Figure 5: Three-dimensional thermohydraulic model consisting of 35 slices with 17,768 triangles for each slice and 1,720,774 tetrahedral elements. The 35 slices are visible along the left model boundary. Model elevation ranges from 670 to −4500 m a.s.l. (see color bar), while the 2D mesh is exploded below the model. Three-dimensional structure of the reservoir producing units (i.e., Scaglia complex, Tuscan nappe complex, and Umbria nappe complex), confined in the area of the buried structural high, is shown in the central portion of the modeled domain (color scale according to Figure 4). Applied pressure and temperature boundary conditions, at the top and the bottom of the model (i.e., Dirichlet type and Neumann type), as well as the initial condition of the pressure and temperature earth gradients, are shown. A no-flow boundary condition is set to the lateral boundaries of the model. The tested configuration of the production and injection sites (separated horizontally by a distance of ca. 2 km) is highlighted by the refinement in the two-dimensional mesh.