Direct measurement of hydrogen relative permeability hysteresis for underground hydrogen storage.

Underground Hydrogen Storage (UHS) is a long-term storage solution which utilises hydrogen as an energy carrier to store large-scale excess renewable energy in the subsurface. Key petrophysical properties, such as wettability and interfacial tension of hydrogen and water have been discovered which provide a practical basis for simulation models. Our work directly measures relative permeability hysteresis during co-injection core floods of hydrogen and water with a capillary number of N c = 2.92 × 10 − 7 . Segmented micro-CT images are used to determine saturation in the Bentheimer sandstone. Our results demonstrate that hydrogen relative permeability in sandstones is very low, with an end-point relative permeability of k r g 0 = 0.049 at S wi = 0.24. Capillary trapping results in residual gas saturation of S gr = 0.4. Wettability analysis confirms the system is water-wet, with contact angles of 57° at S gr and 44° at S wi. These results improve the reliability of numerical simulations and demonstrate the possible challenges involved with the commercial application of UHS. • Single cycle co-injection steady state relative permeability drainage and imbibition for hydrogen/water system. • End-point relative permeability of k r g 0 = 0.049 at S wi = 0.24. • Contact angle of 57° at S gr and 44° at S wi. • Residual gas saturation S gr = 0.4 with land trapping coefficient C = 1.184 and linear trapping coefficient A = 0.53. [ABSTRACT FROM AUTHOR]