GEODYNE ENERGY INCOME PROGRAMS 1998 YEAR-END ESTIMATED VALUATION ON A PER UNIT BASIS(1) CASH DISTRIBUTIONS PER UNIT ------------------------------- 1997 YEAR-END CUMULATIVE FORMATION UNIT 1998 YEAR END PER UNIT ESTIMATED 1998 DISTRIBUTIONS P/SHIP DATE SIZE ESTIMATED VALUATION(2) VALUATION(2) TOTAL THRU 12/31/98 P/SHIP - -------- --------- -------------------------------- ------------- ---------------------- ------ I-B 07/12/85 1,000 70.45 81.63 15.30 562.61 I-B I-C 12/20/85 1,000 64.03 141.63 37.14 924.19 I-C I-D 03/04/86 1,000 237.85 361.18 152.06 1,947.01 I-D I-E 09/10/86 1,000 206.00 313.00 93.98 1,282.73 I-E I-F 12/16/86 1,000 180.84 293.53 85.47 1,255.97 I-F (1) This chart must be read in connection with the letter dated January 29, 1999, providing important assumptions and other information on the methodology used to calculate these estimates. (2) 1998 Year-End estimates use $9.50 per barrel of oil and $2.03 per thousand cubic feet ("MCF") of gas compared to $16.25 per barrel and $2.325 per MCF of gas for the 1997 Year-End estimates.