EXHIBIT 99.1 GEODYNE ENERGY INCOME PROGRAMS 1999 YEAR-END ESTIMATED VALUATION ON A PER UNIT BASIS(1) CASH DISTRIBUTIONS PER UNIT 1999 YEAR 1998 ------------------------------------ END PER UNIT YEAR-END CUMULATIVE FORMATION UNIT ESTIMATED ESTIMATED 1999 DISTRIBUTIONS P/SHIP DATE SIZE VALUATION(2) VALUATION(2) TOTAL THRU 12/31/99 P/SHIP - ------ --------- ---- ------------ ------------ ----- -------------- ------ III-A 11/21/89 $100 $23.41 $20.06 $3.30 $ 98.64 III-A III-B 01/24/90 100 23.84 17.13 3.27 109.26 III-B III-C 02/27/90 100 27.64 22.39 4.99 75.41 III-C III-D 09/05/90 100 39.93 21.06 5.88 70.99 III-D III-E 12/26/90 100 50.34 16.32 2.62 74.87 III-E III-F 03/08/91 100 31.58 18.76 2.23 52.48 III-F III-G 09/20/91 100 35.59 18.92 2.49 50.45 III-G (1) This chart must be read in connection with the letter dated January 28, 2000, providing important assumptions and other information on the methodology used to calculate these estimates. (2) 1999 Year-End estimates use $22.75 per barrel of oil and $2.24 per thousand cubic feet ("MCF") of gas compared to $9.50 per barrel and $2.03 per MCF of gas for the 1998 Year-End estimates.