| Abstract |
Natural fractures typically exhibit inherent preferential flow paths due to aperture heterogeneity, resulting in fracture flow channeling behavior that concentrates fluid migration within narrow zones. During long-term hydrothermal circulation in enhanced geothermal systems (EGS), both rock contraction induced by cold water injection and the mineral dissolution/precipitation triggered by water–rock interactions modify fracture aperture spatially and temporally, thereby reshaping the flow pattern within the fracture. In this work, we develop a single-fracture EGS model that fully couples thermo-hydro-mechanical-chemical (THMC) processes and incorporates a spatially heterogeneous fracture aperture distribution. We use this model to study how the thermoelastic process and mineral reaction influence flow channeling within the fracture and impact the long-term thermal performance of EGS. Results show that the thermoelastic process induced by cold water injection intensifies flow channeling within the fracture, leading to a rapid decline in production temperature. In contrast, mineral dissolution resulting from undersaturated injection conditions mitigates thermoelastic-induced flow channeling by increasing the fracture aperture in regions away from preferential flow paths. However, mineral precipitation resulting from supersaturated conditions exacerbates flow channeling and further accelerates the decline in production temperature. |