Maximum column height and optimum storage depth for geological storage of hydrogen

Abstract

We formulated the maximum hydrogen column height that avoids capillary breakthrough into the caprock above saline aquifers and depleted gas reservoirs. The effects of potential cushion gases such as methane, carbon dioxide, and nitrogen were considered. Using representative rock and fluid properties, the results suggested an optimal depth of approximately 1600 m for hydrogen storage. The use of a cushion gas with a higher density can increase the maximum hydrogen column height and the mass of storable hydrogen. The sensitivity analysis showed that the contact angle and caprock pore radius have the greatest influence on the maximum column height. Uncertainty quantification using Monte-Carlo simulation presented that P10, P50, and P90 for the optimum storage depths are 1760, 1565, and 1370 m, respectively. The mixing of gases resulted in a lower maximum hydrogen height. Moreover, the results indicated a higher dip angle of the formation can decrease the storable hydrogen mass.