Modeling hydrogen – rock – brine interactions for the Jurassic reservoir and cap rocks from Polish Lowlands

Abstract

Hydrogen offers an opportunity to move away from fossil fuels, it may help to alleviate major drawbacks of intermittent renewable energy generation. The results of geochemical modeling of hydrogen-rock-brine interactions for sandstones, mudstones and claystones from the geological structures from Polish Lowland are presented. The pH of the pore water is a critical parameter that controls the extent of the reaction. Several dominant reaction schemes were distinguished, and goethite was indicated as responsible for the consumption of stored hydrogen. It was found that the changes in rock porosity in sandstones were much smaller than in mudstones and claystones. The Zaosie sandstones are more favorable for UHS than those from Chabowo. The degradation of cap rock integrity, requires each time further experimental research. The findings of this study can help for better understanding of the behavior of hydrogen, in terms of gas-rock-brine interactions, in conditions of its underground storage. • Iron compounds are crucial for hydrogen-rock-brine interaction reactions. • Pyrite destabilization and goethite decomposition effects should be included in UHS. • Significant changes in porosity result from hydrogen injection into clay rocks. • pH of the environment is critical parameter controlling the reactions taking place. • Degradation of cap rock integrity due to hydrogen injection requires tests each time.