Geochemical Effects on Storage Gases and Reservoir Rock during Underground Hydrogen Storage: A Depleted North Sea Oil Reservoir Case Study

In this work, geochemical modelling using PhreeqC was carried out to evaluate the effects of reactions on performance underground hydrogen storage (UHS). Equilibrium, exchange, and mineral were considered in model. Moreover, reaction kinetics effect over an extended period 30 years. The developed model first validated against experimental data adopted from published literature by comparing values H2 CO2 solubility water at varying conditions. Furthermore, pressure, temperature, salinity, CO2% inventory rock properties a typical sandstone reservoir evaluated Results show that loss years is negligible (maximum 2%) through studied range relative much more pronounced compared gas, with losses up 72%. Therefore, role as cushion gas will be affected time passes. Hence, remedial injections should maintain pressure throughout injection withdrawal processes. volume increases increase temperature decrease pressure. properties, porosity, permeability, are process and, specifically, presence gas. dissolves carbonate minerals inside rock, causing rock’s porosity permeability. Consequently, capacity flow enhanced.