oa Distinct Element Method for Solid-fluid Coupled Interaction in the Application of Hydraulic Fracturing

The interaction between hydraulically created and natural fracture is of great interest because natural fracture have the significant influence on the effectiveness of the hydraulic fracture. The viscosity of the fluid used in hydraulic fracturing also influences on the geometry of hydraulic fractures. We performed a series of simulations for hydraulic fracturing in naturally fractured rock by using the 2D flow-coupled Discrete Element Method (DEM) code to examine the influence of the fluid viscosity on the interaction between hydraulic and natural fractures. In this study, low and high viscous fluids are used respectively, and the fracture intersects with a single pre-existing fracture with three different strike angles. The results show that the pre-existing fracture influences significantly the propagation direction of hydraulic fractures and the hydraulic fracture does not always propagate in the direction of maximum principle stress. In addition, we concluded that the influence of pre-existing fracture on the propagation of hydraulic fractures could be reduced by the use of high viscous fluid.