The simulations are performed using the reservoir simulator TOUGH2 and investigate one-eighth of a five-spot TDF, similar to . The input file and mesh (included in the Supplemental Information) are based on an example in the TOUGH2 manual and were intentionally changed as little as possible. The mesh contains 37 elements, consistent with the TOUGH2 manual example and previous studies . We apply fixed mass flow rate boundary conditions at the injection and production cells. We maintain the pressure at the corner node as the hydrostatic reservoir pressure by supplying constant pressure fluid as needed. Due to symmetry, there is no flux of heat or fluid across the vertical boundaries. There is also no fluid flux through the top or bottom boundaries because the overlying and underlying rock are assumed to be impermeable. Heat is conducted into the reservoir from the top and bottom boundaries according to a built-in TOUGH2 analytical functionality, which assumes Cartesian, one-dimensional heat conduction coming from the background geothermal temperature (𝑇 𝑒 ), which acts as a local thermal source term to the numerical solution on the grid. The working fluid is water.