煤储层注CO₂过程中，CO₂的扩散和吸附进展缓慢，不同注气压力下吸附-运移时效特征对设计煤层封存CO₂具有重要影响。因此，采用双能X射线CT扫描，并计算分析了煤储层在围压下注气前后煤心密度变化和CO₂浓度。研究结果表明：在煤心的不同区域，气体以不同的速度运移，扩散和吸附进展缓慢；煤心中平均CO₂浓度随时间和CO₂注入压力的增加而增加，CO₂浓度从注气端向出口段沿煤心轴向几乎单调下降；煤心中CO₂浓度分布不均匀，煤心密度较高区域CO₂浓度越低（矿物质影响），煤基质密度较小处CO₂浓度越高。

During the process of injecting CO₂ into coal reservoirs, the diffusion and adsorption of CO₂ are slow process, and the adsorption 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 decreases 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 concentration in areas with low coal matrix density is.