Effects of aqueous solubility and molecular diffusion on CO2-enhanced hydrocarbon recovery and storage from liquid-rich shale reservoirs

This study investigates the effects of aqueous solubility and aqueous molecular diffusion of gaseous components (CO2 and CH4) on the CO2 huff and puff process in the liquid-rich shale reservoirs. In a gas-condensate reservoir, the effects negligibly enhance the hydrocarbon production, but increase the CO2 storage with 4.4% by solubility trapping. In a shale oil reservoir, they increase the production and CO2 storage up to 5% and 14% by more CO2 imbibition and contacting between CO2 and oil. This study clarifies the importance of aqueous solubility and aqueous-phase molecular diffusion of CO2 huff and puff in shale reservoirs.