The artificial fractures in EGS are created within the context of natural factors such as geology, geomechanics, and geochemistry, as well as engineering techniques used during stimulation, such as the use of proppant and acids. Fracture characterization, i.e., gathering information regarding fractures’ physical properties, such as aperture, hydraulic conductivity, and network distribution patterns, provides the source of information for modeling and engineering the subsurface reservoir appropriately. At the near-wellbore scale, the fracture planes around the well are examined to provide an understanding of the feed zone behavior. At the EGS Collab site, it was observed that during a downhole camera survey of a flowing wellbore the inflow pattern from the producing fractures was not sheet-like but rather composed of sporadic point sources. This observation can be explained by considering that fracture surfaces are rough; preferential fluid flow pathways emerged across a fracture plane due to its roughness. To simulate the fluid flow behavior between the crevices of rough fracture, a displacement discontinuity model (DDM) was used to represent rough fracture faces under varying stress regimes. Then, the geometry of the fracture space was built into a three-dimensional model to simulate the fluid flow and heat transfer across the fracture planes using a Computational Fluid Dynamics (CFD) simulator. The rough fracture modeling in this study could successfully model the fluid flow for a roughness distribution corresponding to a shear stress and normal stress combination of -6MPa and 6MPa, respectively. As the stress regimes heavily influence the aperture distribution, subsequent scenarios were modeled across parametric simulation involving a range of shear and normal stress and compared with the reference. Radial flow behavior for each stress regime was simulated to investigate the roughness relationship with varying stress regimes.

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