Physicochemical Investigations of Hydrogen Storage in Underground Porous Media – A Contribution to the Energy Transition

There is little knowledge on the relevant physico-chemical parameters that govern the interaction between hydrogen and reservoir fluids under typical reservoir conditions, which are high salinity, elevated temperature and pressure. Furthermore, high gas losses through diffusion are assumed. As a first step, hydrogen solubilities in synthetic reservoir brines with chloride as anion and Na, Mg, K as cations were determined. Concentrations from 0 to ≤5 molar were individually investigated for a grid of temperatures ranging from 25 to 100 °C and pressures ranging from 1 to 250 bar. The experiments span a three dimensional space with the base factors of concentration, pressure and temperature. In pure water at 25°C, results are in good agreement with predicted values from standard model (PHREEQC, EOS of Spycher & Reed, 1988). However, the solubilities for higher salinity with variable pressure and temperature are more than four times higher compared to predictions from the current standard model. Besides the solubility measurements, experiments to determine diffusion coefficients of the rock types sandstone, claystone and salt rock are planned. For this purpose a novel designed apparatus is under construction and close to finalization. Experiments will follow the construction.