Maximizing Oil Recovery for CO2 Huff and Puff Process in Pilot Scale Reservoir

Abstract

A pilot scale simulation is performed for enhanced oil recovery by CO2 injection to M field in Indonesia. CO2 stimulation (Huff and Puff) method is considered as one of the most successful processes to increase oil recovery. Prior to the CO2 injection, water is injected to support an additional reservoir pressure. 1,000 tons of CO2 are injected into M-19 well for 50 days. After 30 days of soaking, production is resumed and continued for 10 years. Cumulative oil recovery from Huff and Puff process is increased by 2% compared with primary production, mainly due to viscosity reduction observed near the well. The oil viscosity near the wellbore is reduced by 26% due to the dissolved CO2 gas. To maximize the oil recovery from CO2 Huff and Puff process, the operating conditions are optimized. The design parameters include water injection rate, CO2 injection rate, water injection time, and soaking time. Through optimization based on DECE, the oil recovery is increased by 12% and 9.8% compared with primary production and stimulated case without optimization, respectively. The oil viscosity decreases by 70% though CO2 soaking area is smaller than that of non-optimized case. This study shows that CO2 Huff and Puff method has a potential to improve oil recovery and optimized operating design is needed to produce more oil.