Measuring Poromechanical Properties of Berea Sandstone Relevant to Underground Hydrogen Storage

Seasonal fluctuation in electricity generation is a major set-back for the integration of renewable energy sources such as solar and wind into a national grid. Temporary storage of 'green' hydrogen in underground porous reservoirs could be a cost-effective solution to balance renewable energy fluctuations to stabilize the energy grid. However, due to the novelty of Underground Hydrogen Storage (UHS) in deep porous reservoirs, our knowledge about the interaction between hydrogen and host reservoir rock is limited. It is crucial to develop the fundamental understanding of these interactions and their impact on the reservoir rock for successful deployment of UHS. In this study, we measure the poromechanical properties, such as bulk compressibility, in-situ porosity, Biot's effective stress coefficient, and P-wave velocity of Berea sandstone specimen at in-situ reservoir stress condition i.e., depth of ~ 1.25 km. Results showed decrease in bulk compressibility, porosity, and Biot's coefficient due to increase in effective stress. Considered together, results from this study infer change in stress regime in UHS reservoir due to multiple injection/extraction cycles could alter the reservoir capacity and transport properties. In addition, P-wave velocity increased with the effective stress. However, it remained insensitive to different gas (i.e., air and Argon) saturated pores at same effective stress.