Carbon Capture, Utilization, and Storage (CCUS) Hybrid CO₂ Sequestration and Enhanced Oil Recovery: A Sustainable Approach Assessment of CO₂ injection strategies that maximize hydrocarbon recovery while ensuring long-term geological storage stability.

Carbon Capture, Utilization, and Storage (CCUS) technologies play a crucial role in mitigating climate change by capturing CO₂ emissions from industrial sources and securely storing them underground. This paper focuses on the hybrid integration of CO₂ sequestration with Enhanced Oil Recovery (EOR), a strategy that both reduces atmospheric CO₂ and increases hydrocarbon recovery from mature reservoirs. It evaluates different CO₂ injection strategies—such as continuous injection, cyclic injection, water-alternating-gas (WAG), and foam-assisted CO₂ injection—aimed at optimizing oil recovery through mechanisms including miscible displacement, viscosity reduction, and oil swelling. The study also examines the factors governing long-term geological storage stability, including capillary trapping, mineralization, and solubility trapping, and emphasizes the importance of advanced monitoring tools like 4D seismic imaging and pressure monitoring to detect leakage and ensure storage integrity. Finally, it highlights the environmental and economic advantages of hybrid CCUS–EOR systems and discusses the key challenges, cost barriers, technological needs, and regulatory issues that must be addressed for large-scale, sustainable deployment of CCUS.