EXHIBIT 10.2
 
                    AMENDMENT TO PURCHASE AND SALE AGREEMENT
                    ----------------------------------------

          This Amendment to Purchase and Sale Agreement, dated April 10, 1996,
is between ENRON OIL & GAS COMPANY, a Delaware corporation ("SELLER"), and ENRON
OIL & GAS MARKETING, INC., a Delaware corporation ("EOGM"), and MEDALLION
PRODUCTION COMPANY, a Delaware corporation ("BUYER").

          WHEREAS, the parties hereto have entered into a Purchase and Sale
Agreement (the "Purchase Agreement") dated March 30, 1996, providing for the
purchase and sale of certain property of SELLER and EOGM located in Sutton
County, Texas; and

          WHEREAS, the parties hereto have agreed to the amendments to the
Purchase Agreement hereinafter set forth;

          NOW, THEREFORE, in consideration of the foregoing, the parties hereto
hereby agree as follows:

          1.  The first sentence of Section 1.1 of the Purchase Agreement is
hereby amended to read in its entirety as follows:
 
          Subject to the terms of this Agreement (including, without limitation,
          the exclusions provided in Section 1.2): (i) SELLER agrees to sell and
          assign to BUYER and BUYER agrees to purchase and acquire from SELLER
          all of SELLER's right and title to, and interest in, the EOG Property
          (as hereinafter defined) except for the EOG Pipeline Property (as
          hereinafter defined) and all Related Contracts (as hereinafter
          defined) with respect to the EOG Pipeline Property, (ii) SELLER agrees
          to sell and assign to IGS (as hereinafter defined) and BUYER agrees to
          cause IGS to purchase and acquire from SELLER all of SELLER's right
          and title to, and interest in, the EOG Pipeline Property and all
          Related Contracts with respect to the EOG Pipeline Property, (iii)
          SELLER agrees to cause EOGM to sell and assign (and EOGM agrees to
          sell and assign) to IGS and BUYER agrees to cause IGS to purchase and
          acquire from EOGM all of EOGM's right and title to, and interest in,
          the EOGM Property (as hereinafter defined), and (iv) SELLER agrees to
          cause EOGM to sell and assign (and EOGM agrees to sell and assign) to
          BUYER (or its designee) and BUYER agrees to purchase and acquire from
          EOGM all of EOGM's right and title to, and interest in, the EOGM
          Contracts (as hereinafter defined).

          2.   The last sentence of Section 1.1 of the Purchase Agreement is
hereby replaced in its entirety by the following two sentences:

          The term "EOGM Contracts" shall mean the contracts referred to in
          Exhibit E-3 attached hereto and made a part hereof. The terms "EOG

 
          Property," "EOGM Property" and "EOGM Contracts" are collectively
          referred to in this Agreement as the "Property."

          3.   Section 1.4 of the Purchase Agreement is hereby amended to read
in its entirety as follows:

          1.4  Designation of Affiliate.  BUYER hereby designates InterCoast Gas
               ------------------------                                         
          Services Company, an Oklahoma corporation ("IGS"), a wholly owned
          subsidiary of BUYER, as the entity to which the EOGM Property, the EOG
          Pipeline Property and the Related Contracts with respect to the EOG
          Pipeline Property shall be assigned and transferred at the Closing.

          4.   The first sentence of Section 3.3.4 of the Purchase Agreement is
hereby amended to read in its entirety as follows:

          To the best of SELLER's knowledge, there are no material Related
          Contracts other than those described in Exhibits A and B-1 attached to
          this Agreement.

          5.   Section 4.1 of the Purchase Agreement is hereby amended to read
in its entirety as follows:

          5.1  Title; Encumbrances.  IF THE CLOSING OCCURS, (i) SELLER SHALL 
               -------------------   
          WARRANT AND DEFEND DEFENSIBLE TITLE TO THE WARRANTED PROPERTY THAT IS
          EOG PROPERTY AGAINST ALL PERSONS CLAIMING TITLE TO SUCH WARRANTED
          PROPERTY BY, THROUGH OR UNDER SELLER, BUT NOT OTHERWISE, AS PROVIDED
          IN THE ASSIGNMENTS AND BILLS OF SALE SET FORTH IN EXHIBITS E-1 AND E-2
          TO BE DELIVERED PURSUANT TO SECTION 7.3.1, AND (ii) EOGM SHALL WARRANT
          AND DEFEND DEFENSIBLE TITLE TO THE WARRANTED PROPERTY THAT IS EOGM
          PROPERTY AGAINST ALL PERSONS CLAIMING TITLE TO SUCH WARRANTED PROPERTY
          BY, THROUGH OR UNDER EOGM, BUT NOT OTHERWISE, AS PROVIDED IN THE
          ASSIGNMENT AND BILL OF SALE SET FORTH IN EXHIBIT E-2 TO BE DELIVERED
          PURSUANT TO SECTION 7.3.1.

          6.   Clause (b) of the definition of "Defensible Title" in Section
6.2.1 of the Purchase Agreement is hereby amended to read in its entirety as
follows:

               (b) with respect to the EOGM Property and the EOG Pipeline
          Property (including but not limited to the easements and rights-of-way
          related thereto, and contracts and operational rights in respect
          thereof),

                                      -2-

 
          such record title as will entitle IGS to own and operate the same free
          of adverse claims that would materially affect the ability of IGS to
          own and operate such systems in the same manner as presently owned and
          operated by SELLER or EOGM, free and clear of Material Title
          Deficiencies.

          7.   Section 7.3.1(ii) of the Purchase Agreement is hereby amended to
read in its entirety as follows:

               (ii) (A) An Assignment and Bill of Sale (in sufficient
          counterparts for recording) executed and acknowledged by SELLER
          covering the EOG Property (other than the EOG Pipeline Property and
          the Related Contracts with respect thereto) in the form of Exhibit 
          E-1, (B) an Assignment and Bill of Sale (in sufficient counterparts
          for recording) executed and acknowledged by EOGM and SELLER covering
          the EOGM Property, the EOG Pipeline Property and the Related Contracts
          with respect to the EOG Pipeline Property in the form of Exhibit E-2,
          and (C) an Assignment of Contracts executed and acknowledged by EOGM
          covering the EOGM Contracts in the form of Exhibit E-3 and conveying
          the same to BUYER or its designee (the Assignments and Bills of Sale
          described in clauses (A) and (B) and the Assignment of Contracts
          described in clause (C) being herein collectively called the
          "Assignments and Bills of Sale");

          8.   Section 7.3.1(vi) of the Purchase Agreement is hereby amended to
read in its entirety as follows:

               (vi) Letters to third party pipeline operators, executed by
          SELLER or EOGM in form and substance reasonably satisfactory to BUYER,
          notifying such operators that IGS shall operate all pipeline meters
          included in the Property which are currently being operated by SELLER
          or EOGM; and

          9.   Although referred to on page 25 of Exhibit "A" to the Purchase
Agreement, Exhibit "A-1" was not attached to the Purchase Agreement.
Accordingly, Exhibit "A-1" attached hereto and made a part hereof is hereby
added to the Purchase Agreement.

          10.  Pages 20 through 25 of Exhibit "A" to the Purchase Agreement are
hereby replaced with the pages of Appendix "1" attached hereto and made a part
hereof.

          11.  Parts II and III of Exhibit "B-1" to the Purchase Agreement and
Parts II and III of Exhibit "B-2" to the Purchase Agreement are hereby replaced
with Parts

                                      -3-

 
II and III of Exhibit "B-1" and Parts II and III of Exhibit "B-2" attached
hereto and made a part hereof.

          12. Part IV of Exhibit "B-1" to the Purchase Agreement is hereby
deleted from the Purchase Agreement.

          13. Exhibits "E-1" and "E-2" to the Purchase Agreement are hereby
replaced with Exhibits "E-1" and "E-2" attached hereto and made a part hereof.

          14. Exhibit "E-3" attached hereto and made a part hereof is hereby
added to the Purchase Agreement.

          15. Except as hereinabove provided, the Purchase Agreement shall
remain in full force and effect as written.

          The authorized representatives of SELLER, EOGM and BUYER sign below
indicating their agreement to the terms of this Amendment to Purchase Agreement
as of the date first above stated.

ENRON OIL & GAS COMPANY                      MEDALLION PRODUCTION
                                              COMPANY


By:\s\ Lewis P. Chandler, Jr.                By:\s\ David M. Harber
   --------------------------                     -------------------
Name:  Lewis P.  Chandler, Jr.               Name:  David M. Harber
Title:  Sr. Vice President, Law              Title:  Vice President-Engineering 
                                                     and Acquisitions

ENRON OIL & GAS MARKETING, INC.


By:\s\ Andrew N. Hoyle
   -------------------
Name:  Andrew N. Hoyle
Title:  Vice President-Marketing

                                      -4-

 
          The following schedules have been omitted, and the Registrant agrees
to furnish supplementally a copy of any such omitted schedule to the Securities
and Exchange Commission upon its request:

        Exhibits

          A-1  Depiction of Lands
          B    Gas Gathering and Pipeline Systems
          E    Assignments and Bill of Sales

        Appendix

          1    Related Contracts