Research Progress of Friendly Carbon Dioxide Expansion Flooding: A Review

CO₂ expansion flooding technology has the potential to significantly enhance oil recovery in low permeability and ultra-low permeability reservoirs, while also facilitating carbon capture, utilization, and storage (CCUS) to a certain extent. This paper provides a comprehensive review of the mechanism of CO₂ expansion flooding, the current research status of two main methods – self-generated expansion with viscosity reduction and gas injection expansion with viscosity reduction - as well as advancements in simulation studies on expansion flooding. Currently, achieving optimal CO₂ flooding conditions remains challenging due to limited availability of large-scale gas sources and concerns regarding equipment pipeline corrosion during transportation. Finally, this environmentally friendly CO₂ flooding technology is summarized and its future prospects are discussed.