Hydrogen Relative Permeability Hysteresis in Underground Storage

Implementation of the hydrogen economy for emission reduction will require storage facilities, and underground hydrogen storage (UHS) in porous media offers a readily available large‐scale option. Lack of studies on multiphase hydrogen flow in porous media is one of the several barriers for accurate predictions of UHS. This paper reports, for the first time, measurements of hysteresis in hydrogen‐water relative permeability in a sandstone core under shallow storage conditions. We use the steady state technique to measure primary drainage, imbibition and secondary drainage relative permeabilities, and extend laboratory measurements with numerical history matching and capillary pressure measurements to cover the whole mobile saturation range. We observe that gas and water relative permeabilities show strong hysteresis, and nitrogen as substitute for hydrogen in laboratory assessments should be used with care. Our results serve as calibrated input to field scale numerical modeling of hydrogen injection and withdrawal processes during porous media UHS. Plain Language Summary Hydrogen storage facilities will need a ramp‐up when the hydrogen share in the future energy mix increase. Large‐scale hydrogen storage can be implemented in empty hydrocarbon fields or ground water reservoirs. Hydrogen storage in such media involve complex interactions with native rocks and fluids, and injection and withdrawal are typically described by flow functions. Relative permeability is one of the key flow functions that describe how easily hydrogen can flow through porous media in the presence of other fluids. In underground storage, hydrogen is cyclically injected and withdrawn multiple times, and its relative permeability may differ between these two processes, described as hysteresis. In this paper, we investigate hydrogen relative permeability in the laboratory and match with results from numerical simulations. We find that hydrogen relative permeability is different for injection and withdrawal and is also different from that of nitrogen. Our results are directly applicable in computer simulators that predict hydrogen storage efficiency. Key Points Steady state measurements of hydrogen‐water relative permeability Numerical history matching needed for extrapolation Strong hysteresis observed between drainage and imbibition