Surface wettability is a key factor controlling the CO₂ seal capacity and defines the CO₂ storage potential. Limited studies have addressed the shale/water wettability behavior during CO₂ injection, thus considerable attention is needed to understand this concept. In this paper, an ample number of supercritical CO₂ exposure experiments were conducted to evaluate the alteration of shale/water contact angles. Different types of shales with various mineralogy from Eagle Ford, Wolfcamp, and Mancos fields, were exposed to SCCO₂ at different durations, pressures, and temperatures. Shale mineralogy and surface were analyzed using X-ray diffraction and scanning electron microscope. The results indicated a strong relationship between mineral composition and the alteration in shale/water wettability. Clay-rich shales displayed a possible turn in wetting behavior to CO₂-wet with extending the SCCO₂ treatment time and increasing the treatment pressure, caused by SCCO₂ dissolution of clay and carbonate minerals. While the wettability of high-quartz contents shales remained strongly hydrophilic after various SCCO₂ treatment conditions. Increasing the temperature accelerated the CO₂/shale interactions, and a minor effect was observed on the shale hydrophilicity. Increasing the cohesive energy density of CO₂ promotes a favorable CO₂ wetting environment, which reduced the hydrophilicity of the surface and reduces the surface energy. In conclusion, shales with high quartz contents exhibit strong water wetting behavior after SCCO₂ treatment, which leads to better sealing capacity, more efficient integrity of geological storage sites, and higher potential for CO₂ containment.

表面润湿性是控制 CO ₂密封能力的关键因素，并定义了 CO ₂储存潜力。有限的研究已经解决了 CO ₂注入过程中的页岩/水润湿性行为，因此需要相当多的注意力来理解这个概念。在本文中，进行了大量超临界 CO ₂暴露实验以评估页岩/水接触角的变化。来自 Eagle Ford、Wolfcamp 和 Mancos 油田的不同矿物类型的页岩在不同的持续时间、压力和温度下暴露于 SCCO ₂。使用X分析页岩矿物学和表面射线衍射和扫描电子显微镜。结果表明矿物组成与页岩/水润湿性的改变之间存在很强的关系。随着SCCO ₂处理时间的延长和处理压力的增加，由于粘土和碳酸盐矿物的SCCO ₂溶解，富含粘土的页岩的润湿行为可能转变为CO ₂湿的。而高石英含量页岩的润湿性在各种 SCCO ₂处理条件后仍保持强亲水性。升高温度加速了CO ₂ /页岩的相互作用，并且观察到对页岩亲水性的影响较小。提高 CO ₂的内聚能密度促进了有利的 CO ₂润湿环境，从而降低了表面的亲水性并降低了表面能。总之，石英含量高的页岩在 SCCO ₂处理后表现出较强的水润湿行为，这导致更好的密封能力、更有效的地质封存场完整性和更高的 CO ₂围堵潜力。