A novel hydraulic fracturing model based on a nonlocal continuum theory of peridynamics is developed to simulate propagation of multiple non-planar fractures in an arbitrary heterogeneous medium. In this model, poroelastic behavior outside the fracture is also taken into account by coupling a peridynamics porous flow formulation with the peridynamics mechanics model. The fluid flow in the fractured region is modeled by an additional porous flow equation with material permeability dependent on fracture width defined in terms of local dilatation.

(Application/Development) The model is applied to investigate the propagation of a hydraulic fracture (HF) in a naturally fractured rock. We investigate the role of poroelasticity, mechanical properties of the rock, the natural fracture and the fluid properties on the interaction between the HF and the natural fracture. It is shown that this fully coupled geomechanics and porous flow peridynamics model can be applied to understand the complex geometry and network of non-planar, multi-stranded and competing fractures.

(Results/Conclusions) The poroelastic peridynamics model is validated by simulating the classical one dimensional consolidation of fluid saturated rock. The model results are compared with published experimental results. Simulated results show excellent agreement with experimental results, where the interaction between HF and natural fracture are controlled by the principal stress contrast and the approach angle. We then apply the model to outcrops and demonstrate the applicability of the approach to the generation of fracture networks on a field scale.

(Significance of Subject) Several hydraulic fracturing models have been developed with varying degree of complexity, however, the models based on classical theory and linear elastic fracture mechanics remain limited in their ability to simulate the formation of non-planar, complex fracture networks. The peridynamics model presented here overcomes most of the limitations of existing models and provides a novel approach to simulate and understand the interaction between hydraulic fractures and natural fractures.