Sixth Amendment to
               Agreement and Certificate of Limited Partnership of
                 Geodyne Energy Income Limited Partnership III-F


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

     WHEREAS,  on March 7, 1990, Geodyne Production Company  ("Production"),  as
General Partner, and Depositary executed and entered into that certain Agreement
and Certificate of Limited Partnership of the Partnership (the "Agreement"); and

     WHEREAS,  on February 25, 1993,  Production  executed and entered into that
First  Amendment  to the  Agreement  whereby  it  changed  (i)  the  name of the
Partnership from  "PaineWebber/Geodyne  Energy Income Limited Partnership III-F"
to "Geodyne Energy Income Limited  Partnership  III-F",  (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
Second Amendment to the Agreement  whereby it amended certain  provisions 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,  on August 31,  1995,  Production  executed  and entered into that
Third Amendment to the Agreement whereby it amended certain  provisions to allow
transfers  of Units  facilitated  through a matching  service to the extent that
such  transfers   otherwise   comply  with  Internal  Revenue  Service  transfer
regulations  applicable  to  non-permitted  transfers  for  non-publicly  traded
limited partnerships; and

     WHEREAS, on July 1, 1996, Resources, as successor via merger to Production,
executed and entered into, as General Partner,  that certain Fourth Amendment to
the Agreement of Limited Partnership whereby it amended the Agreement to provide
that  Resources,  as successor via merger to Geodyne,  is the General Partner of
the Partnership; and

     WHEREAS,  on February 5, 2001,  Resources  executed  and entered  into that
certain Fifth Amendment to the Agreement whereby the term of the partnership was
extended for an additional two years, until March 7, 2003, and


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     WHEREAS,  Section 2.3 of the Agreement  provides that the Partnership shall
continue  in full  force and effect for a period of ten (10) years from the date
of its  Activation  (as  defined in the  Agreement),  provided  that the General
Partner  may extend the term of the  Partnership  for up to four  periods of two
years each if it believes  each such  extension is in the best  interests of the
Unit Holders or until  dissolution  prior thereto  pursuant to the provisions of
the Agreement, and

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

     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 March 7,
          2005,  provided  that the  General  Partner may extend the term of the
          Partnership  for up to three  periods of two years each if it believes
          such extension is in the best interests of the Unit Holders,  or until
          dissolution prior thereto pursuant to the provisions hereof.

      IN WITNESS WHEREOF, the parties hereto have hereunto set their hands as of
this 10th day of February, 2003.

                                    GEODYNE RESOURCES, INC.,
                                    as General Partner

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

                                    GEODYNE DEPOSITARY COMPANY,
                                    as the Limited Partner

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

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

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