Third Amendment to
                      Agreement of Limited Partnership of
                Geodyne Energy Income Limited Partnership III-A

      This Third Amendment to Agreement of Limited Partnership of Geodyne Energy
Income  Limited  Partnership  III-A (the  "Partnership")  is entered into by and
between Geodyne Production Company  ("Production"),  a Delaware corporation,  as
General  Partner,   Geodyne  Depositary  Company   ("Depositary"),   a  Delaware
corporation,  as the  Limited  Partner,  and all  Substituted  Limited  Partners
admitted to the Partnership.

      WHEREAS,  on November 20, 1989,  Production  and  Depositary  executed and
entered into that certain  Agreement of Limited  Partnership of the  Partnership
(the "Agreement"); and

      WHEREAS,  on February 25, 1993,  Production executed and entered into that
certain  First  Amendment  to the  Agreement of Limited  Partnership  whereby it
changed (i) the name of the Partnership from "PaineWebber/Geodyne  Energy Income
Partnership III-A to "Geodyne Energy Income Limited  Partnership III-A, (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,  Production  executed  and entered  into that
certain Second Amendment to the Agreement of Limited Partnership 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 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,  Production as General  Partner desires to amend the 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.

      NNOW,  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.




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<PAGE>




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

                                    GEODYNE PRODUCTION COMPANY,
                                    as General Partner

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

                                    GEODYNE DEPOSITARY COMPANY,
                                    as the Limited Partner

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


                                    GEODYNE PRODUCTION COMPANY,
                                    as Attorney-in-Fact for all
                                    Substituted Limited Partners


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


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