The Effect of Hysteresis on Cyclic Hydrogen Geo-storage and Withdrawal in a Saline Aquifer

Abstract

Summary Underground hydrogen storage is a promising energy storage technology to increase the flexibility for future energy demand and supply. Current studies typically relied on the empirical model to generate the H2-brine relative permeability (Kr) and capillary pressure (Pc) curve due to the absence of sufficient experimental data. Moreover, it is argued that the hysteretic behaviors would occur in the repeated cycles of hydrogen injection and withdrawal. However, the effect of hysteresis on hydrogen storage at the reservoir scale remains poorly understood. In this study, experimental wettability data of the H2-brine-rock system were collected and used to generate the H2-brine Kr and Pc curves. These Kr and Pc in each hydrogen injection and withdrawal cycle were used in the subsequent cyclic hydrogen storage simulations to investigate the effect of hysteresis. Several existing hysteresis models were considered and compared with our results. The hydrogen storage simulations were implemented in a heterogeneous anticline aquifer model, and the hydrogen recovery factor was evaluated. Our results reveal that the recovery factor can reach over 90%. The results of this study thus broaden our understanding of underground hydrogen storage which in turn assists in de-risk a large-scale hydrogen storage project.