Permeability enhancement of HDR reservoirs by hydraulic fracturing

Abstract : 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-Forêts are simulated.