announcement thereof.

         Purchaser acknowledges that: (i) Rule 14e-1(c) under the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), requires Purchaser to pay
the consideration offered or return the Shares tendered promptly after the
termination or withdrawal of the Offer, and (ii) Purchaser may not delay
acceptance for payment of, or payment for (except as provided in clause (i) of
the first sentence of the preceding paragraph), any Shares upon the occurrence
of any of the events specified in Section 14 without extending the period of
time during which the Offer is open.

         Any such extension, delay, termination, waiver or amendment will be
followed as promptly as practicable by public announcement thereof, such
announcement in the case of an extension to be made no later than 9:00 a.m.,
Houston, Texas time, on the next business day after the previously scheduled
Expiration Date. Subject to applicable law (including Rules 14d-4(c), 14d-6(d)
and 14e-1 under the Exchange Act, which require that material changes in the
information published, sent or given in connection with the Offer be promptly
disseminated to stockholders in a manner reasonably designed to inform them of
such changes) and without limiting the manner in which Purchaser may choose to
make any public announcement, Purchaser shall have no obligation to publish,
advertise or otherwise communicate any such public announcement other than by
issuing a press release to the Dow Jones News Service.

         If Purchaser makes a material change in the terms of the Offer or the
information concerning the Offer, or if it waives a material condition of the
Offer, Purchaser will extend the Offer to the extent required by Rules 14d-4(c),
14d-6(d) and 14e-1 under the Exchange Act.

         If, prior to the Expiration Date, Purchaser should decide to decrease
the number of Shares being sought or to increase or decrease the consideration
being offered in the Offer, such decrease in the number of Shares being sought
or such increase or decrease in the consideration being offered will be
applicable to all of Enex's stockholders whose Shares are accepted for payment
pursuant to the Offer and, if at the time notice of any such decrease in the
number of Shares being sought or such increase or decrease in the consideration
being offered is first published, sent or given to holders of such Shares, the
Offer is scheduled to expire at any time earlier than the period ending on the
tenth business day from and including the date that such notice is first so
published, sent or given, the Offer will be extended at least until the
expiration of such ten business day period. For purposes of the Offer, a
"business day" means any day other than a Saturday, Sunday or federal holiday
and consists of the time period from 12:01 a.m. through 12:00 midnight, Houston,
Texas time.

         Enex has furnished to Purchaser stockholder lists and security position
listings for the purpose of disseminating the Offer to holders of Shares. This
Offer to Purchase, the related Letter of Transmittal and other relevant
materials will be mailed to record holders of Shares and will be furnished by
Purchaser or by Enex, if it so elects, to brokers, dealers, banks, trust
companies and similar persons whose names, or the names of whose nominees,
appear on the stockholder lists or, if applicable, who are listed as
participants in a clearing agency's security position listing, for subsequent
transmittal to beneficial owners of Shares. 




                                      - 8 -

<PAGE>   9



2.       PROCEDURE FOR TENDERING SHARES

         Valid Tender. For a stockholder to validly tender Shares pursuant to
the Offer, either (a) a properly completed and duly executed Letter of
Transmittal (or facsimile thereof), together with any required signature
guarantees or, in the case of a book-entry transfer, an Agent's Message (as
defined below), and any other required documents, must be received by the
Depositary at its address set forth in the Letter of Transmittal prior to the 
Expiration Date and either (i) certificates for tendered Shares must be 
received by the Depositary at such address or (ii) such Shares must be 
delivered pursuant to the procedures for book-entry transfer set forth below
(and a Book-Entry Confirmation [as defined below] must be received by the
Depositary), in each case prior to the Expiration Date, or (b) the tendering
stockholder must comply with the guaranteed delivery procedures set forth below.

         Book-Entry Transfer. The Depositary will establish accounts with
respect to the Shares at American Stock Transfer, Inc. (the "Book-Entry Transfer
Facility") for purposes of the Offer within two business days after the date of
this Offer to Purchase. Any financial institution that is a participant in the
Book-Entry Transfer Facility's system may make book-entry delivery of Shares by
causing the Book-Entry Transfer Facility to transfer such Shares into the
Depositary's account in accordance with such Book-Entry Transfer Facility's
procedures for such transfer. However, although delivery of Shares may be
effected through book-entry transfer into the Depositary's account at the
Book-Entry Transfer Facility, the Letter of Transmittal (or facsimile thereof),
properly completed and duly executed, with any required signature guarantees or
an Agent's Message, and any other required documents, must, in any case, be
transmitted to and received by the Depositary at its address set forth in the
Letter of Transmittal prior to the Expiration Date, or the tendering stockholder
must comply with the guaranteed delivery procedures described below. The
confirmation of a book-entry transfer of the Shares into the Depositary's
account at the Book-Entry Transfer Facility as described above is referred to
herein as a "Book-Entry Confirmation." DELIVERY OF DOCUMENTS TO THE BOOK-ENTRY
TRANSFER FACILITY IN ACCORDANCE WITH SUCH BOOK-ENTRY TRANSFER FACILITY'S
PROCEDURES DOES NOT CONSTITUTE DELIVERY TO THE DEPOSITARY.

         The term "Agent's Message" means a message transmitted by the
Book-Entry Transfer Facility to, and received by, the Depositary and forming a
part of a Book-Entry Confirmation, which states that such Book-Entry Transfer
Facility has received an express acknowledgment from the participant in such
Book-Entry Transfer Facility tendering the Shares that such participant has
received and agrees to be bound by the terms of the Letter of Transmittal and
that Purchaser may enforce such agreement against the participant.

         THE METHOD OF DELIVERY OF THE SHARES, THE LETTER OF TRANSMITTAL AND ALL
OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH THE BOOK-ENTRY TRANSFER
FACILITY, IS AT THE ELECTION AND RISK OF THE TENDERING STOCKHOLDER. THE SHARES
WILL BE DEEMED DELIVERED ONLY WHEN ACTUALLY RECEIVED BY THE DEPOSITARY
(INCLUDING, IN THE CASE OF A BOOK-ENTRY TRANSFER, BY BOOK-ENTRY CONFIRMATION).
IF DELIVERY IS BY MAIL, REGISTERED MAIL WITH RETURN RECEIPT REQUESTED, PROPERLY
INSURED, IS RECOMMENDED.  IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO
ENSURE TIMELY DELIVERY.



                                     - 9 -

<PAGE>   10





         Signature Guarantees. No signature guarantee is required on the Letter
of Transmittal (a) if the Letter of Transmittal is signed by the registered
holder(s) (which term, for purposes of this Section 2, includes any participant
in the Book-Entry Transfer Facility's system whose name appears on a security
position listing as the owner of the Shares) of the Shares tendered therewith
and such registered holder has not completed either the box entitled "Special
Delivery Instructions" or the box entitled "Special Payment Instructions" on the
Letter of Transmittal or (b) if such Shares are tendered for the account of a
financial institution (including most commercial banks, savings and loan
associations and brokerage houses) that is a participant in the Security
Transfer Agents Medallion Program, the New York Stock Exchange Medallion
Signature Guarantee Program or the Stock Exchange Medallion Program (an
"Eligible Institution"). In all other cases, all signatures on the Letter of
Transmittal must be guaranteed by an Eligible Institution. (See Instructions 1
and 5 to the Letter of Transmittal.) If the certificates for the Shares are
registered in the name of a person other than the signer of the Letter of
Transmittal, or if payment is to be made or certificates for the Shares not
tendered or not accepted for payment are to be returned to a person other than
the registered holder of the certificates surrendered, the tendered certificates
must be endorsed or accompanied by appropriate stock powers, in either case
signed exactly as the name or names of the registered holders or owners appear
on the certificates, with the signatures on the certificates or stock powers
guaranteed as aforesaid. (See Instructions 1 and 5 to the Letter of
Transmittal.)

         Guaranteed Delivery. If a stockholder desires to tender the Shares
pursuant to the Offer and such stockholder's certificates for the Shares are not
immediately available or the procedure for book-entry transfer cannot be
completed on a timely basis or time will not permit all required documents to
reach the Depositary prior to the Expiration Date, such stockholder's tender may
be effected if all of the following conditions are met:

                  (i)      such tender is made by or through an Eligible
         Institution;

                  (ii)     a properly completed and duly executed Notice of
         Guaranteed Delivery, substantially in the form provided by Purchaser,
         is received by the Depositary, as provided below, prior to the
         Expiration Date; and

                  (iii)    the certificates for all tendered Shares, in proper
         form for transfer (or a Book-Entry Confirmation with respect to all
         such Shares), together with a properly completed and duly-executed
         Letter of Transmittal (or facsimile thereof), with any required
         signature guarantees or, in the case of a book-entry transfer, an
         Agent's Message, and any other required documents are received by the
         Depositary within three trading days after the date of execution of
         such Notice of Guaranteed Delivery. A "trading day" is any day on which
         the NASDAQ Stock Market is open for business.

         The Notice of Guaranteed Delivery may be delivered by hand to the
Depositary or transmitted by telegram, facsimile transmission or mail to the
Depositary and must include a guarantee by an Eligible Institution in the form
set forth in such Notice of Guaranteed Delivery.



                                     - 10 -

<PAGE>   11




         Notwithstanding any other provision hereof, payment for Shares accepted
for payment pursuant to the Offer will in all cases be made only after timely
receipt by the Depositary of (a) certificates for (or a timely Book-Entry
Confirmation with respect to) such Shares, (b) a Letter of Transmittal (or
facsimile thereof), properly completed and duly executed, with any required
signature guarantees, or, in the case of a book-entry transfer, an Agent's
Message, and (c) any other documents required by the Letter of Transmittal.
Accordingly, tendering stockholders may be paid at different times depending
upon when certificates for the Shares or Book-Entry Confirmations with respect
to the Shares are actually received by the Depositary. UNDER NO CIRCUMSTANCES
WILL INTEREST BE PAID BY PURCHASER ON THE PURCHASE PRICE OF THE SHARES,
REGARDLESS OF ANY EXTENSION OF THE OFFER OR ANY DELAY IN MAKING SUCH PAYMENT.

         The valid tender of the Shares pursuant to one of the procedures
described above will constitute a binding agreement between the tendering
stockholder and Purchaser upon the terms and subject to the conditions of the
Offer, subject to withdrawal rights described in Section 3.

         Appointment. By executing a Letter of Transmittal as set forth above,
the tendering stockholder will irrevocably appoint designees of Purchaser as
such stockholder's attorneys-in-fact and proxies in the manner set forth in the
Letter of Transmittal, each with full power of substitution, to the full extent
of such stockholder's rights with respect to the Shares tendered by such
stockholder and accepted for payment by Purchaser and with respect to any and
all other Shares, rights or other securities or rights issued or issuable in
respect of such Shares on or after February 19, 1998. All such proxies will be
considered coupled with an interest in the tendered Shares. Such appointment
will be effective when, and only to the extent that, Purchaser accepts for
payment the Shares tendered by such stockholder as provided herein. Upon such
appointment, all prior powers of attorney, proxies and consents given by such
stockholder with respect to such Shares or other securities or rights will,
without further action, be revoked and no subsequent powers of attorney,
proxies, consents or revocations may be given (and, if given, will not be deemed
effective). The designees of Purchaser will thereby be empowered to exercise all
voting and other rights with respect to such Shares and other securities or
rights in respect of any annual or special meeting of Enex's stockholders, or
any adjournment or postponement thereof, actions by written consent in lieu of
any such meeting or otherwise, as they in their sole discretion deem proper.
Purchaser reserves the right to require that, in order for the Shares to be
deemed validly tendered, immediately upon Purchaser's acceptance for payment of
such Shares, Purchaser must be able to exercise full voting, consent and other
rights with respect to such Shares and other securities or rights, including
voting at any meeting of Enex's stockholders.

         Determination of Validity. All questions as to the validity, form,
eligibility (including time of receipt) and acceptance of any tender of Shares
will be determined by Purchaser, in its sole discretion, which determination
will be final and binding. Purchaser reserves the absolute right to reject any
or all tenders determined by it not to be in proper form or the acceptance for
payment of or payment for which may, in the opinion of Purchaser's counsel, be
unlawful. Purchaser also reserves the absolute right to waive any defect or
irregularity in the tender of any Shares of any particular stockholder whether
or not similar defects or irregularities are waived in the case of other
stockholders. No tender of Shares will be deemed to have been validly made until
all defects or irregularities relating thereto have been cured or waived. None
of Purchaser, the Depositary or any other person will be under any duty to give
notification of any defects or irregularities



                                     - 11 -

<PAGE>   12




in tenders or incur any liability for failure to give any such notification.
Purchaser's interpretation of the terms and conditions of the Offer (including
the Letter of Transmittal and the instructions thereto) will be final and
binding.

         Backup Withholding. In order to avoid "backup withholding" of federal
income tax on payments of cash pursuant to the Offer, a stockholder tendering
Shares in the Offer must, unless an exemption applies, provide the Depositary
with such stockholder's correct taxpayer identification number ("TIN") on a
Substitute Form W-9 and certify under penalties of perjury that such TIN is
correct and that such stockholder is not subject to backup withholding. If a
stockholder does not provide such stockholder's correct TIN or fails to provide
the certifications described above, the Internal Revenue Service (the "IRS") may
impose a penalty on such stockholder, and payment of cash to such stockholder
pursuant to the Offer may be subject to backup withholding of 31%. All
stockholders surrendering Shares pursuant to the Offer should complete and sign
the main signature form and the Substitute Form W-9 included as part of the
Letter of Transmittal to provide the information and certifications necessary to
avoid backup withholding (unless an applicable exemption exists and is proved in
a manner satisfactory to Purchaser and the Depositary). Certain stockholders
(including, among others, all corporations and certain foreign individuals and
entities) are not subject to backup withholding. In order to avoid backup
withholding, noncorporate foreign stockholders should complete and sign the main
signature form and a Form W-8, Certificate of Foreign Status, a copy of which
may be obtained from the Depositary. (See Instruction 9 to the Letter of
Transmittal.)

3.       WITHDRAWAL RIGHTS

         Except as otherwise provided in this Section 3, tenders of the Shares
are irrevocable. The Shares tendered pursuant to the Offer may be withdrawn
pursuant to the procedures set forth below at any time prior to the Expiration
Date and, unless theretofore accepted for payment and paid for by Purchaser
pursuant to the Offer, may also be withdrawn at any time after March 23, 1998,
or such later time as may apply if the Offer is extended.

         If Purchaser extends the Offer, is delayed in its acceptance for
payment of Shares or is unable to accept Shares for payment pursuant to the
Offer for any reason, then, without prejudice to Purchaser's rights under the
Offer, the Depositary may, nevertheless, on behalf of Purchaser, retain tendered
Shares, and such Shares may not be withdrawn except to the extent that tendering
stockholders are entitled to withdrawal rights as described in this Section 3.
Any such delay will be by an extension of the Offer to the extent required by
law.

         For a withdrawal to be effective, a written, telegraphic or facsimile
transmission notice of withdrawal must be timely received by the Depositary at
its address set forth on the back cover of this Offer to Purchase and must
specify the name of the person having tendered the Shares to be withdrawn, the
number of the Shares to be withdrawn and the name of the registered holder of
the Shares to be withdrawn, if different from the name of the person who
tendered the Shares. If certificates for the Shares have been delivered or
otherwise identified to the Depositary, then, prior to the physical release of
such certificates, the serial numbers shown on such certificates must be
submitted to the Depositary and, unless such Shares have been tendered by an
Eligible Institution, the signatures on the notice of withdrawal must be
guaranteed by an Eligible Institution. If the Shares have been delivered
pursuant to the procedure for book-entry transfer as set forth in Section 2, any



                                     - 12 -

<PAGE>   13




notice of withdrawal must also specify the name and number of the account at the
appropriate Book-Entry Transfer Facility to be credited with the withdrawn
Shares and otherwise comply with such Book-Entry Transfer Facility's procedures.
Withdrawals of tenders of the Shares may not be rescinded, and any Shares
properly withdrawn will thereafter be deemed not validly tendered for purposes
of the Offer. However, withdrawn Shares may be retendered by again following one
of the procedures described in Section 2 at any time prior to the Expiration
Date.

         All questions as to the form and validity (including time of receipt)
of notices of withdrawal will be determined by Purchaser in its sole discretion,
which determination will be final and binding. Neither Purchaser, the Depositary
nor any other person will be under any duty to give notification of any defects
or irregularities in any notice of withdrawal or incur any liability for failure
to give any such notification.

4.       ACCEPTANCE FOR PAYMENT AND PAYMENT FOR SHARES

         Upon the terms and subject to the conditions of the Offer (including,
if the Offer is extended or amended, the terms and conditions of any such
extension or amendment), Purchaser will accept for payment and will pay for all
Shares validly tendered prior to the Expiration Date and not properly withdrawn
in accordance with Section 3 promptly after the later to occur of the Expiration
Date and the satisfaction or waiver of the conditions set forth in Section 14.
All questions as to the satisfaction of such terms and conditions will be
determined by Purchaser in its sole discretion, which determination will be
final and binding. (See Sections 1 and 14.)

         Purchaser expressly reserves the right, in its sole discretion and
subject to the rules of the Commission, to delay acceptance for payment of or
payment for Shares in order to comply in whole or in part with any applicable
law. Any such delays will be effected in compliance with Rule 14e-1(c) under the
Exchange Act (relating to a bidder's obligation to pay for or return tendered
securities promptly after the termination or withdrawal of such bidder's offer).

         In all cases, payment for Shares accepted for payment pursuant to the
Offer will be made only after timely receipt by the Depositary of (a)
certificates for (or a timely Book-Entry Confirmation with respect to) such
Shares, (b) a Letter of Transmittal (or facsimile thereof), properly completed
and duly executed, with any required signature guarantees, or, in the case of a
book-entry transfer, an Agent's Message, and (c) any other documents required by
the Letter of Transmittal. The per-Share consideration paid to any stockholder
pursuant to the Offer will be the highest per-Share consideration paid to any
other stockholder pursuant to the Offer.

         For purposes of the Offer, Purchaser will be deemed to have accepted
for payment, and thereby purchased, Shares properly tendered to Purchaser and
not withdrawn as, if and when Purchaser gives oral or written notice to the
Depositary of Purchaser's acceptance for payment of such Shares. Payment for
Shares accepted for payment pursuant to the Offer will be made by deposit of the
purchase price therefor with the Depositary, which will act as agent for
tendering stockholders for the purpose of receiving payment from Purchaser and
transmitting payment to tendering stockholders. Under no circumstances will
interest be paid on the purchase price of the Shares to be paid by Purchaser,
regardless of any extension of the Offer or any delay in making such payment.
Upon the deposit of funds with the Depositary for the purpose of making



                                     - 13 -

<PAGE>   14




payments to tendering stockholders, Purchaser's obligation to make such payment
shall be satisfied and tendering stockholders must thereafter look solely to the
Depositary for payment of amounts owed to them by reason of the acceptance for
payment of Shares pursuant to the Offer. Purchaser will pay any stock transfer
taxes incident to the transfer to it of validly tendered Shares, except as
otherwise provided in Instruction 6 of the Letter of Transmittal, as well as any
charges and expenses of the Depositary.

         If any tendered Shares are not accepted for payment for any reason
pursuant to the terms and conditions of the Offer, or if Share Certificates are
submitted evidencing more Shares than are tendered, Share Certificates
evidencing unpurchased Shares will be returned, without expense to the tendering
stockholder (or, in the case of Shares tendered by book-entry transfer into the
Depositary's account at the Book-Entry Transfer Facility pursuant to the
procedure set forth in Section 3, such Shares will be credited to an account
maintained at such Book-Entry Transfer Facility), as promptly as practicable
following the expiration or termination of the Offer.

         If, prior to the Expiration Date, Purchaser shall increase the
consideration offered to holders of Shares pursuant to the Offer, such
consideration will be paid to all holders whose Shares are purchased in the
Offer.

         If Purchaser is delayed in its acceptance for payment of or payment for
Shares or is unable to accept for payment or pay for Shares pursuant to the
Offer for any reason, then, without prejudice to Purchaser's rights under the
Offer (but subject to compliance with Rule 14e-1(c) under the Exchange Act), the
Depositary may, nevertheless, on behalf of Purchaser, retain tendered Shares,
and such Shares may not be withdrawn except to the extent tendering stockholders
are entitled to exercise, and duly exercise, withdrawal rights as described in
Section 3.

         Purchaser reserves the right to transfer or assign, in whole or from
time to time in part, to one or more direct wholly-owned subsidiaries of
Purchaser, the right to purchase Shares tendered pursuant to the Offer, but any
such transfer or assignment will not relieve Purchaser of its obligations under
the Offer and will in no way prejudice the rights of tendering stockholders to
receive payment for Shares validly tendered and accepted for payment pursuant to
the Offer.

5.       CERTAIN FEDERAL INCOME TAX CONSEQUENCES

         The following discussion is a summary of certain material federal
income tax consequences of the Offer to holders of Shares who hold the Shares as
capital assets. The discussion set forth below is for general information only
and may not apply to particular categories of holders of Shares subject to
special treatment under the Internal Revenue Code of 1986, as amended (the
"Code"). The discussion is based on the Code as in effect on the date of this
Offer to Purchase, as well as regulations promulgated thereunder and existing
administrative interpretations and court decisions.

         In the opinion of Thrasher, Whitley, Hampton & Morgan, counsel for
Purchaser, each Enex stockholder whose Shares are purchased pursuant to the
Offer will recognize gain or loss for federal income tax purposes measured by
the difference between such stockholder's tax basis in such stockholder's Shares
purchased in the Offer and the amount of cash received by such stockholder. Such
gain or loss will generally 



                                     - 14 -

<PAGE>   15




be capital gain or loss if the Shares are held as a capital asset and will be
long-term capital gain or loss if such Shares are held for more than one year at
the time of the sale, subject to the provisions and limitations of the Code. The
Taxpayer Relief Act of 1997 provides lower maximum tax rates for long-term
capital gain in the case of property held for more than 18 months.

         THE FEDERAL INCOME TAX DISCUSSION SET FORTH ABOVE IS INCLUDED FOR
GENERAL INFORMATION ONLY. THE ABOVE DISCUSSION MAY NOT APPLY TO PARTICULAR
CATEGORIES OF HOLDERS OF SHARES SUBJECT TO SPECIAL TREATMENT UNDER THE CODE,
SUCH AS FOREIGN HOLDERS AND HOLDERS WHOSE SHARES WERE ACQUIRED PURSUANT TO THE
EXERCISE OF AN EMPLOYEE STOCK OPTION OR OTHERWISE AS COMPENSATION, OR WHO HOLD
RESTRICTED STOCK. STOCKHOLDERS OF ENEX ARE URGED TO CONSULT THEIR OWN TAX
ADVISORS TO DETERMINE THE SPECIFIC TAX CONSEQUENCES OF THE OFFER, INCLUDING ANY
STATE, LOCAL OR OTHER TAX CONSEQUENCES OF THE OFFER.

6.       PRICE RANGE OF THE SHARES; DIVIDENDS ON THE SHARES

         The Shares are traded on the NASDAQ National Market System ("NMS") and
prices are quoted under the symbol "ENEX." The following table sets forth, for
each of the periods indicated, the high and low sales prices for the Shares on
the NMS and the amount of cash dividends paid per Share, all as reported in
published financial sources.

<TABLE>
<CAPTION>
                                     ENEX COMMON STOCK
                                                                        Annual
            Fiscal Year Ending                    High        Low      Dividends
            ------------------                    ----        ---      ---------
            <S>                                  <C>        <C>        <C>
            December 31, 1996:                                           $ .25
              First Quarter                       8 3/4      7 3/4
              Second Quarter                     11 3/4      8
              Third Quarter                      10          8 1/4
              Fourth Quarter                     10 1/2      8 1/8
            December 31, 1997:                                           $ .40
              First Quarter                      10 3/4      9 1/4
              Second Quarter                     10 3/4      8 3/4
              Third Quarter                      12 7/8      9 1/2
              Fourth Quarter                     13 1/4     10 1/4
            December 31, 1998:
              First Quarter (through 2/17/98)    12         10 1/2

</TABLE>

         On February 18, 1998, the last reported closing price on NASDAQ was $11
1/2 per Share. The Offer represents a 30% premium over the reported closing
price of the Shares on February 18, 1998. STOCKHOLDERS ARE URGED TO OBTAIN
CURRENT MARKET QUOTATIONS FOR THE SHARES.








                                     - 15 -

<PAGE>   16




7.       CERTAIN INFORMATION CONCERNING ENEX

         The information concerning Enex contained in this Offer to Purchase,
including financial information, has been taken from or based upon information
furnished to Purchaser by Enex or publicly available documents and records on
file with the Commission and other public sources, including, but not limited
to, Enex's annual report on Form 10-KSB for the year ended December 31, 1996
(the "Enex 10-KSB") and Enex's quarterly report on Form 10-QSB for the period
ended September 30, 1997 (the "Enex 10-QSB"). Purchaser assumes no
responsibility for the accuracy or completeness of the information concerning
Enex contained in such documents and records or for any failure by Enex to
disclose events which may have occurred or may affect the significance or
accuracy of any such information but which are unknown to Purchaser. The Enex
10-KSB, the Enex 10-QSB and such other documents should be available for
inspection and copies thereof should be obtainable in the manner set forth below
under 'Available Information.'

         Enex. According to the Enex 10-KSB, Enex is a Delaware corporation, and
its principal executive offices are located at Three Kingwood Place, Suite 200,
Kingwood, Texas 77339. According to the Enex 10-KSB, Enex is an oil and gas
production development company and operates wells in several states, with the
major emphasis in Texas. In addition to acquiring, developing and managing
properties for its own account, Enex also manages over 12,000 wells owned by
limited partnerships.

         Selected Financial Data of Enex. Set forth below is certain selected
consolidated financial information with respect to Enex and its affiliates
excerpted from the information contained in the Enex 10-KSB and the Enex 10-QSB.
More comprehensive financial information is included in the Enex 10-KSB, the
Enex 10-QSB and other documents filed by Enex with the Commission. The following
summary is qualified in its entirety by reference to the Enex 10-KSB, the Enex
10-QSB and such other documents and all the financial information (including any
related notes) contained therein.

<TABLE>
<CAPTION>
                                                                                               Nine Months Ended
                                                                                                 September 30
Dollars in thousands,                                                                            ------------
except per-share data               1992        1993        1994        1995       1996         1996       1997
- ---------------------               ----        ----        ----        ----       ----         ----       ----

<S>                               <C>         <C>         <C>         <C>         <C>          <C>       <C>    
Total revenues                    $ 7,880     $ 6,247     $ 6,871     $ 7,950     $ 8,597      $ 6,109   $ 7,351

Earnings (loss) before income
   taxes                            1,268         968         630         870       1,493(1)     1,067     1,420

Net income (loss)                   1,141         932       1,051       1,269       1,586(1)     1,141     1,477

Net income (loss) per primary
   share                              .82         .69         .75         .90        1.16(1)       .84      1.05

Cash dividend declared
   per common share                   .15         .19         .20         .20         .25          .10       .15

Proved reserves at 12/31:
     Barrels of Oil (thousands)       765         633       1,089         907         812
     Bcf of Gas                      7.79       10.56       12.45       11.57       12.98
</TABLE>

(1)      Excluding nonrecurring $3.9 million SFAS 121 write-down.



                                     - 16 -

<PAGE>   17





         Available Information. Enex is subject to the informational
requirements of the Exchange Act and, in accordance therewith, is required to
file reports relating to its business, financial condition and other matters.
Information as of particular dates concerning Enex's directors and officers,
their remuneration, stock options and other matters, the principal holders of
Enex's securities and any material interest of such persons in transactions with
Enex is required to be disclosed in proxy statements distributed to Enex's
stockholders and filed with the Commission. Such reports, proxy statements and
other information should be available for inspection at the public reference
facilities of the Commission at 450 Fifth Street, N.W., Washington, D.C. 20549,
and at the regional offices of the Commission located at Seven World Trade
Center, 13th Floor, New York, New York 10048 and Citicorp Center, 500 West
Madison Street (Suite 1400), Chicago, Illinois 60661. Copies of such information
should be obtainable, by mail, upon payment of the Commission's customary
charges, by writing to the Commission's principal office at 450 Fifth Street,
N.W.,Washington, D.C. 20549. In addition, the Commission maintains a web site on
the Internet that can be accessed at http://www.sec.gov and that contains
information filed electronically regarding Enex. Such material should also be
available for inspection at the offices of the National Association of
Securities Dealers, Inc., 1735 K Street, N.W., Washington, D.C. 20006.

8.       CERTAIN INFORMATION CONCERNING PURCHASER

         Purchaser. Purchaser is an independent oil and gas exploration and
production company engaged in the exploration, development and production of oil
and gas in the contiguous United States. Middle Bay's strategy focuses on
increasing its reserves of crude oil and natural gas by the acquisition and
development of proved oil and gas properties, primarily in the Mid-Continent and
Gulf Coast regions. By focusing its efforts on increasing reserves during the
current period which Middle Bay believes reflects historically low market prices
for oil and gas, Middle Bay believes that it will be well positioned to benefit
in the event of any future increases in demand for natural gas and oil.
Consistent with its efforts to increase reserve levels, Middle Bay also
participates on a limited basis in drilling and development activities in other
geographic regions of the contiguous United States. Purchaser is an Alabama
corporation with its principal office located at 1221 Lamar, Suite 1020,
Houston, Texas 77010, and its telephone number is (713) 759-6808.

         The name, business address, citizenship, present principal occupation
and employment history for the past five years of each of the directors and
executive officers of Purchaser are set forth on Schedule I of this Offer to
Purchase.

         Selected Financial Data of Purchaser. Set forth below is certain
selected consolidated financial information with respect to Purchaser and its
subsidiaries excerpted from the information contained in Purchaser's Annual
Report on Form 10-KSB for the year ended December 31, 1996 (the "Middle Bay
10-KSB") and Purchaser's Quarterly Report on Form 10-QSB for the quarter ended
September 30, 1997 (the "Middle Bay 10-QSB"). More comprehensive financial
information is included in the Middle Bay 1996 Annual Report to Stockholders
(the "Middle Bay Annual Report"), the Middle Bay 10-KSB, the Middle Bay 10-QSB
and other documents filed by Purchaser with the Commission, and the following
summary is qualified in its entirety by reference to the Middle Bay Annual
Report, the Middle Bay 10-KSB, the Middle Bay 10-QSB



                                     - 17 -

<PAGE>   18




and such other documents and all the financial information (including any
related notes) contained therein. The Middle Bay Annual Report, the Middle Bay
10-KSB, the Middle Bay 10-QSB and such other documents should be available for
inspection and copies thereof should be obtainable in the manner set forth below
under "Available Information."

<TABLE>
<CAPTION>
                                                                                                Nine Months Ended
                                                                                                  September 30
Dollars in thousands,                                                                             ------------
except per-share data               1992        1993        1994        1995       1996         1996       1997
- ---------------------               ----        ----        ----        ----       ----         ----       ----
<S>                               <C>         <C>         <C>         <C>         <C>         <C>        <C>    
Total revenues                    $ 1,731     $ 2,613     $ 2,627     $ 3,539     $ 4,886     $ 3,586    $ 8,237

Earnings (loss) before income
   taxes                             (026)       (135)       (490)       (421)        280         444         71

Net income (loss)                    (026)        022        (457)       (331)        206         444         71

Net income (loss) per primary
   share                             (.02)        .02        (.42)       (.25)        .15         .34       (.11)

Cash dividend declared
   per common share                   .00         .00         .00         .00         .00         .00        .00

Proved reserves at 12/31:
     Barrels of Oil (thousands)       385         538         542         778       1,390
     Bcf of Gas                      4.90        5.25        4.78        6.37        8.96
</TABLE>


         Available Information. Purchaser is subject to the informational
requirements of the Exchange Act and, in accordance therewith, files reports
relating to its business, financial condition and other matters. Information as
of particular dates concerning Purchaser's directors and officers, their
remuneration, stock options and other matters, the principal holders of
Purchaser's securities and any material interest of such persons in transactions
with Purchaser is required to be disclosed in proxy statements distributed to
Purchaser's stockholders and filed with the Commission. Such reports, proxy
statements and other information should be available for inspection at the
Commission and copies thereof should be obtainable from the Commission in the
same manner as is set forth with respect to Enex in Section 7. Such material
should also be available for inspection at the offices of the National
Association of Securities Dealers, Inc., 1735 K Street, N.W., Washington, D.C.
20006.

9.       SOURCE AND AMOUNT OF FUNDS

         Purchaser estimates that the maximum amount of funds required pursuant
to the Offer to purchase the Shares and to pay fees and expenses related to the
Offer will be approximately $20,250,000. (See Section 16.) Purchaser plans to
obtain the necessary funds from available cash and working capital and pursuant
to the revolving credit facility currently existing with Bank of Oklahoma, N.A.
The credit facility allows Purchaser to borrow from time to time up to
$50,000,000 on a secured line-of-credit basis, which loans are convertible into
a 72-month term loan on the conversion date or dates, as defined in the loan
documents. Interest rates may vary and apply periodically at either bank prime
or 1.75-2.00 points above the London Interbank Offered Rates quoted from time to
time at the election of Purchaser. It is anticipated that the indebtedness
incurred by Purchaser under such loan or loans will be secured, in part, by
properties and production of Enex and will be repaid from funds generated
internally by Purchaser (including dividends paid by Enex in the event Purchaser
acquires less than all outstanding Shares), through additional borrowings or
through a combination



                                     - 18 -

<PAGE>   19




of such sources. No final decisions have been made concerning the method
Purchaser will employ to repay such indebtedness. Such decisions when made will
be based on Purchaser's review from time to time of the advisability of
particular actions, as well as on prevailing interest rates and financial and
other economic conditions. This Offer is not conditioned on financing.

10.      BACKGROUND OF THE OFFER; CONTACTS WITH ENEX

         The initial contact with Enex was in a January 2, 1998 telephone call
between John J. Bassett, the President and Chief Executive Officer of Purchaser,
and Gerald B. Eckley, President and Chief Executive Officer of Enex, the purpose
of which was to set up an initial meeting that was held on January 7, 1998.
Subsequent to that meeting, certain Middle Bay officers met or had telephone
conversations with various Enex employees for the purpose of conducting an
investigation of Enex's properties and evaluating its reserves. Mr. Bassett also
had additional telephone conversations with Mr. Eckley concerning a potential
transaction between the two companies. On January 28 and 29, 1998, Mr. Bassett
met with Mr. Eckley to negotiate terms of a letter of intent with regard to the
Offer and certain future compensation payable to Mr. Eckley in the event the
Offer is consummated. The letter of intent, which was executed on January 29,
1998, provides that, subject to satisfactory completion of its due diligence
review of Enex and its properties, Purchaser would (i) commence a cash tender
offer for all of the outstanding capital stock of Enex on or before February 20,
1998; (ii) offer Mr. Eckley, whose employment agreement with Enex has more than
four years left on its term, a severance arrangement under which Purchaser would
pay an aggregate amount equal to Mr. Eckley's current salary for four years in
exchange for consulting services and a first right of refusal on all prospects
and potential acquisitions that he has the opportunity to acquire over the
four-year period; and (iii) offer to the holders of outstanding options to
purchase Enex common stock the difference between the exercise price and $15.00
per share in either cash or shares of Middle Bay stock on a private placement
basis. The stock price is to be determined by taking the previous ten days'
average of the means of the closing bid and asked prices of Purchaser's shares
immediately prior to closing on the tender offer. No definitive agreements have
been entered into with respect to Mr. Eckley's severance arrangement or the
outstanding options.

         In consideration of the foregoing agreements of Purchaser, Enex agreed
not, directly or indirectly, to solicit or encourage inquiries for proposals to
enter into an agreement with regards to the sale of Enex or its assets until
February 20, 1998, except for such actions as may be required to enable Enex and
its officers and directors to comply with their fiduciary duties to Enex
shareholders.

11.      PURPOSE OF THE OFFER; PLANS FOR ENEX

         General. The purpose of the Offer is to acquire all of the Shares of
Enex (but not less than a majority). Following completion of the Offer,
depending upon the number of Shares tendered and accepted by Purchaser,
Purchaser intends to operate Enex as a wholly-owned or majority-owned subsidiary
of Purchaser. Following completion of the Offer, if Purchaser has not acquired
all of the equity interest in Enex, Purchaser will determine whether to propose
a merger of Enex into Purchaser or a wholly-owned subsidiary of Purchaser.
Although no definite plans have been adopted by Purchaser with regard to any
merger of Enex into Purchaser following conclusion of the



                                     - 19 -

<PAGE>   20




Offer, if such a merger is proposed within six months following conclusion of
the Offer, the terms to any remaining Enex shareholders would have a value no
less than the $15.00 per-Share consideration payable pursuant to the Offer.

         The Offer is conditioned upon, among other things, the Minimum Tender
Condition being met, the resignation of the Enex directors and the election of
Purchaser's designees to the Enex Board in anticipation of the replacement of
the existing directors so that such designees shall constitute the Enex Board of
Directors or shall be able to elect additional directors to reconstitute the
Board.

         THIS OFFER IS NEITHER AN OFFER TO SELL NOR A SOLICITATION OF OFFERS TO
BUY ANY SECURITIES WHICH MAY BE ISSUED IN ANY MERGER OR REORGANIZATION OF ENEX
WHICH MAY OCCUR SUBSEQUENT TO THE OFFER OR ANY SIMILAR BUSINESS COMBINATION
INVOLVING PURCHASER AND ENEX. NO MERGER AGREEMENT HAS BEEN ENTERED INTO BETWEEN
PURCHASER AND ENEX.

         Appraisal Rights and Other Matters. No appraisal rights are available
in connection with the Offer. The Commission has adopted Rule 13e-3 under the
Exchange Act which is applicable to certain "going private" transactions and
which may under certain circumstances be applicable to any merger proposed
following the Offer. However, Rule 13e-3 would be inapplicable if (i) the Shares
are deregistered under the Exchange Act prior to the proposed merger or other
business combination or (ii) any proposed merger or other business combination
is consummated within one year after the purchase of the Shares pursuant to the
Offer and the amount paid per Share in the proposed merger or other business
combination is at least equal to the amount paid per Share in the Offer. If
applicable, Rule 13e-3 requires, among other things, that certain financial
information concerning the fairness of the proposed transaction and the
consideration offered to minority stockholders in such transaction be filed with
the Commission and disclosed to stockholders prior to consummation of the
transaction.

         Plans for Enex. In connection with the Offer, Purchaser has reviewed,
and will continue to review, the books and records of Enex, its assets,
corporate structure, dividend policy, capitalization, operations, properties,
policies, management and personnel and will consider and determine what, if any,
changes or strategies would be desirable in light of the circumstances which
then exist. Such strategies could include, among other things, changes in Enex's
business, corporate structure, Certificate of Incorporation, Bylaws,
capitalization, management or dividend policy. In the event the Offer results in
the purchase by Purchaser of fewer than all Shares outstanding, Purchaser may,
but has not agreed to do so (nor are there any definitive intentions with
respect to any such action) seek to merge Enex into Purchaser or a wholly-owned
subsidiary of Purchaser.

         If the Offer is consummated, Purchaser plans to increase capital
expenditures related to drilling and developing Enex's properties, without
reducing capital expenditures related to Purchaser's existing properties. In
addition, Purchaser intends to actively develop Enex properties, with a view
toward increasing the reserves and production from Enex's portfolio of oil and
gas properties. In addition, Purchaser intends to lower operating expenses on
Enex operated properties, improve margins on sales of oil and gas production and
reduce general and administrative expenses. The plans described in the foregoing
are intended to increase the reserves, production and cash flow from the Enex
properties.



                                     - 20 -

<PAGE>   21




         Except as indicated in this Offer to Purchase, Purchaser has no present
plans or proposals which relate to or would result in an extraordinary corporate
transaction, such as a merger, consolidation, reorganization or liquidation,
involving Enex or any of its affiliates, a sale or transfer of a material amount
of assets of Enex or any of its affiliates or any material change in Enex's
capitalization or dividend policy or causing its Shares to be delisted from the
NASDAQ National Market System or any other material changes in Enex's corporate
structure or business, or the composition of the Enex Board or Enex's
management.

12.      DIVIDENDS AND DISTRIBUTIONS

         If, on or after February 19, 1998, Enex should (a) split, combine or
otherwise change the Shares or its capitalization (other than the amendment to
or redemption of the Rights in accordance with their terms), (b) acquire or
otherwise cause a reduction in the number of outstanding Shares or other
securities (other than as aforesaid), or (c) issue or sell additional Shares
(other than the issuance of Shares under option prior to February 10, 1998, in
accordance with the terms of such options as such terms have been disclosed
prior to February 10, 1998), shares of any other class of capital stock, other
voting securities or any securities convertible into, or rights, warrants or
options, conditional or otherwise, to acquire any of the foregoing, then,
subject to the provisions of Section 14, Purchaser in its sole discretion may
make such adjustments as it deems appropriate in the Offer Price and other terms
of the Offer, including without limitation, the number or type of securities
offered to be purchased.

         If, on or after February 19, 1998, Enex should declare or pay any cash
dividend on the Shares or other distribution on the Shares (other than in the
event the Rights are redeemed, the price of redemption thereof), or issue with
respect to the Shares any additional Shares, shares of any other class of
capital stock, other voting securities or any securities convertible into, or
rights, warrants or options, conditional or otherwise, to acquire, any of the
foregoing, payable or distributable to stockholders of record or their nominees
or transferees on Enex's stock transfer records on a date prior to the transfer
of the Shares purchased pursuant to the Offer to Purchase, then, subject to the
provisions of Section 14, (a) the Offer Price may, in the sole discretion of
Purchaser, be reduced by the amount of any such cash dividend or cash
distribution and (b) the whole of any such noncash dividend, distribution or
issuance to be received by the tendering stockholders will (i) be received and
held by the tendering stockholders for the account of Purchaser and will be
required to be promptly remitted and transferred by each tendering stockholder
to the Depositary for the account of Purchaser, accompanied by appropriate
documentation of transfer, or (ii) with respect to convertible securities,
rights, warrants and options, at the direction of Purchaser, be exercised for
the benefit of Purchaser, in which case the proceeds of such exercise will
promptly be remitted to Purchaser. Pending such remittance and subject to
applicable law, Purchaser will be entitled to all rights and privileges as owner
of any such noncash dividend, distribution, issuance or proceeds and may
withhold the entire Offer Price or deduct from the Offer Price the amount or
value thereof, as determined by Purchaser in its sole discretion.




                                     - 21 -

<PAGE>   22



13.      EFFECT OF THE OFFER ON THE MARKET FOR THE SHARES; EXCHANGE LISTING;
         EXCHANGE ACT REGISTRATION; MARGIN REGULATIONS

         Market for the Shares. The purchase of Shares pursuant to the Offer
will reduce the number of holders of Shares and the number of Shares that might
otherwise trade publicly and could adversely affect the liquidity and market
value of the remaining Shares held by the public.

         NASDAQ Listing. The Shares are listed on the National Market System
("NMS") of the NASDAQ Stock Market. According to the NASDAQ published
guidelines, NASDAQ would consider delisting the Shares if, among other things,
the number of holders of Shares should fall below 400, the number of
publicly-held Shares (exclusive of holdings of officers and directors of Enex
and their immediate families and other concentrated holdings of 10% or more)
should fall below 200,000, or the aggregate market value of the publicly-held
Shares should fall below $1,000,000. According to the Enex 10-KSB, there were
919 holders of record of Shares on March 1, 1997 and, according to the Enex
10-QSB, as of September 30, 1997, there were 1,344,452 Shares outstanding.

         If NASDAQ were to delist the Shares, the market therefor could be
adversely affected. It is possible that the Shares would be traded on other
securities exchanges or in the over-the-counter market, and that price
quotations would be reported by such exchanges or other sources. The extent of
the public market for the Shares and the availability of such quotations would,
however, depend upon the number of stockholders and/or the aggregate market
value of the Shares remaining at such time, the interest in maintaining a market
in the Shares on the part of securities firms, the possible termination of
registration of the Shares under the Exchange Act and other factors. If, as a
result of the purchase of the Shares pursuant to the Offer or otherwise, the
Shares no longer meet the requirements of NASDAQ for continued inclusion in the
NMS and the Shares are no longer included in the NMS, the market for and the
value of the Shares could be adversely affected.

         Exchange Act Registration. The Shares are currently registered under
the Exchange Act. Registration of the Shares under the Exchange Act may be
terminated upon application of Enex to the Commission if the Shares are neither
listed on a national securities exchange nor held by 300 or more holders of
record. Termination of registration of the Shares under the Exchange Act would
substantially reduce the information required to be furnished by Enex to its
stockholders and to the Commission and would make certain provisions of the
Exchange Act no longer applicable to Enex, such as the short-swing profit
recovery provisions of Section 16(b) of the Exchange Act, the requirement of
furnishing a proxy statement pursuant to Section 14(a) of the Exchange Act in
connection with stockholders' meetings and the related requirement of furnishing
an annual report to stockholders and the requirements of Rule 13e-3 under the
Exchange Act with respect to "going private" transactions. Furthermore, the
ability of "affiliates" of Enex and persons holding "restricted securities" of
Enex to dispose of such securities pursuant to Rule 144 or 144A promulgated
under the Securities Act may be impaired or eliminated. Purchaser intends to
seek to cause Enex to apply for termination of registration of the Shares under
the Exchange Act as soon after the completion of the Offer as the requirements
for such termination are met.

         Margin Regulations. The Shares are currently "margin securities" under
the regulations of the Board of Governors of the Federal Reserve System (the
"Federal Reserve Board"), which has the effect, among other



                                     - 22 -

<PAGE>   23



things, of allowing brokers to extend credit on the collateral of the Shares.
Depending upon factors similar to those described above regarding listing and
market quotations, it is possible that, following the Offer, the Shares would no
longer constitute "margin securities" for the purposes of the margin regulations
of the Federal Reserve Board and, therefore, could no longer be used as
collateral for loans made by brokers.

14.      CERTAIN CONDITIONS OF THE OFFER

         Notwithstanding any other provisions of the Offer, and in addition to
(and not in limitation of) Purchaser's rights to extend and amend the Offer at
any time in its sole discretion, Purchaser shall not be required to accept for
payment or, subject to any applicable rules and regulations of the Commission,
including Rule 14e-1(c) under the Exchange Act (relating to Purchaser's
obligation to pay for or return tendered Shares promptly after termination or
withdrawal of the Offer), pay for and may delay the acceptance for payment of
or, subject to the restriction referred to above, the payment for any tendered
Shares and may terminate the Offer if, in the sole judgment of Purchaser, (i) at
or prior to the Expiration Date any one or more of the Minimum Tender Condition
or the Board Action Condition has not been satisfied or (ii) at any time on or
after March 16, 1998 and before the time of payment for any such Shares (whether
or not any Shares have theretofore been accepted for payment pursuant to the
Offer), any of the following events shall occur or shall be determined by
Purchaser to have occurred:

                  (a)      there shall be threatened, instituted or pending any
         action, proceeding, application or counterclaim by any government or
         governmental, regulatory or administrative authority or agency,
         domestic, foreign or supranational (each, a "Governmental Entity"), or
         by any other person, domestic or foreign, before any court or
         Governmental Entity, (i)(A) challenging or seeking to or which is
         reasonably likely to make illegal, delay or otherwise directly or
         indirectly restrain or prohibit, or seeking to or which is reasonably
         likely to impose voting, procedural, price or other requirements, in
         addition to those required by federal securities laws and the Delaware
         Law (each as in effect on the date of this Offer to Purchase), in
         connection with the making of the Offer, the acceptance for payment of
         or payment for some of or all the Shares by Purchaser or any affiliate
         of Purchaser or the consummation by Purchaser or any affiliate of
         Purchaser of a merger or other similar business combination with Enex,
         (B) seeking to obtain material damages from Enex or (C) otherwise 
         directly or indirectly relating to the transactions contemplated by the
         Offer or any such merger or business combination, (ii) seeking to
         prohibit the ownership or operation by Purchaser or any affiliate of
         Purchaser of all or any portion of the business or assets of Enex and
         its affiliates or to compel Purchaser or any affiliate of Purchaser to
         dispose of or hold separate all or any portion of the business or
         assets of Enex or any of its affiliates or seeking to impose any
         limitation on the ability of Purchaser or any affiliate of Purchaser to
         conduct such business or own such assets, (iii) seeking to impose or
         confirm limitations on the ability of Purchaser or any affiliate of
         Purchaser effectively to exercise full rights of ownership of the
         Shares, including, without limitation, the right to vote any Shares
         acquired or owned by Purchaser or any affiliate of Purchaser on all
         matters properly presented to Enex's stockholders, (iv) seeking to
         require divestiture by Purchaser or any affiliate of Purchaser of any
         Shares, (v) seeking any material diminution in the benefits expected to
         be derived by Purchaser or any affiliate of Purchaser as a result of
         the transactions contemplated by the Offer or any merger or other
         similar business combination with



                                     - 23 -

<PAGE>   24



         Enex, (vi) otherwise directly or indirectly relating to the Offer or
         which otherwise, in the sole judgment of Purchaser, might materially
         adversely affect Enex or any of its affiliates or Purchaser or any
         affiliate of Purchaser or the value of the Shares or (vii) in the sole
         judgment of Purchaser, materially adversely affecting the business,
         properties, assets, liabilities, capitalization, stockholders' equity,
         condition (financial or otherwise), operations, licenses or franchises,
         results of operations or prospects of Enex or any of its affiliates;

                  (b)      there shall be any action taken, or any statute,
         rule, regulation, legislation, interpretation, judgment, order or
         injunction proposed, enacted, enforced, promulgated, amended, issued or
         deemed applicable to (i) Purchaser or any affiliate of Purchaser or
         Enex or (ii) the Offer or any merger or other similar business
         combination by Purchaser or any affiliate of Purchaser with Enex by any
         government, legislative body or court or Governmental Entity that, in
         the sole judgment of Purchaser, might directly or indirectly result in
         any of the consequences referred to in clauses (i) through (vii) of
         paragraph (a) above;

                  (c)      any change shall have occurred or been threatened (or
         any condition, event or development shall have occurred or been
         threatened involving a prospective change) in the business, properties,
         assets, liabilities, capitalization, stockholders' equity, condition
         (financial or otherwise), operations, licenses or franchises, results
         of operations or prospects of Enex or any of its affiliates that, in
         the sole judgment of Purchaser, is or may be materially adverse to Enex
         or any of its affiliates, or Purchaser shall have become aware of any
         facts that, in the sole judgment of Purchaser, have or may have
         material adverse significance with respect to either the value of Enex
         or any of its subsidiaries or the value of the Shares to Purchaser;

                  (d)      there shall have occurred or been threatened (i) any
         general suspension of trading in, or limitation on prices for
         securities on the NASDAQ Stock Market in the United States, (ii) any
         extraordinary or material adverse change in the financial markets or
         major stock exchange indices in the United States or in the market
         price of Shares, (iii) any change in the general political, market,
         economic or financial conditions in the United States that could, in
         the sole judgment of Purchaser, have a material adverse effect upon the
         business, properties, assets, liabilities, capitalization,
         stockholders' equity, condition (financial or otherwise), operations,
         licenses or franchises, results of operations or prospects of Enex or
         any of its subsidiaries or the trading in or value of the Shares, (iv)
         any material change in United States currency exchange rates or any
         other currency exchange rates or a suspension of or limitation on the
         markets therefor, (v) a declaration of a banking moratorium or any
         suspension of payments in respect of banks in the United States, (vi)
         any limitation (whether or not mandatory) by any government, domestic,
         foreign or supranational, or Governmental Entity on, or other event
         that, in the sole judgment of Purchaser, might affect the extension of
         credit by banks or other lending institutions in the United States,
         (vii) a commencement of a war or armed hostilities or other national or
         international calamity directly or indirectly involving the United
         States (other than presently threatened hostilities involving Iraq), or
         (viii) in the case of any of the foregoing existing at the time of the
         commencement of the Offer, a material acceleration or worsening 
         thereof;

                  (e)      Enex shall have (i) split, combined or otherwise
         changed, or authorized or proposed a split, combination or other change
         of the Shares or its capitalization (other than by redemption of



                                     - 24 -

<PAGE>   25



         the Rights in accordance with their terms as such terms have been
         publicly disclosed prior to February 19, 1998), (ii) acquired or
         otherwise caused a reduction in the number of, or authorized or
         proposed the acquisition or other reduction in the number of,
         outstanding Shares or other securities (other than as aforesaid), (iii)
         issued or sold, or authorized or proposed the issuance, distribution or
         sale of additional Shares (other than the issuance of Shares under
         option prior to February 10, 1998 in accordance with the terms of such
         options as such terms have been publicly disclosed prior to February
         19, 1998), shares of any other class of capital stock, other voting
         securities or any securities convertible into or rights, warrants or
         options, conditional or otherwise, to acquire any of the foregoing,
         (iv) declared or paid, or proposed to declare or pay, any dividend or
         other distribution, whether payable in cash, securities or other
         property, on or with respect to any shares of capital stock of Enex
         other than in the event the Rights are redeemed, the price of
         redemption thereof), (v) altered or proposed to alter any material term
         of any outstanding security (including the Rights) other than to amend
         the Rights Agreement to make the Rights inapplicable to the Offer, (vi)
         incurred any debt other than in the ordinary course of business or any
         debt containing burdensome covenants, (vii) authorized, recommended,
         proposed or entered into an agreement, agreement in principle or
         arrangement or understanding with respect to any merger, consolidation,
         liquidation, dissolution, business combination, acquisition of assets,
         disposition of assets, release or relinquishment of any material
         contractual or other right of Enex or any of its affiliates (other than
         with Purchaser or an affiliate of Purchaser) or any comparable event
         not in the ordinary course of business, (viii) authorized, recommended,
         proposed or entered into or announced its intention to authorize,
         recommend, propose or enter into any agreement, arrangement or
         understanding with any person or group that in the sole judgment of
         Purchaser could adversely affect either the value of Enex or any of its
         affiliates, joint ventures or partnerships or the value of the Shares
         to Purchaser, (ix) entered into or amended any employment, change in
         control, severance, executive compensation or similar agreement,
         arrangement or plan with or for the benefit of any of its employees,
         consultants or directors, or made grants or awards thereunder, other
         than in the ordinary course of business or entered into or amended any
         agreements, arrangements or plans so as to provide for increased or
         accelerated benefits to any such persons, (x) except as may be required
         by law, taken any action to terminate or amend any employee benefit
         plan (as defined in Section 3(2) of the Employee Retirement Income
         Security Act of 1974, as amended) of Enex or any of its affiliates, or
         Purchaser shall have become aware of any such action that was not
         disclosed in publicly-available filings prior to February 19, 1998, or
         (xi) amended or authorized or proposed any amendment to, Enex's
         Certificate of Incorporation or Enex's Bylaws, or Purchaser shall
         become aware that Enex or any of its affiliates shall have proposed or
         adopted any such amendment that was not disclosed to and consented by
         the Purchaser;

                  (f)      a tender or exchange offer for any Shares shall have
         been made or publicly proposed to be made by any other person
         (including Enex or any of its affiliates), or it shall have been
         publicly disclosed or Purchaser shall have otherwise learned that any
         person, entity (including Enex or any of its affiliates) or "group"
         (within the meaning of Section 13(d)(3) of the Exchange Act) shall have
         acquired or proposed to acquire beneficial ownership of more than 15%
         of any class or series of capital stock of Enex (including the Shares),
         through the acquisition of stock, the formation of a group or
         otherwise, or shall have been granted any right, option or warrant,
         conditional or otherwise, to acquire beneficial ownership of more than
         5% of any class or series of capital stock of Enex (including the
         Shares), or any person or group shall have entered into a definitive
         agreement or an agreement in 



                                     - 25 -

<PAGE>   26



         principle or made a proposal with respect to a tender offer or exchange
         offer or a merger, consolidation or other business combination with or
         involving Enex;

                  (g)      any approval, permit, authorization or consent of any
         Governmental Entity (including those described or referred to in
         Section 15) which is required to be obtained in order to consummate (i)
         the purchase of Shares contemplated by the Offer or (ii) a merger or
         other business combination with Enex shall not have been obtained on
         terms satisfactory to Purchaser in its sole discretion; or

                  (h)      Purchaser shall have reached an agreement or
         understanding with Enex providing for termination of the Offer, or
         Purchaser or any affiliate of Purchaser shall have entered into a
         definitive agreement or announced an agreement in principle with Enex
         providing for a merger or other business combination with Enex or the
         purchase of stock or assets of Enex;

which, in the sole judgment of Purchaser makes it inadvisable to proceed with
the Offer and/or with such acceptance for payment or payment.

         The foregoing conditions are for the sole benefit of Purchaser and may
be asserted by Purchaser regardless of the circumstances giving rise to any such
condition or may be waived by Purchaser in whole or in part at any time and from
time to time in its sole discretion. The failure by Purchaser at any time to
exercise any of the foregoing rights will not be deemed a waiver of any such
right, the waiver of any such right with respect to particular facts and
circumstances will not be deemed a waiver with respect to any other facts and
circumstances and each such right will be deemed an ongoing right that may be
asserted at any time and from time to time. Any determination by Purchaser
concerning the events described in this Section 14 will be final and binding
upon all parties.

15.      CERTAIN LEGAL MATTERS

         Appraisal Rights. Holders of the Shares do not have appraisal rights as
a result of the Offer. However, if any subsequent merger of Purchaser and Enex
is consummated, depending on the type of consideration received by the holders
of Shares upon the conversion of such Shares in such merger, holders of the
Shares at the effective time of such merger may have certain rights pursuant to
the provisions of Section 262 of the Delaware Law to dissent and demand
appraisal of their Shares.

         Anti-Trust Laws. Purchaser and Enex are exempt from the pre-merger
notification and waiting period required by the Hart-Scott-Rodino Act, 15 U.S.C.
ss.18a, et seq.                  

16.      FEES AND EXPENSES

         Purchaser has retained Bank of Oklahoma, N.A. to serve as the
Depositary in connection with the Offer. Purchaser may contact holders of Shares
by personal interviews, mail, telephone, facsimile, telegraph and other
electronic means and may request brokers, dealers and other nominee stockholders
to forward materials relating to the Offer to beneficial owners of Shares. The
Depositary has not been retained to make solicitations or recommendations in its
role as Depositary. The Depositary will receive reasonable and customary
compensation for its services, be reimbursed for certain reasonable
out-of-pocket expenses and be indemnified against certain liabilities and
expenses in connection therewith, including certain liabilities and expenses
under the federal securities laws.




                                     - 26 -

<PAGE>   27



         Purchaser will not pay any fees or commissions to any broker or dealer
or other person in connection with the solicitation of tenders of Shares
pursuant to the Offer. Brokers, dealers, banks and trust companies will be
reimbursed by Purchaser upon request for customary mailing and handling expenses
incurred by them in forwarding material to their customers. In the event the
Offer is consummated, Purchaser has agreed to pay a finders fee in an amount yet
to be determined to Clay Sylvester, a petroleum engineer who was instrumental in
introducing Purchaser to Enex. Mr. Sylvester will not participate in the Offer,
nor will he solicit tenders of Shares pursuant to the Offer.

17.      MISCELLANEOUS

         Purchaser is not aware of any jurisdiction where the making of the
Offer is prohibited by any administrative or judicial action pursuant to any
valid state statute. If Purchaser becomes aware of any valid state statute
prohibiting the making of the Offer or the acceptance of the Shares pursuant
thereto, Purchaser will make a good faith effort to comply with such state
statute. If, after such good faith effort, Purchaser cannot comply with any such
state statute, the Offer will not be made to (nor will tenders be accepted from
or on behalf of) the holders of Shares in such state. In any jurisdiction where
the securities, blue sky or other laws require the Offer to be made by a
licensed broker or dealer, the Offer shall be deemed to be made on behalf of
Purchaser by one or more registered brokers or dealers licensed under the laws
of such jurisdiction.

         NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATION ON BEHALF OF PURCHASER NOT CONTAINED HEREIN OR IN THE LETTER OF
TRANSMITTAL AND, IF GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATION MUST NOT
BE RELIED UPON AS HAVING BEEN AUTHORIZED BY PURCHASER. NEITHER THE DELIVERY OF
THIS OFFER TO PURCHASE NOR ANY PURCHASE PURSUANT TO THE OFFER SHALL, UNDER ANY
CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE HAS BEEN NO CHANGE IN THE
AFFAIRS OF PURCHASER OR ENEX SINCE THE DATE AS OF WHICH INFORMATION IS FURNISHED
OR THE DATE OF THIS OFFER TO PURCHASE.

         Purchaser has filed with the Commission a Tender Offer Statement on
Schedule 14D-1, together with exhibits, pursuant to Rule 14d-3 under the
Exchange Act, furnishing certain additional information with respect to the
Offer, and Enex will file with the Commission a Solicitation/Recommendation
Statement pursuant to Section 14(d)(4) of the Exchange Act on Schedule 14D-9,
setting forth the recommendation of the Board of Directors of Enex with respect
to the Offer and other pertinent information as promptly as possible following
the filing of this Schedule 14D-1, but in any event no later than five business
days after the Offer commences, and both may file amendments thereto from time 
to time. Such Schedule 14D-1 and Schedule 14D-9 of Enex and any amendments 
thereto, including exhibits, should be available for inspection and copies 
should be obtainable in the manner set forth in Section 8 (except that such 
material will not be available at the regional offices of the Commission).

                                    MIDDLE BAY OIL COMPANY, INC.
                                    1221 Lamar, Suite 1020
                                    Houston, Texas 77010
                                    (713) 759-6808

February 19, 1998



                                     - 27 -

<PAGE>   28



                                   SCHEDULE I

                  DIRECTORS AND EXECUTIVE OFFICERS OF PURCHASER


         The name, business address, present principal occupation or employment
and five-year employment history of each of the directors and executive officers
of Middle Bay Oil Company, Inc. are set forth below. Unless otherwise indicated,
the principal business address of each director or executive officers is Middle
Bay Oil Company, Inc., 1221 Lamar, Suite 1020, Houston, Texas 77010. Directors
are identified by an asterisk. Each such person is a citizen of the United
States.

         NAME AND BUSINESS
             ADDRESS                      POSITION; PRINCIPAL OCCUPATION OR
                                      EMPLOYMENT; FIVE-YEAR EMPLOYMENT HISTORY


John J. Bassett*                    Mr. Bassett is Middle Bay's President and
                                    Chief Executive Officer, a position he has
                                    held since 1992. Mr. Bassett has also served
                                    as the Chairman of the Board of Directors of
                                    Middle Bay since 1992. He also serves as
                                    President and a director of Bay City Energy
                                    Group, Inc., a principal shareholder of
                                    Middle Bay.

C. J. Lett, III*                    Mr. Lett currently serves as Middle Bay's   
9320 East Central                   Executive Vice President, a position he has 
Wichita, Kansas 67206               held since February, 1997. Mr. Lett also    
                                    serves as President and a director of Bison 
                                    Energy Corporation which he founded in 1981.
                                    In February, 1997, Bison Energy Corporation 
                                    was acquired by Middle Bay. Mr. Lett has    
                                    served as a director of Middle Bay since    
                                    February, 1997.                             
                                    
Stephen W. Herod*                   Mr. Herod currently serves as Vice President
                                    for Corporate Development of Middle Bay, a
                                    position he has held since July, 1997. Prior
                                    to that time, Mr. Herod served as President
                                    of Shore Oil Company from April, 1992 to
                                    June, 1997. Shore Oil Company was acquired
                                    by Middle Bay in July, 1997, and he has
                                    served as a director of Middle Bay since
                                    that time.

Frank C. Turner, II                 Mr. Turner currently serves as the Vice
                                    President and Chief Financial Officer of
                                    Middle Bay, a position he has held since its
                                    organization as a corporation in 1992. Mr.
                                    Turner served as a director of Middle Bay
                                    from 1992 to July, 1997.

Robert W. Hammons                   Mr. Hammons currently serves as Vice
                                    President of Engineering for Middle Bay, a
                                    position he has held since 1993. Mr. Hammons
                                    also served as a director from 1993 to
                                    March, 1995.

Frank E. Bolling, Jr.*              Mr. Bolling is Vice President of Midstream  
6239 Highway 90                     Fuel Services, Inc. and Manager of the      
Moss Point, Mississippi 39563       Dantzler-Pepco Division of Midstream Fuel   
                                    Services, Inc., positions he has held since 
                                    February, 1995. Mr. Bolling formerly served 
                                    as General Manager of Dantzler Bulk Plant,  
                                    Inc., a distributor for Chevron U.S.A., Inc.
                                    from 1989 to January, 1995. Mr. Bolling has 
                                    served as a director of Middle Bay since    
                                    1995.                                       


<PAGE>   29



                                    

Gary R. Christopher*                Mr. Christopher is the Acquisitions         
Kaiser-Francis Oil Company          Coordinator for Kaiser- Francis Oil Company,
6733 South Yale                     a position he has held since February, 1996.
Tulsa, Oklahoma 74136               Prior to that time, Mr. Christopher served  
                                    as Senior Vice President and Manager of
                                    Energy Lending for the Bank of Oklahoma from
                                    serve as a consultant to the Bank of        
                                    Oklahoma. Mr. Christopher became a director 
                                    of Middle Bay in May, 1997.

Alvin V. Shoemaker*                 Mr. Shoemaker's principal occupation for the
8800 First Avenue                   past five years has been as a private       
Stone Harbor, New Jersey 08427      investor. Prior to that time, Mr. Shoemaker 
                                    served as Chairman of the Board of Trustees 
                                    of the University of Pennsylvania and Vice  
                                    Chairman of the Securities Industry         
                                    Association. He has also served as a        
                                    director of Harcourt Brace Jovanovich, Royal
                                    Insurance of America, the Council on Foreign
                                    Relations and the Wharton School of Finance.
                                    Mr. Shoemaker has been a director of Middle 
                                    Bay since July, 1997.                       
                                    
Edward P. Turner, Jr.*              Mr. Turner is a managing partner of the law 
Turner, Onderdonk, Kimbrough &      firm of Turner, Onderdonk, Kimbrough &      
    Howell, P.A.                    Howell, P.A., with whom he has been         
1021 Central Avenue                 associated for over 25 years. Mr. Turner has
Chatom, Alabama 36518               served as a director of Middle Bay since its
                                    inception in 1992.                          
                                    











                                   


<PAGE>   1



                              LETTER OF TRANSMITTAL
                        TO TENDER SHARES OF COMMON STOCK
                                       OF
                           ENEX RESOURCES CORPORATION
            PURSUANT TO THE OFFER TO PURCHASE DATED FEBRUARY 19, 1998
                                       OF
                          MIDDLE BAY OIL COMPANY, INC.


                 THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT
        12:00 MIDNIGHT, CENTRAL STANDARD TIME, ON MONDAY, MARCH 16, 1998,
             UNLESS THE OFFER IS EXTENDED. SHARES WHICH ARE TENDERED
                  PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY
                       TIME PRIOR TO THE EXPIRATION DATE.

The Depositary for the Offer is:

                           THE BANK OF OKLAHOMA, N.A.

<TABLE>
<CAPTION>
       By Mail:                 Facsimile Transmission:            By Hand or Overnight Courier:
       --------                 -----------------------            -----------------------------

<S>                         <C>                                    <C>         
Bank of Oklahoma, N.A.               (405) 936-3964                Bank of Oklahoma, N.A.
Attn:  Cyndi Wilkinson      (For Eligible Institutions Only)       Commerce Center, Suite 110
P.O. Box 24128                   Confirm by Telephone:             9520 North May Avenue
                                 ---------------------
Oklahoma City, OK  73124            (405) 936-3902                 Oklahoma City, OK  73120
</TABLE>


DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS, OR TRANSMISSION OF
INSTRUCTIONS VIA FACSIMILE TO A NUMBER OTHER THAN AS SET FORTH ABOVE, DOES NOT
CONSTITUTE A VALID DELIVERY TO THE DEPOSITARY.

THE INSTRUCTIONS ACCOMPANYING THIS LETTER OF TRANSMITTAL SHOULD BE READ
CAREFULLY BEFORE THIS LETTER OF TRANSMITTAL IS COMPLETED.

         This Letter of Transmittal is to be used if certificates for Shares (as
such term is defined below) are to be forwarded herewith or, unless an Agent's
Message (as defined in Instruction 2 below) is utilized, if delivery of Shares
is to be made by book-entry transfer to an account maintained by the Depositary
at the Book-Entry Transfer Facility (as defined in and pursuant to the
procedures set forth in Section 2 of the Offer to Purchase). Stockholders who
deliver Shares by book-entry transfer are referred to herein as "Book-Entry
Stockholders" and other stockholders who deliver shares are referred to herein
as "Certificate Stockholders."

         Stockholders whose certificates for Shares are not immediately
available or who cannot deliver either the certificates for, or a Book-Entry
Confirmation (as defined in Section 2 of the Offer to Purchase) with respect to,
their Shares and all other documents required hereby to the Depositary prior to
the Expiration Date (as defined in Section 1 of the Offer to Purchase) must
tender their Shares pursuant to the guaranteed delivery procedures set forth in
Section 2 of the Offer to Purchase. (See Instruction 2.) DELIVERY OF DOCUMENTS
TO A BOOK-ENTRY TRANSFER FACILITY DOES NOT CONSTITUTE DELIVERY TO THE
DEPOSITARY.



                                  Page 1 of 22
<PAGE>   2


(BOXES BELOW FOR USE BY ELIGIBLE INSTITUTIONS ONLY)

[ ]      CHECK HERE IF TENDERED SHARES ARE BEING DELIVERED BY BOOK-ENTRY
         TRANSFER TO THE DEPOSITARY'S ACCOUNT AT AMERICAN STOCK TRANSFER, INC.
         AND COMPLETE THE FOLLOWING (ONLY PARTICIPANTS IN A BOOK-ENTRY TRANSFER
         FACILITY MAY DELIVER SHARES BY BOOK-ENTRY TRANSFER):

         Name of Tendering Institution
                                       ----------------------------------------

         Account Number                   Transaction Code Number
                       -----------------                          --------------

[ ]      CHECK HERE IF TENDERED SHARES ARE BEING DELIVERED PURSUANT TO A NOTICE
         OF GUARANTEED DELIVERY PREVIOUSLY SENT TO THE DEPOSITARY AND COMPLETE
         THE FOLLOWING:

         Name(s) of Registered Owner(s)
                                        ----------------------------------------
         Window Ticket Number (if any)
                                       -----------------------------------------

         Date of Execution of Notice of Guaranteed Delivery
                                                            --------------------
         Name of Institution which Guaranteed Delivery
                                                       -------------------------

IF DELIVERED BY BOOK-ENTRY TRANSFER, PLEASE COMPLETE THE FOLLOWING:

         Account Number                   Transaction Code Number
                       -----------------                          --------------


                         DESCRIPTION OF SHARES TENDERED

NAME(S) AND ADDRESS(ES) OF
                                    -----------------------------------------
REGISTERED HOLDER(S):  
                                    -----------------------------------------
(Please fill in blanks exactly 
                                    -----------------------------------------
as Name(s) Appear(s) on 
                                    -----------------------------------------
Certificate(s))
                                    -----------------------------------------


                                 SHARES TENDERED
                  (Attach Additional Signed List if Necessary)

<TABLE>
<CAPTION>
        CERTIFICATE             TOTAL NUMBER OF SHARES             NUMBER OF
       NUMBER(S)(1)        REPRESENTED BY CERTIFICATE(S)(1)   SHARES TENDERED(2)

     <S>                   <C>                                <C>
     -----------------         ----------------------           --------------
     -----------------         ----------------------           --------------
     -----------------         ----------------------           --------------

TOTAL SHARES TENDERED          ======================           ============== 
</TABLE>

(1)      Need not be completed by Book-Entry Stockholders.

(2)      Unless otherwise indicated, it will be assumed that all Shares
         described above are being tendered. (See Instruction 4.)

                    NOTE: SIGNATURES MUST BE PROVIDED BELOW.
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY.



                                  Page 2 of 22
<PAGE>   3

Ladies and Gentlemen:

         The undersigned hereby tenders to Middle Bay Oil Company, Inc., an
Alabama corporation ("Purchaser" or "Middle Bay"), the above-described shares of
Common Stock, par value $0.05 per share (the "Shares"), of Enex Resources
Corporation, a Delaware corporation ("Enex"), pursuant to Purchaser's offer to
purchase all outstanding Shares at a price of $15.00 per Share net to the seller
in cash without interest thereon (the "Offer Price") upon the terms and subject
to the conditions set forth in the Offer to Purchase dated February 19, 1998,
and in this Letter of Transmittal (which together, with any amendments or
supplements thereto or hereto, collectively constitute the "Offer"), receipt of
which is hereby acknowledged.

         Upon the terms and subject to the conditions of the Offer (and if the
Offer is extended or amended, the terms of any such extension or amendment),
subject to and effective upon acceptance for payment of and payment for the
Shares tendered herewith in accordance with the terms of the Offer, the
undersigned hereby sells, assigns and transfers to or upon the order of
Purchaser all right, title and interest in and to all the Shares that are being
tendered hereby (and any and all other Shares or other securities issued or
issuable in respect thereof on or after February 19, 1998) and irrevocably
constitutes and appoints the Depositary the true and lawful agent and
attorney-in-fact of the undersigned with respect to such Shares (and all such
other Shares or securities), with full power of substitution (such power of
attorney being deemed to be an irrevocable power coupled with an interest), to
(a) deliver certificates for such Shares (and all such other Shares or
securities), or transfer ownership of such Shares (and all such other Shares or
securities) on the account books maintained by the Book-Entry Transfer Facility,
together, in any such case, with all accompanying evidences of transfer and
authenticity to or upon the order of Purchaser, (b) present such Shares (and all
such other Shares or securities) for transfer on the books of Enex, and (c)
receive all benefits and otherwise exercise all rights of beneficial ownership
of such Shares (and all such other Shares or securities), all in accordance with
the terms of the Offer.

         If, on or after February 19, 1998, Enex should declare or pay any cash
dividend on the Shares or other distribution on the Shares, or issue with
respect to the Shares any additional Shares, shares of any other class of
capital stock, other voting securities or any securities convertible into, or
rights, warrants or options, conditional or otherwise, to acquire any of the
foregoing, payable or distributable to stockholders of record on a date prior to
the transfer of the Shares purchased pursuant to the Offer to Purchaser or its
nominee or transferee on Enex's stock transfer records, then, subject to the
provisions of Section 14 in the Offer to Purchase, (a) the Offer Price may, in
the sole discretion of Purchaser, be reduced by the amount of any such cash
dividend or cash distribution and (b) the whole of any such noncash dividend,
distribution or issuance to be received by the tendering stockholders will (i)
be received and held by the tendering stockholders for the account of Purchaser
and will be required to be promptly remitted and transferred by each tendering
stockholder to the Depositary for the account of Purchaser, accompanied by
appropriate documentation of transfer or (ii) with respect to convertible
securities, rights, warrants and options, at the direction of Purchaser, be
exercised for the benefit of Purchaser, in which case the proceeds of such
exercise will promptly be remitted to Purchaser. Pending such remittance and
subject to applicable law, Purchaser will be entitled to all rights and
privileges as owner of any such noncash dividend, distribution, issuance or
proceeds and may withhold the 




                                  Page 3 of 22
<PAGE>   4

entire Offer Price or deduct from the Offer Price the amount or value thereof,
as determined by Purchaser in its sole discretion.

         The undersigned hereby irrevocably appoints John J. Bassett, Stephen W.
Herod and Frank C. Turner, II, in their respective capacities as officers of
Purchaser, and any individual who shall thereafter succeed to any such office of
Purchaser, and each of them, the attorneys-in-fact and proxies of the
undersigned, each with full power of substitution, to vote at any annual or
special or adjourned meeting of Enex's stockholders or any adjournment or
postponement thereof or otherwise in such manner as each such attorneys-in-fact
and proxies or their substitutes shall in their sole discretion deem proper with
respect to, to execute any written consent concerning any matter as each such
attorneys-in-fact and proxies or their substitutes shall in their sole
discretion deem proper with respect to, and to otherwise act as each such
attorney-in-fact and proxy or his substitute shall in his sole discretion deem
proper with respect to, all of the Shares tendered hereby (and any and all other
Shares or other securities issued or issuable in respect thereof on or after
February 19, 1998), which have been accepted for payment by Purchaser prior to
the time any action is taken and with respect to which the undersigned is
entitled to vote. This appointment is effective when, and only to the extent
that, Purchaser accepts for payment such Shares as provided in the Offer to
Purchase. This power of attorney and proxy are irrevocable and are granted in
consideration of the acceptance for payment of such Shares in accordance with
the terms of the Offer. Such acceptance for payment shall, without further
action, revoke any prior powers of attorney and proxies appointed by the
undersigned at any time with respect to such Shares (and all such other Shares
or securities), and no subsequent powers of attorney or proxies will be
appointed or be effective with respect thereto.

         The undersigned hereby represents and warrants that the undersigned has
full power and authority to tender, sell, assign and transfer the Shares
tendered hereby (and any and all other Shares or other securities issued or
issuable in respect thereof on or after February 19, 1998) and that when the
same are accepted for payment by Purchaser, Purchaser will acquire good,
marketable and unencumbered title thereto, free and clear of all liens,
restrictions, charges and encumbrances and the same will not be subject to any
adverse claims. The undersigned will, upon request, execute and deliver any
additional documents deemed by the Depositary or Purchaser to be necessary or
desirable to complete the sale, assignment and transfer of the Shares tendered
hereby (and all such other Shares or securities).

         All authority herein conferred or agreed to be conferred shall survive
the death or incapacity of the undersigned, and any obligation of the
undersigned hereunder shall be binding upon the heirs, executors,
administrators, representatives, trustees in bankruptcy, successors and assigns
of the undersigned. Except as stated in the Offer, this tender is irrevocable.

         The undersigned understands that the valid tender of Shares pursuant to
any one of the procedures described in Section 2 of the Offer to Purchase and in
the Instructions hereto will constitute a binding agreement between the
undersigned and Purchaser upon the terms and subject to the conditions of the
Offer (and if the Offer is extended or amended, the terms or conditions of any
such extension or amendment). Without limiting the foregoing, if the price to be
paid in the Offer is amended in accordance with the Offer, the price to be paid
to the undersigned will be the amended price, notwithstanding the fact that a
different price is 




                                  Page 4 of 22
<PAGE>   5

stated in this Letter of Transmittal. The undersigned recognizes that under
certain circumstances set forth in the Offer to Purchase, Purchaser may not be
required to accept for payment any of the Shares tendered hereby.

         Unless otherwise indicated under "Special Payment Instructions," please
issue the check for the purchase price and/or return any certificates for Shares
not tendered or accepted for payment in the name(s) of the registered holder(s)
appearing under "Description of Shares Tendered." Similarly, unless otherwise
indicated under "Special Delivery Instructions," please mail the check for the
purchase price and/or return any certificates for Shares not tendered or
accepted for payment (and accompanying documents, as appropriate) to the
address(es) of the registered holder(s) appearing under "Description of Shares
Tendered." In the event that both the "Special Payment Instructions" and the
"Special Delivery Instructions" are completed, please issue the check for the
purchase price and/or return any certificates for Shares not tendered or
accepted for payment (and any accompanying documents, as appropriate) in the
name(s) of, and deliver such check and/or return any such certificates (and any
accompanying documents, as appropriate) to, the person(s) so indicated. Unless
otherwise indicated herein under "Special Payment Instructions," please credit
any Shares tendered herewith by book-entry transfer that are not accepted for
payment by crediting the account at the Book-Entry Transfer Facility (as defined
herein) designated above. The undersigned recognizes that Purchaser has no
obligation, pursuant to the "Special Payment Instructions," to transfer any
Shares from the name of the registered holder thereof if Purchaser does not
accept for payment any of the Shares so tendered.

[ ]      CHECK HERE IF ANY OF THE CERTIFICATES REPRESENTING SHARES THAT YOU OWN
         HAVE BEEN LOST OR DESTROYED AND SEE INSTRUCTION 11.

                  NUMBER OF SHARES REPRESENTED BY THE LOST OR DESTROYED
- ---------------   CERTIFICATES






















                                  Page 5 of 22
<PAGE>   6



                          SPECIAL PAYMENT INSTRUCTIONS
                        (SEE INSTRUCTIONS 1, 5, 6 AND 7)

         To be completed ONLY if certificates for Shares are not tendered or not
accepted for payment and/or the check for the purchase price of Shares accepted
for payment are to be issued in the name of someone other than the undersigned,
or if Shares delivered by book-entry transfer that are not accepted for payment
are to be returned by credit to an account maintained at a Book-Entry Transfer
Facility other than the account indicated
above.

Issue  [ ] Check   [ ] Certificates to:


Name:
     ---------------------------------------------------------------------------
                                 (PLEASE PRINT)

Address:
         -----------------------------------------------------------------------

- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------
               (TAXPAYER IDENTIFICATION OR SOCIAL SECURITY NUMBER)

Credit unpurchased Shares delivered by book-entry transfer to the Book-Entry
Transfer Facility account set forth below:

- --------------------------------------------------------------------------------

- ----------------------------------------------------
                   (ACCOUNT NUMBER)



















                                  Page 6 of 22
<PAGE>   7



                         SPECIAL DELIVERY INSTRUCTIONS
                        (SEE INSTRUCTIONS 1, 5, 6 AND 7)

         To be completed ONLY if certificates for Shares are not tendered or not
accepted for payment and/or the check for the purchase price of Shares accepted
for payment are to be sent to someone other than the undersigned or to the
undersigned at an address other than that indicated above.

Mail  [ ]  Check   [ ] Certificates to:

Name:
     ---------------------------------------------------------------------------
                                 (PLEASE PRINT)

Address:
        ------------------------------------------------------------------------

- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------
                               (INCLUDE ZIP CODE)

- --------------------------------------------------------------------------------
               (TAXPAYER IDENTIFICATION OR SOCIAL SECURITY NUMBER)

























                                  Page 7 of 22
<PAGE>   8



               SIGN HERE (ALSO COMPLETE SUBSTITUTE FORM W-9 BELOW)


                  ---------------------------------------------------------


                  ---------------------------------------------------------
                              (Signature(s) of Stockholder(s))

Dated:                      , 1998
       ---------------------

         (Must be signed by registered holder(s) as name(s) appear(s) on the
         certificate(s) for the Shares or on a security position listing or by
         person(s) authorized to become registered holder(s) by certificates and
         documents transmitted herewith. If signature is by trustees, executors,
         administrators, guardians, attorneys-in-fact, officers of corporations
         or others acting in a fiduciary or representative capacity, please
         provide the following information and see Instruction 5.)

Name(s):
         -----------------------------------------------------------------------
                                 (Please Print)

Name of Firm:
             -------------------------------------------------------------------

Capacity (full title): 
                      ----------------------------------------------------------

Address:
         -----------------------------------------------------------------------

- --------------------------------------------------------------------------------
                               (Include Zip Code)

Area Code and Telephone No.: 
                            ------------------------------------------

Taxpayer Identification or Social Security No.: 
                                               -----------------------------
















                                  Page 8 of 22
<PAGE>   9



                           GUARANTEE OF SIGNATURE(S)
                           (See Instructions 1 and 5)

Authorized Signature: 
                     -----------------------------------------------------------

Name:
     ---------------------------------------------------------------------------
                                 (Please Print)

Name of Firm:
             -------------------------------------------------------------------

Address:
         -----------------------------------------------------------------------

- --------------------------------------------------------------------------------
                               (Include Zip Code)

Area Code and Telephone No.:
                             ----------------------------------






















                                  Page 9 of 22
<PAGE>   10



                                  INSTRUCTIONS
              FORMING PART OF THE TERMS AND CONDITIONS OF THE OFFER

1.       GUARANTEE OF SIGNATURES. No signature guarantee is required on this
         Letter of Transmittal (a) if this Letter of Transmittal is signed by
         the registered holder(s) (which term, for purposes of this Section,
         includes any participant in the Book-Entry Transfer Facility's system
         whose name appears on a security position listing as the owner of the
         Shares) of Shares tendered herewith, unless such registered holder(s)
         has completed either the box entitled "Special Payment Instructions" or
         the box entitled "Special Delivery Instructions" on the Letter of
         Transmittal or (b) if such Shares are tendered for the account of a
         financial institution (including most commercial banks, savings and
         loan associations and brokerage houses) that is a participant in the
         Security Transfer Agents Medallion Program, the NASDAQ Guarantee
         Program or the Stock Exchange Medallion Program (an "Eligible
         Institution"). In all other cases, all signatures on this Letter of
         Transmittal must be guaranteed by an Eligible Institution. (See
         Instruction 5.)

2.       DELIVERY OF LETTER OF TRANSMITTAL AND SHARES. This Letter of
         Transmittal is to be completed by stockholders either if certificates
         are to be forwarded herewith or, unless an Agent's Message is utilized,
         if delivery of Shares is to be made by book-entry transfer pursuant to
         the procedures set forth in Section 2 of the Offer to Purchase. For a
         stockholder validly to tender Shares pursuant to the Offer, either (a)
         a properly completed and duly executed Letter of Transmittal (or
         facsimile thereof), together with any required signature guarantees or
         an Agent's Message (in connection with book-entry transfer) and any
         other required documents, must be received by the Depositary at one of
         its addresses set forth on page 1 prior to the Expiration Date and
         either (i) certificates for tendered Shares must be received by the
         Depositary at its "By Mail" or its "By Hand or Overnight Courier"
         address prior to the Expiration Date or (ii) Shares must be delivered
         pursuant to the procedures for book-entry transfer set forth herein and
         a Book-Entry Confirmation must be received by the Depositary prior to
         the Expiration Date or (b) the tendering stockholder must comply with
         the guaranteed delivery procedures set forth below and in Section 2 of
         the Offer to Purchase.

         Stockholders whose certificates for Shares are not immediately
         available or who cannot deliver their certificates and all other
         required documents to the Depositary prior to the Expiration Date or
         who cannot comply with the book-entry transfer procedure on a timely
         basis may tender their Shares by properly completing and duly executing
         the Notice of Guaranteed Delivery pursuant to the guaranteed delivery
         procedure set forth in Section 2 of the Offer to Purchase.

         Pursuant to such procedures, (i) such tender must be made by or through
         an Eligible Institution, (ii) a properly completed and duly executed
         Notice of Guaranteed Delivery, substantially in the form provided by
         Purchaser, must be received by the Depositary prior to the Expiration
         Date and (iii) the certificates for all tendered Shares, in proper form
         for transfer (or a Book-Entry Confirmation with respect to all tendered
         Shares), together with a properly completed and duly executed Letter of
         Transmittal (or a facsimile thereof), with any required signature
         guarantees, or, in the case of a book-entry transfer, an Agent's
         Message, and any other required documents are received by the
         Depositary within three trading days after the date of execution of
         such Notice of Guaranteed Delivery, all as provided in Section 2 of the
         Offer to Purchase. A "trading day" is any day on which the NASDAQ
         National Market is open for business.








                                 Page 10 of 22
<PAGE>   11



       The term "Agent's Message" means a message, transmitted by the Book-Entry
       Transfer Facility to and received by the Depositary and forming a part of
       a Book-Entry Confirmation, which states that such Book-Entry Transfer
       Facility has received an express acknowledgment from the participant in
       such Book-Entry Transfer Facility tendering the Shares, that such
       participant has received and agrees to be bound by the terms of the
       Letter of Transmittal and that the Purchaser may enforce such agreement
       against the participant.

       THE METHOD OF DELIVERY OF THE SHARES, THE LETTER OF TRANSMITTAL AND ALL
       OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH THE BOOK-ENTRY
       TRANSFER FACILITY, IS AT THE ELECTION AND RISK OF THE TENDERING
       STOCKHOLDER. THE SHARES WILL BE DEEMED DELIVERED ONLY WHEN ACTUALLY
       RECEIVED BY THE DEPOSITARY (INCLUDING, IN THE CASE OF A BOOK-ENTRY
       TRANSFER, BY BOOK-ENTRY CONFIRMATION). IF DELIVERY IS BY MAIL, REGISTERED
       MAIL WITH RETURN RECEIPT REQUESTED, PROPERLY INSURED, IS RECOMMENDED. IN
       ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY.

       No alternative, conditional or contingent tenders will be accepted, and
       no fractional Shares will be purchased. All tendering stockholders, by
       executing this Letter of Transmittal (or facsimile thereof), waive any
       right to receive any notice of the acceptance of their Shares for
       payment.

3.     INADEQUATE SPACE. If the space provided herein is inadequate, the
       number of Shares tendered and the Share certificate numbers with respect
       to such Shares should be listed on a separate signed schedule attached
       hereto.

4.     PARTIAL TENDERS. (Not applicable to stockholders who tender by
       book-entry transfer). If fewer than all the Shares evidenced by any
       certificate submitted are to be tendered, fill in the number of Shares
       that are to be tendered in the box entitled "Number of Shares Tendered."
       In any such case, new certificate(s) for the remainder of the Shares that
       were evidenced by the old certificate(s) will be sent to the registered
       holder, unless otherwise provided in the appropriate box on this Letter
       of Transmittal, as soon as practicable after the Expiration Date or the
       termination of the Offer. All Shares represented by certificates
       delivered to the Depositary will be deemed to have been tendered unless
       otherwise indicated.

5.     SIGNATURES ON LETTER OF TRANSMITTAL, STOCK POWERS AND ENDORSEMENTS. If
       this Letter of Transmittal is signed by the registered holder(s) of the
       Shares tendered hereby, the signature(s) must correspond with the name(s)
       as written on the face of the certificate(s), without alteration,
       enlargement or any change whatsoever.

       If any of the Shares tendered hereby are held of record by two or more
       joint owners, all such owners must sign this Letter of Transmittal.

       If any of the tendered Shares are registered in different names on
       several certificates, it will be necessary to complete, sign and submit
       as many separate Letters of Transmittal as there are different
       registrations of certificates.




                                 Page 11 of 22
<PAGE>   12



         If this Letter of Transmittal or any certificate or stock power is
         signed by a trustee, executor, administrator, guardian,
         attorney-in-fact, officer of a corporation or other person acting in a
         fiduciary or representative capacity, such person should so indicate
         when signing, and proper evidence satisfactory to Purchaser of the
         authority of such person so to act must be submitted.

         If this Letter of Transmittal is signed by the registered holder(s) of
         the Shares listed and transmitted hereby, no endorsements of
         certificates or separate stock powers are required unless payment or
         certificates for Shares not tendered or accepted for payment are to be
         issued in the name of a person other than the registered holder(s).
         Signatures on any such certificates or stock powers must be guaranteed
         by an Eligible Institution.

         If this Letter of Transmittal is signed by a person other than the
         registered holder(s) of the Shares evidenced by certificates listed and
         transmitted hereby, the certificates must be endorsed or accompanied by
         appropriate stock powers, in either case signed exactly as the name(s)
         of the registered holder(s) appear(s) on the certificates. Signature(s)
         on any such certificates or stock powers must be guaranteed by an
         Eligible Institution.

6.       STOCK TRANSFER TAXES. Except as set forth in this Instruction 6, the
         Purchaser will pay any stock transfer taxes with respect to the
         transfer and sale of Shares to it or its order pursuant to the Offer.
         If, however, payment of the purchase price is to be made to, or if
         certificates for Shares not tendered or accepted for payment are to be
         registered in the name of, any person other than the registered
         holder(s), or if tendered certificates are registered in the name of
         any person other than the person(s) signing this Letter of Transmittal,
         the amount of any stock transfer taxes (whether imposed on the
         registered holder(s) or such person) payable on account of the transfer
         to such person will be deducted from the purchase price unless
         satisfactory evidence of the payment of such taxes or exemption
         therefrom is submitted.

         EXCEPT AS PROVIDED IN THIS INSTRUCTION 6, IT WILL NOT BE NECESSARY FOR
         TRANSFER TAX STAMPS TO BE AFFIXED TO THE CERTIFICATES LISTED IN THIS
         LETTER OF TRANSMITTAL.

7.       SPECIAL PAYMENT AND DELIVERY INSTRUCTIONS. If a check is to be issued
         in the name of, and/or certificates for Shares not accepted for payment
         are to be returned to a person other than the signer of this Letter of
         Transmittal or if a check is to be sent and/or such certificates are to
         be returned to a person other than the signer of this Letter of
         Transmittal, or to an address other than that shown above, the
         appropriate boxes on this Letter of Transmittal should be completed.
         Any stockholder(s) delivering Shares by book-entry transfer may request
         that Shares not purchased be credited to such account maintained at the
         Book-Entry Transfer Facility. If no such instructions are given, any
         such Shares not purchased will be returned by crediting the account at
         the Book-Entry Transfer Facility.

8.       REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES. Questions and requests
         for assistance or additional copies of the Offer to Purchase, this
         Letter of Transmittal, the Notice of Guaranteed Delivery and the
         Guidelines for Certification of Taxpayer Identification Number on
         Substitute Form W-9 may be directed to Purchaser at the address or
         telephone number set forth below.




                                 Page 12 of 22
<PAGE>   13



9.       WAIVER OF CONDITIONS. Purchaser reserves the absolute right in its sole
         discretion to waive, at any time or from time to time, any of the
         specified conditions of the Offer, in whole or in part, in the case of
         any Shares tendered.

10.      BACKUP WITHHOLDING. In order to avoid "backup withholding" of federal
         income tax on payments of cash pursuant to the Offer, a stockholder
         surrendering Shares in the Offer must, unless an exemption applies,
         provide the Depositary with such stockholder's correct taxpayer
         identification number ("TIN") on Substitute Form W-9 in this Letter of
         Transmittal and certify under penalties of perjury that such TIN is
         correct and that such stockholder is not subject to backup withholding.
         If a stockholder does not provide such stockholder's correct TIN or
         fails to provide the certifications described above, the payment to
         such stockholder pursuant to the Offer may be subject to backup
         withholding of 31%.

         Backup withholding is not an additional income tax. Rather, the amount
         of the backup withholding can be credited against the federal income
         tax liability of the person subject to the backup withholding, provided
         that the required information is given to the IRS. If backup
         withholding results in an overpayment of tax, a refund can be obtained
         by the stockholder upon filing an income tax return.

         Certain stockholders (including, among others, all corporations and
         certain foreign individuals and entities) are not subject to backup
         withholding. Noncorporate foreign stockholders should complete and sign
         the main signature form and a Form W-8, Certificate of Foreign Status,
         a copy of which may be obtained from the Depositary, in order to avoid
         backup withholding. (See the enclosed "Guidelines for Certification of
         Taxpayer Identification Number on Substitute Form W-9" for more
         instructions.)

11.      LOST, DESTROYED OR STOLEN CERTIFICATES. If any certificate(s)
         representing Shares has been lost, destroyed or stolen, the stockholder
         should promptly notify the Depositary by checking the box immediately
         preceding the special payment/special delivery instructions and
         indicating the number of Shares lost. The stockholder will then be
         instructed as to the steps that must be taken in order to replace the
         certificate(s). This Letter of Transmittal and related documents cannot
         be processed until the procedures for replacing lost, stolen or
         destroyed certificates have been followed.

         IMPORTANT: THIS LETTER OF TRANSMITTAL (OR FACSIMILE HEREOF), TOGETHER
         WITH ANY REQUIRED SIGNATURE GUARANTEES OR, IN THE CASE OF A BOOK-ENTRY
         TRANSFER, AN AGENT'S MESSAGE, AND ANY OTHER REQUIRED DOCUMENTS MUST BE
         RECEIVED BY THE DEPOSITARY PRIOR TO THE EXPIRATION DATE AND EITHER
         CERTIFICATES FOR TENDERED SHARES MUST BE RECEIVED BY THE DEPOSITARY OR
         SHARES MUST BE DELIVERED PURSUANT TO THE PROCEDURES FOR BOOK-ENTRY
         TRANSFER, IN EACH CASE PRIOR TO THE EXPIRATION DATE, OR THE TENDERING
         STOCKHOLDER MUST COMPLY WITH THE PROCEDURES FOR GUARANTEED DELIVERY.






                                 Page 13 of 22
<PAGE>   14




                         (DO NOT WRITE IN SPACES BELOW)
<TABLE>
<CAPTION>
================================================================================
<S>                             <C>                        <C>
Date Received                   Accepted By                Checked By
             ------------                  ------------               ----------
   Shares     Shares       Shares     Check    Amount      Shares    Certificate
Surrendered   Tendered    Accepted     No.    of Check    Returned        No.
- -----------   --------    --------     ---    --------    --------        ---


Delivery Prepared By                Checked By                  Date
                    -------------             --------------         -----------
================================================================================
</TABLE>


                            IMPORTANT TAX INFORMATION

         Under federal income tax law, a stockholder whose tendered Shares are
accepted for payment is required to provide the Depositary (as payer) with such
stockholder's correct taxpayer identification number on Substitute Form W-9
below. If such stockholder is an individual, the taxpayer identification number
is his or her social security number. If a tendering stockholder is subject to
backup withholding, he or she must cross out item (2) of the Certification box
on the Substitute Form W-9. If the Depositary is not provided with the correct
taxpayer identification number, the stockholder may be subject to a $50 penalty
imposed by the Internal Revenue Service. In addition, payments that are made to
such stockholder with respect to Shares purchased pursuant to the Offer may be
subject to backup withholding.

         Certain stockholders (including, among others, all corporations and
certain foreign individuals) are not subject to these backup withholding and
reporting requirements. In order for a foreign individual to qualify as an
exempt recipient, that stockholder must submit a statement, signed under
penalties of perjury, attesting to that individual's exempt status. Such
statements can be obtained from the Depositary. Exempt stock-holders, other than
foreign individuals, should furnish their TIN, write "Exempt" on the face of the
Substitute Form W-9 below, and sign, date and return the Substitute Form W-9 to
the Depositary. (See the enclosed Guidelines for Certification of Taxpayer
Identification Number on Substitute Form W-9 for additional instructions.)

     If backup withholding applies, the Depositary is required to withhold 31%
of any payments made to the stockholder. Backup withholding is not an additional
tax. Rather, the tax liability of persons subject to backup withholding will be
reduced by the amount of tax withheld. If withholding results in an overpayment
of taxes, a refund may be obtained from the Internal Revenue Service.

PURPOSE OF SUBSTITUTE FORM W-9

         To prevent backup withholding on payments that are made to a
stockholder with respect to Shares purchased pursuant to the Offer, the
stockholder is required to notify the Depositary of his or her correct




                                 Page 14 of 22
<PAGE>   15



taxpayer identification number by completing the form below, certifying that the
taxpayer identification number provided on Substitute Form W-9 is correct (or
that such stockholder is awaiting a taxpayer identification number).

WHAT NUMBER TO GIVE THE DEPOSITARY

         The stockholder is required to give the Depositary the social security
number or employer identification number of the record owner of the Shares. If
the Shares are in more than one name or are not in the name of the actual owner,
consult the enclosed Guidelines for Certification of Taxpayer Identification
Number on Substitute Form W-9 for additional guidance on which number to report.
If the tendering stockholder has not been issued a TIN and has applied for a
number or intends to apply for a number in the near future, he should write
"Applied For" in the space provided for in the TIN in Part I, and sign and date
the Substitute Form W-9. If "Applied For" is written in Part I and the
Depositary is not provided with a TIN within 60 days, the Depositary will
withhold 31% on all payments of the purchase price until a TIN is provided to
the Depositary.



























                                 Page 15 of 22
<PAGE>   16



Substitute Form W-9             REQUEST FOR TAXPAYER
                     IDENTIFICATION NUMBER AND CERTIFICATION

Department of the
Treasury, Internal
Revenue Service

Name (if a joint account or you changed your name, see Specific Instructions):

- --------------------------------------------------------------------------------

Business name, if different from above (see Specific Instructions):

- --------------------------------------------------------------------------------

Check appropriate box:    [ ]  Individual/Sole Proprietor       [ ]  Corporation
                          [ ]  Partnership                [ ]  Other
                                                                     -----------
Address (number, street and apartment or suite no.):

- --------------------------------------------------------------------------------

City, State and Zip Code:

- --------------------------------------------------------------------------------

PART I     TAXPAYER IDENTIFICATION NUMBER (TIN)

<TABLE>
<S>                                                          <C>
Enter your TIN in the appropriate box.  For individuals,     Social Security Number
this is your social security number (SSN).  However, if      ___/___/___/-___/___/-___/___/___/___
you are a resident alien OR a sole proprietor, see the
instructions.  For other entities, it is your employer                        OR
identification number (EIN).  If you do not have a           
number, see instructions.                                    Employer Identification Number       
                                                             ___/___/-___/___/___/___/___/___/___ 
</TABLE>                                                     

PART II     CERTIFICATION

Under penalties of perjury, I certify that:

(1)      The number shown on this form is my correct Taxpayer Identification
         Number (or I am waiting for a number to be issued to me) AND

(2)      I am not subject to backup withholding either because: (a) I am exempt
         from backup withholding, or (b) I have not been notified by the
         Internal Revenue Service (the "IRS") that I am subject to backup
         withholding as a result of a failure to report all interest or
         dividends, or (c) the IRS has notified me that I am no longer subject
         to backup withholding.

CERTIFICATION INSTRUCTIONS -- You must cross out item (2) in above if you have
been notified by the IRS that you are currently subject to backup withholding
because of under-reporting interest or dividends on your tax




                                 Page 16 of 22
<PAGE>   17



returns. However, if after being notified by the IRS that you were subject to
backup withholding, you receive another notification from the IRS that you are
no longer subject to backup withholding, do not cross out such item (2). (Also
see instructions in the enclosed Guidelines).

PART III     Awaiting TIN    [ ]

SIGNATURE                                             DATE 
          -----------------------------------              ---------------------

NOTE:    FAILURE TO COMPLETE AND RETURN THIS FORM MAY RESULT IN BACKUP
         WITHHOLDING OF 31% OF ANY CASH PAYMENTS MADE TO YOU PURSUANT TO THE
         OFFER. PLEASE REVIEW THE ENCLOSED GUIDELINES FOR CERTIFICATION OF
         TAXPAYER IDENTIFICATION NUMBER ON SUBSTITUTE FORM W-9 FOR ADDITIONAL
         INFORMATION.

    YOU MUST COMPLETE THE FOLLOWING CERTIFICATE IF YOU CHECKED THE BOX IN PART 
    III OF SUBSTITUTE FORM W-9.

             CERTIFICATE OF AWAITING TAXPAYER IDENTIFICATION NUMBER

         I certify under penalties of perjury that a Taxpayer Identification
Number has not been issued to me, and either (1) I have mailed or delivered an
application to receive a Taxpayer Identification Number to the appropriate
Internal Revenue Service Center or Social Security Administration Officer or (2)
I intend to mail or deliver an application in the near future. I understand that
if I do not provide a Taxpayer Identification Number to the Depositary by the
time of payment, 31% of all reportable payments made to me will be withheld, but
that such amounts will be refunded to me if I provide a certified Taxpayer
Identification Number to the Depositary within sixty (60) days.

Signature                                             Date 
          -----------------------------------              ---------------------


                         The Purchaser for the Offer is:

                          MIDDLE BAY OIL COMPANY, INC.
                             1221 LAMAR, SUITE 1020
                              HOUSTON, TEXAS 77010
                                 (713) 759-6808







                                 Page 17 of 22
<PAGE>   18



             GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                          NUMBER ON SUBSTITUTE FORM W-9


GUIDELINES FOR DETERMINING THE PROPER IDENTIFICATION NUMBER TO GIVE THE PAYOR.
- -- Social Security numbers have nine digits separated by two hyphens: i.e.,
000-00-0000. Employer identification numbers have nine digits separated by only
one hyphen: i.e., 00-0000000. The table below will help determine the number to
give the payor.

<TABLE>
<CAPTION>
                                                     GIVE THE SOCIAL SECURITY
FOR THIS TYPE OF ACCOUNT:                            NUMBER OF --

<S>                                                  <C>  
1.    An individual's account                        The individual

2.    Two or more individuals (joint                 The actual owner of the 
      account)                                       account or, if combined
                                                     funds, the first individual
                                                     on the account(1)

3.    Husband and wife                               The actual owner of the 
      (joint account)                                account or, if joint funds,
                                                     either person(1)

4.    Custodian account of a minor                   The minor(2)
      (Uniform Gift to Minors Act)

5.    Adult and minor                                The adult or, if the minor 
      (joint account)                                is the only contributor,
                                                     the minor(1)

6.    Account in the name of guardian or             The ward, minor or 
      committee for a designated ward,               incompetent person(3)
      minor or incompetent person

7.    a)     The usual revocable savings             The grantor-trustee(1)
             trust account (grantor is also
             trustee)

      b)     So-called trust account that            The actual owner(1)
             is not a legal or valid trust
             under State law

8.    Sole proprietorship account                    The owner(4)

                                                     GIVE THE TAXPAYER 
                                                     IDENTIFICATION
                                                     NUMBER OF --

9.    A valid trust, estate, or pension              The legal entity  (Do not 
      trust                                          furnish the identifying
                                                     number of the personal 
                                                     representative or trustee
                                                     unless the legal entity 
                                                     itself is not designated in
                                                     the account title.)(5)
</TABLE>






                                 Page 18 of 22
<PAGE>   19



<TABLE>
<S>                                                  <C>  
10.   Corporate account                              The corporation

11.   Religious, charitable, or educational          The organization
      organization account

12.   Partnership account held in the name           The partnership
      of the business

13.   Association, club, or other                    The organization
      tax-exempt organization

14.   A broker or registered nominee                 The broker or nominee

15.   Account with the Department of                 The public entity
      Agriculture in the name of a public
      entity (such as a state or local
      government, school district or
      prison) that receives agricultural
      program payments
</TABLE>


(1)   List first and circle the name of the person whose number you furnish.

(2)   Circle the minor's name and furnish the minor's social security number.

(3)   Circle the ward's, minor's or incompetent person's name and furnish such
      person's social security number.

(4)   Show your individual name. You may also enter your business name. You may
      use either your social security number or your employer identification
      number.

(5)   List first and circle the name of the legal trust, estate or pension 
      trust.

NOTE:    If no name is circled when there is more than one name, the number will
         be considered to be that of the first name listed.

OBTAINING A NUMBER

If you do not have a taxpayer identification number or you don't know your
number, obtain Form SS-5, Application for a Social Security Number Card (for
individuals), or Form SS-4, Application for Employer Identification Number (for
businesses and all other entities), at the local office of the Social Security
Administration or the Internal Revenue Service (the 'IRS') and apply for a
number.

PAYEES AND PAYMENTS EXEMPT FROM BACKUP WITHHOLDING

The following is a list of payees exempt from backup withholding and for which
no information reporting is required. For interest and dividends, all listed
payees are exempt except item (9). For broker transactions,




                                 Page 19 of 22
<PAGE>   20


payees listed in items (1) through (13) and a person registered under the
Investment Advisers Act of 1940 who regularly acts as a broker are exempt.
Payments subject to reporting under sections 6041 and 6041A are generally exempt
from backup withholding only if made to payees described in items (1) through
(7), except a corporation that provides medical and health care services or
bills and collects payments for such services is not exempt from backup
withholding or information reporting. Only payees described in items (2) through
(6) are exempt from backup withholding for barter exchange transactions,
patronage dividends, and payments by certain fishing boat operators.

(1)      A corporation.

(2)      An organization exempt from tax under section 501(a), or an IRA, or a
         custodial account under section 403(b)(7).

(3)      The United States or any of its agencies or instrumentalities.

(4)      A state, the District of Columbia, a possession of the United States,
         or any of their political subdivisions or instrumentalities.

(5)      A foreign government or any of its political subdivisions, agencies or
         instrumentalities.

(6)      An international organization or any of its agencies or
         instrumentalities.

(7)      A foreign central bank of issue.

(8)      A dealer in securities or commodities required to register in the
         United States or a possession of the United States.

(9)      A futures commission merchant registered with the Commodity Futures
         Trading Commission.

(10)     A real estate investment trust.

(11)     An entity registered at all times during the tax year under the
         Investment Company Act of 1940.

(12)     A common trust fund operated by a bank under section 584(a).

(13)     A financial institution.

(14)     A middleman known in the investment community as a nominee or listed in
         the most recent publication of the American Society of Corporate
         Secretaries, Inc., Nominee List.

(15)     A trust exempt from tax under section 664 or described in section 4947.

Payments of dividends and patronage dividends not generally subject to backup
withholding include the following:




                                 Page 20 of 22
<PAGE>   21


- -        Payments to nonresident aliens subject to withholding under Section
         1441 of the Code.

- -        Payments to partnerships not engaged in a trade or business in the U.S.
         and which have at least one nonresident partner.

- -        Payments of patronage dividends where the amount received is not paid
         in money.

- -        Payments made by certain foreign organizations.

- -        Payments made to a nominee.

Payments of interest not generally subject to backup withholding include the
following:

- -        Payments of interest on obligations issued by individuals. NOTE: You
         may be subject to backup withholding if this interest is $600 or more
         and is paid in the course of the payer's trade or business and you have
         not provided your correct taxpayer identification number to the payor.

- -        Payments of tax-exempt interest (including exempt-interest dividends
         under Section 852 of the Code).

- -        Payments described in Section 6049(b)(5) of the Code to non-resident
         aliens.

- -        Payments on tax-free covenant bonds under Section 1451 of the Code.

- -        Payments made by certain foreign organizations.

- -        Payments of mortgage interest to you.

- -        Payments made to an appropriate nominee.

Exempt payees described above should file substitute Form W-9 to avoid possible
erroneous backup withholding. FILE THIS FORM WITH THE PAYOR, FURNISH YOUR
TAXPAYER IDENTIFICATION NUMBER, WRITE "EXEMPT" ON THE FACE OF THE FORM, SIGN AND
DATE THE FORM AND RETURN IT TO THE PAYOR. IF YOU ARE A NON-RESIDENT ALIEN OR A
FOREIGN ENTITY NOT SUBJECT TO BACKUP WITHHOLDING, FILE WITH PAYOR A COMPLETED
INTERNAL REVENUE FORM W-8 (CERTIFICATE OF FOREIGN STATUS).

Certain payments other than interest, dividends, and patronage dividends, that
are not subject to information reporting are also not subject to backup
withholding. For details, see Sections 6041, 6041A(a), 6045, and 6050A and 6050N
of the Code and the regulations promulgated thereunder.

PRIVACY ACT NOTICE. -- Section 6109 requires most recipients of dividend,
interest or other payments to give taxpayer identification numbers to payors who
must report the payments to the IRS. The IRS uses the numbers for identification
purposes. Payors must generally withhold 31% of taxable interest, dividend, and
certain other payments to a payee who does not furnish a taxpayer identification
number to a payor. Certain penalties may also apply.




                                 Page 21 of 22
<PAGE>   22


PENALTIES

(1)      PENALTY FOR FAILURE TO FURNISH TAXPAYER IDENTIFICATION NUMBER. -- If
         you fail to furnish your correct taxpayer identification number to a
         payor, you are subject to a penalty of $50 for each such failure unless
         your failure is due to reasonable cause and not to willful neglect.

(2)      CIVIL PENALTY FOR FALSE INFORMATION WITH RESPECT TO WITHHOLDING. -- If
         you make a false statement with no reasonable basis which results in no
         imposition of backup withholding, you are subject to a penalty of $500.

(3)      CRIMINAL PENALTY FOR FALSIFYING INFORMATION. -- Willfully falsifying
         certifications or affirmations may subject you to criminal penalties
         including fines and/or imprisonment.


         FOR ADDITIONAL INFORMATION, CONTACT YOUR TAX CONSULTANT OR THE
                            INTERNAL REVENUE SERVICE.



















                                 Page 22 of 22

<PAGE>   1
                          NOTICE OF GUARANTEED DELIVERY
                                       FOR
                        TENDER OF SHARES OF COMMON STOCK
                                       OF
                           ENEX RESOURCES CORPORATION
                                       TO
                          MIDDLE BAY OIL COMPANY, INC.

                    (NOT TO BE USED FOR SIGNATURE GUARANTEES)



         This form, or one substantially equivalent hereto, must be used to
accept the Offer (as defined below) if certificates representing shares of
Common Stock, par value $0.05 per share (the "Shares"), of Enex Resources
Corporation, a Delaware corporation, are not immediately available if the
procedure for book-entry transfer cannot be completed on a timely basis, or if
time will not permit all required documents to reach the Depositary prior to the
Expiration Date (as defined in Section 1 of the Offer to Purchase). Such form
may be delivered by hand or transmitted by facsimile transmission or mail to the
Depositary. (See Section 2 of the Offer to Purchase.)

The Depositary for the Offer is:

                           THE BANK OF OKLAHOMA, N.A.

<TABLE>
<CAPTION>
         By Mail:            Facsimile Transmission:      By Hand or Overnight Courier:
         --------            -----------------------      -----------------------------

<S>                          <C>                          <C>                 
Bank of Oklahoma, N.A.         (405) 936-3964             Bank of Oklahoma, N.A.
Attn:  Cyndi Wilkinson                                    Commerce Center, Suite 110
P.O. Box 24128                Confirm by Telephone:       9520 North May Avenue
Oklahoma City, OK  73124       (405) 936-3902             Oklahoma City, OK  73120
</TABLE>


         DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN
AS SET FORTH ABOVE OR TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE TRANSMISSION
OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.



<PAGE>   2



                                    GUARANTEE
                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)


         The undersigned, a participant in the Security Transfer Agents
Medallion Program, the New York Stock Exchange Medallion Signature Guarantee
Program or the Stock Exchange Medallion Program, (a) represents that such tender
of Shares complies with Rule 14e-4 under the Securities Exchange Act of 1934, as
amended (the "Exchange Act"), and (b) guarantees delivery to the Depositary at
one of its addresses set forth above of certificates representing the Shares
tendered hereby in proper form for transfer, or confirmation of book-entry
transfer of such Shares into the Depositary's accounts at American Stock
Transfer, Inc., with delivery of a properly completed and duly executed Letter
of Transmittal (or facsimile thereof), and any other required documents, within
three NASDAQ National Market trading days after the date hereof.

                    ----------------------------------------------
                    (Name of Firm)

                    ----------------------------------------------
                    (Authorized Signature)

                    ----------------------------------------------
                    (Name)

                    ----------------------------------------------
                    (Address)

                    ----------------------------------------------
                    (Zip Code)

                    ----------------------------------------------
                    (Area Code and Telephone No.)

Dated:                        , 1998
       -----------------------

NOTE:      DO NOT SEND CERTIFICATES FOR SHARES WITH THIS NOTICE. CERTIFICATES
           SHOULD ONLY BE SENT WITH YOUR LETTER OF TRANSMITTAL.





<PAGE>   3

Ladies and Gentlemen:

         The undersigned hereby tenders to Middle Bay Oil Company, Inc., an
Alabama corporation, upon the terms and subject to the conditions set forth in
the Offer to Purchase dated February 19, 1998 and the related Letter of
Transmittal (which, together with any amendments or supplements thereto,
constitute the 'Offer'), receipt of which is hereby acknowledged,
_______________ shares of Common Stock, par value $0.05 per share (the
"Shares"), of Enex Resources Corporation, a Delaware corporation, pursuant to
the guaranteed delivery procedure set forth in Section 2 of the Offer to
Purchase.

<TABLE>
<S>                                                   <C>
Signature(s)                                          Address(es) 
            -----------------------------

- ------------------------------------------            ---------------------------------------
                                                      (Zip Code)

Name of Record Holder(s):                             Area Code and Tel. No(s). 
                                                                               --------------
- ------------------------------------------

- ------------------------------------------

- ------------------------------------------

- ------------------------------------------

Please complete if Shares will be tendered by book-entry transfer:

American Stock Transfer, Inc. Account No. 
                                         -----------------------------

Certificate No(s). (if available):

- -----------------------------

- -----------------------------

- -----------------------------
</TABLE>






<PAGE>   1


                           OFFER TO PURCHASE FOR CASH
                        1,343,352 SHARES OF COMMON STOCK
                                       OF
                           ENEX RESOURCES CORPORATION
                                       AT
                              $15.00 NET PER SHARE
                                       BY
                          MIDDLE BAY OIL COMPANY, INC.



                 THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT
                     12:00 MIDNIGHT, HOUSTON, TEXAS TIME, ON
                         MONDAY, MARCH 16, 1998, UNLESS
                              THE OFFER IS EXTENDED
                                February 19, 1998


To Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees:

         Middle Bay Oil Company, Inc., an Alabama corporation ("Purchaser"), is
offering to purchase 1,343,352 shares of common stock, par value $.05 per share
(the "Shares"), of Enex Resources Corporation, a Delaware corporation ("Enex"),
at $15.00 per Share net to the seller in cash, without interest thereon, upon
the terms and subject to the conditions set forth in the Offer to Purchase dated
February 19, 1998 and in the related Letter of Transmittal (which, together,
constitute the "Offer") enclosed herewith.

         Holders of Shares whose certificates for such Shares ("Certificates")
are not immediately available or who cannot deliver their Certificates and all
other required documents to the Depositary (as defined in the Letter of
Transmittal) on or prior to the expiration of the Offer (the "Expiration Date"),
or who cannot complete the procedures for book-entry transfer on a timely basis,
must tender their Shares according to the guaranteed delivery procedures set
forth in Section 2 of the Offer to Purchase.

         Please furnish copies of the enclosed materials to those of your
clients for whose accounts you hold Shares registered in your name or in the
name of your nominee.

         THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, THERE BEING VALIDLY
TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION DATE THAT NUMBER OF SHARES
WHICH REPRESENTS A MAJORITY OF THE TOTAL NUMBER OF OUTSTANDING SHARES OF ENEX.
CERTAIN OTHER CONDITIONS TO CONSUMMATION OF THE OFFER ARE DESCRIBED IN SECTION
14 OF THE OFFER. PURCHASER EXPRESSLY RESERVES THE RIGHT TO WAIVE ANY ONE OR MORE
OF THE CONDITIONS OF THE OFFER.

         Enclosed herewith for your information and for forwarding to your
clients for whose accounts you hold Shares registered in your name or in the
name of your nominee are copies of the following documents:

         1)       The Offer to Purchase dated February 19, 1998;

         2)       The Letter of Transmittal for your use and for the information
                  of your clients (facsimile copies of the Letter of Transmittal
                  may be used to tender Shares);

<PAGE>   2

         3)       A Notice of Guaranteed Delivery to be used to accept the Offer
                  if certificates for Shares are not immediately available or if
                  such certificates and all other required documents cannot be
                  delivered to the Depositary before the expiration of the Offer
                  or if the procedures for book-entry transfer cannot be
                  completed on a timely basis;

         4)       A printed form of letter which may be sent to your clients for
                  whose accounts you hold Shares registered in your name or in
                  the name of your nominee, with space provided for obtaining
                  such clients' instructions with regard to the Offer;

         5)       Guidelines of the Internal Revenue Service for Certification
                  of Taxpayer Identification Number on Substitute Form W-9; and

         6)       A return envelope addressed to the Depositary.

         In order to accept the Offer, (i) a duly executed and properly
completed Letter of Transmittal with any required signature guarantees or any
Agent's Message (as defined in the Offer), or other documentation should be sent
to the Depositary, and (ii) either certificates representing the tendered Shares
should be delivered to the Depositary or such Shares should be tendered by
book-entry transfer into the Depositary's account maintained at the Book-Entry
Transfer Facility (as defined in the Offer), all in accordance with the
instructions set forth in the Letter of Transmittal and the Offer to Purchase.

         If holders of Shares wish to tender, but it is impractical for them to
forward their certificates for such Shares or other required documentation on or
prior to the Expiration Date or to comply with the book-entry transfer
procedures on a timely basis, a tender may be effected by following the
guaranteed delivery procedures specified in Section 2 of the accompanying Offer
to Purchase.

         Purchaser will not pay any commissions or fees to any broker, dealer or
other person for soliciting tenders of Shares pursuant to the Offer. Purchaser
will, however, upon request, reimburse you for customary clerical and mailing
expenses incurred by you in forwarding any of the enclosed materials to your
clients. Purchaser will pay or cause to be paid any stock transfer taxes payable
on the transfer of Shares, except as otherwise provided in Instruction 6 of the
enclosed Letter of Transmittal.

         Any questions or requests for assistance may be directed to Purchaser
at its address and telephone number set forth in both the Offer to Purchase and
the Letter of Transmittal. Requests for additional copies of the Offer to
Purchase, the Letter of Transmittal and other tender offer materials may be
directed to Purchaser or to brokers, dealers, commercial banks or trust
companies.

                                          Very truly yours,

                                          MIDDLE BAY OIL COMPANY, INC.




         NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE
         YOU OR ANY OTHER PERSON THE AGENT OF PURCHASER, THE DEPOSITARY OR ANY
         AFFILIATE OF ANY OF THEM, OR AUTHORIZE YOU OR ANY OTHER PERSON TO MAKE
         ANY STATEMENT OR USE ANY DOCUMENT ON BEHALF OF ANY OF THEM IN
         CONNECTION WITH THE OFFER, OTHER THAN THE ENCLOSED DOCUMENTS AND THE
         STATEMENTS CONTAINED THEREIN.



<PAGE>   1
                           OFFER TO PURCHASE FOR CASH
                        1,343,352 SHARES OF COMMON STOCK
                                       OF
                           ENEX RESOURCES CORPORATION
                                       AT
                              $15.00 NET PER SHARE
                                       BY
                          MIDDLE BAY OIL COMPANY, INC.



                 THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT
                     12:00 MIDNIGHT, HOUSTON, TEXAS TIME, ON
                         MONDAY, MARCH 16, 1998, UNLESS
                             THE OFFER IS EXTENDED.
                    SHARES WHICH ARE TENDERED PURSUANT TO THE
                       OFFER MAY BE WITHDRAWN AT ANY TIME
                          PRIOR TO THE EXPIRATION DATE.



TO OUR CLIENTS:

         Enclosed for your consideration are the Offer to Purchase dated
February 19, 1998 and the related Letter of Transmittal (which, together with
any amendments or supplements thereto, constitute the "Offer") in connection
with the offer by Middle Bay Oil Company, Inc., an Alabama corporation
("Purchaser"), to purchase for cash up to 1,343,352 shares of common stock, par
value $.05 per share (the "Shares"), of Enex Resources Corporation, a Delaware
corporation ("Enex"), or such lesser number of Shares as equals a majority of
the Shares outstanding on a fully-diluted basis as of the Expiration Date (as
defined in the Offer to Purchase). We are the holder of record of Shares held
for your account. A tender of such Shares can be made only by us as the holder
of record and pursuant to your instructions. The enclosed Letter of Transmittal
is furnished to you for your information only and cannot be used by you to
tender Shares held by us for your account.

         We request instructions as to whether you wish us to tender any or all
of the Shares held by us for your account, upon the terms and subject to the
conditions set forth in the Offer.

         Your attention is invited to the following:

         1)       The tender price is $15.00 per Share, net to you in cash
                  without interest.

         2)       The Offer and withdrawal rights expire at 12:00 midnight,
                  Houston, Texas time, on Monday, March 16, 1998, unless the
                  Offer is extended.



<PAGE>   2



         3)       The Offer is conditioned upon, among other things, a majority
                  of the outstanding Shares being properly tendered prior to the
                  Expiration Date and not withdrawn. Certain other conditions to
                  the consummation of the Offer are described in Section 14 of
                  the Offer to Purchase. Purchaser has expressly reserved the
                  right to waive any one or more of the conditions of the Offer.

         4)       Any stock transfer taxes applicable to the sale of Shares to
                  Purchaser pursuant to the Offer will be paid by Purchaser,
                  except as otherwise provided in Instruction 6 of the Letter of
                  Transmittal.

         Except as disclosed in the Offer, Purchaser is not aware of any state
in which the making of the Offer is prohibited by administrative or judicial
action pursuant to any valid state statute. In any jurisdiction in which the
securities, blue sky or other laws require the Offer to be made by a licensed
broker or dealer, the Offer will be deemed to be made on behalf of Purchaser by
one or more registered brokers or dealers licensed under the laws of such
jurisdiction.

         Payment for Shares accepted for payment pursuant to the Offer will be
made only after timely receipt by the Depositary of (i) certificates for such
Shares or timely confirmation of the book-entry transfer of such Shares into the
Depositary's account at the Book-Entry Transfer Facility pursuant to the
procedures set forth in Section 2 of the Offer to Purchase, (ii) the Letter of
Transmittal (or a facsimile thereof), properly completed and duly executed, with
any required signature guarantees or an Agent's Message (as defined in the Offer
to Purchase) in connection with a book-entry transfer (as described in Section 2
of the Offer to Purchase), and (iii) any other documents required by the Letter
of Transmittal. Accordingly, payment may not be made to all tendering
shareholders at the same time, depending upon when certificates for or
confirmations of book-entry transfer of such Shares into the Depositary's
account at the Book-Entry Transfer Facility are actually received by the
Depositary.

         If you wish to have us tender any or all of your Shares, please so
instruct us by completing, executing and returning to us the instruction form
enclosed herewith. An envelope to return your instructions to us is enclosed. If
you authorize tender of your Shares, all such Shares shall be tendered unless
otherwise specified on the following page. Your instructions should be forwarded
to us in ample time to permit us to submit a tender on your behalf prior to the
expiration of the Offer.




<PAGE>   3


                          INSTRUCTIONS WITH RESPECT TO
                        OFFER TO PURCHASE FOR CASH UP TO
                        1,343,352 SHARES OF COMMON STOCK
                                       OF
                           ENEX RESOURCES CORPORATION



         The undersigned acknowledge(s) receipt of your letter and the enclosed
Offer to Purchase dated February 19, 1998 and the related Letter of Transmittal
in connection with the Offer by Middle Bay Oil Company, Inc., an Alabama
corporation, to purchase up to 1,343,352 shares of common stock, par value $.05
per share ("Shares"), of Enex Resources Corporation, a Delaware corporation
("Enex").

         This will instruct you to tender the number of Shares indicated below
(or, if no number is indicated below, all Shares) held by you for the account of
the undersigned, upon the terms and subject to the conditions set forth in the
Offer.


Number of Shares to be Tendered:*   SIGN HERE


                  Shares                               
- -----------------                   -------------------------------------------
                                    Signature(s)

Date:                  , 1998                            
      -----------------             -------------------------------------------

                                    -------------------------------------------
                                    (Please print name(s) and address(es) here)


                                    -------------------------------------------

                                    -------------------------------------------

*Unless otherwise indicated, it will be assumed that all Shares held by us for
your account are to be tendered.



<PAGE>   1
FOR IMMEDIATE RELEASE                       For further information contact:
                                            Steve W. Herod
                                            (713) 759-6808, Ext. 104


                 MIDDLE BAY OIL COMPANY, INC. COMMENCES TENDER
                 OFFER FOR SHARES OF ENEX RESOURCES CORPORATION
                        COMMON STOCK AT $15.00 PER SHARE


Houston, Texas, February 19, 1998... Middle Bay Oil Company, Inc. ("Middle Bay")
(NASDAQ:MBOC) announced today that it has formally commenced a cash tender offer
for common shares of Enex Resources Corporation ("Enex")(NASDAQ:ENEX) at a price
of $15.00 per share.

The purpose of the tender offer is to acquire shares that will represent at
least a majority of the outstanding common stock of Enex. The tender offer is
intended to result in the acquisition of 100% of Enex's outstanding common
stock.

The tender offer is scheduled to expire at 12:00 midnight, Houston, Texas time,
on March 16, 1998, unless extended.

John J. Bassett, President and Chief Executive Officer of Middle Bay, stated,
"We are pleased to make this tender offer for Enex shares and believe we are
offering fair value to the Enex shareholders. Enex's properties are an excellent
fit with out existing production and we have identified numerous exploitation
projects that we look forward to aggressively pursuing."

The tender offer is not subject to any financing condition. It is, however,
conditioned upon, among other things, (i) at least a majority of the Enex common
shares being validly tendered and not withdrawn and (ii) certain actions by the
Board of Directors of Enex to facilitate the tender offer and to provide,
subject to successful completion of the offer, for the replacement of the Enex
Board by the designees of Middle Bay.

Enex Resources Corporation is an independent oil and gas production and
development company, headquartered in Kingwood, Texas, with operations primarily
in Texas.

Middle Bay Oil Company, Inc. is an independent oil and gas exploration and
production company, headquartered in Houston, Texas, with operations in the Gulf
Coast and Mid-Continent regions.

<PAGE>   1
This announcement is neither an offer to purchase nor a solicitation of an offer
to sell Shares.  The Offer is made solely by the Offer to Purchase dated
February 19, 1998 and the related Letter of Transmittal and is not being made
to (nor will tenders be accepted from or on behalf of) holders of Shares in any
jurisdiction in which the making of the Offer or acceptance thereof would not
be in compliance with the laws of such jurisdiction.  In any jurisdiction the
securities, blue sky or other laws of which require the Offer to be made by a
licensed broker or dealer, the Offer is being made on behalf of Purchaser by
one or more registered brokers or dealers licensed under the laws of such
jurisdiction.


                   NOTICE OF OFFER TO PURCHASE FOR CASH UP TO
                        1,343,352 SHARES OF COMMON STOCK
                                       OF
                           ENEX RESOURCES CORPORATION
                        AT $15.00 NET PER SHARE IN CASH
                                       BY
                          MIDDLE BAY OIL COMPANY, INC.


     Middle Bay Oil Company, Inc., an Alabama corporation ("Purchaser"), is
offering to purchase up to 1,343,352 shares of common stock, par value $0.05 per
share (the "Shares"), of Enex Resources Corporation, a Delaware corporation
("Enex"), or such lesser number of Shares as equals a majority of the Shares
outstanding on a fully diluted basis on the Expiration Date (as defined in the
Offer to Purchase) (such lesser number being the "Minimum Number"), at a price
of $15.00 per Share, net to the seller in cash, without interest thereon (the
"Offer Price"), upon the terms and subject to the conditions set forth in the
Offer to Purchase dated February 19, 1998 (the "Offer to Purchase") and in the
related Letter of Transmittal (which, together with any amendments or
supplements thereto, collectively constitute the "Offer").

     The purpose of the Offer is to acquire all of the Shares of Enex that are
presently issued and outstanding but not less than a majority of such Shares on
a fully-diluted basis.  Enex has entered into an agreement with Purchaser 
whereby the Board of Directors of Enex has agreed to recommend acceptance of 
the Offer by Enex stock-holders and to take certain action to facilitate the
Offer by Purchaser, including the Board Action Condition referred to below and
as more fully described in the Offer to Purchase.

     THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, HOUSTON,
TEXAS TIME, ON MONDAY, MARCH 16, 1998, UNLESS THE OFFER IS EXTENDED.  SHARES
WHICH ARE TENDERED PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO
THE EXPIRATION DATE.

     The Offer is conditioned upon, among other things, the satisfaction or,
where applicable, waiver of the following conditions:  (i) there being validly
tendered and not withdrawn prior to the Expiration Date a number of Shares
which, together with Shares owned by Purchaser and its affiliates, will
constitute at least a majority of the total number of outstanding Shares on a
fully diluted basis as of the date the Shares are accepted for payment by
Purchaser pursuant to the Offer, and (ii) Purchaser being satisfied in its sole
discretion that the Board of Directors of Enex has irrevocably taken all such
action (the "Board Action Condition") so that (a) the acquisition of Shares
pursuant to the Offer have been approved pursuant to Section 203 ("Section 203")



                                  Page 1 of 3
<PAGE>   2
of the Delaware General Corporation Law (the "Delaware Law") or the provisions
of Section 203 are otherwise inapplicable to the acquisition of Shares pursuant
to the Offer, (b) the acquisition of Shares pursuant to the Offer has been
approved pursuant to Article Nineteen of Enex's Certificate of Incorporation,
(c) the stock purchase rights issued by Enex have been redeemed or Purchaser is
satisfied in its sole discretion that the rights have been invalidated or are
otherwise inapplicable to the Offer, and (d) Purchaser's designees have been
elected to the Enex Board in anticipation of replacement of existing directors
so that after the resignation of the existing directors, such designees shall
constitute the Enex Board or shall be able to elect additional directors to
reconstitute the Board. The Offer is also subject to other terms and conditions
contained in the Offer to Purchase.

         Upon the terms and subject to the conditions of the Offer, if at least
the Minimum Number of Shares shall be validly tendered and not withdrawn prior
to the Expiration Date, Purchaser will, upon the terms and subject to the
conditions of the Offer, purchase all Shares validly tendered and not withdrawn
prior to the Expiration Date.

         For purposes of the Offer, Purchaser will be deemed to have accepted
for payment, and thereby purchased, Shares properly tendered to Purchaser and
not withdrawn as, if and when Purchaser gives oral or written notice to Bank of
Oklahoma, N.A. (the "Depositary") of its acceptance for payment of such Shares.
Payment for Shares accepted for payment pursuant to the Offer will be made by
deposit of the purchase price therefor with the Depositary, which will act as
agent for tendering stockholders for the purpose of receiving payment from
Purchaser and transmitting payment to tendering stockholders. In all cases,
payment for Shares accepted for payment pursuant to the Offer will be made only
after timely receipt by the Depositary of (a) certificates for (or a timely
Book-Entry Confirmation with respect to) such Shares, (b) a Letter of
Transmittal (or facsimile thereof), properly completed and duly executed, with
any required signature guarantees or, in the case of a book-entry transfer, an
Agent's Message, and (c) any other documents required by the Letter of
Transmittal. The per-Share consideration paid to any stockholder pursuant to
the Offer will be the highest per-Share consideration paid to any other
stockholder pursuant to the Offer. Under no circumstances will interest be paid
on the purchase price of the Shares to be paid by Purchaser, regardless of any
extension of the Offer or any delay in making such payment.

         Except as otherwise provided below, tenders of the Shares are
irrevocable. The Shares tendered pursuant to the Offer may be withdrawn
pursuant to the procedures set forth in Section 3 of the Offer to Purchase at
any time prior to the Expiration Date and, unless theretofore accepted for
payment and paid for by Purchaser pursuant to the Offer, may also be withdrawn
at any time after March 23, 1998, or at such later time as may apply if the
Offer is extended. For a withdrawal to be effective, a written, telegraphic or
facsimile transmission notice of withdrawal must be timely received by the
Depositary at one of its addresses set forth in the Letter of Transmittal and
must specify the person who tendered the Shares to be withdrawn, the number of
the Shares to be withdrawn and the name of the registered holder of the Shares
to be withdrawn, if different from the name of the person who tendered the
Shares. If certificates for the Shares have been delivered or otherwise
identified to the Depositary, then, prior to the physical release of such
certificates, the serial numbers shown on such certificates must be submitted to
the Depositary and, unless such Shares have been tendered by an Eligible
Institution (as defined in Section 2 of the Offer to Purchase), the signatures
on the notice of withdrawal must be guaranteed by an Eligible Institution. If
the Shares have been delivered pursuant to the procedure for book-entry transfer
as set forth in Section 2 of the Offer to Purchase, any notice of withdrawal


                                  Page 2 of 3
<PAGE>   3
must also specify the name and number of the account at the appropriate
Book-Entry Transfer Facility to be credited with the withdrawn Shares and
otherwise comply with such Book-Entry Transfer Facility's procedures.
Withdrawals of tenders of the Shares may not be rescinded, and any Shares
properly withdrawn will thereafter be deemed not validly tendered for purposes
of the Offer. However, withdrawn Shares may be retendered by again following
one of the procedures described in Section 2 of the Offer to Purchase at any
time prior to the Expiration Date. All questions as to the form and validity
(including time of receipt) of notices of withdrawal will be determined by
Purchaser in its sole discretion, which determination will be final and
binding. Neither Purchaser, the Depositary nor any other person will be under
any duty to give notification of any defects or irregularities in any notice of
withdrawal or incur any liability for failure to give any such notification.

         Purchaser reserves the right, in its sole discretion, at any time and
from time to time, and regardless of whether or not any of the events or facts
set forth in Section 14 of the Offer to Purchase shall have occurred, to (a)
extend the period of time during which the Offer is open, and thereby delay
acceptance for payment of and the payment for any Shares, by giving oral or
written notice of such extension to the Depositary and (b) amend the Offer in
any other respect by giving oral or written notice of such amendment to the
Depositary. Under no circumstances will interest be paid on the purchase price
for tendered Shares, whether or not Purchaser exercises its right to extend the
Offer.

         The information required to be disclosed by Rule 14d-6(e)(1)(vii) of
the General Rules and Regulations under the Securities Exchange Act of 1934, as
amended, is contained in the Offer to Purchase and is incorporated herein by
reference.

         Purchaser shall use Enex's stockholder lists and security position
listings for the purpose of disseminating the Offer to holders of Shares. The
Offer to Purchase, the related Letter of Transmittal and other relevant
materials will be mailed to record holders of Shares and will be furnished to
brokers, dealers, banks, trust companies and similar persons whose names, or
the names of whose nominees, appear on the stockholder lists or, if applicable,
who are listed as participants in a clearing agency's security position listing
for subsequent transmittal to beneficial owners of Shares by Purchaser.

         The Offer to Purchase and the related Letter of Transmittal contain
important information that should be read before any decision is made with
respect to the Offer.

         Questions and requests for assistance or for copies of the Offer to
Purchase, the related Letter of Transmittal and other tender offer materials
may be directed to Middle Bay Oil Company, Inc., as set forth below, and copies
will be furnished promptly at Purchaser's expense. No fees or commissions will
be payable to brokers, dealers or other persons for soliciting tenders of
Shares pursuant to the Offer.


                          MIDDLE BAY OIL COMPANY, INC.
                             1221 Lamar, Suite 1020
                              Houston, Texas 77010
                           Telephone: (713) 759-6808
                              Fax: (713) 650-0352

February 19, 1998


                                  Page 3 of 3

<PAGE>   1


                                     SECOND
                                    RESTATED
                                REVOLVING CREDIT
                                       AND
                               TERM LOAN AGREEMENT



                                   Dated as of
                                 August 25, 1997


                                      among

                          MIDDLE BAY OIL COMPANY, INC.

                            BISON ENERGY CORPORATION

                                       and

                                SHORE OIL COMPANY

                                   "Borrowers"

                                       and


                     BANK OF OKLAHOMA, NATIONAL ASSOCIATION

                                     "Bank"


<PAGE>   2

                                     SECOND
                            RESTATED REVOLVING CREDIT
                                       AND
                               TERM LOAN AGREEMENT


         THIS SECOND RESTATED REVOLVING CREDIT AND TERM LOAN AGREEMENT, dated as
of August 25, 1997, is made and entered into between and among MIDDLE BAY OIL
COMPANY, INC., an Alabama corporation ("Middle Bay"), BISON ENERGY CORPORATION,
a Kansas corporation, ("Bison") and SHORE OIL COMPANY, a Texas corporation
("Shore") (Middle Bay, Bison and Shore being collectively referred to as the
"Borrowers") and BANK OF OKLAHOMA, NATIONAL ASSOCIATION ("BOk").

         WITNESSETH:

         WHEREAS, Middle Bay, Bison and BOk entered into that certain Restated
Revolving Credit and Term Loan Agreement dated as of March 31, 1997 (the
"Existing Agreement") pursuant to which BOk issued a $15,000,000.00 convertible
revolving credit facility commitment and a $50,000.00 irrevocable standby letter
of credit facility (collectively the "Existing Commitments") as secured by the
Collateral and Security Instruments described and defined in the Existing
Agreement;

         WHEREAS, Middle Bay has acquired all of the outstanding issued capital
stock of Shore and has also acquired (with loan proceeds extended by the Bank
under the Existing Agreement) from Great River Oil & Gas Corporation ("Seller")
certain interests in two (2) oil and gas wells located in the State of Louisiana
("Seller Properties");

         WHEREAS, Shore has an outstanding credit commitment from Wells Fargo
Bank, N.A. ("Wells Fargo") in the maximum principal amount of $20,000,000.00
(the "Shore Commitment") secured by the Shore Properties described and defined
in Article IV hereof below, which indebtedness evidenced and issued pursuant to
the Shore Commitment has been assumed by Middle Bay as a result of Middle Bay's
acquisition of Shore;

         WHEREAS, the Borrowers have applied to BOk to modify the existing
convertible revolving credit facility commitment (including consolidation
therewith of the Shore Commitment by discharge of Shore's existing indebtedness
to Wells Fargo) in the increased maximum principal amount of FIFTY MILLION and
NO/100 DOLLARS ($50,000,000.00), subject in all respects to the borrowing base
and other provisions, limitations and conditions hereof, including, without
limitation, Section 10.1 hereof, and to be evidenced by Borrowers' promissory
note payable to the order of BOk and dated as of even date herewith (the
"Convertible Note"), the outstanding principal balance of which shall be
converted on the Conversion Date to a term facility maturing March 31, 2004
(collectively the "Commitments"); and

         WHEREAS, BOk is willing to extend its Percentage Interest in the
Commitment to the Borrowers upon the terms and conditions herein set forth and
upon Borrowers' granting, continuing, ratifying and restating in favor of Bank a
continuing and continuous first and prior mortgage lien, pledge of and security
interest in certain oil and gas leasehold, mineral and mining interests, all as
more particularly described and defined in the Sixth Amended Mortgage and the
Louisiana Mortgage, each of even date, as collateral and security for all
indebtedness incurred pursuant to the Commitments described and defined in the
Existing Agreement or herein, including without limitation, the Shore Properties
and the Seller Properties, subject in all respects to BOk's Commitment hereunder
not in excess of $15,000,000 and subject to Borrowers' agreement to such
additional Bank(s), Assignee(s) or Credit Participant(s) as may be obtained by
mutual consent of BOk and Borrowers in accordance with the provisions of
Articles X and XI hereof.
<PAGE>   3

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
contained herein, and other good and valuable consideration, receipt of which is
acknowledged by the parties hereto, the parties agree, as follows:


                                    ARTICLE I

                               CERTAIN DEFINITIONS

         When used herein, the following terms shall have the following
meanings:

         1.1      "Adjusted Gross Proceeds" shall mean (i) all proceeds received
by the Borrowers during the applicable period, whether directly or indirectly,
from purchasers of Hydrocarbons produced from the Mortgaged Property, plus (ii)
all amounts which Borrowers were entitled to receive during such period but
which were offset by the purchaser of production or an intermediary against
obligations owing by the Borrowers; less the amount of all gathering, severance
and windfall profits taxes required to be paid by the Borrowers with respect to
said proceeds and all royalty and overriding royalty payments to third parties
and all ordinary and necessary operating expenses paid by the Borrowers with
respect to the Mortgaged Property, if not already deducted or withheld by the
purchaser or an intermediary, excluding only such expenses that (i) qualify as
capitalized items under GAAP or (ii) are defined or described in the energy
industry as workover expenses or costs.

         1.2      "Administrative Agent" shall mean BOk as appointed by the
Banks pursuant to Section 10.2 hereof.

         1.3      "Applicable Prime Rate" shall mean the annual rate of interest
announced by Chase Manhattan Bank, National Association, New York, New York
("Chase") from time to time as its prime or base rate, which shall be the rate
used by Chase as a base or standard for pricing purposes and which shall not
necessarily be its "best" or lowest rate. Should Chase cease to announce a prime
or base rate, or should it be merged, consolidated, liquidated or dissolved in
such a manner that it loses its separate corporate or banking identity, then the
Applicable Prime Rate shall be the Prime Rate published by the Wall Street
Journal in its "Money Rates" column or a similar rate if such rate ceases to be
published. Any change in the Applicable Prime Rate shall be effective as of the
date of the change.

         1.4      "Assignee(s)" shall have the meaning ascribed thereto in
Section 11.2 hereof.

         1.5      "Bank" shall initially mean only BOk and "Banks" shall mean
each of the Persons listed as Banks on the signature page hereto, including BOk
in its capacity as a Bank and such other Persons who may from time to time own a
Percentage Interest in the Convertible Loan in accordance with Article X hereof,
but the term "Bank" shall not include any Bank Participant.

         1.6      "Bank Borrowing Base" shall mean the lesser of the (i)
Commitments or (ii) the Collateral Borrowing Base calculated in accordance with
the provisions of Section 3.1 hereof.

         1.7      "BOk Borrowing Base" shall mean the lesser of the "BOk
Commitment" or (ii) BOk's Percentage Interest in the Bank Borrowing Base.

         1.8      "BOk Commitment" shall mean BOk's portion of the Commitments
which shall not exceed $15,000,000 unless and until BOk agrees in writing to
increase such BOk Commitment above $15,000,000 pursuant to the provisions of
Articles X and XI hereof.

         1.9      "Business Day" shall mean a day other than a Saturday, Sunday
or a day upon which banks in the State of Oklahoma are closed to business
generally.



                                     - 2 -
<PAGE>   4

         1.10     "CERCLA" shall mean the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended, together with all
regulations and rulings promulgated with respect thereto.

         1.11     "Closing Date" shall mean the date the Loan Documents are
executed and delivered to the Bank.

         1.12     "Collateral" shall have the meaning assigned to that term in
Article IV of this Agreement.

         1.13     "Collection Account" shall mean the Collection Account
described in Section 5.1 of this Agreement.

         1.14     "Commitments" shall mean the agreement of the Banks at any
time prior to the Conversion Date to make Convertible Loan advances under this
Agreement in the maximum aggregate outstanding principal amount of $50,000,000,
including therein the $50,000 Letter of Credit facility previously extended by
BOk under Section 2.4 of the Existing Agreement.

         1.15     "Conversion Date" shall mean March 31, 1998, or such later
date as the Banks shall agree to in writing.

         1.16     "Convertible Loan" shall have the meaning ascribed to it in
Section 2.1 of this Agreement.

         1.17     "Corresponding Source of Funds" shall mean in the case of any
Libor-Rate Funding Period, the proceeds of hypothetical receipts by the Banks
through a branch, subsidiary or affiliate of one or more Dollar deposits in the
interbank eurodollar market at the beginning of the applicable thirty (30),
sixty (60), ninety (90) or one hundred eight (180) day Libor-Rate Funding Period
and in an aggregate amount approximately equal to the Convertible Loan advance
covered by such Funding Period(s).

         1.18     "Credit Participant" is defined in Section 11.2 of this
Agreement.

         1.19     "Default Rate" shall mean the Applicable Prime Rate plus six
percentage points (6.0%) per annum.

         1.20     "Dollar", "Dollars" and the symbol "$" shall mean lawful money
of the United States of America.

         1.21     "Environmental Laws" shall mean Laws, including without
limitation federal, state or local Laws, ordinances, rules, regulations,
interpretations and orders of courts or administrative agencies or authorities
relating to pollution or protection of the environment (including, without
limitation, ambient air, surface water, groundwater, land surface and subsurface
strata), including without limitation CERCLA, SARA, RCRA, HSWA, OPA, HMTA, TSCA
and other Laws relating to (i) Polluting Substances or (ii) the manufacture,
processing, distribution, use, treatment, handling, storage, disposal or
transportation of Polluting Substances.

         1.22     "ERISA" shall mean the Federal Employee Retirement Income
Security Act of 1974, as amended, together with all regulations and rulings
promulgated with respect thereto.



                                     - 3 -
<PAGE>   5

         1.23     "Event of Default" shall mean any of the events specified in
Section 9.1 of this Agreement, and "Default" shall mean any event, which
together with any lapse of time or giving of any notice, or both, would
constitute an Event of Default.

         1.24     "Funding Period(s)" shall have the meaning assigned to such
term in Section 2.6(b) hereof.

         1.25     "GAAP" shall mean generally accepted accounting principles
applied on a consistent basis in all material respects to those applied in the
preceding period. Unless otherwise indicated herein, all accounting terms will
be defined according to GAAP.

         1.26     "hereby", "herein", "hereof", "hereunder" and similar such
terms shall mean and refer to this Agreement as a whole and not merely to the
specific section, paragraph or clause in which the respective word appears.

         1.27     "HMTA" shall mean the Hazardous Materials Transportation Act,
as amended, together with all regulations and rulings promulgated with respect
thereto.

         1.28     "HSWA" shall mean the Hazardous and Solid Waste Amendments of
1984, as amended, together with all regulations and rulings promulgated with
respect thereto.

         1.29     "Hydrocarbons" shall have the meaning assigned to that term in
the Mortgages.

         1.30     "Indebtedness" shall mean and include any and all: (i)
indebtedness, obligations and liabilities of the Borrowers to the Banks incurred
or which may be incurred hereafter pursuant to the terms of this Agreement or
any of the other Loan Documents, and any extensions, renewals, substitutions,
amendments and increases in amount thereof, including such amounts as may be
evidenced by the Notes and all lawful interest thereon, all outstanding and
unadvanced Letters of Credit, letter of credit fees, commitment fees and other
charges, and all reasonable costs and expenses incurred by the Administrative
Agent or the Banks in connection with the preparation, filing and recording of
the Loan Documents, including attorneys fees; (ii) all reasonable costs and
expenses, including attorneys' fees, paid or incurred by the Administrative
Agent or the Banks in enforcing or attempting to enforce collection of any
Indebtedness and in enforcing or realizing upon or attempting to enforce or
realize upon any collateral or security for any Indebtedness and in protecting
and preserving the Banks' interest in the Indebtedness or any collateral or
security for any Indebtedness in any bankruptcy or reorganization proceeding,
including interest on all sums so expended by the Administrative Agent or the
Banks accruing from the date upon which such expenditures are made until paid,
at an annual rate equal to the Default Rate; (iii) sums expended by the
Administrative Agent or the Banks in curing any Event of Default or Default of
the Borrowers under the terms of this Agreement, the other Loan Documents or any
other security agreement or other writing evidencing or securing the payment of
the Notes and the Letters of Credit together with interest on all sums so
expended by the Administrative Agent or the Banks accruing from the date upon
which such expenditures are made until paid, at an annual rate equal to the
Default Rate; and (iv) all "Indebtedness" or "Secured Indebtedness" as said
terms are defined in each of the Loan Documents.

         1.31     "Laws" shall mean all statutes, laws, ordinances, regulations,
orders, writs, injunctions, or decrees of the United States, any state or
commonwealth, any municipality, any foreign country, any territory or
possession, or any Tribunal.

         1.32     "Letters of Credit" shall mean any and all letters of credit
now existing or hereafter issued by the Bank pursuant to the request of any of
the Borrowers in accordance with the provisions of Section 2.12.1 hereof which
at any time remain outstanding and subject to draw by the



                                     - 4 -
<PAGE>   6

beneficiary, whether in whole or in part, including without limitation, the
$50,000 standby letter of credit issued pursuant to Section 2.4 of the Existing
Credit Agreement.

         1.33     "Letter of Credit Exposure" means, at any date, the sum of (a)
the aggregate face amount of all drafts that may then or thereafter be presented
by beneficiaries under all Letters of Credit then outstanding, plus (b) the
aggregate face amount of all drafts that the Letter of Credit Issuer has
previously accepted under Letters of Credit but has not paid.

         1.34     "Letter of Credit Issuer" means, for any Letter of Credit,
BOk, or in the event BOk does not for any reason issue a requested Letter of
Credit, another Bank designated by BOk to issue such Letter of Credit in
accordance with Section 2.12.1 of this Agreement.

         1.35     "Libor-Rate" and "Libor-Rate Options" shall have the meanings
assigned to those terms as described in Section 2.6(a) hereof.

         1.36     "Libor-Rate Funding Periods" shall have the meaning assigned
to that term as described in Section 2.6(b) hereof.

         1.37     "Lien" shall mean any mortgage, pledge, security interest,
encumbrance, lien or charge of any kind (including any agreement to give any of
the foregoing, any conditional sale or other title retention agreement, any
lease in the nature thereof, and the filing of or agreement to give any
financing statement or other similar form of public notice under the Laws of any
jurisdiction).

         1.38     "Lien Notice" shall mean notice received or obtained by the
Banks or knowledge obtained by the Banks of any Lien being claimed (whether
valid or not) by any Person, other than the Banks or a trustee on behalf of the
Banks, with respect to the Mortgaged Property.

         1.39     "Loan Documents" shall mean this Agreement, the Notes, the
Security Instruments and all other documents, instruments, title reports, title
opinions and certificates executed and delivered to the Administrative Agent or
the Banks by the Borrowers pursuant to the terms of this Agreement or the
Existing Agreement.

         1.40     "London Business Day" shall mean a day for dealing in deposits
in Dollars by and among banks in the London interbank market which is also a
Business Day.

         1.41     "Month", with respect to a Libor-Rate Funding Period, shall
mean the interval between the Fixed Dates in consecutive calendar months as to
such Libor-Rate Funding Period. The "Fixed Date" shall mean the first day of
such Period and in a succeeding calendar month as to such Period shall mean the
day in such calendar month numerically corresponding to such first day except
(a) if there is no such numerically corresponding day in a succeeding calendar
month the "Fixed Date" for such calendar month shall mean the last London
Business Day of such calendar month, (b) if such first day is the last day of a
calendar month the "Fixed Date" for any succeeding calendar month shall mean the
last London Business Day of such calendar month and (c) otherwise, if a
numerically corresponding day in a succeeding calendar month is not a London
Business Day, the "Fixed Date" for such calendar month shall mean the next
following day that is a London Business Day.

         1.42     "Mortgages" shall have the meaning assigned to that term in
Section 4.1(a) of this Agreement.

         1.43     "Mortgaged Property" shall have the meaning assigned to that
term in the Mortgages.



                                     - 5 -
<PAGE>   7

         1.44     "Notes" shall mean (i) the Convertible Note described in
Section 2.2 of this Agreement and (ii) the Letter of Credit Note described in
Section 2.4 of the Existing Agreement, together with each and every extension,
renewal, modification, replacement, substitution and change in form of either
thereof which may be from time to time and for any term or terms effected.

         1.45     "Official Body" shall mean any government or political
subdivision or any agency, authority, bureau, central bank, commission,
department or instrumentality of either, or any court, tribunal, grand jury or
arbitrator, in each case whether foreign or domestic.

         1.46     "OPA" shall mean the Oil Pollution Act of 1990, as amended,
together with all regulations and rulings promulgated with respect thereto.

         1.47     "Options" shall mean the Prime Rate Option and the Libor-Rate
Options, as the case may be.

         1.48     "Person" shall mean and include an individual, a partnership,
a joint venture, a corporation, a trust, an unincorporated organization, and a
government or any department, agency or political subdivision thereof.

         1.49     "Polluting Substances" shall mean all pollutants,
contaminants, chemicals or industrial, toxic or hazardous substances or wastes
and shall include, without limitation, any flammable explosives, radioactive
materials, oil, hazardous materials, hazardous or solid wastes, hazardous or
toxic substances or related materials defined in CERCLA/SARA, RCRA/HSWA and in
the HMTA; provided, in the event either CERCLA/SARA, RCRA/HSWA or HMTA is
amended so as to broaden the meaning of any term defined thereby, such broader
meaning shall apply subsequent to the effective date of such amendment and,
provided further, to the extent that the Laws of any State or other Tribunal
establish a meaning for "hazardous substance, "hazardous waste," "hazardous
material," "solid waste" or "toxic substance" which is broader than that
specified in CERCLA/SARA, RCRA/HSWA, or HMTA, such broader meaning shall apply.

         1.50     "Prime Rate Option" shall have the meaning assigned to that
term as described in Section 2.6(a)(i) hereof.

         1.51     "RCRA" shall mean the Resource Conservation and Recovery Act
of 1976, as amended, together with all regulations and rulings promulgated with
respect thereto.

         1.52     "Register" is defined in Section 11.1.3 of this Agreement.

         1.53     "Required Banks" with respect to any approval, consent,
modification, waiver or other action to be taken by the Administrative Agent or
the Banks under the Loan Documents which require action by the Required Banks,
such Banks that own 66 2/3% of the outstanding Percentage Interests (it being
stipulated that notwithstanding BOk's Percentage Interest set forth in Section
10.1 hereof, that for so long as BOk is the only Bank under this Agreement, BOk
shall be deemed to be the holder of 100% of the outstanding Percentage Interest
for purposes of the definition of "Required Banks" as contemplated hereby),
except only as otherwise provided in Section 10.6 of this Agreement.

         1.54     "SARA" shall mean the Superfund Amendments and Reauthorization
Act of 1987, as amended, together with all regulations and rulings promulgated
with respect thereto.

         1.55     "Security Instruments" shall mean the Mortgages and all other
financing statements, mortgages, assignments, security agreements, documents or
writings of any and all amendments and supplements thereto, granting,
conveying, assigning, transferring or in any manner providing the



                                     - 6 -
<PAGE>   8

Bank with a security interest or mortgage lien in any property as security for
the repayment of all or any part of the Indebtedness.

         1.56     "Standard Notice" shall mean an irrevocable notice provided to
the Banks on a Business Day which is at least one Business Day in advance in the
case of selection of, conversion to or renewal of a Libor-Rate Option or Libor
Funding Period(s) or prepayment of either of such Options. Standard Notice must
be provided no later than 10:00 a.m., Central Time in Tulsa, Oklahoma, on the
last day permitted for such notice.

         1.57     "Taxes" shall mean all taxes, assessments, fees, or other
charges or levies from time to time or at any time imposed by any Laws or by any
Tribunal.

         1.58     "Tribunal" shall mean any municipal, state, commonwealth,
Federal, foreign, territorial or other sovereign, governmental entity,
governmental department, court, commission, board, bureau, agency or
instrumentality.

         1.59     "TSCA" shall mean the Toxic Substances Control Act, as
amended, together with all regulations and rulings promulgated with respect
thereto.

         Accounting Principles, Terms and Determinations. All references in this
Agreement to "GAAP" shall be deemed to refer to generally accepted accounting
principles in effect in the United States at the time of application thereof.
Unless otherwise specified herein, all accounting terms used herein shall be
interpreted, all determinations with respect to accounting matters hereunder
shall be made, and all unaudited financial statements and certificates and
reports as to financial matters required to be furnished hereunder shall be
prepared, in accordance with generally accepted accounting principles, applied
on a basis consistent with the most recent audited consolidated financial
statements of the Borrowers and their Subsidiaries delivered pursuant to clause
(b) of Section 7.9 or, if no such statements have been so delivered, the most
recent audited financial statements referred to in Section 8.3 hereof.



                                   ARTICLE II

                                      LOANS

         2.1      Convertible Loan. The Banks agree, upon the terms and subject
to the conditions hereinafter set forth, severally in accordance with their
respective Percentage Interests and Commitments to make revolver loans and issue
Letters of Credit from time to time on or after the Closing Date to the
Borrowers jointly, the unpaid principal balance of which revolver loans is
automatically convertible to a seventy-two (72) month term loan on the
Conversion Date ("Convertible Loan") in an amount equal to the lesser of the
unpaid principal balance of the Convertible Note on the Conversion Date
(including without limitation, draws on Letters of Credit issued hereunder or on
the Letter of Credit Note), or the Collateral Borrowing Base as defined in
Section 3.1 hereof, proceeds of which Convertible Loan advances shall be
requested only for the limited purposes hereinafter described.

         Each Convertible Loan requested by the Borrowers from the Banks from
the Closing Date until the Conversion Date shall (i) be requested in writing by
Middle Bay (as agent on behalf of all of the Borrowers) pursuant to a
Convertible Loan Advance Request, the form of which is annexed hereto as Exhibit
A, no later than 12:00 noon (applicable current time in Tulsa, Oklahoma) on the
date upon which the advance is to be made, (ii) be in the amount of $10,000.00
or an integral



                                     - 7 -
<PAGE>   9

multiple thereof (unless the amount then available to borrow is less than
$10,000.00, in which event an advance may be made in the amount available);
(iii) not cause the aggregate outstanding and unpaid principal amount of the
Convertible Note to exceed the Collateral Borrowing Base; and (iv) be advanced
by the Banks on the applicable date, provided the request is timely made in
accordance with Section 2.1(i) hereof and all other conditions of funding are
met. All advances made by the Banks shall, for mutual convenience, be deposited
to Borrowers' general deposit account No. 207928428 with the Administrative
Agent (the "General Account"). The Banks shall have no responsibility to monitor
the distribution of such advances in any other respect. The Borrowers may
reborrow subject to the limitations and conditions for the Convertible Loan
contained herein. All advances made by the Banks on the Convertible Note
(including the payment of drafts drawn on Letters of Credit) and all payments or
prepayments of principal and interest thereon made by the Borrowers shall be
recorded by the Administrative Agent in its records, and the aggregate unpaid
principal amount so recorded shall be conclusive evidence of the principal
amount owing and unpaid on the Convertible Note. The failure to so record shall
not, however, limit or otherwise affect the joint and several obligations of the
Borrowers hereunder or under the Convertible Note to repay the principal amount
of each Convertible Loan together with all interest accrued thereon. If
additional lines or blanks shall be needed for the purpose of recording advances
or payments on the schedule, one or more additional schedules may be annexed to
the Convertible Note and shall become a part thereof.

         2.2      Convertible Note. On the Closing Date the Borrowers shall
execute and deliver to the order of BOk their joint and several promissory note
in the principal amount of $50,000,000.00, the form of which is annexed hereto
as Exhibit "B-1" and hereby made a part hereof (hereinafter referred to as the
"Convertible Note"). The Convertible Note shall be dated as of the Closing Date,
shall provide for monthly interest payments due on the last day of every month
commencing August 31, 1997. The unpaid and outstanding principal balance of the
Convertible Note shall be converted on the Conversion Date to a term loan
payable in seventy-one (71) consecutive monthly principal payments, each equal
to one-seventy-second (1/72nd) of the lesser of the then outstanding principal
balance of the Convertible Note or the Collateral Borrowing Base (initially
$15,000,000.00 from the Closing Date through the first effective date of the
Redetermined Borrowing Base) as redetermined as of September 30, 1997 (the
"Redetermined Borrowing Base") payable on the last day of each calendar month
commencing March 31, 1998, with the remaining principal payable at final
maturity on March 31, 2004. The Convertible Note shall bear interest on unpaid
balances of principal from time to time outstanding and on any past due interest
at a variable annual Option rate or Option rates per annum determined pursuant
to Section 2.6 hereof, but in no event at a rate greater than permitted by
applicable law. All payments received shall be applied first to accrued interest
and then to the outstanding principal amount owing on the Convertible Note. The
Borrowers may from time to time make prepayments of principal without premium or
penalty, provided that on or after April 1, 1998, interest on the amount
prepaid, accrued to the prepayment date, shall be paid on such prepayment date.
The Borrowers may not reborrow any amounts paid or prepaid on the Convertible
Note on or after the Conversion Date. All payments and prepayments shall be made
in lawful money of the United States of America. Any payments or prepayments on
the Convertible Note received by the Administrative Agent after 12:00 noon
(applicable current time in Tulsa, Oklahoma) shall be deemed to have been made
on the next succeeding Business Day. All outstanding principal of and unpaid
accrued interest on the Convertible Note not previously paid hereunder shall be
due and payable at final maturity on March 31, 2004, unless such final maturity
shall be extended by the Banks in writing or accelerated pursuant to the terms
hereof. After maturity (whether by acceleration or otherwise) the Convertible
Note shall bear interest at the Default Rate, payable on demand. Interest shall
be calculated on the basis of a year of 360 days but assessed for the actual
number of days elapsed in each accrual period.

         2.3      Proceeds of Convertible Loans. Proceeds of the Convertible
Loan shall be used only for the purposes of (i) consolidation herewith of the
existing Convertible Loan of Middle Bay and



                                     - 8 -
<PAGE>   10

Bison to the Bank outstanding pursuant to the Existing Agreement, (ii)
discharging the Shore indebtedness to Wells Fargo by payment in full thereof to
Wells Fargo, including extinguishment of the Shore Commitment and (iii) funding
Borrowers' future oil and gas mining and mineral acquisitions and development
thereof subject to the Collateral Borrowing Base, the Bank Borrowing Base and
the BOk Commitment.

         Unless its Convertible Loan Commitment shall be sooner terminated
pursuant to the provisions of this Agreement or the other Loan Documents, the
Convertible Loan shall mature on March 31, 2004. All advanced but unpaid amounts
on Bison's and Middle Bay's existing $15,000,000.00 Convertible Loan credit with
the Bank, as presently established under the Existing Agreement, and any
outstanding amounts owed to Wells Fargo on the Shore Commitment shall be paid in
full out of the Convertible Loan proceeds. The outstanding principal balance on
the existing Convertible Note issued pursuant to the Existing Agreement is
$8,851,298.47 as of the date hereof. The remaining funds available under the
Convertible Loan shall be used by Borrowers in their acquisition and development
of certain oil and gas working interests and other acquisitions of proven
developed reserve properties.

         2.4      Proceeds of Sale of Mortgaged Property. In the event any
undivided interest in any of the Mortgaged Property is sold when the Borrowers
are not in default hereunder, the "Sales Proceeds" of any such sale shall be
applied to the outstanding principal balance of the Convertible Note in the
inverse order of the due date of scheduled monthly installments; provided,
however, no such sale shall occur without the prior written consent of each of
the Banks, not to be unreasonably withheld. All such amounts shall be applied to
principal installments due under the Convertible Note in inverse order of their
maturity. For purposes of this section, "Sales Proceeds" shall mean the greater
of (i) sixty-five percent (65%) of the gross sales price of such Mortgaged
Property; or (ii) sixty-five percent (65%) of the discounted present worth of
the Mortgaged Property as evaluated and determined by BOk's most recent
semi-annual engineering reports required by Section 3.1 hereof. In the event the
oil and gas properties sold were not individually evaluated in the most recent
semi-annual BOk engineering report, sixty-five percent (65%) of the gross sales
price thereof shall be applied in reduction of the principal balance of the
Convertible Note in the inverse order of the due date of scheduled monthly
installments.

         2.5      Commitment Fees. From the Closing Date until the Convertible
Loan is converted to the term loan pursuant to Section 2.2 hereof, the Borrowers
shall pay to the Administrative Agent for the benefit of the Banks, as a
commitment fee for its Convertible Loan Commitment, an amount equal to three
eighths percentage point (0.375%) per annum of the amount by which the then
applicable Convertible Borrowing Base exceeds the aggregate of the outstanding
unpaid principal balance of the Convertible Note plus the unfunded and
outstanding portion of Letters of Credit from time to time computed daily on the
basis of a calendar year of 360 days but assessed for the actual number of days
elapsed during each accrual period. Such fee shall be payable quarterly as the
same accrues on the fifteenth (15th) day after the end of each quarter-annual
period ending March 31, June 30, September 30 and December 31, commencing
October 15, 1997, and at the maturity of the Convertible Note, whether by
acceleration or otherwise. Not sooner than three (3) days following the mailing
by regular mail of notice of an intended debit, the amount of Commitment Fees
payable for each such quarter shall be paid by debit to the General Account of
Borrowers at BOk as more particularly described in Section 2.1 hereof) in such
amount. For the purposes of this Section 2.5, Borrowers hereby appoint the
Administrative Agent its attorney-in-fact for the execution and performance of
such debits, and hereby absolves the Banks and the Administrative Agent of any
loss or negligence arising by virtue of its exercise of such power, except only
for gross negligence or willful misconduct. Said power shall be deemed a power
coupled with an interest and shall be irrevocable.



                                     - 9 -
<PAGE>   11
         2.6      Interest Rates; Funding Period; Transactional Amounts.

         (a)      Subject to the provisions hereof, Middle Bay, as agent for all
of the Borrowers, shall select either the Prime Rate Option or the Libor-Rate
Option for Convertible Loan advances hereunder. The Prime Rate Option is a rate
per annum for each day equal to the Applicable Prime Rate for such day. There
shall be no minimum Funding Period under the Prime Rate Option. The Libor-Rate
Option from which Borrowers may select is a rate per annum (based on a year of
360 days and actual days elapsed) equal to the per annum Libor-Rate plus per
annum percentage points (the "Libor Margin") as follows:

<TABLE>
<CAPTION>
         Percentage of Collateral
         Borrowing Base Advanced
         Under Convertible Loan
         (including pending request
               per Section 2.1)                          Libor Margin
         ---------------------------                     -------------
         <S>                                       <C>                   
                  < 75%                            1.75% above Libor-Rate
                  > 75%                            2.00% above Libor-Rate
                  -
</TABLE>

"Libor-Rate" shall mean the rate of interest quoted for the "London Interbank
Offered Rates (LIBOR)" category of the "Money Rates" column in the Wall Street
Journal on the date of the Borrowers' initial Request for Advance for a Funding
Period (or, if no Wall Street Journal is published on such day, the next
previous publication date thereof) as the average of quotations at major money
center banks for the applicable thirty (30), sixty (60), ninety (90) or one
hundred eighty (180) day Funding Period available hereunder for the Libor-Rate
Option two (2) London Business Days prior to the first day of such applicable
Libor-Rate Funding Period. The Libor-Rate established on the date of the initial
Request for Advance for a Funding Period shall be the interest rate basis used
for each day in the applicable thirty (30), sixty (60), ninety (90) or one
hundred eighty (180) day Libor-Rate Funding Period.

         The Administrative Agent shall give prompt notice to Middle Bay of the
Libor-Rate so determined or adjusted, which determination or adjustment shall be
conclusive if made in good faith. If the Wall Street Journal shall cease to
publish such Libor-Rate quotations, the Administrative Agent shall determine
such rates as the average of such Libor-Rate quotations of three (3) major New
York money center banks of whom the Administrative Agent shall inquire.

         At the end of each applicable Funding Period, the Borrowers may either:
(i) repay all outstanding balances of principal and interest; or (ii) select the
same or a different Option described above, including the same or a different
Libor Rate Funding Period described below to apply to at least $1,000,000 of the
outstanding principal balance of the Convertible Note. During any applicable
Libor-Rate Funding Period, the Borrowers may not prepay (in part or in whole)
the outstanding principal balance of the Note evidenced by such Funding Period
amount and the Libor-Rate Funding Period shall continue until the end of the
applicable Libor-Rate Funding Period.

         If the Prime Rate Option is selected, then at any time during the term
of the Convertible Loan, Middle Bay may notify the Administrative Agent that
Borrowers wish to convert to the Libor Rate Option. In such event, a minimum of
$1,000,000 of the outstanding principal balance of principal on the Convertible
Note shall convert to the Libor Rate Option.

         At any one time during the term of the Convertible Loan, only two (2)
Libor-Rate Funding Periods may be in effect.

         (b)      Funding Periods. At any time when Middle Bay shall select,
convert to or renew one of the applicable Libor-Rate Funding Periods to apply to
the Convertible Loan (in no event less than 



                                     - 10 -
<PAGE>   12

$1,000,000), it shall fix such period during which such Libor-Rate shall apply,
such periods (the "Funding Period") being set forth in the chart below:

<TABLE>
<CAPTION>
        Interest Rate Option                    Available Funding Periods
        --------------------                    -------------------------

        <S>                                     <C>           
        Libor-Rate                              Option One month (30 days), 
                                                two months (60) days, 
                                                three months (90) days, 
                                                or six months (180) days 
                                                ("Libor-Rate Funding Periods");
</TABLE>

provided, that each Libor-Rate Funding Period shall begin on a London Business
Day and the duration of each applicable Libor-Rate Funding Period shall be
determined in accordance with the definition of the term "Month" herein.

         (c)      Interest After Maturity. After the principal amount of the
Convertible Loan outstanding shall have become past due (by acceleration or past
the stated maturity date except as renewed pursuant to Section 2.7(a) hereof),
such Convertible Loan shall bear interest for each day until paid (before and
after judgment) at the Default Rate.

        (d)       Libor-Rate Unascertainable; Impracticability. If

                  (i)      on any date on which a Libor-Rate would otherwise be
         set the Administrative Agent shall have in good faith determined (which
         determination shall be conclusive) that:

                           (A)      adequate and reasonable means do not exist
                  for ascertaining such Libor-Rate,

                           (B)      a contingency has occurred which materially
                  and adversely affects the issuance of negotiable certificates
                  of deposit by the Administrative Agent or the interbank
                  eurodollar market, as the case may be, or

                           (C)      the effective cost to the Administrative
                  Agent of funding a Funding Period of the Libor-Rate Option
                  from a Corresponding Source of Funds shall exceed the
                  Libor-Rate applicable to such Funding Period, or

                  (ii)     at any time the Administrative Agent shall have
         determined in good faith (which determination shall be conclusive) that
         the making, maintenance or funding of the Libor-Rate Option has been
         made impracticable or unlawful by compliance by the Banks in good faith
         with any Law or guideline or interpretation or administration thereof
         by any Official Body charged with the interpretation or administration
         thereof or with any request or directive of any such Official Body
         (whether or not having the force of law);

then, and in any such event, the Administrative Agent may notify Middle Bay of
such determination. Upon such effective date as shall be specified in such
notice (which shall not be earlier than the date such notice is given) the
obligation of the Banks to allow the Borrowers to select, convert to or renew
the Libor-Rate Option, as the case may be, shall be suspended until the
Administrative Agent shall have later notified Middle Bay of the Banks'
determination in good faith (which determination shall be conclusive) that the
circumstances giving rise to such previous determination no longer exists.

        At the time the Banks make a determination under subsection (i) or (ii)
of this Section 2.6(d) such notification by the Administrative Agent to the
Borrower shall be deemed to provide for





                                     - 11 -
<PAGE>   13

conversion of then existing Libor-Rate Option amounts to the Prime Rate Option
on the effective date specified in such Administrative Agent's notification.
Commencing on such effective date, the Banks shall utilize the Applicable Prime
Rate or prepay such Libor Rate Option amounts in accordance with Section 2.8
hereof. If Middle Bay has previously notified the Administrative Agent of the
selection of one or more Libor-Rate Option Funding Periods that have not yet
gone into effect as of the foregoing notification date, such notification shall
be deemed to provide for selection of or conversion to or renewal of the Prime
Rate Option instead of the Libor-Rate Option(s).

        2.7       Conversion or Renewal of Libor-Rate Options.

         (a)      Conversion or Renewal. Subject to the provisions of Section
2.11 hereof the Borrowers may convert the expiring portion of the Convertible
Loan to a different interest rate Option and/or may renew the Libor-Rate Option
in accordance with Section 2.6(a) above. Whenever Borrowers desire to convert or
renew any Libor Funding Period, Middle Bay shall provide the Administrative
Agent with the following information:

                  (i)      The date, which shall be a Business Day, on which the
         proposed conversion or renewal is to be made; and

                  (ii)     The then applicable Libor Funding Period selected in
         accordance with Section 2.6(a) hereof.

Notice having been so provided, after the date specified in such notice
(telephonic or where applicable, in writing) interest shall be calculated upon
the entire principal amount of the Convertible Loan as so converted or renewed.
Interest on the principal amount of the Convertible Loan converted or renewed
(automatically or otherwise) shall be due and payable in accordance with the
provisions of Section 2.9 hereof below.

         (b)      Failure to Convert or Renew. Absent due notice from Middle Bay
of conversion or renewal in the circumstances described in Section 2.6(a)(ii)
hereof, the Libor Funding Period for which such notice is not received shall be
converted automatically to the Prime Rate Option on the last day of the
applicable expiring Funding Period.

         2.8      Prepayments. Subject to the provisions of Section 2.11 hereof
the Borrowers shall have the right at their option from time to time to prepay
the Convertible Loan in whole or part without premium or penalty at any time
with respect to the Prime Rate Option. Borrowers may prepay any part of the
Convertible Loan funded under an unexpired Libor Rate Funding Period on the date
specified on a notice by the Administrative Agent pursuant to Section 2.6(d)
hereof. In connection with any prepayment permitted hereby, Middle Bay shall
provide the Administrative Agent with the following information:

                  (a)      the date, which shall be a Business Day, on which the
         proposed prepayment is to be made; and

                  (b)      the aggregate principal amount of such partial
         prepayment, which shall be the sum of the principal amounts selected
         pursuant to this Section 2.8 and which shall be an integral multiple of
         $100,000 plus applicable fees or charges, if any, imposed by the Banks
         in accordance with Section 2.11 hereof.





                                     - 12 -
<PAGE>   14

         2.9      Interest Payments Dates. Interest on the Convertible Note
shall be due and payable on the last day of each month after the date hereof and
on March 31, 2004. After maturity of the Convertible Loan (by acceleration or
otherwise), interest thereon shall be due and payable on demand.

         2.10     Payments. All payments to be made in respect of principal,
interest or other amounts due from the Borrowers hereunder or under the
Convertible Note shall be payable at 2:00 P.M., Central Time in Tulsa, Oklahoma,
on the day when due without presentment, demand, protest or notice of any kind,
all of which are hereby expressly waived, and an action therefor shall
immediately accrue. Such payments shall be made to the Administrative Agent at
its Tulsa, Oklahoma main banking office in Dollars in funds immediately
available at such office without setoff, counterclaim or other deduction of any
nature. To the extent permitted by law, after there shall have become due (by
acceleration or otherwise) interest or any other amounts due from the Borrowers
hereunder or under the Convertible Note (excluding overdue principal, which
shall bear interest as described in Section 2.6(c) hereof, but including
interest payable under this Section 2.10), such amounts shall bear interest for
each day until paid (before and after judgment), payable on demand, at the
Default Rate.

        2.11      Additional Compensation in Certain Circumstances.

         (a)      Compensation for Taxes, Reserves and Expenses on Outstanding
Loans. If any Law or guideline or interpretation or application thereof by any
Official Body charged with the interpretation or administration thereof or
compliance with any request or directive of any Official Body (whether or not
having the force of law):

                  (i)      imposes, modifies or deems applicable any reserve,
         special deposit or similar requirement against assets held by, credit
         extended by, deposits with or for the account of, or other acquisition
         of funds by, the Banks (other than requirements expressly included
         herein in the determination of the Libor-Rate hereunder), or

                  (ii)     imposes upon the Banks any other condition or expense
         with respect to this Agreement, the Convertible Note or its making,
         maintenance or funding of any part of the Convertible Loan or any
         security therefor,

and the result of either of the foregoing is to increase the cost to, reduce the
income receivable by or impose any expense (including loss of margin) upon the
Banks with respect to this Agreement, the Convertible Note or the funding of any
part of the Convertible Loan by an amount which the Banks deem to be material
(the Banks being deemed for this purpose to have made, maintained and funded
each Funding Period(s) of a Libor-Rate Option from a Corresponding Source of
Funds), the Administrative Agent shall from time to time notify Middle Bay of
the amount determined in good faith by the Banks together with reasonable
substantiation thereof (which determination shall be conclusive) to be necessary
to compensate the Banks for such increase in cost, reduction in income or
additional expense. Such amount shall be due and payable by the Borrowers to the
Administrative Agent ten (10) Business Days after such notice is given.

         (b)      Indemnity. In addition to the compensation required by
subsection (a) of this Section 2.11, the Borrowers shall indemnify the
Administrative Agent and the Banks against any loss or expense (including loss
of margin) which the Administrative Agent and/or any of the Banks has sustained
or incurred as a consequence of any attempt by the Borrowers to revoke
(expressly, by later inconsistent notices or otherwise) in whole or part any
notice stated herein to be irrevocable (the Banks having in their sole
discretion the options (A) to give effect to such attempted revocation and
obtain indemnity under this Section 2.11(b) or (B) to treat such attempted
revocation as having no force or effect, as if never made). If the Banks sustain
or incur any such loss or expense the




                                     - 13 -
<PAGE>   15

Administrative Agent shall from time to time notify Middle Bay of the amount
determined in good faith by the Banks (which determination shall be conclusive
absent manifest error) to be necessary to indemnify the Banks for such loss or
expense (the Banks being deemed for this purpose to have made, maintained or
funded each Funding Period(s) of the Libor-Rate Option from a Corresponding
Source of Funds). Such amount shall be due and payable by the Borrowers to the
Administrative Agent ten (10) Business Days after such notice is given.

         2.12.1   Letters of Credit. Upon the Borrowers' application from time
to time by use of BOk's standard form Letter of Credit Application Agreement and
subject to the terms and provisions therein and herein set forth, BOk agrees to
issue standby letters of credit on behalf of the Borrowers under the BOk
Commitment in an aggregate unfunded amount not in excess of $1,000,000
(including, without limitation, the outstanding $50,000 standby Letter of Credit
issued pursuant to Section 2.4 of the Existing Agreement), provided that (i) any
letters of credit issued on behalf of or on the account of Borrowers with an
expiry date later than March 31, 1998, will, at the Bank's sole option, be fully
secured and collateralized by cash or cash equivalent (certificate of deposit,
time deposit or comparable investments) acceptable to the Bank in its sole
discretion and held thereby from and after March 31, 1998, until expiration or
cancellation of such letter(s) of credit or payment of all draws made thereon on
demand of the Bank and (ii) no letter of credit will be issued on behalf of or
for the account of the Borrowers if at the time of issuance the outstanding
amount of all unpaid Convertible Loan advances (including the aggregate
outstanding and unfunded amount of unexpired letters of credit then existing)
under the Commitments as evidenced by the Convertible Note plus the maximum
amount of such Letter of Credit then being requested would exceed the Bank
Borrowing Base. If any letter of credit is drawn upon at any time, each amount
drawn, whether a full or partial draw thereon, shall be automatically reflected
by the Bank as an advance on the Convertible Note effective as of the date of
BOk's honoring the sight draft. In consideration of BOk's agreement to issue
standby letters of credit hereunder, the Borrowers agree to pay to BOk letter of
credit fees equal to one and one-half percentage points (1.5%) per annum on the
face amount of each letter of credit, which such fee shall be due and payable to
BOK at the time of issuance of each applicable letter of credit.

         2.12.2   Banks' Participation in Letters of Credit. Upon the issuance
of any Letter of Credit, a participation therein, in an amount equal to each
Bank's Percentage Interest, shall automatically be deemed granted by the Letter
of Credit Issuer to each Bank on the date of such issuance and the Banks shall
automatically be obligated, as set forth in Section 10.4, to reimburse the
Letter of Credit Issuer to the extent of their respective Percentage Interests
for all obligations incurred by the Letter of Credit Issuer to third parties in
respect of such Letter of Credit not reimbursed by the Borrowers. The Letter of
Credit Issuer will send to each Bank a confirmation regarding the participations
in Letters of Credit outstanding during such month.

         2.12.3   Presentation. The Letter of Credit Issuer may accept or pay
any draft presented to it, regardless of when drawn and whether or not
negotiated, if such draft, the other required documents and any transmittal
advice are presented to the Letter of Credit Issuer and dated on or before the
expiration date of the Letter of Credit under which such draft is drawn. Except
insofar as instructions actually received may be given by the Borrowers in
writing expressly to the contrary with regard to, and prior to, the Letter of
Credit Issuer's issuance of any Letter of Credit for the account of the
Borrowers and such contrary instructions are reflected in such Letter of Credit,
to the maximum extent permitted by law the Letter of Credit Issuer may honor as
complying with the terms of the Letter of Credit and with this Agreement any
drafts or other documents otherwise in order signed or issued by an
administrator, executor, conservator, trustee in bankruptcy, debtor in
possession, assignee for benefit of creditors, liquidator, receiver or other
legal representative of the party authorized under such Letter of Credit to draw
or issue such drafts or other documents.



                                     - 14 -
<PAGE>   16

         2.12.4   Uniform Customs and Practice. The Uniform Customs and Practice
for Documentary Credits (1993 Revision), International Chamber of Commerce
Publication No. 500, and any subsequent revisions thereof approved by a Congress
of the International Chamber of Commerce and adhered to by the Letter of Credit
Issuer (the "Uniform Customs and Practice"), shall be binding on the Borrowers
and the Letter of Credit Issuer except to the extent otherwise provided herein,
in any Letter of Credit or in any other Loan Document. Anything in the Uniform
Customs and Practice to the contrary notwithstanding:

                  (a)      Neither the Borrowers nor any beneficiary of any
         Letter of Credit shall be deemed an agent of any Letter of Credit
         Issuer.

                  (b)      With respect to each Letter of Credit, neither any
         Letter of Credit Issuer nor its correspondents shall be responsible,
         except to the extent required by law, for or shall have any duty to
         ascertain:

                           (i)      the genuineness of any signature;

                           (ii)     the validity, form, sufficiency, accuracy,
                  genuineness or legal effect of any endorsements;

                           (iii)    delay in giving, or failure to give, notice
                  of arrival, notice of refusal of documents or of discrepancies
                  in respect of which any Letter of Credit Issuer refuses the
                  documents or any other notice, demand or protest;

                           (iv)     the performance by any beneficiary under any
                  Letter of Credit of such beneficiary's obligations to the
                  Borrowers;

                           (v)      inaccuracy in any notice received by the
                  Letter of Credit Issuer;

                           (vi)     the validity, form, sufficiency, accuracy,
                  genuineness or legal effect of any instrument, draft,
                  certificate or other document required by such Letter of
                  Credit to be presented before payment of a draft, or the
                  office held by or the authority of any Person signing any of
                  the same; or

                           (vii)    failure of any instrument to bear any
                  reference or adequate reference to such Letter of Credit, or
                  failure of any Person to note the amount of any instrument on
                  the reverse of such Letter of Credit or to surrender such
                  Letter of Credit or to forward documents in the manner
                  required by such Letter of Credit.

                  (c)      In the event of any conflict between the provisions
         of this Agreement and the Uniform Customs and Practice and Article 5 of
         the Uniform Commercial Code, the provisions of this Agreement shall
         govern to the maximum extent permitted by applicable law.

         2.12.5   Modification, Consent. If the Borrowers request or consent in
writing to any modification or extension of any Letter of Credit, or waive any
failure of any draft, certificate or other document to comply with the terms of
such Letter of Credit, and if the Letter of Credit Issuer consents thereto, the
Letter of Credit Issuer shall be entitled to rely on such request, consent or
waiver. This Agreement shall be binding upon the Borrowers with respect to such
Letter of Credit as so modified or extended, and with respect to any action
taken or omitted by such Letter of Credit Issuer pursuant to any such request,
consent or waiver.





                                     - 15 -
<PAGE>   17

                                   ARTICLE III

                            COLLATERAL BORROWING BASE

         3.1      Semi-annual Engineering Reports.

         (a)      The Borrowers shall deliver to the Administrative Agent at the
Borrower's cost by each February 20 and August 20, commencing August 20, 1997
and at least twenty (20) days prior to any sale or disposition of any portion of
the Mortgaged Property of $250,000.00 or more, as contemplated by Section 2.4
hereof, such current data, reports and engineering information as is necessary
or appropriate for the Banks' engineers or any other independent petroleum
engineer acceptable to the Banks to compile and prepare by each March 31 and
September 30 (commencing September 30, 1997), and where applicable, by the
closing of the prospective sale of Mortgaged Property as contemplated above, an
engineering report in form and substance satisfactory to BOk, evaluating the
proven producing oil and gas reserves attributable to the Borrowers' aggregate
interest in the Mortgaged Property (as defined in subsection (b) below),
together with the expenses attributable thereto. The engineering data and
information furnished to the Administrative Agent by or on behalf of the
Borrowers shall be accompanied by such other information as shall be requested
by the Administrative Agent in order for it to make its determination of the
Collateral Borrowing Base, and by a certificate of the Borrowers certifying that
the Borrowers have good and defensible title to the Mortgaged Properties valued
and that payments are being received from purchasers of production with respect
to said interests. At any time after thirty (30) days of the receipt of such
information and in no event later than each March 31 and September 30
(commencing September 30, 1997) the Administrative Agent, on behalf of the Banks
shall make a determination concerning compliance of the present worth, using
such pricing and discount factor as it deems appropriate pursuant to BOk's then
applicable energy lending policies and procedures, of the future net revenue
estimated by the Administrative Agent to be received by the Borrowers from
production from the Mortgaged Properties so evaluated, multiplied by a
percentage then determined by the Administrative Agent to be appropriate on the
basis of the Bank's then applicable energy lending policies and criteria. The
"Collateral Borrowing Base" shall not exceed the remainder of (i) the initial
Collateral Borrowing Base amount of Fifteen Million Dollars ($15,000,000.00), or
such redetermined Collateral Borrowing Base (the initial redetermination being
effective as of September 30, 1997) less, after the Conversion Date, (ii) the
then aggregate sum of all scheduled principal reductions payable on the
Convertible Note as of such applicable March 31 or September 30 (inclusive
thereof). The good faith determinations of the Administrative Agent in such
respects shall be conclusive.

         (b)      The term "Mortgaged Property" shall refer only to such
properties covered by the Mortgage (or a supplemental mortgage or deed of trust,
duly executed, acknowledged and delivered by the Borrowers to the Administrative
Agent in form satisfactory to counsel for the Banks) and which properties are,
at the time:

                  (i)      Particularly and adequately described under the
         Mortgage or other supplemental mortgage or deed of trust;

                  (ii)     Completed or developed (in the case of oil and gas
         leases) to the extent that value is being assigned to them by the
         Administrative Agent in connection with such evaluation and the
         Administrative Agent has determined that such properties are capable of
         producing oil or gas in commercial quantities; and

                  (iii)    Approved as to title to the satisfaction of the
         Administrative Agent.



                                     - 16 -
<PAGE>   18

         (c)      The initial Collateral Borrowing Base is stipulated to be
$15,000,000.00 and shall remain in effect until September 30, 1997 or until
otherwise changed by written agreement between the Borrower and the Banks or by
the Administrative Agent pursuant to the procedures established herein.

         (d)      Borrowers agree that the Banks shall be entitled at all times
at its option to have the "Mortgaged Property" covered and encumbered by the
Mortgage or supplemental mortgages or deeds of trust constitute one-hundred
percent (100%) of the aggregate value of Borrowers' Proven Reserves determined
in accordance with sub-sections 3.1(a) and (b) above. For the purpose of
determining the Collateral Borrowing Base and compliance herewith, the term
"Proven Reserves", in addition to properties that qualify as "Mortgaged
Property" pursuant to the criteria hereof and of subsection 3.1(b), shall refer
only to such other oil and gas mining, mineral and/or leasehold interests of
Borrowers, if any, that satisfy the criteria of clauses (ii) and (iii) of
subsection 3.1(b) hereof above in all respects.

         3.2      Collateral Deficiency. Should the aggregate unpaid outstanding
principal balance of the Convertible Note (including outstanding portions of
unexpired Letters of Credit) at any time be greater than the Collateral
Borrowing Base in effect at such time, the Administrative Agent may notify the
Borrowers in writing of the deficiency. Within ten (10) days from and after the
date of any such deficiency notice the Borrowers shall notify the Administrative
Agent in writing of its election to:

                  (a)      Make a cash prepayment upon the Convertible Note in
         an amount sufficient to reduce the sum of the unpaid principal amount
         of the Convertible Note plus outstanding Letters of Credit to an amount
         equal to or less than the amount of the Collateral Borrowing Base;

                  (b)      Adjust upward the monthly principal installments due
         on the Convertible Note for the next six (6) successive monthly
         payments to an amount that will reduce the sum of the outstanding
         principal balance of the Convertible Note plus outstanding Letters of
         Credit to the projected Collateral Borrowing Base as of the next
         immediate semi-annual redetermination thereof in accordance with the
         provisions of Section 3.1(a) hereof; or

                  (c)      Convert the portion of the outstanding principal
         balance of the Convertible Note in compliance with the Collateral
         Borrowing Base to the seventy-two (72) month term payout provisions of
         Sections 2.1 and 2.2 hereof with the excess principal balance of the
         Convertible Note to be paid in accordance with the provisions of clause
         (b) hereof above.

If the Borrowers shall have elected to make a prepayment on the Convertible Note
under Section 3.2(a) hereof, such prepayment shall be due within five (5) days
after the Borrowers shall have notified the Administrative Agent of such
election, and the prepayment shall be applied, at the Administrative Agent's
option, to the principal payments of the Convertible Note in inverse order of
maturity. If Borrowers shall elect to increase the Convertible Note monthly
principal payments due to the Banks under Section 3.2(b) hereof, the
Administrative Agent shall roll forward its then most current engineering
determination and determine the projected Collateral Borrowing Base for the next
successive determination date (either March 31 or September 30 as the case may
be).



                                     - 17 -
<PAGE>   19


                                   ARTICLE IV

                                    SECURITY

         4.1      Collateral. The repayment of the Indebtedness shall be secured
by a first and prior mortgage lien and security interest in and to all of the
portions of the Mortgaged Property owned or hereafter acquired by the Borrowers,
which has been granted to the Bank, pursuant to the terms of that certain (i)
Sixth Amended and Supplemental Mortgage, Deed of Trust, Security Agreement,
Financing Statement and Assignment (with power of sale) dated as of even date
herewith (the "Sixth Amended Mortgage") including properties situated in Texas,
Arkansas, Alabama and Mississippi previously mortgaged to Wells Fargo by Shore
and (ii) Collateral Act of Mortgage and Security Agreement dated as of even date
herewith (the "Louisiana Mortgage") including the Louisiana properties and
interests previously mortgaged to Wells Fargo by Shore and the interests in the
two (2) Louisiana wells being acquired concurrently herewith from Seller
(respectively the "Shore Properties" and the "Seller Properties") (via
acquisition of Shore or otherwise) or its related entities with the Convertible
Loan proceeds (collectively referred to as the "Mortgages") together with all
prior security and collateral documents and/or instruments described or defined
therein (including the Original Mortgage, the First Amended Mortgage, the Second
Amended Mortgage, the Third Amended Mortgage, the Fourth Amended Mortgage and
the Fifth Amended Mortgage defined therein) and all proceeds and products of the
items or types of collateral described in this Article IV including without
limitation, insurance proceeds and all cash, money, deposits and deposit or
demand accounts of either or more or all of the Borrowers at any time in the
possession or control of the Administrative Agent (the collateral described
herein and in the Security Instruments being collectively referred to as the
"Collateral").

         4.2      Additional Properties. In order to satisfy the BOk's optional
one-hundred percent (100%) of Proven Reserves policy described in subsection
3.1(d) above, the Administrative Agent has the right, in its sole discretion, to
elect to take any or all oil and gas reserves of all of the Borrowers as
Collateral for the Indebtedness pursuant to such supplemental or additional
mortgages, deeds of trusts or security agreements covering such additional
properties in form and substance satisfactory to BOk and its counsel and in full
compliance with the criteria of clauses (i), (ii) and (iii) of subsection 3.1(b)
above as additional security for the Notes and the Indebtedness. All of such
additional properties will be deemed part and parcel of the Collateral
constituting security for the repayment of the Indebtedness.


                                    ARTICLE V

                               COLLECTION ACCOUNT

         5.1      Deposit of Production Proceeds. At the option of the
Administrative Agent upon written notice to Middle Bay, Borrowers promptly
thereafter shall cause all production payments and production run checks payable
to Borrowers (whether or not encumbered by the Mortgages or any supplemental
mortgages or deeds of trust) to be remitted by the purchasers thereof directly
to a special joint lockbox account of the Borrowers established at the
Administrative Agent's (the "Collection Account"), pursuant to its standard
lockbox agreement to be executed by the Borrowers concurrently herewith.

         5.2      Transfer of Deposited Proceeds. So long as no Default has
occurred hereunder or under any of the other Loan Documents, the Administrative
Agent shall, on the earliest Business Day such funds are collected, transfer all
such collected funds, if any, in the Collection Account to Borrowers' demand
deposit account at the Administrative Agent. The Administrative Agent shall have
no liability for the distribution of funds from such demand deposit account.



                                     - 18 -
<PAGE>   20

         5.3      Application After Default or Lien Notice. If Default has
occurred under any of the Loan Documents or the Administrative Agent has
received a Lien Notice or Lien Notices representing in the aggregate at least
$50,000.00 in Liens outstanding at any time, the Administrative Agent shall be
entitled to retain all funds paid into the Collection Account and to apply the
same as received to the Indebtedness in such order and to such extent as the
Administrative Agent shall determine in its discretion.

         5.4      Exculpation. The Banks and the Administrative Agent are hereby
absolved from all liability for failure to enforce collection of any proceeds so
assigned and from all other responsibility in connection therewith, except the
responsibility to account to the Borrowers for funds actually received.

                                   ARTICLE VI

                          CONDITIONS PRECEDENT TO LOANS

         6.1      Conditions Precedent. The obligation of each Bank to make the
Convertible Loan advances is subject to the satisfaction of all of the following
conditions on or prior to the Closing Date (in addition to the other terms and
conditions set forth herein):

                  (a)      No Default. There shall exist no Event of Default or
         Default on the Closing Date.

                  (b)      Representations and Warranties. The representations,
         warranties and covenants set forth in Article VIII shall be true and
         correct on and as of the Closing Date, with the same effect as though
         made on and as of the Closing Date.

                  (c)      Certificate. Borrowers shall have delivered to the
         Administrative Agent a Certificate, dated as of the Closing Date, and
         signed by the President or Vice President and the Secretary or
         Assistant Secretary of Borrowers certifying (i) to the matters covered
         by the conditions specified in subsections (a) and (b) of this Section
         6.1, (ii) that each of the Borrowers has performed and complied with
         all agreements and conditions required to be performed or complied with
         by it prior to or on the Closing Date, (iii) to the name and signature
         of each officer of Borrowers authorized to execute and deliver the Loan
         Documents and any other documents, certificates or writings and to
         borrow under this Agreement, and (iv) to such other matters in
         connection with this Agreement which the Administrative Agent shall
         determine to be advisable. The Banks may conclusively rely on such
         Certificate until the Administrative Agent receives notice in writing
         to the contrary.

                  (d)      Proceedings. Prior to the Closing Date, all corporate
         proceedings of the Borrowers shall be taken in connection with the
         transactions contemplated by the Loan Documents and shall be
         satisfactory in form and substance to the Administrative Agent and its
         counsel; and the Administrative Agent shall have received certified
         copies, in form and substance satisfactory to the Administrative Agent
         and its counsel, of the Articles or Certificate of Incorporation and
         By-Laws of the Borrowers and the resolutions of the Board of Directors
         of the Borrowers, as adopted, authorizing the execution and delivery of
         the Loan Documents, the borrowings under this Agreement, and the
         granting of the security interests




                                     - 19 -
<PAGE>   21

         in the Collateral pursuant to the Security Instruments, to secure the
         payment of the Indebtedness.

                  (e)      Loan Documents/Security Instruments. The Borrowers
         shall have delivered to the Administrative Agent this Loan Agreement
         and each of the Mortgages, each appropriately executed by the
         appropriate parties and, where applicable, and acknowledged to the
         satisfaction of the Administrative Agent and dated as of the Closing
         Date, together with such financing statements, and other documents as
         shall be necessary and appropriate to perfect the Banks' mortgage
         liens, pledge and security interests in the Collateral covered by said
         Security Instruments.

                  (f)      Convertible Note. The Borrowers shall have jointly
         delivered the Convertible Note to the order of BOk, each appropriately
         executed. The initial funding on the Convertible Note shall be used
         solely for the purposes of paying in full the Convertible Note of
         Middle Bay and Bison issued pursuant to the Existing Agreement
         (including extinguishment of the existing Convertible Loan Commitment)
         and Shore's obligations to Wells Fargo on the Shore Commitment 
         (approximately $2,105,000) principal balance plus accrued interest 
         thereon.

                  (g)      Title. Borrowers shall have provided the
         Administrative Agent with evidence satisfactory to the Administrative
         Agent and its legal counsel that Borrowers have valid, merchantable
         title to the Shore Properties and the Seller Properties, including
         (without limitation) title reports or title opinions (division order or
         otherwise).

                  (h)      Closing Opinion. The Administrative Agent shall have
         received from counsel to Borrowers a favorable closing opinion,
         satisfactory in form and substance to the Administrative Agent and its
         legal counsel.

                  (i)      Other Information. The Administrative Agent shall
         have received such other information, documents and assurances as shall
         be reasonably requested by the Banks.


                                   ARTICLE VII

                                    COVENANTS

        The Borrowers covenant and agree with the Banks that from the date
hereof and so long as this Agreement is in effect (by extension, amendment or
otherwise) and until payment in full of all Indebtedness and the performance of
all other obligations of the Borrower under this Agreement, unless the Banks
shall otherwise consent in writing:

         7.1      Payment of Taxes and Claims. The Borrowers will pay and
discharge or cause to be paid and discharged all Taxes imposed upon the income
or profits of the Borrowers or upon the property, real, personal or mixed, or
upon any part thereof, belonging to Borrowers before the same shall be in
default, and all lawful claims for labor, rentals, materials and supplies which,
if unpaid, might become a Lien upon its property or any part thereof; provided
however, that the Borrowers shall not be required to pay and discharge or cause
to be paid or discharged any such Tax, assessment or claim so long as the
validity thereof shall be contested in good faith by appropriate proceedings,
and adequate book reserves shall be established with respect thereto, and the
Borrowers



                                     - 20 -
<PAGE>   22

shall pay such Tax, charge or claim before any property subject thereto shall
become subject to execution.

         7.2      Maintenance of Corporate Existence. The Borrowers will do or
cause to be done all things necessary to preserve and keep in full force and
effect their respective corporate existences, rights and franchises and will
continue to conduct and operate their respective businesses substantially as
being conducted and operated presently. Borrowers will become and remain
domesticated as a foreign corporation in each jurisdiction where the nature of
the business or ownership of property by Borrowers may require such
domestication.

         7.3      Preservation of Property. Borrowers will at all times
maintain, preserve and protect all of Borrowers' properties which are used or
useful in the conduct of Borrowers' business whether owned in fee or otherwise,
or leased, in good repair and operating condition; from time to time make, or
cause to be made, all needful and proper repairs, renewals, replacements,
betterments and improvements thereto so that the business carried on in
connection therewith may be properly and advantageously conducted at all times;
and comply with all material leases to which it is a party or under which it
occupies property so as to prevent any material loss or forfeiture thereunder.

         7.4      Insurance. Borrowers will keep or cause to be kept (whether
Borrower or, if applicable, the operator of the Proven Reserves,) adequately
insured by financially sound and reputable insurers Borrowers' equipment, motor
vehicles, and all other property of a character usually insured by businesses
engaged in the same or similar businesses, including the Collateral. Upon demand
by the Banks any insurance policies covering the Collateral shall be endorsed to
provide for payment of losses to the Banks as their interests may appear, to
provide that such policies may not be canceled, reduced or affected in any
manner for any reason without thirty (30) days prior notice to the
Administrative Agent, and to provide for any other matters which the Banks may
reasonably require; and such insurance shall be against fire, casualty and any
other hazards normally insured against and shall be in the amount of the full
value (less a reasonable deductible not to exceed amounts customary in the
industry for similarly situated businesses and properties) of the property
insured. Borrowers shall at all times maintain or, where applicable, cause the
operators of the Proven Reserves to maintain adequate insurance by financially
sound and reputable insurers, including, without limitation, insurance against
damage to persons and property, including comprehensive general liability,
worker's compensation and automobile liability.

         7.5      Compliance with Applicable Laws. Borrowers will comply with
the requirements of all applicable Laws and orders of any Tribunal and obtain
any licenses, permits, franchises or other governmental authorizations necessary
to the ownership of Borrowers' properties or to the conduct of Borrowers'
respective business.

         7.6      Environmental Covenants. Borrowers will immediately notify the
Administrative Agent of and provide the Administrative Agent with copies of any
notifications of discharges or releases or threatened releases or discharges of
a Polluting Substance on, upon, into or from the Collateral which are given or
required to be given by or on behalf of the Borrower to any federal, state or
local Tribunal if any of the foregoing may materially and adversely affect
Borrowers or any part of the Collateral, and such copies of notifications shall
be delivered to the Administrative Agent at the same time as they are delivered
to the Tribunal. Borrowers further agree promptly to undertake and diligently
pursue to completion any appropriate and legally required or authorized remedial
containment and cleanup action in the event of any release or discharge or
threatened release or discharge of a Polluting Substance on, upon, into or from
the Collateral. At all times while owning and operating the Collateral, the
Borrowers will maintain and retain complete and accurate records of all
releases, discharges or other disposal of Polluting Substances on, onto, into or
from the Collateral, including, without limitation, records of the quantity and
type of any Polluting Substances disposed of on or off the Collateral.



                                     - 21 -
<PAGE>   23

         7.7      Environmental Indemnities. Borrowers hereby agree to
indemnify, defend and hold harmless the Administrative Agent and the Banks and
each of their respective officers, directors, employees, agents, consultants,
attorneys, contractors and each of its affiliates, successors or assigns, or
transferees from and against, and reimburse said Persons in full with respect
to, any and all loss, liability, damage, fines, penalties, costs and expenses,
of every kind and character, including reasonable attorneys' fees and court
costs, known or unknown, fixed or contingent, occasioned by or associated with
any claims, demands, causes of action, suits and/or enforcement actions,
including any administrative or judicial proceedings, and any remedial, removal
or response actions ever asserted, threatened, instituted or requested by any
Persons, including any Tribunal, arising out of or related to: (a) the breach of
any representation or warranty of Borrowers contained in Section 8.5 set forth
herein; (b) the failure of Borrowers to perform any of its covenants contained
in Section 7.5 or 7.6 hereunder; (c) the ownership, construction, occupancy,
operation, use of the Collateral prior to the earlier of the date on which (i)
the Indebtedness and obligations secured hereby have been paid and performed in
full and the Security Instruments have been released, or (ii) the Collateral has
been sold by Banks following Banks' ownership of the Collateral by way of
foreclosure of the Liens granted pursuant hereto, deed in lieu of such
foreclosure or otherwise (the "Release Date"); provided, however, this indemnity
shall not apply with respect to matters caused by or arising solely from the
Bank's activities during any period of time after the Banks acquire ownership of
the Collateral.

        The indemnities contained in this Section 7.7 apply, without limitation,
to any violation on or before the Release Date of any Environmental Law and any
liability or obligation relating to the environmental conditions on, under or
about the Lands or the Collateral on or prior to the Release Date (including,
without limitation: (a) the presence on, upon or in the Collateral or release,
discharge or threatened release on, upon or from the Collateral of any Polluting
Substances generated, used, stored, treated, disposed of or otherwise released
prior to the Release Date, and (b) any and all damage to real or personal
property or natural resources and/or harm or injury including wrongful death, to
persons alleged to have resulted from such release of any Polluting Substances
regardless of whether the act, omission, event or circumstances constituted a
violation of any Environmental Law at the time of its existence or occurrence).
The term "release" shall have the meaning specified in CERCLA/SARA and the terms
"stored," "treated" and "disposed" shall have the meanings specified in
RCRA/HSWA; provided, however, any broader meanings of such terms provided by
applicable laws of the State of Oklahoma shall apply.

        The provisions of this Section 7.7 shall be in addition to any other
obligations and liabilities Borrowers may have to the Banks at common law and
shall survive the Release Date and shall continue thereafter in full force and
effect.

        The Banks agree that in the event that such claim, suit or enforcement
action is asserted or threatened in writing or instituted against them or any of
their respective officers, employers, agents or contractors or any such
remedial, removal or response action is requested of it or any of its officers,
employees, agents or con tractors for which the Banks may desire indemnity or
defense hereunder, the Banks shall give written notification thereof to the
Borrowers.

        Notwithstanding anything to the contrary stated herein, the indemnities
created by this Section 7.7 shall only apply to losses, liabilities, damages,
fines, penalties, costs and expenses actually incurred by the Administrative
Agent or Banks as a result of claims, demands, actions, suits or proceedings
brought by Persons who are not the beneficiaries of any such indemnity. The
Administrative Agent shall act as the exclusive agent for all indemnified
Persons under this Section 7.7. With respect to any claims or demands made by
such indemnified Persons, the Administrative Agent shall notify the Borrower
within thirty (30) days after the Administrative Agent's receipt of a writing
advising the Administrative Agent of such claim or demand. Such notice shall
identify (i) when such claim or demand was first made, (ii) the identity of the
Person making it, (iii) the indemnified Person and (iv) the substance of such
claim or demand. Failure by the




                                     - 22 -
<PAGE>   24

Administrative Agent to so notify the Borrowers within said thirty (30) day
period shall reduce the amount of the Borrowers' obligations and liabilities
under this Section 7.7 by an amount equal to any damages or losses suffered by
the Borrower resulting from any prejudice caused the Borrowers by such delay in
notification from the Administrative Agent. Upon receipt of such notice, the
Borrowers shall have the exclusive right and obligation to contest, defend,
negotiate or settle any such claim or demand through counsel of their own
selection (but reasonably satisfactory to the Administrative Agent) and solely
at Borrowers' own cost, risk and expense; provided, that the Administrative
Agent, at its own cost and expense shall have the right to participate in any
such contest, defense, negotiations or settlement. The settlement of any claim
or demand hereunder by the Borrowers may be made only upon the prior approval of
the Banks of the terms of the settlement, which approval shall not be
unreasonably withheld.

         7.8      Quarterly Production Reports. At the Administrative Agent's
written request (but not more frequently than quarterly) Borrowers shall furnish
to the Administrative Agent as soon as practicable and in any event within
thirty (30) days after such written request, a production report and an expense
report for such quarter, certified by Middle Bay's chief financial officer as
being true, correct and complete, showing on a well by well basis (i) the gross
proceeds from the sale of Hydrocarbons produced from the Mortgaged Property
(including additional properties mortgaged subsequent to the Closing pursuant to
Section 4.2 above) owned by Borrowers, (ii) the severance, production and
gathering taxes deducted from or paid from the proceeds, (iii) the Adjusted
Gross Proceeds, (iv) the quantity of Hydrocarbons produced and sold and the
number and identity of wells operated, drilled or abandoned, and (v) for each of
the wells such operating and other expense and net income information pertaining
to the Mortgaged Property owned by Borrowers as the Administrative Agent may
request or specify including, without limitation, a listing of material royalty
liabilities and obligations on a well by well basis.

        7.9       Financial Statements and Reports.

                  (a)      Quarterly Operating Statements. The Borrowers shall
         maintain a standard system of accounting and shall furnish to the
         Administrative Agent as soon as practicable after the end of each
         calendar quarter, commencing with the quarter ending September 30,
         1997, and in any event within thirty (30) days after the end of each
         said calendar quarter, consolidated and consolidating operating
         statements for the Borrowers certified, on the Borrowers' behalf, by
         the President or the chief financial officer of Middle Bay to have been
         prepared in accordance with GAAP consistently applied and to fairly
         present the consolidated financial condition of the Borrowers for such
         period, and shall include at least a consolidated and consolidating
         balance sheet as at the end of such period, and a statement of income
         and a consolidated and consolidating statement of cash flows for such
         period, all in reasonable detail, setting forth, in each case, the
         comparative figures for the corresponding date or period from the
         operating statements for the immediately preceding fiscal year.

                  (b)      Annual Financial Statements. As soon as practicable
         after the end of each fiscal year and in any event within one hundred
         twenty (120) days thereafter, the Borrowers shall furnish to the
         Administrative Agent the following audited consolidated and
         consolidating financial statements, together with a report thereon and
         an unqualified opinion, prepared in accordance with GAAP of reputable
         independent certified public accountants selected by Borrowers and
         acceptable to the Administrative Agent:



                                     - 23 -
<PAGE>   25

                           (i)      A consolidated balance sheet of Borrowers at
                  the end of such year,

                           (ii)     A consolidated statement of income of
                  Borrowers for such year, and

                           (iii)    A consolidated statement of cash flows of
                  Borrowers for such year,

         setting forth in each case in comparative form the figures for the
         previous fiscal year, if applicable, all in reasonable detail. Upon
         receipt thereof, Borrowers shall also deliver to the Administrative
         Agent a copy of each report submitted to the Borrowers by independent
         accountants in connection with any annual, special or other audit or
         report made by them including, without limitation, any comment letter
         submitted thereby to management pertaining thereto or in connection
         with their audit and all reports and notices of proxy statements sent
         by Borrowers to their shareholders, all registration statement,
         periodic and other reports, schedules or filings made by the Borrowers
         to the Securities and Exchange Commission or any similar state or
         federal governmental authority.

                  (c)      SEC Filings/Special Auditing Reports. Promptly upon
         receipt thereof, the Borrowers shall deliver to the Administrative
         Agent copies of each 10-Q and 10-K filing with the Securities and
         Exchange Commission and a full and complete copy of each report
         submitted to the Borrowers by independent accountants in connection
         with any annual, interim or special audit made by them of the books and
         records of the Borrowers, including, without limitation, any comment
         letter submitted by such accountants to management in connection with
         their audit.

                  (d)      Income Tax Returns. As soon as practicable after the
         preparation and filing of all federal and state income tax returns and
         in any event not later than September 15 of each calendar year, the
         Borrowers shall deliver to the Administrative Agent copies of each such
         return filed by or for the Borrowers whether filed as joint return with
         other parties, or not, for the preceding calendar or fiscal year,
         together with all schedules and addenda thereto in the form filed with
         the appropriate taxing authorities.

         7.10     Notice of Default. Immediately upon the happening of any
condition or event which constitutes an Event of Default or Default or any
default or event of default under any other loan, mortgage, financing or
security agreement, the Borrowers will give the Administrative Agent a written
notice thereof specifying the nature and period of existence thereof and what
actions, if any, the Borrowers are taking and proposes to take with respect
thereto.

         7.11     Notice of Litigation. Immediately upon becoming aware of the
existence of any action, suit or proceeding at law or in equity before any
Tribunal, an adverse outcome in which would (i) materially impair the ability of
the Borrowers to carry on their businesses substantially as now conducted, (ii)
materially and adversely affect the condition (financial or otherwise) of the
Borrowers, or (iii) result in monetary damages in excess of $100,000.00, the
Borrowers will give the Administrative Agent a written notice specifying the
nature thereof and what actions, if any, the Borrowers are taking and propose to
take with respect thereto.


                                     - 24 -
<PAGE>   26

         7.12     Notice of Claimed Default. Immediately upon becoming aware
that the holder of any note or any evidence of indebtedness or other security of
Borrowers has given notice or taken any action with respect to a claimed default
or event of default thereunder, the Borrowers will give the Administrative Agent
a written notice specifying the notice given or action taken by such holder and
the nature of the claimed default or event of default thereunder and what
actions, if any, the Borrowers are taking and propose to take with respect
thereto.

         7.13     Requested Information. With reasonable promptness, the
Borrowers will give the Administrative Agent such other data and information as
from time to time may be reasonably requested by the Administrative Agent or any
of the Banks.

         7.14     Inspection. Borrowers will keep complete and accurate books
and records with respect to the Collateral and their other properties, business
and operations and will permit employees and representatives of the
Administrative Agent, upon reasonable notice, to audit, inspect and examine the
same and to make copies thereof and extracts therefrom during normal business
hours. All such records shall be at all times kept and maintained at the
principal offices of Borrower in Mobile, Alabama. Upon any Default or Event of
Default of the Borrower, it will surrender all of such records relating to the
Collateral to the Administrative Agent upon receipt of any request therefor from
the Administrative Agent.

         7.15     Maintenance of Employee Benefit Plans. The Borrowers will
maintain each employee benefit plan as to which Borrowers may have any liability
or responsibility in compliance with ERISA and all other Laws applicable
thereto.

         7.16     Limitation on Liens. Borrowers will not create or suffer to
exist any Lien upon any of their respective properties or assets except (i)
Liens in favor of the Banks securing the Indebtedness; (ii) Liens arising in the
ordinary course of business for sums not due or sums being contested in good
faith and by appropriate proceedings and not involving any deposits, advances,
borrowed money or the deferred purchase price of property or services; (iii)
liens existing as of the Closing Date and described on Exhibit C annexed hereto;
and (iv) Liens permitted to exist under the terms of any of the Security
Instruments.

         7.17     Disposition/Negative Pledge re Encumbrance of Collateral and
Other Assets. Borrowers will not sell or encumber any of the Collateral without
first obtaining the Administrative Agent's written consent thereto and Borrowers
will not sell, lease, transfer, scrap or otherwise dispose of or mortgage,
pledge, grant a security interest in or otherwise encumber any of Borrowers'
other oil and gas mining or mineral properties or assets, whether for
replacement or not, unless such sale or disposition shall be in the ordinary
course of business and for a full and fair consideration, subject to the
Borrowers' limited right to sell up to $150,000.00 worth in the aggregate of
their properties or assets not constituting Collateral in the aggregate during
any calendar year thereof (other than and expressly excluding oil and gas
leasehold, mining or other mineral interests wherever located) in the ordinary
course of business during any calendar year without obtaining the Administrative
Agent's prior consent. In no event shall Borrowers cause or permit the voluntary
or involuntary pledge, mortgage or other encumbrance, attachment or levy of or
against any of the properties or assets of whatsoever nature or type to any
Person (financial institution or otherwise) without first obtaining the
Administrative Agent's written consent thereto.

         7.18     Other Agreements. Borrowers will not enter into or permit to
exist any agreement (i) which would cause an Event of Default or a Default
hereunder; or (ii) which contains any provision which would be violated or
breached by the performance of Borrowers' obligations hereunder or under any of
the other Loan Documents.



                                     - 25 -
<PAGE>   27

         7.19     Limitation on Other Indebtedness. The Borrowers will not
create, incur, assume, become or be liable in any manner in respect of, or
suffer to exist, any indebtedness whether evidenced by a note, bond, debenture,
agreement, letter of credit or similar or other obligation, or accept any
deposits or advances of any kind, in excess of $250,000.00 in the aggregate
during any fiscal year of Borrowers except (i) trade payables and current
indebtedness (other than for borrowed money) incurred in, and deposits and
advances accepted in, the ordinary course of Borrowers' existing business; (ii)
the Indebtedness or (iii) the existing indebtedness more particularly described
on Exhibit D hereto, the Administrative Agent's review and approval of which is
noted thereon.

         7.20     Collection Account. Upon notice of the Administrative Agent's
exercise of its option, the Borrowers agree to promptly notify all purchasers of
hydrocarbons from all of the Borrowers' oil and gas interests, whether or not
covered by the Security Instruments, to remit proceeds of production to the
Collection Account to be established pursuant to Section 5.1 above. The
Borrowers agree that any payments received by the Borrowers which should have
been remitted to the Collection Account will be promptly deposited by the
Borrowers in the Collection Account.

         7.21     Notice of Change of Management. Within two (2) Business Days
after any change in management of the Borrowers or any officers of either of the
Borrowers holding an office of President, Chairman or chief financial officer,
the Borrowers shall give written notice thereof to the Administrative Agent,
together with a description of the reasons for the change.

         7.22     Merger, Consolidation, Acquisition. The Borrowers will not nor
will they permit any subsidiary to, merge or consolidate with or into any other
Person; or permit any other Person to consolidate with or merge into the
Borrowers or any subsidiary; or acquire all or substantially all of the assets
or properties or capital stock of any other Person; or adopt or effect any plan
of reorganization, recapitalization, liquidation or dissolution; or acquire any
properties or assets, other than in the ordinary course of business, to the
extent that such acquisitions exceed $250,000.00 in the aggregate during any
calendar year.

         7.23     Dividends. The Borrowers will not declare, pay or become
obligated to declare or pay any dividend on any class of their capital stock now
or hereafter outstanding, make any distribution of cash or property to holders
of any shares of such stock, or redeem, retire, purchase or otherwise acquire,
directly or indirectly, any shares of any class of its capital stock now or
hereafter outstanding except only for dividends currently paid by Borrowers on
preferred stock issued as of the Closing Date hereof in amounts not in excess of
the lesser of the dividend rates paid thereon during the previous or current
fiscal year of the Borrower.

         7.24     Current Ratio. Borrowers shall maintain at all times during
each fiscal year thereof a minimum Current Ratio (excluding from such
calculation all Bay City Minerals, Inc. accounts and/or accounts receivable and
current maturities of Borrowers' long term debt owed to the Banks) of at least
 .9 to 1.0.

         7.25     Change of Fiscal Year. Borrowers will not change their fiscal
year from their present fiscal year.

         7.26     Articles of Incorporation; By-Laws and Assumed Names. The
Borrowers will not, nor will any of the Borrowers permit any subsidiary to,
amend, alter, modify or restate their Articles or Certificate of Incorporation
or By-Laws in any way which would (i) change the corporate name or adopt a trade
name for either the Borrowers or any other subsidiary thereof; or (ii) in any
manner adversely affect either of the Borrowers' obligations or covenants to the
Banks hereunder.

         7.27     Lockbox Arrangements. Following receipt of the Administrative
Agent's written request, Borrowers agree to promptly notify all purchasers of
hydrocarbons from all of the



                                     - 26 -
<PAGE>   28
Borrowers' oil and gas interests, whether or not covered by the Security
Instruments, to remit proceeds of production to the Collection Account in
accordance with Section 5.1 above. The Borrowers agree that any payments
received by the Borrowers which should have been remitted to the Collection
Account will be promptly deposited thereby in the Collection Account.

         7.28     Additional Mortgaged Properties. The Borrower agrees that upon
request by the Administrative Agent the Borrowers will, within five (5) days of
such request, grant the Banks a first and prior mortgage or deed of trust lien
on any oil and gas properties owned or hereafter acquired thereby whether by
virtue of acquisition, drilling or otherwise.



                                  ARTICLE VIII

                         REPRESENTATIONS AND WARRANTIES

         To induce the Banks to enter into this Agreement and to make the
Convertible Loan advances to the Borrowers under the provisions hereof, and in
consideration thereof, the Borrowers represent, warrant and covenant as follows:

         8.1      Litigation. Except as set forth on Exhibit E attached hereto,
there is no action, suit, investigation or proceeding threatened or pending
before any Tribunal against or affecting any of the Borrowers or any properties
or rights of the Borrowers, which, if adversely determined, would result in a
liability of greater than $100,000.00 or would otherwise result in any material
adverse change in the business or condition, financial or otherwise, of
Borrowers. Borrowers are not in default with respect to any judgment, order,
writ, injunction, decree, rule or regulation of any Tribunal.

         8.2      Conflicting Agreements and Other Matters. The Borrowers are
not in default in the performance of any obligation, covenant, or condition in
any agreement to which it is a party or by which it is bound. The Borrowers are
not parties to any contract or agreement or subject to any charter or other
corporate restriction which materially and adversely affects its business,
property or assets, or financial condition. The Borrowers are not a parties to
or otherwise subject to any contract or agreement which restricts or otherwise
affects the right or ability of the Borrowers to execute the Loan Documents or
the performance of any of their respective terms. Neither the execution nor
delivery of any of the Loan Documents, nor fulfillment of nor compliance with
their respective terms and provisions will conflict with, or result in a breach
of the terms, conditions or provisions of, or constitute a default under, or
result in any violation of, or result in the creation of any Lien (except those
created by the Loan Documents) upon any of the properties or assets of the
Borrowers pursuant to, or require any consent, approval or other action by or
any notice to or filing with any Tribunal (other than routine filings after the
Closing Date with the Securities and Exchange Commission, any securities
exchange and/or state blue sky authorities) pursuant to any award of any
arbitrator, or any agreement, instrument or Law to which either of the Borrowers
is subject.

         8.3      Financial Statements. The financial statements of Borrowers
furnished to the Bank have been prepared on an accrual basis in accordance with
GAAP, show all material liabilities, direct and contingent, and fairly present
the financial condition of the Borrowers as at date thereof and the results of
its operations for the periods then ended, and since such date there has been no
material adverse change in the business, financial condition or operations of
the Borrowers.

         8.4      Title to Properties; Authority. Borrowers have full power,
authority and legal right to own and operate the properties which they now own
and operate, and to carry on the lines of business in which they are now
engaged, and has good and marketable title to the Mortgaged



                                     - 27 -
<PAGE>   29

Property in corporate capacity subject to no Lien of any kind except Liens
permitted by this Agreement. On or prior to the Closing Date hereof, the
Borrowers will own a working interest and net revenue interest in the oil and
gas leasehold estate for the Mortgaged Property of not less than the amounts set
forth on a well by well basis on Exhibit E attached to the Existing Agreement,
as supplemented by Exhibit G annexed hereto (covering the Shore Properties and
the Seller Properties only). Borrowers have full power, authority and legal
right to execute and deliver and to perform and observe the provisions of this
Agreement and the other Loan Documents. Borrowers further represent to the Bank
that any and all after acquired interest in any one or more of the Mortgaged
Property being concurrently or subsequently assigned of record to Borrowers is
and shall be deemed encumbered by the Mortgage in all respects.

         8.5      Environmental Representations.

                  (a)      To the best of Borrowers' knowledge, neither Borrower
         is subject to any liability or obligation relating to (i) the
         environmental conditions on, under or about the Collateral, including,
         without limitation, the soil and ground water conditions at the
         location of any of the Borrowers' properties, or (ii) the use,
         management, handling, transport, treatment, generation, storage,
         disposal, release or discharge of any Polluting Substance;

                  (b)      Borrowers have not obtained and are not required to
         obtain or make application for any permits, licenses or similar
         authorizations to construct, occupy, operate or use any buildings,
         improvements, facilities, fixtures and equipment forming a part of the
         Collateral by reason of any Environmental Laws;

                  (c)      Borrowers have taken all steps necessary to determine
         and have determined that no Polluting Substances have been disposed of
         or otherwise released on, onto, into, or from the Collateral (the term
         "release" shall have the meanings specified in CERCLA/SARA, and the
         term "disposal" or "disposed" shall have the meanings specified in
         RCRA/HSWA; provided, in the event either CERCLA/SARA or RCRA/HSWA is
         amended so as to broaden the meaning of any term defined thereby, such
         broader meaning shall apply subsequent to the effective date of such
         amendment and provided further, to the extent that the laws of any
         State or Tribunal establish a meaning for "release," "disposal" or
         "disposed" which is broader than that specified in CERCLA/SARA,
         RCRA/HSWA or other Environmental Laws, such broader meaning shall
         apply);

                  (d)      To the best of Borrowers' knowledge, there are no
         PCB's or asbestos-containing materials, whether in the nature of
         thermal insulation products such as pipe boiler or breech coverings,
         wraps or blankets or sprayed-on or troweled-on products in, on or upon
         the Collateral; and

                  (e)      To the best of Borrowers' knowledge, there is no urea
         formaldehyde foam insulation ("UFFI") in, on or upon the Collateral.

         8.6      Oil and Gas Contracts. All contracts, agreements and leases
related to any of the oil and gas mining, mineral or leasehold properties and
all contracts, agreements, instruments and leases to which either of the
Borrowers is a party, are valid and effective in accordance with their
respective



                                     - 28 -
<PAGE>   30

terms, and all agreements included in the oil and gas mining, mineral or
leasehold properties in the nature of oil and/or gas purchase agreements, and
oil and/or gas sale agreements are in full force and effect and are valid and
legally binding obligations of the parties thereto and all payments due
thereunder have been made, except for those suspended for reasonable cause in
the ordinary course of business; and, there is not under any such contract,
agreement or lease any existing default by any party thereto or any event which,
with notice or lapse of time, or both, would constitute such default, other than
minor defaults which, in the aggregate, would not result in losses or damages of
more than $100,000.00 to Borrowers.

         8.7      Natural Gas Policy Act and Natural Gas Act Compliance. To the
best of Borrowers' knowledge, all material filings and approvals under the
Natural Gas Policy Act of 1978, as amended, and the Natural Gas Act, as amended,
or with the Federal Energy Regulatory Commission (the "FERC") or required under
any rules or regulations adopted by the FERC which are necessary for the
operation of Borrowers' businesses or the Collateral in the manner in which they
are presently being operated have been made and the terms of the agreements and
contractual rights included in the Borrowers' businesses or the Collateral do
not conflict with or contravene any such Law, rule or regulation.

         8.8      Take or Pay Obligations, Prepayments, BTU Adjustments and
Balancing Problems. To the best of the Borrowers' knowledge, after diligent
inquiry, there is no take or pay obligation under any gas purchase agreement
comprising a portion of the Collateral which is not matched by a commensurate
and corresponding pay or take obligation binding upon the purchaser under a
corresponding gas sales agreement such that with respect to the ownership and
operation of the business operations of Borrowers or the Collateral, any such
obligation in favor of any seller under any gas purchase agreement to which
either of the Borrowers is a "buyer" is matched by a corresponding obligation on
the part of "purchasers" under corresponding gas sales agreements pursuant to
which either of the Borrowers is the "seller". Neither the Borrowers nor the
Collateral is subject to requirements to make BTU adjustments or effect gas
balancing in favor of third parties which would result in Borrowers being
required to (i) deliver gas at a price below that established in applicable gas
sales agreements or on behalf of and for the benefit of third parties in
exchange or to otherwise compensate for prior above market or above contract
purchases of gas from Borrowers or their predecessors in interest, or (ii)
balance in kind by allowing other owners in the Collateral to make up the past
imbalances in gas sales, or (iii) balance in cash by paying other owners of the
collateral for the past gas imbalances in the aggregate in excess of $100,000.00
except only for the matters described on Exhibit F hereto which have been
disclosed to the Banks.

         8.9      Gas Purchase Obligations in Excess of Gas Sales Rights. The
ownership and operation of the business operations of Borrowers or the
Collateral have not resulted or will not result in the existence of minimum
purchase obligations under any gas purchase agreement (relating to the volume of
gas to be taken thereunder or the price to be paid with respect thereto for the
duration of any such gas purchase agreement) which are not matched by
corresponding and commensurate rights to sell all such gas under applicable gas
sales agreements at prices in excess of the amount to be paid therefor under gas
purchase agreements (without regard to costs associated with transporting any
such gas and risks of volume "shrinkage" occurring in the transportation
process).

         8.10     Purposes. Borrowers are not engaged principally, or as one of
its important activities, in the business of extending credit for the purpose of
purchasing or carrying margin stock (within the meaning of Regulation U of the
Board of Governors of the Federal Reserve System) and no part of the proceeds of
any borrowing hereunder will be used to purchase or carry any margin stock or to
extend credit to others for the purpose of purchasing or carrying any margin
stock. If requested by the Bank, the Borrowers will furnish to the
Administrative Agent a statement in conformity with the requirements of Federal
Reserve Form U-1, referred to in Regulation U, to the foregoing effect.



                                     - 29 -
<PAGE>   31

Neither the Borrowers nor any agent acting on their behalves has taken or will
take any action which might cause this Agreement or the Note to violate any
regulation of the Board of Governors of the Federal Reserve System (including
Regulations G, T, U and X) or to violate any Securities Laws, state or federal,
in each case as in effect now or as the same may hereafter be in effect.

         8.11     Compliance with Applicable Laws. The Borrowers are in
compliance with all Laws, ordinances, rules, regulations and other legal
requirements applicable to them and the businesses conducted thereby, the
violation of which could or would have a material adverse effect on their
respective business conditions, financial or otherwise.

         8.12     Possession of Franchises, Licenses. Borrowers possess all
franchises, certificates, licenses, permits and other authorizations from
governmental political subdivisions or regulatory authorities, free from
burdensome restrictions, that are necessary in any material respect for the
ownership, maintenance and operation of their respective properties and assets,
and Borrowers are not in violation of any thereof in any material respect.

         8.13     Leases, Easements and Rights of Way. Borrowers enjoy peaceful
and undisturbed possession of all leases, easements and rights of way necessary
in any material respect for the operation of their properties and assets, none
of which contains any unusual or burdensome provisions which might materially
affect or impair the operation of such properties and assets. All such leases,
easements and rights of way are valid and subsisting and are in full force and
effect.

         8.14     Taxes. Borrowers have filed all Federal, state and other
income tax returns which are required to be filed and have paid all Taxes, as
shown on said returns, and all Taxes due or payable without returns and all
assessments received to the extent that such Taxes or assessments have become
due. All Tax liabilities of the Borrowers are adequately provided for on the
books of the Borrowers, including any interest or penalties. No income tax
liability of a material nature has been asserted by taxing authorities for Taxes
in excess of those already paid.

         8.15     Disclosure. Neither this Agreement nor any other Loan Document
or writing furnished to the Bank by or on behalf of the Borrowers in connection
herewith contains any untrue statement of a material fact nor do such Loan
Documents and writings, taken as a whole, omit to state a material fact
necessary in order to make the statements contained herein and therein not
misleading. There is no fact known to Borrowers and not reflected in the
financial statements provided to the Banks which materially adversely affects
their assets or in the future may materially adversely affect the business,
property, assets or financial conditions of Borrowers which has not been set
forth in this Agreement, in the Loan Documents or in other documents furnished
to the Bank by or on behalf of the Borrowers prior to the date hereof in
connection with the transactions contemplated hereby.

         8.16     ERISA. Since the effective date of Title IV of ERISA, no
Reportable Event has occurred with respect to any Plan. For the purposes of this
section the term "Reportable Event" shall mean an event described in Section
4043(b) of ERISA. For the purposes hereof the term "Plan" shall mean any plan
subject to Title IV of ERISA and maintained for employees of Borrowers, or of
any member of a controlled group of corporations, as the term "controlled group
of corporations" is defined in Section 1563 of the Internal Revenue Code of
1986, as amended (the "Code"), of which either of the Borrowers is a part. Each
Plan established or maintained by Borrowers is in material compliance with the
applicable provisions of ERISA, and the Borrowers have filed all reports
required by ERISA and the Code to be filed with respect to each Plan. Borrowers
have met all requirements with respect to funding Plans imposed by ERISA or the
Code. Since the effective date of Title IV of ERISA there have not been any nor
are there now existing any events or conditions that would permit any Plan to be
terminated under circumstances which would cause the lien provided under Section
4068 of ERISA to attach to the assets of Borrowers. The value of each 




                                     - 30 -
<PAGE>   32

Plan's benefits guaranteed under Title IV of ERISA on the date hereof does not
exceed the value of such Plan's assets allocable to such benefits on the date
hereof.

         8.17     Ownership of Mortgaged Property. The Borrowers hereby
represent, warrant and covenant that as of the Funding Date the Borrowers will
own working interests, royalty interests and net revenue interests in the oil
and gas leasehold estate for the Mortgaged Property covered by the Mortgages not
less than the amounts set forth on a well by well basis on Exhibit G attached to
the Existing Agreement, as supplemented by Exhibit G annexed hereto (only
insofar as the Shore Properties and the Seller Properties are concerned).

         8.18     Organization and Capacity. Middle Bay is duly organized,
validly existing and in good standing under the Laws of the State of Alabama as
a corporation, Bison is duly organized, validly existing and in good standing
under the laws of the State of Kansas and Shore is duly organized, validly
existing and in good standing under the laws of the State of Texas. Bison and
Shore are wholly owned subsidiaries of Middle Bay. Borrowers have the corporate
capacity and authority to enter into this Agreement, the Convertible Note and
the Security Instruments and to perform and carry out the terms and provisions
hereof.



                                   ARTICLE IX

                                EVENTS OF DEFAULT

         9.1      Events of Default. The occurrence of any one or more of the
following events shall constitute an Event of Default (whether such occurrence
shall be voluntary or involuntary or come about or be effected by operation of
Law or otherwise):

                  (a)      The Borrowers shall fail to make any monthly payment
         due on either of the Notes, or fail to pay either of the Notes within
         five (5) days after the same shall become due and payable (whether by
         extension, renewal, acceleration, maturity or otherwise); or

                  (b)      Any representation or warranty of the Borrowers made
         herein or in any writing furnished in connection with or pursuant to
         any of the Loan Documents shall have been false or misleading in any
         material respect on the date when made; or

                  (c)      Borrowers shall fail to duly observe, perform or
         comply with any covenant, agreement or term (other than payment
         provisions which are governed by Section 9.1(a) hereof) contained in
         this Agreement or any of the Loan Documents and such default or breach
         shall have not been cured or remedied within the earlier of thirty (30)
         days after Borrowers shall know (or should have known) of its
         occurrence or thirty (30) days following receipt of notice thereof from
         the Administrative Agent; or

                  (d)      Borrowers shall default in the payment of principal
         or of interest on any other obligation for money borrowed or received
         as an advance (or any obligation under any conditional sale or other
         title retention agreement, or any obligation issued or assumed as full
         or partial payment for property whether or not secured by purchase
         money Lien, or any obligation under notes payable or drafts accepted
         representing extensions of credit) beyond any grace period provided
         with respect



                                     - 31 -
<PAGE>   33

         thereto, or shall default in the performance of any other agreement,
         term or condition contained in any agreement under which such
         obligation is created (or if any other default under any such agreement
         shall occur and be continuing beyond any period of grace provided with
         respect thereto) if the effect of such default is to cause, or to
         permit the holder or holders of such obligation (or a trustee on behalf
         of such holder or holders) to cause such obligation to become due prior
         to its date of maturity; or

                  (e)      Any of the following: (i) any of the Borrowers shall
         be unable to pay its debts as they mature, or shall make an assignment
         for the benefit of creditors or admit in writing its inability to pay
         its debts generally as they become due or fail generally to pay its
         debts as they mature; or (ii) an order, judgment or decree is entered
         adjudicating such Borrower or insolvent or an order for relief under
         the United States Bankruptcy Code is entered with respect to such
         Borrower or (iii) either of the Borrowers shall petition or apply to
         any Tribunal for the appointment of a trustee, receiver, custodian or
         liquidator of such Borrower or of any substantial part of the assets of
         such Borrower or shall commence any proceedings relating to such
         Borrower under any bankruptcy, reorganization, compromise, arrangement,
         insolvency, readjustment of debts, dissolution, or liquidation Law of
         any jurisdiction, whether now or hereafter in effect; or (iv) any such
         petition or application shall be filed, or any such proceedings shall
         be commenced, against such Borrower and such Borrower by any act shall
         indicate its approval thereof, consent thereto or acquiescence therein,
         or an order, judgment or decree shall be entered appointing any such
         trustee, receiver, custodian or liquidator, or approving the petition
         in any such proceedings, and such order, judgment or decree shall
         remain unstayed and in effect for more than thirty (30) days; or (vi)
         any of the Borrowers shall fail to make timely payment or deposit of
         any amount of tax required to be withheld by such Borrower and paid to
         or deposited to or to the credit of the United States of America
         pursuant to the provisions of the Internal Revenue Code of 1986, as
         amended, in respect of any and all wages and salaries paid to employees
         of such Borrower; or

                  (f)      Any final judgment on the merits for the payment of
         money in an amount in excess of $100,000.00 shall be outstanding
         against any of the Borrowers and such judgment shall remain unstayed
         and in effect and unpaid for more than thirty (30) days; or

                  (g)      Any Reportable Event described in Section 8.16 hereof
         which the Banks determine in good faith might constitute grounds for
         the termination of a Plan therein described or for the appointment by
         the appropriate United States District Court of a trustee to administer
         any such Plan shall have occurred and be continuing thirty (30) days
         after written notice to such effect shall have been given to Borrowers
         or any such Plan shall be terminated, or a trustee shall be appointed
         by an appropriate United States District Court to administer any such
         Plan or the Pension Benefit Guaranty Corporation shall institute
         proceedings to terminate any such Plan or to appoint a trustee to
         administer any such Plan; or



                                     - 32 -
<PAGE>   34

                  (h)      Any default or event of default under the Mortgages
         or any of the other Loan Documents.

         9.2      Remedies. Upon the occurrence of any Event of Default referred
to in Section 9.1(e) the Convertible Loan Commitment shall immediately and
automatically terminate and the Convertible Note and all other Indebtedness
shall be immediately due and payable, without notice of any kind. Upon the
occurrence of any other Event of Default, and without prejudice to any other
right or remedy of the Banks under this Agreement or the Loan Documents or under
applicable Law of under any other instrument or document delivered in connection
herewith, the Banks may (i) declare the Convertible Loan Commitment terminated
or (ii) declare the Convertible Loan Commitment terminated and declare the
Convertible Note and the other Indebtedness, or any part thereof, to be
forthwith due and payable, whereupon the Convertible Note and the other
Indebtedness, or such portion as is designated by the Banks, shall forthwith
become due and payable, without presentment, demand, notice or protest of any
kind, all of which are hereby expressly waived by the Borrowers. No delay or
omission on the part of the Administrative Agent or the Banks in exercising any
power or right hereunder or under either of the Notes, the Loan Documents or
under applicable law shall impair such right or power or be construed to be a
waiver of any default or any acquiescence therein, nor shall any single or
partial exercise by the Administrative Agent or the Banks of any such power or
right preclude other or further exercise thereof or the exercise of any other
such power or right by the Administrative Agent or the Banks. In the event that
all or part of the Indebtedness becomes or is declared to be forthwith due and
payable as herein provided, the Banks shall have the right to set off the amount
of all the Indebtedness of the Borrowers owing to the Banks against, and shall
have a lien upon and security interest in, all property of the Borrowers in the
Administrative Agent's or any Banks' possession at or subsequent to such
default, regardless of the capacity in which the Administrative Agent or the
Banks possess such property, including but not limited to any balance or share
of any deposit, demand, collection or agency account. At any time after the
occurrence of any Event of Default, the Banks may, at their option, cause an
audit of any and/or all of the books, records and documents of the Borrowers to
be made by auditors satisfactory to the Banks at the expense of the Borrowers.
The Banks also shall have, and may exercise, each and every right and remedy
granted to it for default under the terms of the other Loan Documents.



                                    ARTICLE X

                                 LOAN OPERATIONS

         10.1     Interests in Loans/Commitments. The percentage interest of BOk
and each other Bank that may hereafter become an Assignee or Credit Participant
pursuant to Article XI hereof for Commitment amounts in excess of the BOk
Commitment or, alternatively, subject to BOk's consent, the Banks extend to
Borrowers hereunder Commitments not in excess of $35,000,000 in the aggregate
(in addition to the existing $15,000,000 BOk Commitment) to be evidenced by an
additional Convertible Note jointly and severally issued hereunder by Borrowers
to the order of such additional Bank(s) in form and content similar to the
Convertible Note annexed hereto as Exhibit A (in which event such existing
$50,000,000 Convertible Note would be reissued concurrently therewith in a
correspondingly reduced original principal amount but in no event shall the sum
of all Convertible Notes issued hereunder plus the existing Letter of Credit
Note exceed $50,000,000 in the aggregate), in the Convertible Loan and Letters
of Credit, and the Commitments, shall be computed based on the maximum principal
amount for each Bank as follows:




                                     - 33 -
<PAGE>   35

<TABLE>
<CAPTION>
               Bank             Maximum Commitment Amount   Percentage Interest
               ----             -------------------------   -------------------


        <S>                     <C>                         <C>   
        BOk                            $15,000,000                  30.00%

        Other Bank(s)
        hereafter extending
        Commitment(s) or as
        Assignee(s) (other
        than a Credit
        Participant(s)
        pursuant to 
        Article XI below)              $35,000,000                  70.00%
                                       -----------                 -------

            Total                      $50,000,000                 100.00%
</TABLE>

The foregoing percentage interests, as from time to time in effect and reflected
in the Register, are referred to as the Percentage Interest with respect to all
or any portion of the Convertible Loan advances and the Commitments. BOk has no
obligation to increase the BOk Commitment above either its existing Percentage
Interest or the maximum amount of $15,000,000 (including the existing $50,000
Letter of Credit Note) and any future determination of BOk to increase the BOk
Commitment shall be in its sole and absolute discretion and subject to BOk
obtaining Assignee(s) or Credit Participant(s) under Article XI hereof for all
amounts of the Commitments in excess of the existing $15,000,000 BOk Commitment.

         10.2     Administrative Agent's Authority to Act. Each of the Banks
appoints and authorizes BOk to act for the Banks as Administrative Agent in
connection with the transactions contemplated by this Agreement and the other
Loan Documents on the terms set forth herein. In acting hereunder, the
Administrative Agent is acting for the account of BOk to the extent of its
Percentage Interest and for the account of each other Bank to the extent of such
Bank's Percentage Interest, and all action in connection with the enforcement
of, or the exercise of any remedies (other than the Banks' rights of set-off as
provided herein or in any other Loan Document) in respect of the Loans and the
Indebtedness shall be taken by the Administrative Agent.

         10.3     Borrowers to Pay Administrative Agent. The Borrowers shall be
fully protected in making all payments in respect of the Convertible Note or the
Letter of Credit Note to the Administrative Agent, in relying upon consents,
modifications and amendments executed by the Administrative Agent purportedly on
the Banks' behalf, and in dealing with the Administrative Agent as herein
provided. Upon three (3) Business Days notice, the Administrative Agent may
charge the accounts of the Borrowers, on the dates when the amounts thereof
become due and payable, with the amounts of the principal of and interest on the
Convertible Loan, and all other fees and amounts owing under any Loan Document.

         10.4     Bank Operations for Advances.

                  10.4.1   Advances. On the funding date for each Convertible
         Loan advance, each Bank shall advance to the Administrative Agent in
         immediately available funds such Bank's Percentage Interest in the
         portion of a Loan advanced on such funding date prior to 1:00 P.M.
         (Tulsa, Oklahoma time). If such funds are not received at such time,
         but all applicable conditions set forth in Article VI have been
         satisfied, each Bank authorizes and requests the Administrative Agent
         to advance for such Bank's account, pursuant to the terms hereof, the
         Bank's respective Percentage Interest in such portion of such Loan and
         agrees to reimburse the Administrative Agent in immediately available
         funds for the amount thereof prior to 3:00 p.m. (Tulsa, Oklahoma time)
         on the day any portion of such Loan is advanced hereunder; provided,
         however, that the Administrative Agent is not authorized to make any
         such


                                     - 34 -
<PAGE>   36

         advance for the account of any Bank who has previously notified the
         Administrative Agent in writing that such Bank will not be performing
         its obligations to make further advances hereunder; and provided,
         further, that the Administrative Agent shall be under no obligation to
         make any such advance.

                  10.4.2   Letters of Credit. Each of the Banks authorizes and
         requests each Letter of Credit Issuer to issue the Letters of Credit
         provided for in Section 2.12.1 and agrees to purchase a participation
         in each of such Letters of Credit in an amount equal to its Percentage
         Interest in the amount of each such Letter of Credit. Promptly upon the
         request of any Letter of Credit Issuer, each Bank shall reimburse such
         Letter of Credit Issuer in immediately available funds for such Bank's
         Percentage Interest in the amount of all obligations to third parties
         incurred by the Letter of Credit Issuer in respect of each Letter of
         Credit and each draft accepted under a Letter of Credit to the extent
         not timely reimbursed by the Borrowers. Each Letter of Credit Issuer
         will notify each Bank (and the Administrative Agent if the
         Administrative Agent is not the Letter of Credit Issuer) of the
         issuance of each Letter of Credit, the amount and date of payment of
         any draft drawn or accepted under a Letter of Credit and whether in
         connection with the payment of any such draft the amount thereof was
         added to the Revolving Credit Loan or was reimbursed by the Borrowers.

                  10.4.3   Administrative Agent to Allocate Payments. All
         payments of principal and interest in respect of the extensions of
         credit made pursuant to this Agreement, reimbursement of amounts paid
         by each Letter of Credit Issuer to third parties under Letters of
         Credit or drafts presented thereunder, commitment fees, Letter of
         Credit issuance fees and other fees under this Agreement (except for
         the standard Letter of Credit application/processing fees of any Letter
         of Credit Issuer), which shall not be shared by the Banks shall, as a
         matter of convenience, be made by the Borrowers to the applicable
         Letter of Credit Issuer or the applicable Administrative Agent, as the
         case may be. The share of each Bank shall be credited to such Bank by
         the Administrative Agent in immediately available funds in such manner
         that the principal amount of the Loans constituting Credit Obligations
         to be paid shall be paid proportionately in accordance with the Banks'
         respective Percentage Interests in such Loans, except as otherwise
         provided in this Agreement.

                  10.4.4   Delinquent Banks; Nonperforming Banks. In the event
         that any Bank fails to reimburse the Administrative Agent pursuant to
         Section 10.4.1 for the Percentage Interest of such Bank (a "Delinquent
         Bank") in any credit advanced by the Administrative Agent pursuant
         hereto, overdue amounts (the "Delinquent Payment") due from the
         Delinquent Bank to the Administrative Agent shall bear interest,
         payable by the Delinquent Bank on demand, at a per annum rate equal to
         (a) the Federal Funds Rate for the first three days overdue and (b) the
         sum of two percentage points (2%) plus the Federal Funds Rate for any
         longer period. Such interest shall be payable to the Administrative
         Agent for its own account for the period commencing on the date of the
         Delinquent Payment and ending on the date the Delinquent Bank
         reimburses the Administrative Agent on account of the Delinquent
         Payment (to the extent not paid by the Borrowers as provided below) and
         the accrued interest thereon (the "Delinquency Period"), whether
         pursuant to the assignments referred to below or otherwise. Upon notice
         by the Administrative Agent, the Borrowers will pay to the
         Administrative Agent the principal (but not the interest) portion of
         the Delinquent Payment. During the Delinquency Period, in order to make
         reimbursements for the Delinquent Payment and accrued interest thereon,
         the Delinquent Bank shall be deemed to have assigned to the
         Administrative Agent all interest, commitment fees and other payments
         made by the Borrowers hereunder that would have thereafter otherwise
         been payable under the Loan Documents to the Delinquent Bank. During
         any other period in which any Bank is not performing its obligations to
         extend credit under Article II hereof (a "Nonperforming Bank"), the
         Nonperforming Bank shall be deemed to have assigned to each Bank that
         is not a 





                                     - 35 -
<PAGE>   37

         Nonperforming Bank (a "Performing Bank") all principal and other
         payments made by the Borrowers that would have thereafter otherwise
         been payable thereunder to the Nonperforming Bank. The Administrative
         Agent shall credit a portion of such payments to each Performing Bank
         in an amount equal to the Percentage Interest of such Performing Bank
         in an amount equal to the Percentage Interest of such Performing Bank
         divided by one minus the Percentage Interest of the Nonperforming Bank
         until the respective portions of the Loans owed to all the Banks are
         the same as the Percentage Interests of the Banks immediately prior to
         the failure of the Nonperforming Bank to perform its obligations under
         Article II hereof. The foregoing provisions shall be in addition to any
         other remedies the Administrative Agent, the Performing Banks or the
         Borrowers may have under law or equity against the Delinquent Bank as a
         result of the Delinquent Payment or against the Nonperforming Bank as a
         result of its failure to perform its obligations under Article II
         hereof.

         10.5     Sharing of Payments. To the extent permitted by applicable
Bank regulatory and legal requirements, each Bank agrees that (i) if by
exercising any right of set-off or counterclaim or otherwise, it shall receive
payment of (a) a proportion of the aggregate amount due with respect to its
Percentage Interest in the Convertible Loan advances and Letter of Credit
Exposure which is greater than (b) the proportion received by any other Bank in
respect of the aggregate amount due with respect to such other Bank's Percentage
Interest in the Convertible Loan advances and Letter of Credit Exposure and (ii)
if such inequality shall continue for more than 10 days, the Bank receiving such
proportionately greater payment shall purchase participations in the Percentage
Interests in the Convertible Loan advances and Letter of Credit Exposure held by
the other Banks, and such other adjustments shall be made from time to time
(including rescission of such purchases of participations in the event the
unequal payment originally received is recovered from such Bank through
bankruptcy proceedings or otherwise), as may be required so that all such
payments of principal and interest with respect to the Convertible Loan advances
and Letter of Credit Exposure held by the Banks shall be shared by the Banks pro
rata in accordance with their respective Percentage Interests; provided,
however, that this Section 10.5 shall not impair the right of any Bank to
exercise any right of set-off or counterclaim it may have and to apply the
amount subject to such exercise to the payment of Indebtedness of Borrowers
other than Borrowers' Indebtedness with respect to the Convertible Loan advances
and Letter of Credit Exposure. Each Bank that grants a participation in the
Convertible Loan and Commitments to a Credit Participant shall require as a
condition to the granting of such participation that such Credit Participant
agree to share payments received in respect of the Indebtedness as provided in
this Section 10.5. The provisions of this Section 10.5 are for the sole and
exclusive benefit of the Banks and no failure of any Bank to comply with the
terms hereof shall be available to any of the Borrowers as a defense to the
payment of the Loans.

         10.6     Amendments, Consents, Waivers. Except as otherwise set forth
herein the Administrative Agent may (and upon the written request of the
Required Banks the Administrative Agent shall) take or refrain from taking any
action under this Agreement or any other Loan Document, including giving its
written consent to any modification of or amendment to and waiving in writing
compliance with any covenant or condition in this Agreement or any other Loan
Document or any Default or Event of Default, all of which actions shall be
binding upon all of the Banks; provided, however, that:

         (i)      Without the written consent of the Banks owning at least two
thirds (2/3) of the Percentage Interests (other than Delinquent Banks during the
existence of a Delinquency Period so long as such Delinquent Bank is treated the
same as the other Banks with respect to any actions enumerated below), no
written modification of, amendment to, consent with respect to, waiver of
compliance with or waiver of a Default under, any of the Loan Documents shall be
made, including



                                     - 36 -
<PAGE>   38

without limitation, Section 9.1 of this Agreement, the related defined terms or
this Section 10.6(a) shall be made.

         (ii)     Without the written consent of such Banks as own 100% of the
Percentage Interests (other than Delinquent Banks during the existence of a
Delinquency Period so long as such Delinquent Bank is treated the same as the
other Banks with respect to any actions enumerated below):

                  (a)      No reduction shall be made in (A) the amount of
         principal of any of the Convertible Loan advances or reimbursement
         obligations for payments made under Letters of Credit, (B) the interest
         rate on the Convertible Loan advances or (C) the Letter of Credit
         processing/application fees, the amount of which shall be within the
         sole discretion of each Letter of Credit Issuer or commitment
         (non-usage) fees.

                  (b)      No change shall be made in the stated time of payment
         of all or any portion of any of the Convertible Loan advances or
         interest thereon or reimbursement of payments made under Letters of
         Credit or fees relating to any of the foregoing payable to all of the
         Banks and no waiver shall be made of any Default under Section 9.1(a).

                  (c)      No increase shall be made in the amount, or extension
         of the term, of the Commitments.

                  (d)      No alteration shall be made of the Banks' rights of
         set-off contained herein or in the other Loan Documents.

                  (e)      No release of any Collateral shall be made (except
         that the Administrative Agent may release particular items of
         Collateral in dispositions permitted by the Security Instruments and
         may release all Collateral upon payment in full of the Loans evidenced
         by the Convertible Note and termination of the Commitments without the
         written consent of the Banks).

                  (f)      No amendment to or modification of this Section
         10.6(ii) shall be made.

         10.7     Administrative Agent's Resignation. The Administrative Agent
may resign at any time by giving at least 30 days' prior written notice of its
intention to do so to each other of the Banks and the Borrowers and upon the
appointment by the Required Banks of a successor Administrative Agent
satisfactory to the Borrowers. If no successor Administrative Agent shall have
been so appointed and shall have accepted such appointment within 45 days after
the retiring Administrative Agent's giving of such notice of resignation, then
the retiring Administrative Agent may with the consent of the Borrowers, which
shall not be unreasonably withheld, appoint a successor Administrative Agent
which shall be a bank or a trust Borrowers organized under the laws of the
United States of America or any state thereof and having a combined capital,
surplus and undivided profit of at least $50,000,000; provided, however, that
any successor Administrative Agent appointed under this sentence may be removed
upon the written request of the Required Banks, which request shall also appoint
a successor Administrative Agent satisfactory to the Borrowers. Upon the
appointment of a new Administrative Agent hereunder, the term "Administrative
Agent" shall for all purposes of this Agreement thereafter mean such successor.
After any retiring Administrative Agent's resignation hereunder as
Administrative Agent, or the removal hereunder of any successor Administrative
Agent, the provisions of this Agreement shall continue to inure to the benefit
of such Administrative Agent as to any actions taken or omitted to be taken by
it while it was Administrative Agent under this Agreement.



                                     - 37 -
<PAGE>   39

         10.8     Concerning the Administrative Agent.

                  10.8.1   Action in Good Faith. The Administrative Agent and
         its officers, directors, employees and agents shall be under no
         liability to any of the Banks or to any future holder of any interest
         in the Indebtedness for any action or failure to act taken or suffered
         in good faith, and any action or failure to act in accordance with an
         opinion of its counsel shall conclusively be deemed to be in good
         faith. The Administrative Agent shall in all cases be entitled to rely,
         and shall be fully protected in relying, on instructions given to the
         Administrative Agent by the Required Holders of the Bank Note
         evidencing the Bank Obligations as provided in this Agreement.

                  10.8.2   No Implied Duties. The Administrative Agent shall
         have and may exercise such powers as are specifically delegated to the
         Administrative Agent under this Agreement or any other Loan Document
         together with all other powers incidental thereto. The Administrative
         Agents shall have no implied duties to any Person or any obligation to
         take any action under this Agreement or any other Loan Document except
         for action specifically provided for in this Agreement or any other
         Loan Document to be taken by the Administrative Agent. Before taking
         any action under this Agreement or any other Loan Document, the
         Administrative Agent may request an appropriate specific indemnity
         satisfactory to it from each Bank in addition to the general indemnity
         provided for in Section 10.11. Until the Administrative Agent has
         received such specific indemnity, the Administrative Agent shall not be
         obligated to take (although such Administrative Agent may in its sole
         discretion take) any such action under this Agreement or any other Loan
         Document. Each Bank confirms that the Administrative Agent does not
         have a fiduciary relationship to them under the Loan Documents. The
         Borrowers and its Subsidiaries party hereto confirm that neither the
         Administrative Agent nor any other Bank has a fiduciary relationship to
         them under the Loan Documents.

                  10.8.3   Validity. The Administrative Agent shall not be
         responsible to any Bank or any future holder of any interest in the
         Convertible Loan and Indebtedness (a) for the legality, validity,
         enforceability or effectiveness of this Agreement or any other Loan
         Document, (b) for any recitals, reports, representations, warranties or
         statements contained in or made in connection with this Agreement or
         any other Loan Document, (c) for the existence or value of any assets
         included in any security for the Convertible Loan and Indebtedness, (d)
         for the effectiveness of any Lien purported to be included in the
         Collateral, (e) for the specification or failure to specify any
         particular assets to be included in the Collateral, or (f) unless the
         Administrative Agent shall have failed to comply with Section 10.8.1,
         for the perfection of the security interests in the Collateral.

                  10.8.4   Compliance. The Administrative Agent shall not be
         obligated to ascertain or inquire as to the performance or observance
         of any of the terms of this Agreement or any other Loan Document; and
         in connection with any extension of credit under this Agreement or any
         other Loan Document, the Administrative Agent shall be fully protected
         in relying on a certificates of the Borrowers as to the fulfillment by
         the Borrowers of any conditions to such extension of credit.

                  10.8.5   Employment Administrative Agent and Counsel. The
         Administrative Agent may execute any of their respective duties as
         Administrative Agent under this Agreement or any other Loan Document by
         or through employees, agents and attorneys-in-fact and shall not be
         responsible to any of the Banks, the Borrowers for the default or
         misconduct of any such Administrative Agent or attorneys-in-fact
         selected by the Administrative Agent acting in good faith. The
         Administrative Agent shall be entitled to advice of counsel concerning
         all



                                     - 38 -
<PAGE>   40

         matters pertaining to the agency hereby created and its duties
         hereunder or under any other Loan Document.

                  10.8.6   Reliance on Documents and Counsel. The Administrative
         Agent shall be entitled to rely, and shall be fully protected in
         relying, upon any affidavit, certificate, cablegram, consent,
         instrument, letter, notice, order, document, statement, telecopy,
         telegram, telex or teletype message or writing reasonably believed in
         good faith by the Administrative Agent to be genuine and correct and to
         have been signed, sent or made by the Person in question, including any
         telephonic or oral statement made by such Person, and, with respect to
         legal matters, upon an opinion or the advice of counsel selected by
         such Administrative Agent.

                  10.8.7   Administrative Agent's Reimbursement. Each of the
         Banks severally agrees to reimburse the Administrative Agent, in the
         amount of such Bank's Percentage Interest, for any reasonable expenses
         not reimbursed by the Borrowers (without limiting the obligation of the
         Borrowers to make such reimbursement): (a) for which the Administrative
         Agent are entitled to reimbursement by the Borrowers under this
         Agreement or any other Loan Document, and (b) after the occurrence of a
         Default, for any other reasonable expenses incurred by the
         Administrative Agent on the Banks' behalf in connection with the
         enforcement of the Banks' rights under this Agreement or any other Loan
         Document.

         10.9     Rights as a Bank. With respect to any Loan(s) or advance(s)
extended by it hereunder, the Administrative Agent shall have the same rights,
obligations and powers hereunder as any other Bank and may exercise such rights
and powers as though it were not an Administrative Agent, and unless the context
otherwise specifies, the Administrative Agent shall be treated in their
respective individual capacities as though they were not the Administrative
Agent hereunder. Without limiting the generality of the foregoing, the
Percentage Interest of the Administrative Agent shall be included in any
computations of Percentage Interests. The Administrative Agent and its
Affiliates may accept deposits from, lend money to, act as trustee for and
generally engage in any kind of banking or trust business with the Borrowers,
any of its Subsidiaries or any Affiliate of any of them and any Person who may
do business with or own an equity interest in the Borrowers, any of its
Subsidiaries or any Affiliate of any of them, all as if the Administrative Agent
were not the Administrative Agent and without any duty to account therefor to
the other Banks.

         10.10    Independent Credit Decision. Each of the Banks acknowledges
that it has independently and without reliance upon either of the Administrative
Agent, based on the financial statements and other documents referred to in
Section 8.3, on the other representations and warranties contained herein and on
such other information with respect to the Borrowers and their Subsidiaries as
such Bank deemed appropriate, made such Bank's own credit analysis and decision
to enter into this Agreement and to make the extensions of credit provided for
hereunder. Each Bank represents to the Administrative Agent that such Bank will
continue to make its own independent credit and other decisions in taking or not
taking action under this Agreement or any other Loan Document. Each Bank
expressly acknowledges that neither the Administrative Agent nor any of its
respective officers, directors, employees, agent, attorneys-in-fact or
Affiliates has made any representations or warranties to such Bank, and no act
by the Administrative Agent taken under this Agreement or any other Loan
Document, including any review of the affairs of the Borrowers and their
Subsidiaries, shall be deemed to constitute any representation or warranty by
either of the Administrative Agent. Except for notices, reports and other
documents expressly required to be furnished to each Bank by the Administrative
Agent under this Agreement or any other Loan Document, the Administrative Agent
shall not have any duty or responsibility to provide any Bank with any credit or
other information concerning the business, operations, property, condition,
financial or otherwise, or creditworthiness of the Borrowers or any Subsidiary
which may come into



                                     - 39 -
<PAGE>   41

the possession of the Administrative Agent or any of their respective officers,
directors, employees, agent, attorneys-in-fact or Affiliates.

         10.11    Indemnification. The holders of the Indebtedness shall
indemnify the Administrative Agent and its respective officers, directors,
employees and Administrative Agent (to the extent not reimbursed by the
Borrowers and without limiting the obligation of the Borrowers to do so), pro
rata in accordance with their respective Percentage Interests, from and against
any and all liabilities, obligations, losses, damages, penalties, actions,
judgments, suits, costs, expenses or disbursements of any kind whatsoever which
may at any time be imposed on, incurred by or asserted against either of the
Administrative Agent or such Persons relating to or arising out of this
Agreement, any other Loan Document, the transactions contemplated hereby or
thereby, or any action taken or omitted by the Administrative Agent in
connection with any of the foregoing; provided, however, that the foregoing
shall not extend to actions or omissions which are taken by the Administrative
Agent with gross negligence or willful misconduct.


                                   ARTICLE XI

                           ASSIGNMENTS/PARTICIPATIONS

         11.      Successors and Assigns; Bank Assignment and Participations.
Any reference in this Agreement to any party hereto shall be deemed to include
the successors and assigns of such party, and all covenants and agreements by or
on behalf of the Borrowers, the Administrative Agent or the Banks that are
contained in this Agreement or any other Loan Documents shall bind and inure to
the benefit of their respective successors and assigns; provided, however, that
(a) the Borrowers may not assign their rights or obligations under this
Agreement, and (b) the Banks shall be not entitled to assign their respective
Percentage Interests in the Convertible Loan evidenced by the Convertible Note
hereunder except as set forth below in this Section 11.

         11.1     Assignments by Banks.

                  11.1.1   Assignees and Assignment Procedures. Each Bank may
         (i) without the consent of the Administrative Agent or the Borrowers if
         the proposed assignee is already a Bank hereunder or a Wholly Owned
         Subsidiary of the same corporate parent of which the assigning Bank is
         a Subsidiary, or (ii) otherwise with the consents of the Administrative
         Agent and (so long as no Event of Default exists) the Borrowers (which
         consents will not be unreasonably withheld), in compliance with
         applicable laws in connection with such assignment, assign to one or
         more commercial banks or other financial institutions (each, an
         "Assignee") all or a portion of its interests, rights and obligations
         under this Agreement and the other Loan Documents, including all or a
         portion, which need not be pro rata among the Convertible Loan advances
         and the Letter of Credit Exposure, of its Commitments, the portion of
         the Convertible Loan advances and the Letter of Credit Exposure at the
         time owing to it and the Convertible Note held by it, but excluding its
         rights and obligations as one of the Administrative Agent; provided,
         however, that:

                  (i)      the aggregate amount of the Commitments of the
         assigning Bank subject to each such assignment to any Assignee other
         than another Bank (determined as of the date the Assignment and
         Acceptance with respect to such assignment is delivered to the
         Administrative Agent) shall be not less than $1,000,000 and in
         increments of $500,000; and

                  (ii)     the parties to each such assignment shall execute and
         deliver to the Administrative Agent an Assignment and Acceptance (the
         "Assignment and Acceptance") 



                                     - 40 -
<PAGE>   42

         in the form satisfactory to the Administrative Agent, together with the
         Convertible Note or Notes subject to such assignment.

                  Upon acceptance and recording pursuant to Section 11.1.4, from
         and after the effective date specified in each Assignment and
         Acceptance (which effective date shall be at least five (5) Business
         Days after the execution thereof unless waived in writing by the
         Administrative Agent):

                  (A)      the Assignee shall be a party hereto and, to the
                           extent provided in such Assignment and Acceptance,
                           have the rights and obligations of a Bank under this
                           Agreement; and

                  (B)      the assigning Bank shall, to the extent provided in
                           such assignment, be released from its obligations
                           under this Agreement (and, in the case of an
                           Assignment and Acceptance covering all or the
                           remaining portion of an assigning Bank's rights and
                           obligations under this Agreement, such Bank shall
                           cease to be a party hereto but shall continue to be
                           entitled to any fees accrued for its account
                           hereunder and not yet paid).

                  11.1.2   Terms of Assignment and Acceptance. By executing and
         delivering an Assignment and Acceptance, the assigning Bank and
         Assignee shall be deemed to confirm to and agree with each other and
         the other parties hereto as follows:

                  (a)      other than the representation and warranty that it is
         the legal and beneficial owner of the interest being assigned thereby
         free and clear of any adverse claim, such assigning Bank makes no
         representation or warranty and assumes no responsibility with respect
         to any statements, warranties or representations made in or in
         connection with this Agreement or the execution, legality, validity,
         enforceability, genuineness, sufficiency or value of this Agreement,
         any other Loan Document or any other instrument or document furnished
         pursuant hereto;

                  (b)      such assigning Bank makes no representation or
         warranty and assumes no responsibility with respect to the financial
         condition of the Borrowers and their Subsidiaries or the performance or
         observance by the Borrowers or any of their Subsidiaries of any of its
         obligations under this Agreement, any other Loan Document or any other
         instrument or document furnished pursuant hereto;

                  (c)      such Assignee confirms that it has received a copy of
         this Agreement, together with copies of the most recent quarterly or
         annual financial statements delivered pursuant hereto and such other
         documents and information as it has deemed appropriate to make its own
         credit analysis and decision to enter into such Assignment and
         Acceptance;

                  (d)      such Assignee will independently and without reliance
         upon the Administrative Agent, such assigning Bank or any other Bank,
         and based on such documents and information as it shall deem
         appropriate at the time, continue to make its own credit decisions in
         taking or not taking action under this Agreement;

                  (e)      such Assignee appoints and authorizes the
         Administrative Agent to take such action as Administrative Agent on its
         behalf and to exercise such powers under this Agreement as are
         delegated to the Administrative Agent by the terms hereof, together
         with such powers as are reasonably incidental thereto; and




                                     - 41 -
<PAGE>   43


                  (f)      such Assignee agrees that it will perform in
         accordance with the terms of this Agreement all the obligations which
         are required to be performed by it as a Bank.

                  11.1.3   Register. The Administrative Agent shall maintain at
         its main Tulsa, Oklahoma banking office a register (the "Register") for
         the recordation of (a) the names and addresses of the Banks and the
         Assignees which assume rights and obligations pursuant to an assignment
         under Section 11.1.1, (b) the Percentage Interest of each such Bank as
         set forth in Section 10.1 and (c) the amount of the Convertible Loan
         owing to each Bank from time to time. The entries in the Register shall
         be conclusive, in the absence of manifest error, and the Borrowers, the
         Administrative Agent and the Banks may treat each Person whose name is
         registered therein for all purposes as a party to this Agreement. The
         Register shall be available for inspection by the Borrowers or any Bank
         at any reasonable time and from time to time upon reasonable prior
         notice.

                  11.1.4   Acceptance of Assignment and Assumption. Upon its
         receipt of a completed Assignment and Acceptance executed by an
         assigning Bank and an Assignee, in exchange for the Convertible Note
         subject to such assignment, together with the Convertible Note or Notes
         subject to such assignment, and the processing and recordation fee
         referred to in Section 11.1.1, the Administrative Agent shall (a)
         accept such Assignment and Acceptance, (b) record the information
         contained therein in the Register and (c) give prompt notice thereof to
         the Borrowers. Within five (5) Business Days after receipt of notice,
         the Borrowers, at its own expense, shall execute and deliver to the
         Administrative Agent, in exchange for the surrendered Convertible Note
         or Notes, a new Convertible Note or Notes to the order of such Assignee
         in a principal amount equal to the applicable Commitments and Loans
         assumed by it pursuant to such Assignment and Acceptance and, if the
         assigning Bank has retained Commitments and Convertible Loan advances,
         a new Convertible Note or Notes to the order of such assigning Bank in
         a principal amount equal to the applicable Commitments and its
         Percentage Interest in the Convertible Loan retained by it. Such new
         Convertible Note or Notes shall be in an aggregate principal amount
         equal to the aggregate principal amount of such surrendered Convertible
         Note or Notes, and shall be dated the date of the surrendered
         Convertible Note or Notes which it or they replace. All such
         Convertible Notes so replaced shall be delivered by the Administrative
         Agent to the Borrowers or, alternatively, at the Administrative Agent's
         election, marked appropriately to evidence the replacement thereof by
         such replacement Convertible Note(s).

                  11.1.5   Federal Reserve Bank. Notwithstanding the foregoing
         provisions of this Section 11, any Bank may at any time pledge or
         assign all or any portion of such Bank's rights under this Agreement
         and the other Loan Documents to a Federal Reserve Bank; provided,
         however, that no such pledge or assignment shall release such Bank from
         such Bank's obligations hereunder or under any other Loan Document.

                  11.1.6   Further Assurances. The Borrowers and their
         Subsidiaries shall sign such documents and take such other actions from
         time to time reasonably requested by an Assignee to enable it to share
         in the benefits of the rights created by the Loan Documents.

         11.2     Credit Participants. Each Bank may, without the consent of the
Borrowers and with the consent of the Administrative Agent, in compliance with
applicable laws in connection with such participation, sell to one or more
commercial banks or other financial institutions (each a "Credit Participant")
participations in all or a portion of its interests, rights and obligations
under this Agreement and the other Loan Documents (including all or a portion of
its Percentage Interest in the Commitments, the Convertible Loan advances and
Letter of Credit Exposure owing to it and the Convertible Notes held by it);
provided, however, that:



                                     - 42 -
<PAGE>   44

         (i)      such Bank's obligations under this Agreement shall remain
unchanged;

         (ii)     such Bank shall remain solely responsible to the other parties
hereto for the performance of such obligations;

         (iii)    the Credit Participant shall be entitled to the benefit of any
cost protection provisions contained in the Credit Agreement, but shall not be
entitled to receive any greater payment thereunder than the selling Bank would
have been entitled to receive with respect to the interest so sold if such
interest had not been sold; and

         (iv)     the Borrowers, the Administrative Agent and the other Banks
shall continue to deal solely and directly with such Bank in connection with
such Bank's rights and obligations under this Agreement, and such Bank shall
retain the sole right as one of the Banks to vote with respect to the
enforcement of the obligations of the Borrowers relating to the Convertible Loan
and Letter of Credit Exposure and the approval of any amendment, modification or
waiver of any provision of this Agreement (other than amendments, modifications,
consents or waivers described in Section 10.6(ii)).

Borrowers agree, to the fullest extent permitted by applicable law, that any
Credit Participant and any Bank purchasing a participation from another Bank
pursuant to Section 11.1 may exercise all rights of payment (including the right
of set-off), with respect to its participation as fully as if such Credit
Participant or such Bank were the direct creditor of the Borrowers and a Bank
hereunder in the amount of such participation. Upon receipt of notice of the
address of each Credit Participant, the Borrowers shall thereafter supply such
Credit Participants with the same information and reports communicated to the
Banks. The Borrowers hereby acknowledge and agree that Credit Participants shall
be deemed a holder of the applicable Convertible Notes to the extent of their
respective participations, and the Borrowers hereby waive their right, if any,
to offset amounts owing to the Borrowers from the Banks against each Credit
Participant's portion of the applicable Convertible Notes.


                                   ARTICLE XII

                                  MISCELLANEOUS

         12.1     Notices. Unless otherwise provided herein, all notices,
requests, consents and demands shall be in writing and shall be either
hand-delivered (by courier or otherwise) or mailed by certified mail, postage
prepaid, to the respective addresses specified below, or, as to any party, to
such other address as may be designated by it in written notice to the other
parties:

         If to the Borrowers, to:

                  Middle Bay Oil Company, Inc.
                  1221 Lamar
                  Suite 1020
                  Houston, Texas  77010




                                     - 43 -
<PAGE>   45

         If to the Banks, to:

                  Bank of Oklahoma, N.A.
                  P. O. Box 2300
                  Tulsa, Oklahoma 74192
                  Attention:  Energy Department

All notices, requests, consents and demands hereunder will be effective when
hand-delivered by the Administrative Agent to the applicable notice address of
the Borrowers or when mailed by certified mail, postage prepaid, addressed as
aforesaid by either party hereto.

         12.2     Place of Payment. All sums payable hereunder shall be paid in
immediately available funds to the Administrative Agent, at its principal
banking offices at Bank of Oklahoma Tower, One Williams Center in Tulsa,
Oklahoma, or at such other place as the Administrative Agent shall notify the
Borrowers in writing. If any interest, principal or other payment falls due on a
date other than a Business Day, then (unless otherwise provided herein) such due
date shall be extended to the next succeeding Business Day, and such extension
of time will in such case be included in computing interest, if any, in
connection with such payment.

         12.3     Survival of Agreements. All covenants, agreements,
representations and warranties made herein shall survive the execution and the
delivery of Loan Documents. All statements contained in any certificate or other
instrument delivered by the Borrower hereunder shall be deemed to constitute
representations and warranties by the Borrowers.

         12.4     Parties in Interest. All covenants, agreements and obligations
contained in this Agreement shall bind and inure to the benefit of the
respective successors and assigns of the parties hereto, except that the
Borrowers may not assign their rights or obligations hereunder without the prior
written consent of the Banks.

         12.5     Governing Law. This Agreement and the Notes shall be deemed to
have been made or incurred under the Laws of the State of Oklahoma and shall be
construed and enforced in accordance with and governed by the Laws of Oklahoma.

         12.6     SUBMISSION TO JURISDICTION. THE BORROWERS HEREBY CONSENT TO
THE JURISDICTION OF ANY OF THE LOCAL, STATE, AND FEDERAL COURTS LOCATED WITHIN
TULSA COUNTY, OKLAHOMA AND WAIVE ANY OBJECTION WHICH BORROWERS MAY HAVE BASED ON
IMPROPER VENUE OR FORUM NON CONVENIENS TO THE CONDUCT OF ANY PROCEEDING IN ANY
SUCH COURT AND WAIVES PERSONAL SERVICE OR ANY AND ALL PROCESS UPON EITHER OF
THEM, AND CONSENTS THAT ALL SUCH SERVICE OF PROCESS BE MADE BY MAIL OR MESSENGER
DIRECTED TO IT AT THE ADDRESS SET FORTH IN SUBSECTION 12.1 HEREOF AND THAT
SERVICE SO MADE SHALL BE DEEMED TO BE COMPLETED UPON THE EARLIER OF ACTUAL
RECEIPT OR THREE (3) BUSINESS DAYS AFTER MAILED OR DELIVERED BY MESSENGER.

         12.7     Maximum Interest Rate. Regardless of any provision herein, the
Banks shall never be entitled to receive, collect or apply, as interest on the
Indebtedness any amount in excess of the maximum rate of interest permitted to
be charged by the Banks by applicable Law, and, in the event the Banks shall
ever receive, collect or apply, as interest, any such excess, such amount which
would be excessive interest shall be applied to other Indebtedness and then to
the reduction of principal; and, if the other Indebtedness and principal are
paid in full, then any remaining excess shall forthwith be paid to the
Borrowers.



                                     - 44 -
<PAGE>   46

         12.8     No Waiver; Cumulative Remedies. No failure to exercise, and no
delay in exercising, on the part of the Banks, any right, power or privilege
hereunder or under any other Loan Document or applicable Law shall preclude any
other or further exercise thereof or the exercise of any other right, power or
privilege of the Banks. The rights and remedies herein provided are cumulative
and not exclusive of any other rights or remedies provided by any other
instrument or by law. No amendment, modification or waiver of any provision of
this Agreement or any other Loan Document shall be effective unless the same
shall be in writing and signed by the Banks. No notice to or demand on the
Borrowers in any case shall entitle the Borrowers to any other or further notice
or demand in similar or other circumstances.

         12.9     Costs. The Borrowers agree to pay to the Administrative Agent
on demand all recording fees and filing costs and all reasonable attorneys fees
and legal expenses incurred or accrued by the Administrative Agent or the Banks
in connection with the preparation, negotiation, closing, administration of the
Loan Documents and the filing and recording of the Security Instruments or any
amendment, waiver, consent or modification to and of the Loan Documents. In any
action to enforce or construe the provisions of this Agreement or any of the
Loan Documents, the prevailing party shall be entitled to recover its reasonable
attorneys' fees and all costs and expenses related thereto.

         12.10    Headings. The article and section headings of this Agreement
are for convenience of reference only and shall not constitute a part of the
text hereof nor alter or otherwise affect the meaning hereof.

         12.11    Severability. The unenforceability or invalidity as determined
by a Tribunal of competent jurisdiction, of any provision or provisions of this
Agreement shall not render unenforceable or invalid any other provision or
provisions hereof.

         12.12    Exceptions to Covenants. The Borrowers shall not be deemed to
be permitted to take any action or fail to take any action which is permitted as
an exception to any of the covenants contained herein or which is within the
permissible limits of any of the covenants contained herein if such action or
omission would result in the breach of any other covenant contained herein.

         12.13    Replacement of Existing Agreement. This Agreement modifies and
amends the Existing Agreement and the Convertible Loan Commitment therein
established together with all Indebtedness described or defined therein are
renewed, extended and restructured into and become a part of the Commitments and
all Indebtedness, including the Notes, described and/or defined herein, all of
which shall be continuously secured by all of the Collateral described and
defined in the Security Instruments, including without limitation, the
Mortgages.

         12.14    Counterparts. This Agreement may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
instrument.

         12.15    WAIVER OF JURY. BORROWERS FULLY, VOLUNTARILY AND EXPRESSLY
WAIVE ANY RIGHT TO A TRIAL BY JURY IN ANY ACTION OR PROCEEDING TO ENFORCE OR
DEFEND ANY RIGHTS UNDER THE NOTES, THIS AGREEMENT, THE SECURITY INSTRUMENTS OR
UNDER ANY AMENDMENT, SUPPLEMENT, INSTRUMENT, DOCUMENT OR AGREEMENT DELIVERED (OR
WHICH MAY IN THE FUTURE BE DELIVERED) IN CONNECTION HEREWITH OR ARISING FROM ANY
BANKING RELATIONSHIP EXISTING IN CONNECTION WITH THIS AGREEMENT. BORROWERS AGREE
THAT ANY SUCH ACTION OR PROCEEDING SHALL BE TRIED BEFORE A COURT AND NOT BEFORE
A JURY.



                                     - 45 -
<PAGE>   47

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed and delivered in Tulsa, Oklahoma as of the day and year first
above written by the undersigned duly authorized corporate officers.

                                  MIDDLE BAY OIL COMPANY, INC.


                                  By   /s/ John J. Bassett
                                       -----------------------------------------
                                       John J. Bassett, President

                                              "Middle Bay"

                                  BISON ENERGY CORPORATION


                                  By   /s/ John J. Bassett
                                       -----------------------------------------
                                       John J. Bassett,
                                       Chief Executive Officer

                                                 "Bison"

                                  SHORE OIL COMPANY


                                  By   /s/ John J. Bassett
                                       -----------------------------------------
                                       John J. Bassett,
                                       Chairman and Chief Executive Officer

                                                   "Shore"

                                    Collectively the "Borrowers"

                                    BANK OF OKLAHOMA, NATIONAL
                                    ASSOCIATION


                                    By /s/ Michael M. Coats
                                       -----------------------------------------
                                         Michael M. Coats, Senior Vice President

                                                "Bank"












                                     - 46 -
<PAGE>   48



                                    EXHIBITS


                  Exhibit A                  Convertible Loan Advance Request

                  Exhibit B-1                Convertible Note

                  Exhibit C                  Existing Liens

                  Exhibit D                  Other Indebtedness

                  Exhibit E                  Litigation

                  Exhibit F                  Take or Pay Disputes

                  Exhibit G                  Title to Properties



<PAGE>   49

                                    EXHIBIT A

                         LOAN REQUEST, CERTIFICATION AND
                         CONFIRMATORY SECURITY AGREEMENT
                              FOR CONVERTIBLE NOTE


Bank of Oklahoma, National Association
P.O. Box 2300
Tulsa, Oklahoma 74192
Attn: Energy Department

Gentlemen:

        Pursuant to the provisions of the Second Restated Revolving Credit and
Term Loan Agreement dated as of August 25, 1997, as amended (collectively the
"Credit Agreement"), between and among MIDDLE BAY OIL COMPANY, BISON ENERGY
CORPORATION and SHORE OIL COMPANY (collectively the "Borrower") and you, the
undersigned, hereby (i) confirms and ratifies your continuing first and prior
security interest and mortgage lien in and to all of the Collateral (including
proceeds thereof) described or referred to in the Credit Agreement or in the
Security Instruments described therein; (ii) applies to you for a Convertible
Loan in the amount of $_____________ on the Convertible Note; (iii) certifies
that no Event of Default or Default under the Credit Agreement has occurred and
is continuing as of the date hereof or exists or would continue to exist but for
the lapse of time or giving of notice, or both; (iv) represents and warrants to
you that the representations, covenants and warranties set forth or referred to
in the Credit Agreement are true and correct on and as of this date; and (v)
certifies to you the accuracy of the following information concerning the
Collateral Borrowing Base for the Convertible Note:

<TABLE>
        <S>   <C>                                                <C>                   <C>
        1.    Collateral Borrowing Base
               (determined/redetermined
               as of each March 31 and September 30,
               initially on September 30, 1997)                                        $15,000,000
                                                                                       -----------

        2.    Convertible Loan Balance                           $
               (including the outstanding portions of             --------------
               unexpired Letters of Credit issued pursuant
               to Section 2.12.1 of the Credit Agreement -
               not to exceed $1,000,000 in the aggregate)

        3.    New Convertible Loan Balance                                             $
               (Line 2 + $__________ advance                                            -----------
               requested hereby but not to exceed
               lesser of Line 1 or Bank Borrowing Base
               (per ss. 1.6 of Credit Agreement)
</TABLE>

        IN WITNESS WHEREOF, the undersigned has hereunto set his hand this
______ day of _______________, 199__.

                                    MIDDLE BAY OIL COMPANY, INC.




                                    By
                                      -----------------------------------------
                                                                       (Title)

                                    (As agent for and on behalf of Bison Energy
                                    Corporation, Shore Oil Company and itself)




<PAGE>   50






                                   EXHIBIT B-1

                                 PROMISSORY NOTE

$50,000,000.00
                                                                 Tulsa, Oklahoma
                                                                 August 25, 1997

         FOR VALUE RECEIVED, MIDDLE BAY OIL COMPANY, INC., BISON ENERGY
CORPORATION and SHORE OIL COMPANY (collectively the "Borrowers"), hereby jointly
and severally promise to pay to the order of BANK OF OKLAHOMA, NATIONAL
ASSOCIATION (the "Bank"), at the Bank's principal offices in Tulsa, Oklahoma, in
lawful money of the United States of America, the principal sum of FIFTY MILLION
and NO/100 DOLLARS ($50,000,000.00), payable in seventy-one (71) consecutive
monthly installments of principal in an amount equal to one seventy-second
(1/72nd) of the lesser of the outstanding principal balance hereof on March 31,
1998 (the "Conversion Date") or the then applicable Collateral Borrowing Base in
effect as of the Conversion Date, each due on the last day of each calendar
month, commencing April 30, 1998, together with interest from the date funds are
advanced hereunder on the unpaid balance of principal from time to time
outstanding, and on any past due interest, at the variable annual rate of
interest hereinafter specified, at the Option rate or rates per annum determined
pursuant to Section 2.6 of the Loan Agreement (as hereinafter defined) and due
and payable monthly as it accrues on the last day of each calendar month,
commencing August 31, 1997, with a final payment of all unpaid principal and
accrued but unpaid interest due and payable at final maturity on March 31, 2004.

         For the purposes of this Note, the "Applicable Prime Rate" shall mean
the annual rate of interest announced by Chase Manhattan Bank (National
Association) New York, New York ("Chase") from time to time as its prime or base
rate, which shall be the rate used by Chase as a base or standard for pricing
purposes and which shall not necessarily be its "best" or lowest rate.

         After default in the payment of any amount of principal or interest
owing hereunder within five (5) days of the due date thereof (whether on
maturity, acceleration or otherwise) or upon the occurrence of any Default or
Event of Default as described in the Second Restated Revolving Credit and Term
Loan Agreement of even date herewith among the Borrowers and the Bank (said
Second Revolving Credit and Term Loan Agreement as the same may at any time be
amended, supplemented, extended or modified and in effect being herein called
the "Loan Agreement"), the unpaid principal amount hereof shall bear interest
computed at a variable annual rate equal from day to day to the Applicable Prime
Rate plus six percentage points (6.0%). Upon default in the payment of any
installment of principal or interest payable hereunder, such interest shall, to
the full extent permitted by law, bear interest at the same rate as principal.

         This Note is made pursuant to the Loan Agreement and is the Convertible
Note therein described. The Loan Agreement, among other things, contains
prepayment provisions, provisions for semi-annual collateral borrowing base
calculations and provisions for acceleration of the maturity hereof upon the
events, terms and conditions therein specified.



<PAGE>   51

Promissory Note
August 25, 1997
Page 2


         This Note is secured by the Collateral described in the Security
Instruments defined in the Loan Agreement which have been executed by the
Borrowers and delivered to the Bank. Reference is hereby made to the Security
Instruments for a description of the property, assets and interests thereby
mortgaged, conveyed and/or assigned, as the case may be, the nature and extent
of the security thereunder and the security interests or mortgage liens created
thereby, and the rights of the Bank (or the holder of this Note) and the
Borrower in respect thereof.

         Should the indebtedness represented by this Note or any part thereof be
collected at law or in equity or in bankruptcy, receivership or other court
proceedings or this Note be placed in the hands of attorneys for collection
after default, the Borrowers agree to pay hereunder, in addition to the
principal and interest due and payable hereon, reasonable attorneys fees, court
costs and other collection fees and expenses incurred by the holder hereof.

         The Borrowers hereby waive presentment for payment, demand, notice of
nonpayment, protest and notice of protest with respect to any payment hereunder
and agree to any extension of time with respect to any payment due hereunder, to
any substitution or release of the security or collateral described in the
Security Instruments and to the addition or release of any party liable
hereunder. No delay on the part of the holder hereof in exercising any rights
hereunder shall operate as a waiver of such rights.

         This Note constitutes a replacement and modification of that certain
$15,000,000.00 Convertible Note from Middle Bay Oil Company, Inc. and Bison
Energy Corporation payable to the order of the Bank dated March 31, 1997, as
more particularly described in the Existing Agreement defined in the Loan
Agreement. This Note and the indebtedness evidenced hereby shall be construed
and enforced in accordance with and governed by the laws of the State of
Oklahoma and is delivered to the order of the Bank in Tulsa, Oklahoma, by the
undersigned duly authorized corporate officers of the respective Borrowers.

         Notwithstanding the stated principal amount on the face of this Note in
no event shall the Bank's funding obligation hereunder or pursuant to Article II
of the Loan Agreement exceed the lesser of (i) the Bank's Maximum Commitment
Amount pursuant to Section 10.1 of the Loan Agreement or (ii) the Bank Borrowing
Base defined in the Loan Agreement, as it may be redetermined from time to time
pursuant to the terms and provisions of the Loan Agreement.


                                         MIDDLE BAY OIL COMPANY, INC.


                                         By
                                            ----------------------------------
                                            John J. Bassett, President


<PAGE>   52


Promissory Note
August 25, 1997
Page 3


                                BISON ENERGY CORPORATION


                                By
                                   ------------------------------------------
                                     John J. Bassett,
                                     Chief Executive Officer


                                SHORE OIL COMPANY


                                By
                                   ------------------------------------------
                                     John J. Bassett,
                                     Chairman and Chief Executive Officer

                                            "Borrowers"



Due: March 31, 2004


<PAGE>   53




                                    EXHIBIT C

                                 Existing Liens
                                 (Section 7.16)


                                      NONE


<PAGE>   54



                                    EXHIBIT D

                               Other Indebtedness
                                 (Section 7.19)


                                      NONE


<PAGE>   55



                                    EXHIBIT E

                                   Litigation
                                  (Section 8.1)


1.       Civil Action No. 97-40-A-M2, J. B. Hanks Co., Inc. v. Shore Oil
         Company, in the United States District Court for the Middle District of
         Louisiana.

2.       Civil Action No. H-97-0158, Shore Oil Company v. J. B. Hanks Co., Inc.,
         in the United States District Court for the Southern District of Texas,
         Houston Division.

3.       Everett A. Giroir, Jr., et al. v. Shore Oil Company, et al., 32nd
         Judicial District Court, Parish of Terrebonne, Number 113341, Division
         "E."





<PAGE>   56



                                    EXHIBIT F

                              Take or Pay Disputes
                                  (Section 8.8)



                                      NONE


<PAGE>   57



                                    EXHIBIT G

                               Title to Properties
                                 (Section 8.17)










<PAGE>   1
                                                                    


[MIDDLE BAY OIL COMPANY, INC. LETTERHEAD]

January 29, 1997

Mr. Gerald B. Eckley
President and Chief Executive Officer
Enex Resources Corporation
800 Rockmead
Kingswood, Texas 77339

Dear Gerald:

Middle Bay Oil Company, Inc., (hereinafter collectively referred to as "MBOC")
is pleased to make the following offer to Enex Resources Corporation,
(hereinafter referred as "ENEX"), for due consideration by it's Board of
Directors a proposal cash tender offer (the "Tender Offer") by MBOC for all of
the outstanding capital stock of ENEX, as described below.

The securities proposed to be purchased shall include 100% of ENEX outstanding
common stock and all options and warrants outstanding to purchase common stock
(the ENEX common stock hereinafter referred to as the "Shares").

Based on MBOC's present understanding of ENEX, the Tender Offer will offer
$15.00 (Cash) per share of ENEX ($20,144,265).  In addition, we intend to offer
the following: (1) Severance - MBOC is willing to pay your current salary for
four years in exchange for your consulting for MBOC and a first right of refusal
on all prospects and potential acquisitions that you have the opportunity to
acquire over the four-year period. (1) Options - MBOC will offer to the option
holders the difference between the exercise price and $15.00 per share in either
cash or stock.  The stock price is to be determined by taking the previous 10
days average of the means of the closing bid and asked prices of MBOC share
immediately prior to closing with ENEX Resources Corporation.

This offer is subject to the following understanding between MBOC and ENEX:

1.     To the extent allowable by applicable rules and standards, the economic
       affect of the purchase of ENEX shares by MBOC for accounting purposes
       shall be retroactive to January 1, 1998 at 7:00 a.m. local time.  The
       closing of the Tender Offer and purchase shall occur at a mutually
       acceptable date, time and place, but in no event later than March 15,
       1998.

2.     MBOC reserves the right to withdraw this offer if written notice of
       acceptance of this letter is not received by MBOC by 5:00 p.m. Central
       Standard Time on January 29, 1998.

3.     Conditions precedent to proceeding with the Tender Offer are as follows:

              a.     On or before February 20, 1998, ENEX shall have reviewed a
                     draft of MBOC's tender offer materials, including but not
                     limited to a Tender Offer Statement on form Schedule 14D-1
                     prepared pursuant to Securities and Exchange Commission
                     ("SEC") Rule 14d-2 as MBOC proposes to use in conducting
                     the Tender Offer (collectively, the "Tender Offer
                     Materials"), and all of ENEX's comments shall have been
                     satisfactorily addressed by MBOC.

              b.     MBOC shall have reviewed a draft of ENEX's
                     Solicitation/Recommendation Statement on form Schedule
                     14D-9 prepared pursuant to SEC Rule 14d-9, and all of
                     MBOC's comments thereon shall have been satisfactorily
                     addressed by ENEX.

              c.     MBOC will complete a satisfactory due diligence review of
                     ENEX, including but not limited to ENEX's title to its
                     properties.  The costs of such review shall be borne by
                     MBOC. Subject to the terms of confidentiality set forth in
                     the previously executed confidentiality agreement between
                     MBOC and ENEX, ENEX shall make available, in its offices,
                     upon reasonable prior notice, during normal business hours
                     all of their files, records and data relating to land,
                     legal, geological, engineering, and accounting matters in
                     connection with the properties.

<PAGE>   2

Page 2



       d.     Satisfactory review and acceptance by MBOC of the ENEX engineering
              and geological information and interpretations.

       e.     Satisfactory review and acceptance by MBOC of accounting
              information and current financial statements of ENEX.

       f.     There shall occur no adverse material change to the financial and
              economic status of ENEX from September 30, 1997 until closing.

       g.     Securing all requisite governmental consents and approvals,
              including such as may be required under the Hart-Scott-Rodino
              Antitrust Improvements Act of 1976, as amended.

       h.     The absence of any litigation or other governmental proceeding
              which could result in a material adverse effect on either ENEX or
              MBOC or which seeks to enjoin the consummation of the Tender
              Offer.

       i.     The absence of any breach of any of the terms and
              conditions set forth in this letter of intent by the other party.

4.     The parties acknowledge that they shall jointly prepare any press release
       or other disclosure documents required by law and that neither party
       shall make any public disclosure of this letter of intent or the
       transactions contemplated hereby without the prior written approval of
       the other party.

This letter is intended to evidence the understanding which we have reached
regarding the proposed transaction and our mutual intent to proceed in good
faith and use our best efforts to cause the Tender Offer to be published and
distributed to the ENEX shareholders in accordance with the applicable laws and
with the terms herein.  In consideration of the foregoing and MBOC instructing
its counsel to proceed with preparing the Tender Offer materials, you hereby
agree that, pending publication of the Tender Offer, you will not, directly or
indirectly, solicit, or encourage inquires for proposals to enter into an
agreement with regards to the sale of ENEX or its assets except that nothing
herein shall be deemed to inhibit ENEX or it officers and directors from taking
such actions as may be required to enable them to comply with their fiduciary
duties to ENEX shareholders.  MBOC and ENEX represent and warrant to each other
that neither party has employed any broker or finder in connection with the
transactions described in this letter and neither owes nor will owe any
consideration to any broker or finder contingent upon the occurrence of future
events or transactions, other than Clay Sylvester, whose fee in connection with
the transactions described in this letter, if any, shall be paid by MBOC.

If the foregoing is acceptable to you, please sign and return the enclosed copy
of this letter.  It is understood that this letter expresses the present intent
of MBOC, subject to MBOC's satisfaction with its investigation of ENEX's
properties and financial, engineering and geological information.  In the event
that MBOC has not commenced the Tender Offer of $15.00 per share for 100% of
ENEX outstanding common stock in accordance with the terms and conditions of
this letter of intent on or before February 20, 1998, then this letter of intent
shall terminate and be of no further force and effect.

Sincerely,

MIDDLEBAY OIL COMPANY, INC.

/s/ John J. Basset

John J. Basset,
President and Chief Executive Officer

AGREED AND ACCEPTED THIS ____ DAY OF JANUARY 1998.

ENEX RESOURCES CORPORATION

By:  /s/ Gerald B. Eckley
   --------------------------------
    Gerald B. Eckley
    President & Chief Executive Officer


<PAGE>   1
                                  LAW OFFICES
                      THRASHER, WHITLEY, HAMPTON, & MORGAN
                           A PROFESSIONAL CORPORATION
                             FIVE CONCOURSE PARKWAY
                                   SUITE 2150
                             ATLANTA, GEORGIA 30328

                                    -------

                            TELEPHONE (770) 804-8000
                            FACSIMILE (770) 804-5555
                              E-mail: [email protected]

                               February 18, 1998



Middle Bay Oil Company, Inc.
1221 Lamar
Suite 1020
Houston, Texas 77010

          Re:  Federal Income Tax Consequences
               Offer to Purchase dated February 19, 1998 (the "Offer to
                     Purchase") annexed to Schedule 14D-1, filed with the U.S.
                     Securities and Exchange Commission, in connection with the
                     Offer to Purchase for Cash Up to 1,343,352 Shares of Common
                     Stock of Enex Resources Corporation at $15.00 Net Per
                     Share by Middle Bay Oil Company, Inc.





Gentlemen:

     We have reviewed the text under the heading, "Certain Federal Income Tax
Consequences," in the offer to Purchase referenced above.  Terms defined in the
Offer to Purchase have the same respective meanings when used in this letter.

     In our opinion, such text accurately summarizes the material federal income
tax consequences of the Offer to noncorporate holders of Shares who hold the
Shares as capital assets, subject to the conditions, provisions and limitations
set forth therein and elsewhere in the Offer to Purchase.


                                        Very truly yours,

                                        THRASER, WHITLEY, HAMPTON & MORGAN

                                        /s/ THRASER, WHITLEY, HAMPTON & MORGAN 

RPV:ccs


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