DEM Modeling of Simultaneous Propagation of Multiple Hydraulic Fractures Across Different Regimes, from Toughness- to Viscosity-Dominated

To improve the effectiveness of fracturing treatment, it is vital to understand how multiple fractures interact with each other. This study presents a fully coupled hydraulic fracture model that considers both Newtonian fluids and power-law fluids to investigate the effect of stress shadowing in different propagation regimes, from toughness- to viscosity-dominated, under limited entry conditions. The dimensionless parametric space for a plane-strain fracture driven by power-law fluids is outlined, and numerical analysis is performed in the parametric space to simplify the problem. Moreover, the numerical scheme for the coupled hydromechanical problem is verified by comparing the results to the existing analytic solutions. It is shown that the simultaneous propagation of multiple fractures is significantly influenced by the fracture propagation regime and cluster spacing. Fractures tend to grow uniformly in the viscosity-dominated regime, and the fracture reorientation can be observed if both the cluster spacing and stress anisotropy are small. In contrast, fractures propagating in the toughness-dominated regime tend to propagate in the opposite direction of the adjacent fractures to avoid each other, resulting in minimal overlap between fracture lengths. The influence of fracture propagation regime is consistent for Newtonian and power-law fluids. Additionally, as the cluster spacing increases, the effect of stress shadow decreases, and the behavior of each individual fracture resembles that of an isolated fracture.