Development and Applications of CO₂-Responsive Gels in CO₂ Flooding and Geological Storage

Gel systems are widely used as plugging materials in the oil and gas industry. Gas channeling can be mitigated by reducing the heterogeneity of the formation and the mobility ratio of CO₂ to crude oil. Cracks and other CO₂ leaking pathways can be plugged during the geological storage of CO₂ to increase the storage stability. By adding CO₂-responsive groups to the classic polymer gel's molecular chain, CO₂ responsive gel is able to seal and recognize CO₂ in the formation while maintaining the superior performance of traditional polymer gel. The application of CO₂ responsive gels in oil and gas production is still in the stage of laboratory testing on the whole. To actually achieve the commercial application of CO₂ responsive gels in the oil and gas industry, it is imperative to thoroughly understand the CO₂ responsive mechanisms of the various types of CO₂ responsive gels, as well as the advantages and drawbacks of the gels and the direction of future development prospects. This work provides an overview of the research progress and response mechanisms of various types of CO₂ responsive groups and CO₂ responsive gels. Studies of the CO₂ responsive gel development, injectivity, and plugging performance are comprehensively reviewed and summarized. The shortcomings of the existing CO₂ responsive gels system are discussed and the paths for future CO₂ responsive gel development are suggested.