Application of Foam for Enhanced CO₂ Geological Storage: A Mini-Review

Global climate change is one of the most pressing environmental challenges facing the world, and numerous efforts are currently being undertaken to mitigate and reverse the effects. Carbon dioxide (CO2) is a major contributor to greenhouse gas emissions, totaling 76% of emissions. Hence, numerous methods have been proposed and utilized to convert, utilize, or permanently store CO2. A typical example is the dual application of CO2 for enhanced oil recovery (EOR) and subsequent storage, which is highly required in the oil and gas industry due to the widespread availability of marginal fields and depleted oil reservoirs. Nonetheless, the injection of pure CO2 into underground geologic formations faces some challenges owing to its high mobility, which can cause early breakthrough of the injected gas. As a result of these challenges, a significant amount of hydrocarbon is bypassed during the EOR process, which leads to poor sweep efficiency. To address these challenges, the utilization of CO2 foam for EOR and subsequent storage is being examined. Foam enhances storage capacity by increasing a reservoir’s sweep efficiency and minimizing early breakthrough, which allows more CO2 to fill the empty pore spaces. In this paper, the application of CO2 foam for EOR and CO2 geological storage (geo-storage) is reviewed. First, an overview of the CO2 foam flooding process is provided. Moreover, the trapping mechanism of CO2 geo-storage by foam is discussed. Besides, existing experimental studies on improving the storage capacity of CO2 are analyzed. Finally, the technical challenges facing the application of CO2 foam are identified, and recommendations for future research are offered.