Third Amendment to
      Geodyne Institutional/Pension Energy Income Limited Partnership P-6
             Amended and Restated Agreement of Limited Partnership

      This  Third  Amendment  to  Geodyne  Institutional/Pension  Energy  Income
Limited  Partnership P-6 (the  "Partnership")  Amended and Restated Agreement of
Limited  Partnership  is entered into by and between  Geodyne  Properties,  Inc.
("Properties"),   a   Delaware   corporation,   as  General   Partner,   Geodyne
Institutional Depositary Company ("Depositary"),  a Delaware corporation, as the
Limited  Partner,   and  all  Substituted   Limited  Partners  admitted  to  the
Partnership.

      WHEREAS,  on November 28, 1989,  Properties  and  Depositary  executed and
entered  into  that  certain  PaineWebber/Geodyne  Institutional/Pension  Energy
Income  Limited   Partnership   P-6  Agreement  of  Limited   Partnership   (the
"Agreement"); and

      WHEREAS,  on September 5, 1990,  Properties  and  Depositary  executed and
entered  into  that  certain  PaineWebber/Geodyne  Institutional/Pension  Energy
Income  Limited  Partnership  P-6  Amended  and  Restated  Agreement  of Limited
Partnership (the "Amended and Restated Agreement"); and

      WHEREAS,  on February 25, 1993,  Properties executed and entered into that
certain  First  Amendment  to said  Amended and  Restated  Agreement  whereby it
changed   (i)   the   name   of  the   Partnership   from   "PaineWebber/Geodyne
Institutional/Pension   Energy  Income  Limited   Partnership  P-6  to  "Geodyne
Institutional/Pension Energy Income Limited 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 August 4, 1993,  Properties  executed  and entered  into that
certain Second Amendment to said Amended and Restated  Agreement in order to (i)
expedite  the  method  of  accepting  transfers  of Unit  Holders'  Units in the
Partnership  and (ii)  provide  for an optional  right of  repurchase/redemption
which may be exercised by the Unit Holders; and

      WHEREAS,  Section 11.1 of the Amended and Restated Agreement provides that
the General  Partner  may,  without  prior notice or consent of any Unit Holder,
amend any provision of this  Agreement if, in its opinion,  such  amendment does
not have a material adverse effect upon the Unit Holders; and

      WHEREAS,  Properties as General  Partner  desires to amend the Amended and
Restated  Agreement in order to allow transfers of Units  facilitated  through a
matching  service to the extent  they  otherwise  comply with  Internal  Revenue
Service  transfer   regulations   applicable  to  non-permitted   transfers  for
non-publicly traded limited partnerships.



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<PAGE>




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

      I.    Section 8.1.A(ii) of the Agreement is hereby deleted.

      II.   The  remaining  subsections  of Section  8.1A shall be  renumbered
            accordingly.

      IN WITNESS WHEREOF, the parties hereto have hereunto set their hands as of
this 31st day August, 1995.

                                    GEODYNE PROPERTIES, INC.,
                                    as General Partner

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


                                    GEODYNE INSTITUTIONAL DEPOSITARY
                                    COMPANY, as the Limited Partner

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


                                    GEODYNE PROPERTIES, INC.,
                                    as Attorney-in-Fact for all
                                    Substituted Limited Partners


                                    By:   /s/ Drew S. Phillips
                                          ---------------------------------
                                          Drew S. Phillips
                                          Vice President-Controller


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