The mechanical properties and permeability of shales after supercritical carbon dioxide (SC-CO₂) imbibition are vital to shale gas production and CO₂ sequestration in shale reservoirs. In this study, triaxial compressive strength tests, steady state permeability tests, and CT scanning tests are performed on shale samples with 30 days of SC-CO₂ imbibition. The results show that minerals dissolution and precipitation occur during SC-CO₂ imbibition. The porosity calculated by the digital core increases by 19.190%. The axial stresses of samples with or without SC-CO₂ imbibition increase with increasing confining pressure. When the confining pressure changes between 5 and 20 MPa, the reductions range from 6 to 13% for strength and from 11.26 to 16.47% for Young’s modulus, respectively. The strength of the samples with or without imbibition agrees well with the Mohr–Coulomb criterion. The values of cohesion and internal friction angles are very close which indicates that shale samples with SC-CO₂ imbibition can still refer to the failure criterion for samples without CO₂ imbibition. The permeability of the sample after SC-CO₂ imbibition increases exponentially with the increase in injection pressure and decreases exponentially with an increase of effective pressure. The permeability of the sample before and after imbibition is more sensitive to the change of pore pressure than confining pressure. SC-CO₂ imbibition enhances the increase of permeability. The ratio of the shale permeability after imbibition to that before imbibition varies from the minimum of 42 times to the maximum of 827 times. The reduction of strength and increasing of permeability are beneficial for shale gas recovery.

超临界二氧化碳（SC-CO ₂）吸收后的页岩的机械性能和渗透性对页岩气生产和页岩储层中的CO ₂固存至关重要。在这项研究中，对30天SC-CO ₂吸收的页岩样品进行了三轴抗压强度测试，稳态渗透性测试和CT扫描测试。结果表明，在SC-CO ₂吸收过程中发生了矿物的溶解和沉淀。数字核心计算出的孔隙率增加了19.190％。有或没有SC-CO ₂的样品的轴向应力随着围压的增加，吸力增加。当围压在5至20 MPa之间变化时，强度的降低幅度分别为6％至13％，杨氏模量的降低幅度分别为11.26％至16.47％。有或没有吸收的样品的强度与Mohr-Coulomb标准非常吻合。内聚角和内摩擦角的值非常接近，这表明具有SC-CO ₂吸收作用的页岩样品仍可以参考无CO ₂吸收作用的样品的破坏准则。SC-CO ₂后样品的磁导率吸力随注入压力的增加呈指数增长，而随有效压力的增加呈指数下降。吸水前后样品的渗透率对孔隙压力的变化比围压更敏感。SC-CO ₂吸收增强了渗透性的增加。吸水后页岩渗透率与吸水前页岩渗透率的比值从最小值的42倍到最大值的827倍不等。强度降低和渗透率增加有利于页岩气的回收。