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.