Upscaling of the single-phase flow and heat transport in fractured geothermal reservoirs using nonlocal multicontinuum method

In this work, we consider a single-phase flow and heat transfer problem in fractured geothermal reservoirs. Mixed dimensional problems are considered, where the temperature and pressure equations are solved for porous matrix and fracture networks with transfer term between them. For the fine-grid approximation, a finite volume method with embedded fracture model is employed. To reduce size of the fine-grid system, an upscaled coarse-grid model is constructed using the nonlocal multicontinuum (NLMC) method. We present numerical results for two-dimensional problems with complex fracture distributions and investigate an accuracy of the proposed method. The simulations using upscaled model provide very accurate solutions with significant reduction in the dimension of problem.