Research on the Competition Mechanism of Fractures in Multi-Cluster Fracturing of Horizontal Wells: Dynamic Response and Influence of Engineering Parameters

In multi-cluster horizontal well fracturing, non-uniform propagation due to inter-cluster interference severely limits the effectiveness of reservoir stimulation. This study employs the discrete lattice method for numerical simulation, investigating the influence of cluster spacing, fracturing fluid injection rate, and horizontal stress difference on fracture propagation morphology by monitoring, in real time, the dynamic changes in flow pressure, flow rate, and fluid intake volume for each cluster. The results indicate that the stress shadow effect is the fundamental cause of non-uniform fracture propagation. Cluster spacing is a key parameter controlling the maximum flow pressure difference between the central and edge clusters. When cluster spacing decreases from 4 to 2 m, the maximum flow pressure difference increases by 7.32 MPa, while the fluid intake volume decreases by nearly three times. Increasing the injection rate of the fracturing fluid raises the maximum fracture width from 7.35 to 15.1 mm and reduces the maximum inter-cluster flow pressure difference from 4.48 to 0.53 MPa. A reduction in the horizontal stress difference mitigates the stress shadow effect. When the horizontal stress difference decreases from 5 to 1 MPa, the maximum fracture width increases by 3.97 mm. This study elucidates the influence of various parameters on hydraulic fracturing effectiveness, providing theoretical guidance for optimizing fracturing parameters in fracture-propagation design.