An Environmental-Friendly Amphiphilic Molecule for Simultaneously Improving CO₂ Geological Storage and Utilization

CO₂ injection into subsurface reservoirs is an effective method for CO₂ storage and higher geological resources recovery in low-permeability reservoirs. However, substantial CO₂ coproduction during conventional CO₂ flooding limits storage efficiency. In this study, a natural amphiphilic molecule (ARGS) is introduced to enhance oil recovery and CO₂ storage by regulating CO₂-oil-water-rock interfacial and mass-transfer properties under saline conditions, achieving a 9.7% increase in oil recovery compared with conventional CO₂-enhanced oil recovery (CO₂-EOR) and a CO₂ storage ratio of up to 85% simultaneously. Under high-salinity formation-water conditions, ARGS increased CO₂ solubility by 4-fold and reduced the interfacial tension of the CO₂-formation water system by 36%. At the water-rock interface, ARGS shifted pore-surface wettability from neutral-wet to water-wet. During ARGS-assisted CO₂ injection, oil displacement efficiency in micro- and mesopores increased by 10%-15%, expanding the CO₂ sweep range and providing more pore space for CO₂ storage. By enhancing the water-wetness of pore walls, ARGS increased CO₂ flow resistance and consequently promoted both dissolved and trapped CO₂ storage. Ultimately, the proportion of dissolved CO₂ can reach 70%. This study provides an environmentally friendly approach for the efficient CO₂ geological storage and utilization in low-permeability reservoirs.