Caprock wettability: A cross-process perspective from CO₂ sequestration to underground hydrogen storage
Abstract
Caprock wettability is a fundamental control on the sealing capacity and integrity of subsurface energy storage systems. In CO₂ geological sequestration, a strongly water wet caprock ensures high capillary entry pressures, effectively preventing CO₂ migration. However, increased pressure and brine salinity can weaken hydrophilicity and compromise long-term sealing. In underground hydrogen storage, caprocks generally remain water wet, yet the high diffusivity of H₂ reduce capillary sealing efficiency and may induce wettability alteration due to microbial or redox processes. Repeated injection-withdrawal cycles further cause transient wetting-drying and hysteresis, altering interfacial structures and capillary behavior. Understanding these dynamic wettability responses under varying physicochemical conditions is crucial for assessing storage security. Future studies should integrate in-situ characterization and molecular modeling to reveal reactive and reversible wettability mechanisms, providing a unified framework for CO₂ and H₂ storage systems.
Document Type: Perspective
Cited as: Tao, L., Liu, L., Zhu, S., Zhang, H. Caprock wettability: A cross-process perspective from CO₂ sequestration to underground hydrogen storage. Advances in Geo-Energy Research, 2025, 18(2): 199-201. https://doi.org/10.46690/ager.2025.11.09
DOI:
https://doi.org/10.46690/ager.2025.11.09Keywords:
Geological CO₂ sequestration, underground H₂ storage, wettability, caprock, capillary sealingReferences
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