封闭空间煤心固碳过程CO2吸附-运移特征OA北大核心CSTPCD

During the process of injecting CO2 into coal reservoirs,the diffusion and adsorption of CO2 are slow process,and the ad-sorption and migration time characteristics under different injection pressures have a significant impact on the design of coal seam CO2 storage.Therefore,dual energy X-ray CT scanning was used to calculate and analyze the changes of coal core density and CO2 concentration before and after gas injection in coal reservoirs under confining pressure.The results show that in different regions of coal core,gas migrates at different speed conditions,and diffusion and adsorption progress are slow.The average CO2 concentration in the coal core increases with the increase of time and CO2 injection pressure,and the CO2 concentration almost monotonically de-creases along the axial direction of coal core from gas injection end to outlet section.The distribution of CO2 concentration in coal core is uneven.The lower the CO2 concentration in areas with high core density(mineral influence)is,the higher the CO2 concentra-tion in areas with low coal matrix density is.