The investigation of gas trapping and relative permeability alteration during optimization of CO₂-EOR and sequestration

CO2 trapping in porous media is one attractive sequestration option in which the CO2 trapped for long periods and also enhanced oil recovery (EOR) simultaneously. The aim of this study is to design a process such that improved both gas storage efficiency and field oil efficiency. Based on the continuous CO2 flooding results, the residual gas saturation increases up to 10% compared to solution gas injection. Also, the high oil swelling factor and the interfacial tension (IFT) reduction confirmed the changing in curvature of the relative permeability curves which causes pore throat space more available for CO2 trapping. In addition, the genetic algorithm has successfully improved the gas storage efficiency for 3.2% and field oil efficiency for 7.2% during the full field reservoir simulation. Accordingly, the objective value increased by 2.12% and indicates that the residual and CO2 capillary trappings in porous media enhanced the security and capacity of storage.