EXHIBIT 10.20

                               THIRD AMENDMENT TO
                            AGREEMENT OF PARTNERSHIP
                           GEODYNE NPI PARTNERSHIP P-6


      This Third  Amendment  to  Agreement  of  Partnership  of  PW/Geodyne  NPI
Partnership  P-6 (the  "Partnership")  is entered  into by and  between  Geodyne
Resources,  Inc.  ("Resources"),  a Delaware corporation,  as successor Managing
Partner, and Geodyne Institutional/Pension Energy Income Limited Partnership P-6
("Geodyne P-6"), as General Partner.

      WHEREAS,  on November 28, 1989,  Geodyne  Energy  Company  ("Energy"),  as
Managing Partner, and Geodyne P-6, as General Partner, executed and entered into
that certain  Agreement of Partnership of PW/Geodyne  NPI  Partnership  P-6 (the
"Agreement"); and

      WHEREAS, on February 26, 1993, Energy and Geodyne P-6 executed and entered
into that certain First Amendment to Agreement,  whereby it changed (i) the name
of the  Partnership  from  "PW/Geodyne  NPI  Partnership  P-6" to  "Geodyne  NPI
Partnership  P-6",  (ii) the  address of the  Partnership's  principal  place of
business,  and (iii) the  address  for the  Partnership's  agent for  service of
process; and

      WHEREAS,  on July 1, 1996,  Resources,  as successor via merger to Energy,
executed and entered into, as Managing Partner, that certain Second Amendment to
the Amended  Agreement  whereby it amended the Amended Agreement to provide that
Resources,  as successor  via merger to Energy,  is the Managing  Partner of the
Partnership; and

      WHEREAS,  Section 10.1 of the Amended Agreement provides that the managing
partner of the partnership (the "Managing Partner") may, without prior notice or
consent of any other  Partner (as defined in the Amended  Agreement),  amend any
provision of this Amended Agreement if, in its opinion,  such amendment does not
have a material  adverse effect upon the Limited  Partnership (as defined in the
Amended Agreement); and

       WHEREAS,   Section  2.3  of  the  Amended  Agreement  provides  that  the
Partnership  shall  continue in full force and effect  until  December 31, 2005,
provided  that the Managing  Partner may extend such term for up to five periods
of two years each, or until dissolution prior thereto pursuant to the provisions
of the Amended Agreement; and

       WHEREAS,  Resources as Managing Partner has elected to extend the life of
the Partnership for an additional two years.

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       NOW,  THEREFORE,  in  consideration  of  the  covenants,  conditions  and
agreements herein contained, the parties hereto hereby agree as follows:

      Section 2.3. is hereby amended and restated as follows:

                  The  Partnership  shall  continue  in force and  effect  until
            December 31, 2007, provided that the Managing Partner may extend the
            term of the  Partnership for up to four periods of two years each if
            it believes such  extension is in the best  interests of the Limited
            Partnership,  or until  dissolution  prior  thereto  pursuant to the
            provisions hereof.

       IN WITNESS  WHEREOF,  the parties hereto have hereunto set their hands as
of the 27th day of October, 2005.

                                       Geodyne Resources, Inc.
                                       as Managing Partner

                                       By:  //s// Dennis R. Neill
                                            ----------------------
                                            Dennis R. Neill
                                            President

                                       Geodyne Institutional/Pension
                                       Energy Income Limited
                                       Partnership P-6
                                       as General Partner

                                       By Geodyne Resources, Inc.
                                          General Partner

                                       By:  //s// Dennis R. Neill
                                            ----------------------
                                            Dennis R. Neill
                                            President



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