Modelled CO2 injection and pressure propagation, Danish site

When injecting CO₂ in to the subsoil for permanent storage the overpressure development in the surroundings of the storage site must be addressed. The overpressure may affect nearby potential subsoil operations as well as the geomechanical properties of both faults and caprock. The operator of a storage site must be able to demonstrate to the relevant authorities how the overpressure propagates in space and time and clarify if mitigation procedures should be established.

Reservoir simulation procedures can be used to predict the overpressure development and, combined with geomechanical modelling, the impact on caprock integrity and fault stability can be assessed. The deliverable D4.2 documents how the overpressure develops during a potential CO₂ injection operation into the Vedsted structure, a prospective storage site onshore Denmark.

A procedure to secure proper boundary conditions for reservoir simulations is presented. It is argued that regional geological modelling is essential.

Results from geomechanical modelling show the importance of incorporating the faults and assigning the right properties for the faults. Further, the reduced stress field in the reservoir due to the increased pore pressure during injection might cause surface uplift in the order of 10 cm.