Exhibit 2.1



                                  AMENDMENT TO


                                   AGREEMENT


                                      AND


                                 PLAN OF MERGER


                                  by and among


                            CODA ACQUISITION, INC.,


                      JOINT ENERGY DEVELOPMENT INVESTMENTS
                              LIMITED PARTNERSHIP


                                      and


                               CODA ENERGY, INC.


                         Dated as of December 22, 1995

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                                  AMENDMENT TO
                          AGREEMENT AND PLAN OF MERGER

     THIS AMENDMENT (this "Amendment") TO AGREEMENT AND PLAN OF MERGER, dated as
of December 22, 1995, by and among Coda Acquisition, Inc., a Delaware
corporation ("Sub"), Coda Energy, Inc., a Delaware corporation (the "Company")
and Joint Energy Development Investments Limited Partnership, a Delaware limited
partnership ("JEDI"):

                                  WITNESSETH:
                                  -----------

     WHEREAS, Sub, the Company and JEDI have entered into that certain Agreement
and Plan of Merger dated as of October 30, 1995 (the "Agreement") providing for
the merger of Sub with and into the Company (the "Merger");

     WHEREAS, Sub, the Company and JEDI now desire to amend the Agreement as
hereinafter set forth;

     NOW, THEREFORE, in consideration of the foregoing premises and the
representations, warranties, covenants and agreements contained herein, the
parties hereto agree as follows:

                                   ARTICLE I

                                  DEFINITIONS

     Section 1.1    Definitions.    Capitalized terms used in this Amendment, to
                    -----------                                                 
the extent not otherwise defined herein, shall have the same meanings as in the
Agreement as amended hereby.

                                   ARTICLE II

                                   AMENDMENTS

     Section 2.1    Amendment to Section 3.1.  Effective as of the date hereof,
                    ------------------------                                   
the reference in Section 3.1 of the Agreement to $8.00 is hereby amended to
                  -----------                                               
$7.75.

     Section 2.2    Amendment to Section 3.6 (a) and (b).  Effective as of the
                    ------------------------------------                      
date hereof, the references in Section 3.6 (a) and (b) of the Agreement to $8.00
are hereby amended to $7.75.

     Section 2.3    Amendment to Article IV.  Effective as of the date hereof
                    -----------------------                                  
Article IV of the Agreement is hereby amended to delete the definitions of
"Approved Taurus Disposition Agreement", "Taurus Disposition", "Taurus
Disposition Agreement" and "Taurus Disposition Notice."

     Section 2.4    Amendment to Section 8.1(a).  Effective as of the date
                    ---------------------------                           
hereof, Section 8.1(a) of the Agreement is hereby amended by deleting the
        --------------                                                   
parenthetical phrase therein.

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     Section 2.5  Amendment to Section 9.6.  Effective as of the date hereof,
                  ------------------------                                   
Section 9.6 of the Agreement is hereby amended by deleting the penultimate
- -----------                                                               
sentence thereof.

     Section 2.6    Amendment to Section 9.7.  Effective as of the date hereof,
                    ------------------------                                   
Section 9.7 of the Agreement is hereby amended and restated in its entirety to
- -----------                                                                   
read as follows:

      Section 9.7     No Taurus Disposition.  The Company shall not
                      ---------------------                        
     negotiate and shall not enter into any agreement providing for the sale of
     Taurus, whether by merger, sale of all or substantially all of the assets
     of Taurus, sale of all of the capital stock of Taurus or otherwise,
     without, in each such case, obtaining the prior written consent of JEDI.

     Section 2.7    Amendment to Section 10.3.  Effective as of the date hereof,
                    -------------------------                                   
Section 10.3 of the Agreement is hereby amended by deleting subsection (d) in
- ------------                                                                 
its entirety.

     Section 2.8    Amendment to Section 11.1.  Effective as of the date hereof,
                    -------------------------                                   
Section 11.1 of the Agreement is hereby amended by deleting subsection (h) in
- ------------                                                                 
its entirety.

     Section 2.9    Amendment to Option Relinquishment and Release Agreement and
                    ------------------------------------------------------------
Warrant Relinquishment and Release Agreement.  Effective as of the date hereof,
- --------------------------------------------                                   
the references in the recitals of both the Option Relinquishment and Release
Agreement and the Warrant Relinquishment and Release Agreement to $8.00 are
amended to $7.75.

                                  ARTICLE III

                                 MISCELLANEOUS

     Section 3.1    Ratifications;  Waiver of Claims.  The terms and provisions
                    --------------------------------                           
set forth in this Amendment shall modify and supersede all inconsistent terms
and provisions set forth in the Agreement and except as expressly modified and
superseded by this Amendment, the terms and provisions of the Agreement are
ratified and confirmed and shall continue in full force and effect.  Sub, the
Company and JEDI agree that the Amendment is, and the Agreement as amended
hereby shall continue to be, legal, valid, binding and enforceable in accordance
with its respective terms, subject, however, to (i) the execution, on or prior
to January 15, 1996, of amendments to the Subscription Agreement and the
Stockholders Agreement (the "Management Agreements") satisfactory to JEDI, in
its sole discretion, and (ii) the receipt, on or prior to January 15, 1996, by
the Company of oral or written confirmation, in form and substance acceptable to
the Special Committee and to the Board of Directors of the Company, from Bear,
Stearns & Co. Inc. ("Bear Stearns"), financial advisor to the Company, that the
Merger, based on the revised Merger Consideration, is fair to the stockholders
of the Company from a financial point of view (except that such advice need not
be provided to management stockholders who will participate in the equity
ownership of the Surviving Corporation).  If either (x) amendments to the
Management Agreements satisfactory to JEDI, in its sole discretion, are not
executed on or prior to January 15, 1996 or (y) the Company has not received
such confirmation from Bear Stearns on or prior

                                                                        Page - 6

 
to January 15, 1996, then this Amendment shall become void and the Agreement
shall continue in full force and effect without giving effect to this Amendment.

     Section 3.2    Representations and Warranties.  Each of Sub, the Company
                    ------------------------------                           
and JEDI hereby represents and warrants to the other of such parties that the
execution, delivery and performance of this Amendment has been authorized by all
requisite corporate action on the part of each of Sub, the Company and JEDI and
will not violate the articles or certificate of incorporation, bylaws or
partnership agreement, as applicable, of any of Sub, the Company and JEDI.

     Section 3.3    Reference to Agreement.  The Agreement is hereby amended so
                    ----------------------                                     
that any reference therein to the Agreement shall mean a reference to the
Agreement as amended hereby.

     IN WITNESS WHEREOF, Sub, JEDI and the Company have caused this Amendment to
be signed by their respective officers thereunder duly authorized all as of the
date first written above.

                                    CODA ACQUISITION, INC.

                                    By:    /s/ C. John Thompson
                                       --------------------------------
                                    Name:  C. John Thompson
                                    Title:    Vice President



                                    CODA ENERGY, INC.



                                    By:    /s/ Douglas H. Miller
                                       ----------------------------------
                                    Name:  Douglas H. Miller
                                    Title:  Chairman of the Board
                                             and Chief Executive Officer

                                                                        Page - 7

 
                                    JOINT ENERGY DEVELOPMENT
                                    INVESTMENTS LIMITED PARTNERSHIP

                                    By:  Enron Capital Management Limited
                                         Partnership, its general partner

                                    By:  Enron Capital Corp., its general
                                         partner



                                    By:      /s/ C. John Thompson
                                          -------------------------------------
                                    Name:  C. John Thompson
                                    Title:  Agent and Attorney-in-Fact


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