Optimal Design of Horizontal Well Cluster Spacing Based on Extended Finite Element and Numerical Simulation

As a crucial component of volumetric fracturing in unconventional oil and gas reservoirs, the design and optimization of cluster spacing significantly impact the morphology and production of fractures. Therefore, this paper establishes a multi-fracture propagation geological model based on the extended finite element method to study the scale and morphology of fracture propagation. Simultaneously, a gas reservoir model is established using CMG software, guided by production goals, and incorporating rock mechanics and physical parameters from region M to optimize cluster spacing design. The results indicate that smaller cluster spacing results in greater stress shadow effects, hindering the propagation of central fractures, and increasing the overlap of pressure drop zones, leading to possible repeated modifications during construction. Conversely, larger cluster spacing reduces stress shadow effects but may leave some areas between clusters unmodified, affecting production. Thus, through combined simulation optimization using both methods, a cluster spacing of 10-15 meters is recommended for region M, which has shown good on-site application results, significantly reducing the rate of repeated modifications.