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                                                                    EXHIBIT 10.2

                        SECOND AMENDMENT TO SYNDER GAS 
                     PLANT AMENDED JOINT VENTURE AGREEMENT

     This Amendment to Synder Gas Plant Joint Venture Agreement (the
"Amendment"), is made and entered into as of July 1, 1995, to modify and amend
the Amended Joint Venture Agreement dated July 29, 1993 (the "Joint Venture
Agreement"), between BELLWETHER EXPLORATION COMPANY, a Colorado corporation
("Managing Venturer"), and NGL ASSOCIATES, a Texas general partnership ("NGL"),
as amended by that certain Amendment dated as of March 14, 1994.

                                 W I T N E S S E T H:

     WHEREAS, the Managing Venturer and NGL desire to amend the Joint Venture
Agreement in order to provide for a contingent venturer fee payable to NGL and
to reallocate the pre-payout sharing ratio and depreciation;

     NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

     1. Amendment to Article 2 of Joint Venture Agreement. Effective as of July
1, 1995, the definition of the terms "Pre-Payout Sharing Ratio" and "Venture
Expenses" contained in Article 2 of the Joint Venture Agreement are hereby
amended in their entirety to read as follows:

          "Pre-Payout Sharing Ratio" shall mean 100% to the Managing Venturer
          and 0% to NGL.

          "Venture Expenses" shall mean: (i) the actual verifiable cost and
          expenses of services from outside sources paid by the Managing
          Venturer for the benefit of the Venture in connection with matters of
          periodic tax reporting, monthly revenue, accounting and preparation of
          periodic financial statements that pertain to the business of the
          Venture, which charge to the Venture shall not exceed a maximum
          monthly charge of $3,675.00 per month; plus (ii) the actual verifiable
          cost of any additional non-recurring third party expenses (including
          but not limited to legal services and financial or tax audits); plus
          (iii) the Contingent Venturer Fee.

Effective as of July 1, 1995, the definition "Contingent Venturer Fee" is hereby
added to Article 2 of the Joint Venture Agreement:

          "Contingent Venturer Fee" shall have the meaning set forth in Section
          7.4.

     2. Amendment to Section 7.1.1 of the Joint Venture Agreement. A new
sentence is hereby added to the end of Section 7.1.1 of the Joint Venture
Agreement as follows:

          Provided, however, all deductions against income relating to
          depreciation or amortization of the Gas Plants attributable to the
          time period from 
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          inception to July 1, 1995 shall be allocated 90% to the Managing
          Venturer and 10% to NGL.

     3. Amendment to Article 7 of the Joint Venture Agreement. The Joint Venture
Agreement shall be amended to add a Section 7.4 thereto which shall read in its
entirety as follows:

           Section 7.4 Contingent Venturer Fee. Effective as of July 1, 1995, on
           or before the 30th day of each month prior to Payout, Managing
           Venturer shall distribute to NGL a contingent venturer fee. Such fee
           shall equal 10% of the Distributable Funds for the prior month (plus
           or minus amounts, if any, attributable to post-period adjustments
           from prior months) ("Contingent Venturer Fee").

     5. Governing Law. THE TERMS AND PROVISIONS OF THIS AMENDMENT SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS.

     6. Binding Agreement; Ratification of Joint Venture Agreement. This
Amendment shall be binding upon the successors and assigns of the parties
hereto. Except as expressly modified hereby, the Joint Venture Agreement shall
continue in full force and effect in accordance with its terms.

     EXECUTED as of the date first above written.

                              NGL ASSOCIATES,
                              a Texas general partnership


                              By:   /s/ Richard Bobigian
                                 -----------------------------------------
                              Name:     Richard Bobigian
                                   ---------------------------------------
                              Title:    General Partner
                                    --------------------------------------

                              BELLWETHER EXPLORATION COMPANY,
                              a Colorado corporation


                              By:   /s/ J. Darby Sere'
                                 -----------------------------------------
                                       J. Darby Sere'
                                       President