CO₂ injection into shale facilitates a dual-purpose utility in enabling geological CO₂ sequestration with enhanced gas recovery (CS-EGR). Unfortunately, the CS-EGR responses under anisotropic/heterogeneous permeability and in-situ stress remain unclear. This study presents a thermal-hydraulic-mechanical coupled model to numerically determine how the anisotropic/heterogeneous permeability and/or in-situ stress affect the efficiency of CS-EGR in shale. The modelling results indicated that the permeability anisotropy was promoted significantly during the CS-EGR process, which determines the asymmetrical CO₂/CH₄ distribution in the modeling reservoir. It is also concluded that the anisotropic/heterogeneous permeability has a greater influence than in-situ stress on the CS-EGR. For a single shale layer, higher horizontal permeability or lower horizontal in-situ stress provide positive contributions in obtaining a better CS-EGR performance. For two contiguous shale layers, 1) the CS-EGR outputs are mainly controlled by the horizontal permeability or in-situ stress of the lower layer where the CO₂ injection well located; 2) greater horizontal permeability difference between the two layers enhance the magnitude of CO₂ accumulation and CH₄ desorption. Furthermore, the implication of this work is applied by an optimization of the location of the production well focusing on different CS-EGR objectives, under the background of the anisotropic/heterogeneous Silurian Longmaxi formation. In summary, the anisotropic/heterogeneous permeability and in-situ stress distributions, which exists in real shale reservoirs, provide significant influence in predicting a responsible CS-EGR outcome.

向页岩中注入CO ₂有助于实现双重用途，从而能够实现地质CO ₂封存和更高的气体回收率（CS-EGR）。不幸的是，各向异性/非均质渗透率和原地应力下的CS-EGR响应仍然不清楚。这项研究提出了一种热-液压-机械耦合模型，以数值方式确定各向异性/非均质渗透率和/或原位应力如何影响页岩CS-EGR的效率。建模结果表明，在CS-EGR过程中渗透率各向异性得到了显着提高，这决定了CO ₂ / CH ₄的不对称性。分布在模型库中。还得出结论，各向异性/非均质渗透率对CS-EGR的影响要大于原地应力。对于单页岩层，较高的水平渗透率或较低的水平原地应力为获得更好的CS-EGR性能提供了积极的贡献。对于两个连续的页岩层，1）CS-EGR输出量主要由注入CO _2的井下层的水平渗透率或原位应力控制；2）两层之间较大的水平渗透率差异会增加CO ₂积累和CH _4的数量解吸。此外，在各向异性/非均质志留系Longmaxi地层的背景下，通过优化生产井的位置（针对不同的CS-EGR目标）来应用这项工作的含义。总而言之，存在于实际页岩储层中的各向异性/非均质渗透率和原地应力分布在预测可靠的CS-EGR结果方面具有重要影响。