Molecular dynamics and experimental study of the effect of pressure on CO2 foam stability and its effect on the sequestration capacity of CO2 in saline aquifer

CO2 foam flooding technology is one of the important methods to improve the efficiency of CO2 sequestration in saline aquifers. This article explores the influence rules of pressure on CO2 foam stability and its micro-mechanisms, and its effect on the efficiency of CO2 foam to enhance CO2 sequestration. Increasing pressure is conducive to delaying the foam drainage and inhibiting CO2 diffusion between the liquid films, micro-mechanisms showed that the binding effect of surfactants on water and CO2 molecules was enhanced due to increased pressure. Then core-nuclear magnetic resonance was used to study the effect of pressure on CO2 sequestration characteristics from core scale, the bubble population accumulation in the macropores increased with the enhanced pressure, promoting the diversion effect of foam to the meso-and micropores. In addition to enhancing the CO2 sequestration potential of the macropores, the utilization of storage space of meso-and micropores was improved.