Effect of Grid Resolution on Underground Hydrogen Storage Compositional Reservoir Simulation

Abstract

AbstractHydrogen is poised to play a critical role in the global transition to sustainable and securable energy. Exploration of Hydrogen energy technologies is gaining unprecedented momentum due to its promising potential as a low carbon energy storage technology. Hydrogen is also a versatile fuel with economy-scale applications in transportation and industrial processes. Among the challenges that arise from considering economy-scale hydrogen utilization is the large volume seasonal storage. While hydrogen has an energy mass density higher than gasoline, it requires an ample and secure storage medium due to its gaseous utilization form and low volumetric density. As such, the development of storage technologies such as Underground Hydrogen Storage (UHS) is necessary. As a sub-domain of gas reservoir engineering, UHS applications face similar challenges to those faced by other subsurface technologies in terms of understanding the geological substrata. Reservoir simulation offers an approach to improve our understanding of hydrogen behavior in geological reservoirs. However, as an emerging technology, best practices in simulating hydrogen storage in porous reservoirs is not fully understood in the literature. One key factor to consider is numerical grid size and its effect on simulation results.In this paper, the effect of numerical grid resolution on UHS simulations is investigated using a commercial compositional reservoir simulator. Additionally, a real field geological model is used to evaluate the grid resolution effect on hydrogen storage volume, reservoir pressure, cushion gas, working gas capacity, water production, hydrogen solubility in water, and residual trapping of hydrogen. The published measured hydrogen properties, relative permeability, and capillary pressure are incorporated in these simulations. Results indicate that grid size is highly influential to accurately model hydrogen migration during injection and production cycles. In addition, solubility quantification of hydrogen was found to be affected by grid resolution.