Development of 3-D Curved Fracture Swarms in Shale Rock Driven by Rapid Fluid Pressure Buildup: Insights From Numerical Modeling

Despite the variety of studies that have investigated the development of fracture networks during kerogen maturation in organic-rich shale, the fracture interaction modes and generation mechanisms in three-dimensions are not yet fully understood. In this study, we introduce a novel numerical approach to model the evolution of fracture swarms with three-dimensional nonplanar geometries. This model enables precise simulation of the propagation, interplay, and coalescence of the fracture swarms with variable apertures and geometries via solving fluid flow, fracture growth, and stress interference. Our results suggest five basic fracture interaction modes between neighboring fractures. The evolving fracture swarms exhibit simultaneous, alternant, and differential growth characteristics at different development phases. We also elucidate the mechanical mechanisms that determine the evolution of three-dimensional curved fracture swarms. This work yields an improved understanding of fluid-driven fracture swarms' development in organic-rich shale due to rapid fluid generation.