There have been many studies carried out in the past decade to evaluate the long-term integrity of seals in CO₂ storage sites. These seals (caprock and faults) are often dominated by shale and may act as a capillary barrier against the CO₂ migration. Thus, geochemical reactions, mineral transformations, surface wettability alteration and reduction of capillary pressure that may take place in a geological storage site must be deeply understood. The main objective of this study is to examine the changes in the mineralogy and surface wettability of shales with different clay contents once exposed to supercritical CO₂ for 6 months. The results obtained indicated that quartz dissolution and kaolinite precipitation can be induced in the presence of supercritical CO₂. It appeared that brine in a concentration less than 4000 ppm could help to maintain the water wettability of the clay surface. Changes of surface wettability in a storage site could be a dynamic process and linked to the reduction of the surface areas in clays and their affinity to absorb CO₂. Given that the interactions between CO₂ and rocks are very slow and may take place over a long period of time, further studies are needed to ensure the integrity of seals in storage sites during and after injection.

在过去十年中进行了许多研究，以评估 CO ₂储存场所密封的长期完整性。这些密封层（盖层和断层）通常以页岩为主，可以作为防止 CO ₂迁移的毛细管屏障。因此，必须深入了解地质储存场地中可能发生的地球化学反应、矿物转化、表面润湿性改变和毛细管压力降低。本研究的主要目的是检查暴露于超临界 CO ₂ 6 个月后具有不同粘土含量的页岩的矿物学和表面润湿性的变化。结果表明，在超临界CO存在下可以诱导石英溶解和高岭石沉淀。₂ . 浓度低于 4000 ppm 的盐水似乎有助于保持粘土表面的水润湿性。储存场地表面润湿性的变化可能是一个动态过程，与粘土表面积的减少及其吸收 CO ₂的亲和力有关。鉴于 CO ₂和岩石之间的相互作用非常缓慢，并且可能会持续很长时间，因此需要进一步研究以确保注入期间和之后存储地点的密封完整性。