Design, Operation and Results of Garber CO2 Tertiary Pilot

ARCO Oil and Gas Company started work on a tertiary CO2 Pilot in the Garber Field during early 1980. The purpose of the pilot was to investigate the CO2 flooding of relatively shallow sands which were previously waterflooded to depletion. The pilot is in the Crews sand, a shallow Pennsylvanian sand, located at an average depth of 1950 ft. The main pilot is a 10.4 acres, normal 5-spot, which is enclosed by backup water injectors and outside producers. It was initially waterflooded to raise the reservoir pressure and to establish a base production curve. CO2 injection started in late October 1981. In all, 27,000 tons of C02, representing 35% of HCPV within the effective area, was injected in this pilot. The response of the pilot has been very encouraging. It has already recovered over 70,000 STBO. Ultimate recovery should exceed 14% of the original oil in place within the effective area. The success of this pilot opens up possibilities for shallow reservoirs, which had not been seriously considered for CO2 flooding.