A coupled dual continuum and discrete fracture model for subsurface heat recovery with thermoporoelastic effects

We consider heat recovery from geothermal fractured resources with thermoporoelastic effects. To this end, a hierarchical fracture representation is considered, where small-scale highly connected fractures are represented by the classical dual porosity model whereas large scale dense fractures are represented by the discrete fracture model. The mathematical model is described by a system of equations for mass and heat transfer for coupled dual continuum model as well as discrete fractures. Geomechanical deformations are written in the general form. For numerical solution of the resultant coupled system of equations including multicontinuum temperatures, pressures and deformations, we use the finite-element method. Numerical results are presented for two- and three-dimensional examples, showing applicability of the proposed method.