Subsurface reservoirs are targeted formations for geologic carbon dioxide (CO₂) storage. Even if proper management of injection pressures minimizes the risks of induced seismicity, high pressure CO₂ can interact with brine-saturated host rock and cause microstructural changes that lead to alterations in poromechanical properties of the rock. The effect is well pronounced in carbonate-rich rock, but observations on silica-rich reservoirs are ambiguous. In this study, we report a broad range of experiments performed on Berea sandstone, consisting mainly of quartz (∼90%), in three different states: pristine, thermally damaged, and thermally damaged then treated with liquid CO₂. Drained and undrained poromechanical tests, ultrasonic velocity measurements, acoustic emission (AE), X-ray diffraction (XRD), and petrographic analyses are conducted. The tests reveal that thermal damage alone does not significantly affect poromechanical properties. However, CO₂ injection does affect strength (10–15 % decrease), permeability (up to 100% increase), porosity (10% increase), and elastic creep rate (more than twice); corresponding microstructural changes were observed from XRD test results. At the same time, the poroelastic moduli measured in triaxial compression experiments and load-induced fracture processes, as interpreted through acoustic emission data collected in uniaxial compression tests, were affected insignificantly. These experimental observations provide better understanding of the mechanical behavior of low-carbonate reservoir rocks that are subjected to high pressure CO₂ injection.

地下储层是用于地质二氧化碳（CO ₂）储存的目标地层。即使适当控制注入压力可以最大程度地降低诱发地震的风险，但高压CO ₂仍会与盐水饱和的主体岩石相互作用，并引起微观结构变化，从而导致岩石的岩石力学特性发生变化。在富含碳酸盐的岩石中这种作用是很明显的，但是对富含二氧化硅的储层的观测却是模棱两可的。在这项研究中，我们报告了对Berea砂岩进行的一系列实验，这些砂岩主要由石英（约90％）组成，处于三种不同状态：原始，热损坏和热损坏，然后用液态CO ₂处理。进行了排水的排水试验，超声速度测量，声发射（AE），X射线衍射（XRD）和岩石学分析。这些测试表明，单独的热损伤并不会显着影响汽相力学性能。但是，CO ₂注射确实会影响强度（降低10-15％），渗透率（提高100％），孔隙率（提高10％）和弹性蠕变速率（超过两倍）。从XRD测试结果观察到相应的微观结构变化。同时，通过单轴压缩试验中收集的声发射数据解释的，在三轴压缩实验和载荷诱导的断裂过程中测得的孔隙弹性模量受到的影响很小。这些实验观察提供了对经受高压CO ₂注入的低碳酸盐岩储层岩石力学行为的更好理解。