Salinity, temperature and pressure effect on hydrogen wettability of carbonate rocks

Abstract

Hydrogen had been injected into the geologic formations, and the geologic formation wettability would influence the hydrogen storage. Hydrogen wettability of sandstone reservoirs (quartz), mica and other rocks have been explored in the previous study. However, the research on hydrogen wettability of carbonate rocks was lacked. In this study, we studied the carbonate rock wettability alteration when exposed to the hydrogen environments. Salinity, temperature and pressure effect on H 2 /carbonate rock/brine wettability were explored. When the solutions ions concentration increased, the advancing/receding contact angle would increase, and divalent ions could make the contact angle higher than monovalent ion, which was because ions could compress the electric double layer. The carbonate rock powder in brine showed negative charge, and the zeta potential increased with higher ions concentration. When temperature increased and the pressure decreased, the contact angle would decrease, which was related to the H 2 gas density and molecular interactions. • The divalent ions showed higher effect on the hydrogen wettability alteration than monovalent ion. • The contact angle increased with the increase of ions concentration. • The contact angle increased with the decrease of temperature. • The contact angle increased with the increase of pressure. • The high salinity could compress the electric double layer, and increased the contact angle.