Sensitivity Analysis of Geological Parameters to Evaluate Uncertainty in Underground Hydrogen Storage Performance for a Saline Aquifer at Ketzin (Germany)

A numerical sensitivity analysis of a hydrogen pore storage system is carried out on a reservoir-scale geological model of the Ketzin site (Germany) to analyze the influence of uncertainty in geological parameters and fluid properties on storage performance. Therefore, the following physical geological parameters and fluid properties were investigated: Porosity and permeability of the reservoir rock, the brine salinity, relative permeability and capillary pressure and mechanical dispersion. The range of the applied parameters is based on experimental and field data of the chosen location obtained during the former CO2 storage projects at the Ketzin site from 2008 to 2013. Using the open-source reservoir software MUFITS for the numerical simulations, strong differences between the results can be observed. The results were evaluated based on measures to quantify performance, such as the ratio of produced hydrogen mass to produced cushion gas (nitrogen), productivity index and sustainability index. The strongest impact on the performance parameters was observed with variations in the capillary pressure and the relative permeability curves followed by the absolute permeabilities, while the least impact was seen with changes in the porosity and salinity of the brine. This work is not only crucial as a pre-feasibility study for the Ketzin storage site for hydrogen storage but also as a basis for decision-making for other potential storage sites in sedimentary basins.