Physical simulation study on the generation mechanism of dense-cluster fracturing network under strong stress interference

Horizontal well multi-stage fracturing is an effective technique for the development of shale oil and gas reservoirs. However, as the spacing between fracture clusters decreases, the intensity of multi-fracture stress interference significantly increases. Furthermore, the coupled effects of fracturing fluid dynamics, stress interference, and reservoir mechanical properties collectively influence the propagation behavior of multiple fractures. In this study, laboratory-scale physical simulations using cement specimens were conducted to investigate the pump pressure curves and fracture morphology associated with multi-cluster hydraulic fracturing in shale formations. By integrating post-fracturing fracture morphology observations with pump pressure curve analysis, the synchronous propagation behavior of densely spaced fracture clusters was elucidated. Additionally, a multi-cluster staged fracturing experiment in a horizontal well was conducted, with sequential multi-fracture initiation tests revealing the impact of pre-existing fractures within a fractured section on the propagation dynamics of newly initiated fractures under dense-cluster conditions.