Co2 immiscible flooding is an enhanced oil recovery (EOR) process involving the injection of carbon dioxide into a hydrocarbon reservoir under thermodynamic conditions where the CO2 and reservoir oil remain as distinct, non-mixing phases. As a research concept and field of study, it investigates the complex multiphase flow dynamics, interfacial phenomena (such as mass transfer and interface evolution), compositional changes, and reservoir rock interactions that govern oil displacement efficiency and CO2 storage potential in systems where distinct CO2 and oil phases coexist. Its significance lies in its practical applicability due to relative simplicity and cost-efficiency, and its role in providing fundamental understanding for optimizing oil recovery under non-miscible conditions and assessing associated CO2 storage mechanisms.