Fracture propagation characteristics in shale bedding planes within structurally complex zones

To address the unclear mechanisms of hydraulic fracture propagation in shale reservoirs with well-developed bedding and complex thin interbedded layers, this study first employed three-point bending tests combined with Digital Image Correlation technology to reveal the fundamental laws of fracture propagation. Building on this, a numerical model for vertical fracture propagation was established, taking into account bedding planes with different orientations. The model utilizes globally embedded cohesive zone elements to simulate the initiation and propagation of hydraulic fractures in the vertical direction. Simulations were conducted to investigate fracture vertical propagation behavior under bedding-developed conditions, and a systematic analysis was performed on the controlling effects of key geological parameters on fracture morphology. The results clarify the influence mechanisms of reservoir and interlayer physical properties on fracture pathways, providing direct guidance for the design and optimization of hydraulic fracturing in similar strongly heterogeneous shale reservoirs.