Reorientation of hydraulic fractures and stress-shadow effect in double-well fracturing of hydrocarbon reservoirs: 3D numerical model and analysis

Multistage fracturing technology has been used to enhance tight hydrocarbon resource recovery. Determining the proper well spacing and fracturing strategy is crucial for generating a complex fracture network that facilitates oil and gas flow in reservoirs. The stress-shadow effect that occurs between multiple wells significantly affects the development of fracture networks in reservoirs. However, the quantification of the stress-shadow effect and its influence on fracture networks has not been satisfactorily resolved because of the difficulties in detecting and identifying fracture propagation and reorientation in reservoirs. In this study, based on the geological information from the Shengli oilfield, we applied a hybrid finite element-discrete element method to analyze engineering-scale three-dimensional fracture propagation and reorientation by altering well spacings and fracturing strategies. The results indicate that the fracturing area generated by the synchronous fracturing scheme is much smaller than those generated by the sequential and alternative schemes. An alternative hydrofracturing scheme is optimal with respect to fracturing area. The stress-blind area was defined to quantify the mechanical disturbance between adjacent wells. Our study improves the understanding of the effect of fracturing schemes on fracture networks and the impact of independent factors contributing to stress-shadow effects.