Optimization of geothermal energy production from fracture-controlled reservoirs via 3D numerical modeling and simulation

We develop a computation framework from scratch that allows us to conduct 3D numerical simulations of groundwater flow and heat transport in hot fractured reservoirs to find optimal placements of injection and production wells that sustainably optimize geothermal energy production. We model the reservoirs as geologically consistent randomly generated discrete fracture networks (DFN) in which the fractures are 2D manifolds with polygonal boundary embedded in a 3D porous medium. The wells are modeled as line sources and sinks.The flow and heat transport in the DFN-matrix system are modeled by solving the balance equations for mass, momentum, and energy.The fully developed computational framework combines the finite element method with semi-implicit time-stepping and algebraic flux correction.To perform the optimization, we use various gradient-free algorithms. We present our latest results for several geologically and physically realistic scenarios.