Multi‐factor coupling effects in hydraulic fracturing of laminated shale: Experimental insights and physics‐informed neural network‐driven optimization

Against the backdrop of deep shale gas development, the unclear multi‐factor coupling mechanisms in laminated shale fracturing limit exploitation efficiency. To reveal the influencing mechanism of the comprehensive effects of differential stress, the bedding dip angle, and the injection rate on fracture network formation, this study conducted a series of hydraulic fracturing experiments using shale cores with a diameter of 25 mm and a length of 50 mm. Through macro‐mechanical response testing and computed tomography scanning‐based micro‐characterization, the overall damage characteristics and internal micro‐damage specificity of the rock mass after fracturing were systematically analyzed. Combined with an orthogonal test design, a physics‐informed neural network (PINN) surrogate model, and Sobol global sensitivity analysis, a multi‐factor coupling framework was established to quantify the factor importance and interaction effects on fracturing performance within the experimental domain, providing qualitative implications for field‐scale hydraulic fracturing in laminated shale. The results indicate that when the axial pressure is adjusted, the fracturing response of specimens with bedding dip angles of 30° shows a more significant improvement. After the initiation of fractures in laminated specimens, the fractures undergo angular deviation in the vertical direction due to the bedding effect, propagate along the bedding planes, and gradually extend toward the direction of the maximum principal stress. The trained PINN prediction model shows excellent robustness and generalization ability, and further identifies the differential stress, the bedding dip angle, and the injection rate as the key factors governing shale breakdown pressure, with their first‐order Sobol sensitivity indices quantified as 0.87, 0.74, and 0.48, respectively. Finally, a targeted parameter optimization strategy is proposed, providing important references for onsite hydraulic fracturing construction.