Geological Storage of Carbon Dioxide and Hydrogen in Jordanian Shale Formations

The success of large-scale geological storage of gases highly depends on the interfacial properties and gas adsorption capacity of the formation in question. To infer a clear understanding of the behavior of hydrogen (H2) and carbon dioxide (CO2) at conditions relevant to their storage, a systematic study relating pressure to the gas adsorption capacity of Jordanian shale formations is conducted. Additionally, the pendant drop method and the Axisymmetric Drop Shape Analysis technique are used to measure and evaluate brine-gas interfacial tension (IFT) as a function of pressure and salinity at 333 K. The wettability of Jordanian shale is also measured using the sessile drop method at different gas pressures and varying salinities. The results show that the adsorption capacity of shale is positively correlated with pressure. CO2 adsorption capacity is found to be orders of magnitude higher than that of H2 under similar conditions. Conversely, the measured CO2 diffusivity is an order of magnitude lower than the diffusivity of H2. The results also show that IFT increases with increasing salinity in both brine-gas systems and decreases with pressure, nevertheless, the reduction in IFT is much more evident in brine-CO2 systems. Additionally, the initially water-wet shale becomes highly CO2-wet at elevated pressures, while for H2, the shale remains water wet under all experimental conditions.