Using underground gas storage facilities in a safe, efficient, and long-term manner is an essential component of a sustainable energy transition, particularly when combined with an increasing use of hydrogen, and since hydrogen requires furthermore space than other gases, a large-scale storage method is required. A key objective of the project is to develop safe and innovative development concepts for the expansion, use, and monitoring of underground gas storage facilities (UGS) for storing hydrogen. The development concept includes a dynamic simulation of the reservoir to assess the storage behavior within the geological structure of a depleted hydrocarbon reservoir. For this purpose, models of simulation of pore storage, cycles of injection/production of hydrogen, investigation of the reactivation potential of faults and the possible failure of the cover of a Storage using hydromechanically coupled models and UGS monitoring are implemented to contribute to a safe and sustainable energy supply.

Based on 3D seismic and drilling data provided by the project's industrial partners, structural models are created for the two case studies and parameterized with hydromechanical parameters. The dynamic simulations are calibrated by history-matching the natural gas production phase. Various scenarios with different injection and withdrawal cycles for the working gas hydrogen and different cushion gases (CH4, N2, CO2, H2) are then modelled. Economic efficiency calculations are also carried out for each of these scenarios. Finally, the dynamic simulations are coupled with geomechanical modelling so that the mechanical integrity of faults and cap rock during storage operation can also be investigated.