Gas and water reinjection strategy to enhance oil productivity with voidage replacement

Abstract

During the last few years enhanced oil recovery (EOR) methods including water alternative gas (WAG) have been sufficient in recovering a portion of the unrecovered oil specifically when it is combined with other strategy such as voidage replacement. In this paper oil productivity enhancement is observed by implementing voidage replacement with WAG process. Secondary plan and WAG are simulated and evaluated by ECLIPSE-100 software. WAG achieved a recovery factor of 63% during 30 years of simulation prediction process with primary and secondary plans. Surface facility was designed to run under WAG & voidage replacement ratio (VRR) principles. VRR values of 1.5-1.2 & 2.0-1.4 were maintained in WAG-1 and WAG-360 scenarios respectively for the last five years of production life when it was at high VRR value before. That VRR drop essentially due to the WAG process and as it was correlated with the reservoir-X average pressure that was maintained at (3100-3300) psi in reservoir-X performance.