Fourth Amendment to
                              Amended and Restated
               Agreement and Certificate of Limited Partnership of
                  Geodyne Energy Income Limited Partnership I-F


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

     WHEREAS, on September 10, 1986, Geodyne Properties, Inc. ("Properties"), as
General  Partner,  and the Initial Limited Partner,  Susan Layman,  executed and
entered into that certain  PaineWebber/Geodyne Energy Income Limited Partnership
I-F  Agreement  and  Certificate  of  Limited   Partnership  (the  "Preformation
Agreement"); and

     WHEREAS,  on December 17, 1986,  Properties as General Partner executed and
entered into that certain  Amended and Restated  Agreement  and  Certificate  of
Limited Partnership (the "Agreement"); and

     WHEREAS,  on February 25, 1993,  Properties as General Partner 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  I-F" to "Geodyne Energy Income Limited  Partnership  I-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 4th, 1993,  Properties as General Partner  executed and
entered into that Second  Amendment to the Agreement  whereby it amended certain
provisions to the Agreement to (i) expedite the method of accepting transfers of
Limited  Partners'  Units in the  Partnership  and (ii)  provide for an optional
right of  repurchase/redemption  which may be exercised by the Limited Partners;
and

     WHEREAS, on June 30, 1997, Properties merged into Resources; and

     WHEREAS, on July 1st, 1997, Resources as successor via merger to Properties
executed  and entered  into that Third  Amendment  to the  Agreement  whereby it
amended the Agreement to provide that Geodyne Resources,  Inc., as successor via
merger with Properties, is the General Partner of the Partnership; and




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<PAGE>





     WHEREAS,  Section 2.4 of the Agreement  provides that the Partnership shall
continue in full force and effect until  December 31,  1999,  provided  that the
General Partner may extend the term of the Partnership for up to five periods of
two years each if it believes  each such  extension is in the best  interests of
the  Limited  Partners  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 2.4. is hereby amended and restated as follows:

                  The  Partnership  shall  continue  in force and  effect  until
            December 31, 2001,  provided that the General 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
            Partners,  or  until  dissolution  prior  thereto  pursuant  to  the
            provisions hereof.

       IN WITNESS  WHEREOF,  the parties hereto have hereunto set their hands as
of the 23rd day of December, 1999.

                                       Geodyne Resources, Inc.
                                       as General Partner


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

                                       Geodyne Resources, Inc.,
                                       as Attorney-in-Fact for all
                                       Substituted Limited Partners


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