For underground gas storage projects that use depleted gas reservoirs, cyclic gas injection will change the stress fields and cause rock deformation. In-depth knowledge of the stress-induced deformation of reservoir rocks is important for secure gas storage. In this study, we performed a uniaxial compression computed tomography (CT) test with a reservoir sandstone sample to investigate the influence of rock deformation on the pore and permeability properties. Based on scanned 3D images, we analyzed the axial strain evolution by using the digital volume correlation (DVC) technique and the variations in pore properties with the microstructures and permeability properties that were extracted by the pore network modeling method. The DVC analysis shows that strain localization develops gradually with increasing axial stress. The initial porosity distribution with sample height is inhomogeneous. The local porosity variations are not completely consistent with the global porosity variations under increasing axial stress. The level of inconsistency will decrease with increasing axial stress in both the volumetric compression and dilation stages. Increases in axial stress mainly induce the variations in pore numbers and pore volumes. The variations in pore connectivity are not significant. For the permeability evolution, X-ray CT scanning combined with pore network modeling can simulate the permeability decreases during volumetric compression. For high porosity sandstones (>15%), the permeability still decreases in the volumetric dilation stage due to grain size reductions and tortuosity increases. However, this technique has limitations in analyzing the permeability reductions in the volumetric dilation stage. The microcracks that are induced inside the grain particles are too small to be recognized. The variations in the relative gas and water permeabilities at different axial stresses are not significant.

对于利用枯竭气藏的地下储气库工程，循环注气会改变应力场，引起岩石变形。深入了解储层岩石的应力诱发变形对于安全储气很重要。在这项研究中，我们对储层砂岩样品进行了单轴压缩计算机断层扫描(CT) 测试，以研究岩石变形对孔隙和渗透率特性的影响。基于扫描的 3D 图像，我们使用数字体积相关 (DVC) 技术分析了轴向应变演化，以及通过孔隙网络建模方法提取的微观结构和渗透率特性随孔隙特性的变化。DVC 分析表明随着轴向应力的增加，应变局部化逐渐发展。初始孔隙率随样品高度分布是不均匀的。在轴向应力增加的情况下，局部孔隙度变化与整体孔隙度变化并不完全一致。在体积压缩和膨胀阶段，不一致性水平将随着轴向应力的增加而降低。轴向应力的增加主要引起孔数和孔体积的变化。孔隙连通性的变化并不显着。对于渗透率演化，X射线CT扫描结合孔隙网络建模可以模拟体积压缩过程中渗透率的下降。对于高孔隙度砂岩(>15%)，在体积膨胀阶段，由于晶粒尺寸减小和曲折度增加，渗透率仍然下降。然而，该技术在分析体积膨胀阶段的渗透率降低方面存在局限性。在颗粒内部诱发的微裂纹太小而无法识别。不同轴向应力下相对气体和水渗透率的变化并不显着。