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.