Large-Scale Numerical Simulation of Fracture-Fluid-Rock Interactions Controlled by the Strike Slip Fault System in...

This study investigates the interactions among fractures, hydrothermal fluids, and formation rocks in six Cambrian-Ordovician strata of the Shunbei area, Tarim Basin, based on actual geological settings and numerical simulation methods. By construction of a large-scale 3D geological model and simulation of the dynamic processes of hydrothermal migration and reactions along fractures, the following key findings are revealed: (1) fluid-rock reaction mechanisms: hydrothermal fluids migrate upward along high-permeability fractures, leading to the dissolution of minerals such as calcite and kaolinite and the precipitation of quartz. Acidic fluids, obstructed by caprocks at fracture tops, form reflux zones that concentrate H⁺ and enhance the localized dissolution. (2) Mineral distribution patterns: calcite dissolution dominates within fracture zones, while calcite precipitation occurs along fracture margins due to Ca²⁺ saturation. Geothermal gradients further regulate the spatial differentiation of the mineral reactions. (3) Fracture-controlled reservoir effects: branching fractures divert flow, reducing the velocity in main fractures and prolonging the reaction time. Nonpenetrating fractures induce lateral fluid seepage, creating zones of superimposed dissolution and precipitation. This study provides a theoretical foundation for predicting high-quality carbonate reservoirs in deep formations, highlighting how fracture architecture and thermobaric conditions jointly control the reservoir storage space evolution. The findings offer significant guidance for the hydrocarbon exploration.