Numerical Simulation Study on the Through-Layer Propagation Law of Hydraulic Fracturing in Highly Deviated Wells in...

To clarify the through-layer propagation law of hydraulic fracturing in highly deviated wells in offshore multilayer gently dipping formations, this paper establishes a fluid-solid coupling numerical model for hydraulic fracturing in highly deviated wells based on the 3D lattice method. Combined with theoretical method and field microseismic monitoring data, the validity of the model for multilayer stacked gently dipping formations at the field scale is verified. On this basis, single-factor sensitivity analysis is performed to evaluate the effects of formation and treatment parameters on fracture through-layer propagation, and the gray relational analysis method integrated with entropy weighting is introduced to quantify the influence weights of the individual factors. The results show that under high injection rate (≥12 m³/min) and high viscosity (50 mPa·s) conditions, the net pressure within the fracture dominates, which weakens the sensitivity of traditional geological barriers such as interlayer stress difference and barrier thickness. Based on the quantitative evaluation results of parameter sensitivity for fracture through-layer propagation, the criteria were established for hydraulic fracture through-layer propagation, using the efficiency of stimulated reservoir area within the perforated reservoir as the indicator. The study reveals the propagation law and mechanisms of through-layer fracturing in highly deviated wells under high-intensity injection conditions, but the obtained thresholds are dependent on the model and working conditions.