FIRST AMENDMENT TO AGREEMENT OF PARTNERSHIP PW/GEODYNE NPI PARTNERSHIP P-6 The Agreement of Partnership of PW/Geodyne NPI Partnership P-6 dated November 28, 1989 (the "Agreement") is hereby amended as follows: A. The first sentence of Section 2.1 is hereby deleted and replaced by the following provision: "The NPI Partnership shall be conducted under the name Geodyne NPI Partnership P-6." B. All references in the Agreement to "PW/Geodyne NPI Partnership P-6" are hereby changed to "Geodyne NPI Partnership P-6". C. The third sentence of Section 2.1 is hereby deleted and replaced by the following provision: "The office and principal place of business of the NPI Partnership shall be c/o Geodyne Energy Company, Two West Second, Tulsa, Oklahoma 74103." D. The name of the "General Partner" and the "Limited Partnership" reflected in Article One has been changed from "PaineWebber/Geodyne Institutional/Pension Energy Income Limited Partnership P-6" to "Geodyne Institutional/Pension Energy Income Limited Partnership P-6". All references in the Agreement to the name of the "General Partner" and the "Limited Partnership" are hereby changed to reflect this name change. This change reflects a name change only and not a change of entity. In all other respects the Agreement is hereby ratified and affirmed. DATED: February 26, 1993 Managing Partner: Geodyne Energy Company /s/ Michael E. Luttrell ------------------------------- Michael E. Luttrell Executive Vice President -1- General Partner: Geodyne Institutional/Pension Energy Income Limited Partnership P-6 By: Geodyne Properties, Inc., General Partner By: /s/ Michael E. Luttrell --------------------------- Michael E. Luttrell, Executive Vice President -2-