Effects of mechanical properties of the underburden on induced seismicity along a basement fault during hydrogen storage in a depleted reservoir.

This study models the geomechanical deformation of a depleted gas field, wherein gaseous hydrogen is stored in a North Sea reservoir, and is cyclically injected and withdrawn. A fault is modeled within the underburden, and its slip is investigated during a three year storage period. Parametric simulations are conducted to study the influence of the underburden mechanical properties, such as Young's modulus, Poisson's ratio, and permeability on induced seismicity. The fault is predominantly in stick during the bulk of the injection, storage, and withdrawal periods, but minor fault slip ( 4 mm) occurs shortly after a change in operational regime. The Young's modulus of the underburden unit has the strongest control on fault slip. To reduce the seismic hazard, an underburden with low Young's modulus ( 15 GPa), high Poisson's ratio ( 0.25), low Biot coefficient, and low permeability ( m) is found to be most suitable for hydrogen storage.