Dynamic flow partitioning during competitive fracture propagation in multiscale heterogeneous shale

ABSTRACT Inter-cluster flow competition remains a fundamental challenge in multi-cluster hydraulic fracturing of layered shale reservoirs. This behavior is governed by multiscale heterogeneity and near-wellbore hydraulic resistance. A multi-scale numerical framework is developed to resolve dynamic cluster-wise flow partitioning under closely spaced perforation conditions. The formulation couples heterogeneous mechanical properties with stress interference and hydraulic resistance evolution. The results indicate that asymmetric near-wellbore initiation and sustained flow imbalance are the primary mechanisms driving uneven fracture propagation. Strongly heterogeneous formations exhibit 15 to 30 percent greater inter-cluster flow uniformity than weakly heterogeneous cases. Perforation parameters regulate flow allocation, with influence ranked as perforation diameter, perforation density, and cluster number. Limited-entry behavior occurs for perforation diameters no greater than 0.005 m or densities of at least 8 holes per cluster. Five to seven clusters per stage improve flow uniformity under closely spaced conditions. These findings clarify the role of dynamic flow partitioning in competitive fracture growth and provide a quantitative basis for evaluating perforation parameters in heterogeneous shale.