Combinational CO2 and Polymer Injections for EOR and CO2 Storage in Depleted Reservoirs: A Mini Review on Laboratory, Simulation and Field Studies

Water-alternating-gas is commonly used in most of the existing enhanced oil recovery (EOR) projects in the world to regulate gas mobility and reduce fingering problems. Unfortunately, the expected recovery factor from most of the fields could not be attained with such EOR method. Development strategies of mature oil fields during the energy transition period may therefore involve the combination of polymer and CO2 injections to achieve incremental oil recovery and at the same time provide longterm geological storage solution for carbon. This paper therefore presents overview of the processes of polymer and CO2 floodings, and then highlights the overall benefits to be derived from the combination of CO2 and polymer flooding techniques in depleted hydrocarbon reservoirs, especially oil reservoirs. Reviews on studies related to the combinational CO2 and polymer injections are then carried out. Highlights of areas of the combinational CO2 and polymer injections needing more attention are also mentioned.