Underground Hydrogen Storage in Porous Media: The Role of Petrophysics

Abstract

The demand for hydrogen is growing. The IEA 2021 Hydrogen report showed that global hydrogen demand reached 94 Mt in 2021, a 5% increase in demand from 2020. Hydrogen demand is expected to reach 180 Mt by 2030. This increasing demand would require storage at scale. Of existing and potential hydrogen storage technologies, underground hydrogen storage in porous media is being considered for large-scale hydrogen storage based on successes with underground gas storage. However, there are no detailed site selection criteria for underground hydrogen storage in porous media. The objective of this study is to showcase the key geological and reservoir engineering parameters that affect underground hydrogen storage and demonstrate how petrophysical data could help in screening sites, site characterization, and hydrogen plume monitoring. We used numerical simulation modeling of a synthetic reservoir to create a base-case model representative of the hydrodynamic conditions relevant to underground hydrogen storage in porous media. We carried out a two-step sensitivity analysis. In the first step, we determined the key parameters impacting the storage and flow of hydrogen in porous media. In the second stage, we examined in detail the extent further ranges of those key parameters had on hydrogen storage potential. The findings of the two-step sensitivity analysis resulted in the development of preliminary site selection criteria. The study showed that the reservoir depth or current pressure, the reservoir dip, and the flow capacity were the top three factors impacting the optimal withdrawal of hydrogen. These highly sensitive parameters also indicate the need to reduce the uncertainty associated with these parameters when selecting potential sites for hydrogen storage in porous media. When the site selection criteria were applied to depleted fields in Northern California, we were able to see how uncertainties in geological and reservoir parameters can change a site’s ranking for potential hydrogen storage. This study quantifies uncertainties in data and identifies where and how petrophysical measurements could reduce the uncertainty associated with the key parameters relevant to underground hydrogen storage, selecting optimal sites for hydrogen storage, and tracing hydrogen leaks during the monitoring phase.