Mechanism of hydraulic fracture propagation and deflection in the vicinity of normal fault.

This article focuses on the influence of normal fault characteristics on hydraulic fracture (HF) propagation in reservoirs, using a stress-seepage-damage numerical model validated by laboratory experiments and field microseismic data. Four key fault parameters—elastic modulus ratio (KE), fault dip angle (FD), fault thickness (FT), and vertical distance from the wellbore to fault (VD)—were systematically analyzed to understand their effects on fracture morphology, deflection, and stimulated reservoir area (SRA). Results indicate that when VD is less than 25 m, faults significantly disturb fracture propagation, causing deflection and secondary fractures, while beyond 40 m, fractures align with the maximum principal stress direction. Lower KE (<0.3) and smaller FD promote fracture deflection and complexity, whereas increased FT reduces fault reactivation risk and fracture deflection; secondary fractures induced by faults can enhance reservoir stimulation despite limiting main fracture growth. The study emphasizes optimizing fracturing designs by considering these fault parameters to improve production efficiency and reduce geological risks, noting that findings are most applicable to reservoirs with similar normal fault conditions.