Pore Deformation of Shale under Supercritical Carbon Dioxide based on MIP

This paper studies the characteristics of pore changes before and after supercritical CO2 action, and discusses the influence of supercritical CO2 action on shale pores. Taking the shale of the Silurian Longmaxi Formation in the eastern Sichuan Basin as the experimental sample, the MIP experiment was used to analyze the process of mercury in and out of shale before and after the action of supercritical CO2, and changes in pore structure of shale after supercritical CO2 treatment The mercury injection amount of shale after supercritical CO2 treatment increases significantly. Because of the extraction reaction and dissolution reaction with shale pore surface minerals after supercritical CO2 injection, some micropores and mesopores are transformed into mesopores and macropores through dissolution, and new micropores are generated, resulting in the increase of mesopore PV and macropore SSA in shale. Ultimately, experiments have shown that supercritical CO2 can expand the average pore size of shale and improve the seepage channels inside the shale, thereby enhancing shale oil recovery.