H2 Storage Simulations Using Effective Hydraulic Properties – Comparison with Heterogeneous Cases

In this work 10 different methods to calculate an effective permeability are used to generate homogenous rock models based on a heterogeneous rock model of an existing geologic structure in Northern Germany. Subsequently, simulation results of a hypothetical H2 storage operation obtained for the various homogeneous models are compared to those of the heterogeneous ensemble to evaluate the applicability of the individual methods. It is shown that the upper bound of storage performance metrics such as storage flow rates or power output can be estimated for the given structure using simulations in which permeability is estimated by an arithmetic mean. Likewise, the lower bound of the results obtained for the heterogeneous ensemble can be estimated by simulations in which effective permeability is estimated using a geometric average of the vertical arithmetic averages. The overpressure signal induced by the storage operation are slightly underestimated in the far field of the storage wells, being within 0.5 bars of the median of the heterogeneous ensemble for most homogeneous cases.