Study on the influence of stress difference coefficient on hydraulic fractures in deep shale reservoir and the formation method of complex fracture network

作者：Guozhou Qiu, Xin Chang, Jing Li, Yintong Guo, Lei Wang, Wuhao Guo, Zhenhui Bi · 发表于：Geomechanics and Geophysics for Geo-Energy and Geo-Resources · 年份：2025 · DOI：10.1007/s40948-025-01049-8 · 被引用次数：4 · 研究领域：Hydraulic Fracturing and Reservoir Analysis、Groundwater flow and contamination studies、Rock Mechanics and Modeling

With the gradual shift of unconventional energy exploration to deep shale reservoirs, the difficulty in forming complex fracture networks and limited reservoir reconstruction scope under high in-situ stress have become key bottlenecks restricting efficient development. This study aimed to clarify the influence of horizontal stress difference coefficients on hydraulic fracture propagation in deep shale and explore a technical approach to construct complex fracture networks while controlling fracture direction. A multi-method integrated research framework was established: (1) True triaxial hydraulic fracturing experiments were conducted on deep shale outcrop samples under different horizontal stress difference coefficients to simulate high-stress geological conditions; (2) A rock brittleness evaluation method based on energy evolution (integrating pre-peak elastic energy ratio and post-peak energy release rate) was used to quantify the brittleness degradation law of deep shale under high confining pressure; (3) Fractal theory and energy release rate principle were combined to characterize hydraulic fracture morphology (fractal dimension) and analyze the interaction mechanism between fractures and bedding planes; (4) Hydraulic fracturing experiments with varying fracturing fluid viscosities and injection rates were designed, and multiple linear regression was applied to establish the coupling relationship between fluid parameters and fracture fractal dimension. Novel findings we...