Evaluation of different effective parameters during continual gas and water alternating gas (WAG) injections in oil reservoirs

Abstract

Oil recovery from the reserevoirs is devided into three stage of primary, secondary and tertiary stage. Primary recovery is done using the antural energy of the reservoir, while the secondary recovery occures after the primary recovery. It ususlly consists of water and gas injection into the reservoirs for improving the oil recovery. Finally, tertiary ecovery takes in place, which is consists of different methods that are after the secondary recovery. The purpose of this paper is to investigate and compare different gas injection scenarios in an Iranian oil reservoir using Eclipse 300 software. It models recovery factor, cumulative recovery, and the effective parameters of gas injection during different procedures of CO 2 gas injection and Water Alternating gas (WAG) injection. Recovery factor, cumulative recovery, remaining oil saturation, and reservoir pressure are studied and compared during different CO 2 gas injection and WAG injection scenarios to specify an optimized pattern of injection process for EOR purpose. Laboratory data of reservoir rock and fl uid are matched by using PVTi software and the results imported into Eclipse for modeling miscible CO 2 injection and WAG injection. The results showed that oil recovery and remaining oil saturation during WAG injection in reservoir are 31.8 and 56.6% and during miscible CO 2 injection are 25.8 and 60.4% respectively. In case if WAG injection is highly suggested instead of miscible CO 2 injection.