Geomechanical and Petrophysical Effects of Long-Term Hydrogen Exposure on Berea Sandstone – An Experimental Study

Hydrogen is gaining traction on a global scale as a future low-carbon energy carrier. Underground Hydrogen Storage (UHS) is critical to successfully implementing the hydrogen economy. UHS requires many lab-scale and large-scale studies to understand the behavior of hydrogen in the subsurface before they can be incorporated into the energy system. So far, most of the experimental investigations conducted on UHS focus on the microbial, hydrogeological, and geochemical effects of hydrogen storage in the subsurface. However, studies focused on the geomechanical effects are scarce. In this work, eight Berea sandstone cores were exposed to brine, pure hydrogen, and hydrogen in the presence of brine for 90 days at reservoir conditions of 10 MPa and 60°C to study the geomechanical effects of hydrogen on the samples. Tests for the Berea sandstone's properties for petrophysical (permeability and porosity) and geomechanical (strength, Young's modulus, and Poisson's ratio) properties. The results demonstrate that long-term interactions with hydrogen cause changes in all the properties of the cores. The results also demonstrate changes in the geomechanical properties of the reservoir after three months of hydrogen exposure, which has not been extensively studied, and the results can be used in simulation, site selection, and risk assessment studies. 1. INTRODUCTION Renewable energy production is viewed as an alternative to environmentally detrimental fossil fuel energies (coal, oil, and natural gas), contributing to global net-zero carbon emissions by 2050(Perera, 2023; Ugarte et al., 2023). According to a study by the International Renewable Energy Agency (IRENA), renewable energy will become the primary energy source, increasing worldwide share from 16% in 2020 to 77% by 2050 (IRENA, 2023). While there is a rising global interest in renewable energy, wind and solar energy have limitations: they depend on unpredictable factors such as weather. Renewable energy's intermittent generation creates a supply-demand imbalance, making renewable energies unreliable since they cannot maintain a continuous supply (Abdellatif et al., 2023; Heinemann et al., 2021; Kanaani & Sedaee, 2022; Muhammed et al., 2022; P. & P.G., 2023). To balance supply and demand, surplus energy from wind and solar energies can be converted to hydrogen through electrolysis, stored in the energy storage system, and subsequently utilized when demand arises (Okoroafor et al., 2022; Zamehrian & Sedaee, 2022).