Comparison of solute/heat transport in fractured formations using discrete fracture and equivalent porous media modeling at the reservoir scale

Abstract

In deep reservoirs, the formations consist of naturally or artificially fractured rocks. The fluid flow coupled with heat transfer through fractures is commonly modeled by discrete fracture approach. In this study, fluid flow and solute/heat transport phenomena were investigated using the equivalent porous media approach and compared to discrete fracture modeling. In the equivalent porous media approach, the fractures were replaced with a porous medium. Its effective porosity and permeability were adjusted to get the simulation results similar to discrete fracture modeling results. In addition, the solid deformation, in equivalent porous media approach, was coupled with heat transfer, while it was de-coupled with fluid flow to increase the simulations’ efficiency. The equivalent porous media approach was applied to two benchmark problems; geothermal doublet, and thermohaline aquifer-aquitard-aquifer model. The comparisons between the equivalent porous media and discrete fracture modeling approaches were in a good agreement and implied the feasibility and efficiency of the equivalent porous media relative to the fully coupled discrete fracture modeling approach.