Caprock Permeabilities Must be Considered in Assessments of Ground Surface Displacements in Geological Underground Utilization

Ground surface displacements resulting from geological underground utilization may induce serious damages to surface infrastructure. We carried out coupled hydro-mechanical simulations to compare the impact of caprock permeability on vertical displacements at a storage reservoir top and the ground surface. A 3D numerical scenario analysis was employed to assess the effects of caprock permeabilities equal to zero and varied between 10-20 m2 and 10-16 m2. Simulation results show that vertical ground surface displacements almost double with each order of magnitude increase in caprock permeability and that vertical ground surface displacements are generally higher than those observed at the reservoir top.