Permeability enhancement of HDR reservoirs by hydraulic fracturing

The permeability of geothermal reservoirs needs to be enhanced. Hydraulic Fracturing (HF) is the standard tool used for that purpose. Here HF is introduced in a thermo-poroelastic framework. The main ingredient of the HF scheme is a fracturing model that governs the evolution of the size and width of the fractures. At any geometrical point, a fracture-induced anisotropic permeability tensor is calculated: next to the injection pressure, the directional properties of this tensor are strongly influenced by the geological stresses. This fracturing model is integrated into a domestic Fortran 90 finite element code. Circulation tests and thermal recovery from the enhanced geothermal reservoir of Soultz-Sous-Forets are simulated.