Chemical plugging systems for preventing gas channeling in CO₂ flooding: Progress and prospects

As an important component of carbon capture, utilization, and storage (CCUS), CO₂ flooding technology can improve oil recovery while realizing CO₂ geological storage. However, due to reservoir heterogeneity and physical property differences between CO₂ and formation fluids, gas channeling severely limits its development efficiency. This paper systematically summarizes the dominant mechanisms of gas channeling and accordingly reviews in depth the research progress and technical characteristics of three major chemical plugging systems: foam-based gas channeling control, gel-based gas channeling control, and CO₂-responsive intelligent gas channeling control. Foam systems achieve selective plugging based on the Jamin effect, gel systems form physical barriers through three-dimensional network structures, and CO₂-responsive systems trigger in-situ gelation by the acidity of CO₂ itself. Each of the three has unique advantages, but limitations remain in its plugging strength, environmental adaptability, and long-term stability. On this basis, the applicable conditions and key bottlenecks of various technologies are compared and analyzed, and their future development trends are prospected. Gas channeling control technology requires the coordinated development of material innovation and process optimization: on the one hand, developing intelligent composite materials with multi-response characteristics, temperature resistance, and salt tolerance; on the other hand, building a data-driven intelligent decision-making platform to realize precise placement of plugging agents and dynamic optimization of processes. Ultimately, a systematic solution featuring “intelligent sensing–precise regulation–long-term stability” will be formed, providing technical support for the large-scale application of CO₂ flooding.