CO2 Recovery of Heavy Oil: Wilmington Field Test

Abstract

Champlin Petroleum Co.'s pilot test of the CO/sub 2/ immiscible-drive oil recovery process has been in continuous operation for 50 months in the Wilmington field, Tar zone, Fault Block III Unit reservoir. First CO/sub 2/ injection was in March 1981. The pilot, containing 1,700 acre-ft (2.1 x 10/sup 6/ m/sup 3/) includes four injection wells and three producers. The reservoir is an unconsolidated sandstone at 2,500 ft (762 m) that contained 920 bbl/acre-ft (0.12 m/sup 3//m/sup 3/) of 14/sup 0/API (0.97-g/cm/sup 3/) crude oil at the start of the CO/sub 2/ pilot. This is the first test of immiscible CO/sub 2/ tertiary oil recovery in a late-life waterflood reservoir. Cumulative water injection before start of the CO/sub 2/ pilot was three PV's. Through May 1, 1985, 2.1 Bcf (60 x 10/sup 6/ m/sup 3/) of produced and purchased CO/sub 2/ had been injected intermittently with water. Cumulative purchased CO/sub 2/ through May 1, 1985, was 1.5 Bcf (42.5 x 10/sup 6/ m/sup 3/). Each of the three producing wells has shown stimulated oil response with production rates increasing an average of seven-fold. One producing well, converted from a former water-injection well, produced 100% water for 5 months after first CO/submore » 2/ injection. The well has since steadily increased in production to over 40 B/D (6.4 m/sup 3//d) of oil. All produced oil is considered incremental oil since the pre-CO/sub 2/-flood oil rates were essentially at the economic limit and the wells would soon have been plugged and abandoned.« less