Wettability of Hydrogen-rock-brine systems: Implications for Underground Hydrogen Storage

Abstract

Summary Underground hydrogen storage (UHS) in depleted reservoirs has gained a great interest as part of the green energy transition. The wettability of the hydrogen-rock-brine system is crucial to the UHS process as it affects the geo-storage capacity as well as the hydrogen flow and migration behavior. However, the wettability of the hydrogen-rock-brine system shows a wide data spared and has not been fully investigated. This article conducts a meta-analysis of the recent published datasets on hydrogen wettability for different rock types and key minerals. The measured contact angle dataset of the hydrogen-rock-brine systems of the different rock types and minerals are correlated against various parameters that affect hydrogen wettability. This includes the effect of organic acid concentration, temperature, pressure, salinity, mineralogy, and total organic content (TOC). The results show that higher contact angles are observed with the increase in organic acid concentration indicating the system to be more H2-wet with increasing organic acids. Also, the results show an increase in advancing and receding contact angles with increasing pressure reflecting that the surface de-wets at high pressure or at deeper storage locations. This article gives more insight into the wettability of the hydrogen-rock-brine system and the critical parameters influencing UHS.