CO can be safely stored in geological formations, such as deep saline aquifers and depleted oil or gas reservoirs. However, knowledge about caprock and storing bed integrity is essential for safe storage in sedimentary porous rocks. In this study typical carbonate and sandstone minerals present in the reservoir and caprocks have been exposed to carbonated water above supercritical conditions of CO for short time periods (7 days) to investigate the CO-brine-rock interactions and their effects on mineral stability. After exposure, the equilibrated brine composition was determined and any changes to the mineral samples were examined by SEM, EDX and XRD analyses. The solubility of CO in brines was low, increasing with pressure and decreasing with salinity, and no significant increase in CO solubility was observed above critical pressure and temperature for CO. Quartz and clay minerals were the least reactive sandstone minerals, while ion exchange reactions were observed for the feldspar minerals. For calcite minerals, calcium ion liberation was observed accompanied by a pH increase, which is linked to mineral dissolution. SEM, EDX and XRD analyses did not detect any changes on the surfaces of silicate and carbonate minerals exposed to the carbonated water. The overall results confirm minimal effects on silicate and carbonate minerals after short-term exposure to carbonated water above supercritical conditions of CO.

中文翻译：

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碳酸水对碳捕获和储存的储层和盖层矿物的地球化学影响

二氧化碳可以安全地储存在地质构造中，例如深层咸水层和枯竭的石油或天然气储层。然而，有关盖层和储存层完整性的知识对于沉积多孔岩的安全储存至关重要。在这项研究中，储层和盖层中存在的典型碳酸盐和砂岩矿物已短时间（7 天）暴露于高于 CO2 超临界条件的碳酸水中，以研究 CO2-盐水-岩石相互作用及其对矿物稳定性的影响。暴露后，确定平衡盐水成分，并通过 SEM、EDX 和 XRD 分析检查矿物样品的任何变化。 CO 在盐水中的溶解度较低，随着压力的增加而增加，随着盐度的增加而减少，并且在高于 CO 的临界压力和温度时没有观察到 CO 的溶解度显着增加。石英和粘土矿物是反应性最低的砂岩矿物，而离子交换反应则较弱。观察到长石矿物。对于方解石矿物，观察到钙离子释放伴随着 pH 值的增加，这与矿物溶解有关。 SEM、EDX 和 XRD 分析未检测到暴露于碳酸水中的硅酸盐和碳酸盐矿物的表面有任何变化。总体结果证实，短期暴露于高于 CO2 超临界条件的碳酸水后，对硅酸盐和碳酸盐矿物的影响极小。