Regarding CO₂ enhanced shale gas recovery, this work focuses on changes in the multiphase (free/adsorbed) CH₄ in the process of CO₂ enhanced shale gas recovery, by utilizing a rigorous numerical model with real geological parameters. This work studies nine injection well (IW) and CH₄ production well (PW) combinations of CO₂ to determine the influence of IW and PW locations on the dynamic interaction of multiphase CH₄ during 10000 d of CO₂ injection. The results indicate that the content of both the adsorbed CH₄ and free CH₄ is strongly variable before (and during) the CO₂-CH₄ displacement. In addition, during the simulation process, the proportion of the adsorbed CH₄ among all extracted CH₄ phases dynamically increases first and then tends to stabilize at 70%–80%. Moreover, the IW-PWs combinations significantly affect the outcomes of CO₂ enhanced shale gas recovery — for both the proportion of adsorbed/free CH₄ and the recovery efficiency. A longer IW-PW distance enables more adsorbed CH₄ to be recovered but results in a lower efficiency of shale gas recovery. Basically, a shorter IW-PWs distance helps recover CH₄ via CO₂ injection if the IW targets the bottom layer of the Wufeng-Longmaxi shale formation. This numerical work expands the knowledge of CO₂ enhanced gas recovery from depleted shale reservoirs.

关于CO ₂增强页岩气体回收，此工作的重点是在多相（游离/吸附）CH变化₄中CO的过程₂增强页岩气体回收，通过利用与实际地质参数严格数值模型。这项工作研究了CO _2的9个注入井（IW）和CH ₄生产井（PW）组合，以确定在10000 d CO ₂注入期间IW和PW位置对多相CH ₄动力相互作用的影响。结果表明，吸附的CH ₄和游离CH ₄的含量在CO ₂ -CH之前（和期间）变化很大。₄排量。此外，在模拟过程中，所有提取的CH ₄相中吸附的CH ₄的比例首先动态增加，然后趋于稳定在70％–80％。此外，IW-PWs组合显着影响CO ₂提高页岩气回收率的结果-无论是吸附的游离CH ₄的比例还是回收效率。更长的IW-PW距离可以回收更多吸附的CH ₄，但导致页岩气回收效率较低。基本上，较短的IW-PWs距离有助于通过CO ₂回收CH ₄如果IW瞄准五峰—龙马溪组页岩层的底层，则进行注入。这项数值研究扩展了从贫化页岩气藏中提高CO ₂采收率的知识。