Experimental Investigation of Shale Wettability and Its Alteration Mechanisms in Supercritical CO 2 –Brine–Oil Systems: Implications for CO 2 Storage and Enhanced Oil Recovery

作者：Lili Jiang, Leng Tian, Can Huang, Jiaxin Wang, Zhenqian Xue, Xiaolong Chai, Hengli Wang, Zhangxin Chen · 发表于：ACS Omega · 年份：2025 · DOI：10.1021/acsomega.5c01350 · 被引用次数：12 · 研究领域：Enhanced Oil Recovery Techniques、CO2 Sequestration and Geologic Interactions、Hydrocarbon exploration and reservoir analysis

High Resolution Image Download MS PowerPoint Slide CO 2 is highly effective at enhancing shale oil recovery while facilitating geological sequestration. The interaction between supercritical CO 2 (ScCO 2 ) and shale significantly alters the wettability, a key factor influencing both the oil recovery efficiency and the CO 2 storage capacity. A novel investigation was carried out to explore the dynamic characteristics of the CO 2 –brine–oil–shale multiphase system and the mechanisms underlying wettability alteration using samples from the Yanchang shale formation in China. The wettability of shale samples was characterized by high-temperature and high-pressure contact angle tests, while quantitative analysis of the mineral composition was conducted through ScCO 2 -shale reaction experiments combined with XRD. FTIR and zeta potential tests determined the types and amounts of surface charged groups, and 3D surface morphology scanning reflected structural changes. Results showed that ScCO 2 injection significantly weakened the water-wetness of shale. Temperature and pressure were key external factors: increasing temperature shifted the wettability from water-wet toward neutral-wet, while higher pressure drove it closer to oil-wet. After ScCO 2 treatment, significant alterations in the physicochemical properties of shale were observed, which fundamentally influenced its wettability. The content of clay minerals, encompassing both hydrophilic and hydrophobic phases, was reduced, whe...