Modeling of Fluid-Driven Fractures Using XFEM

The eXtended Finite Elements Method (XFEM) refers to a simulation technique where a fracture is modeled via splitting of special enriched finite elements during the course of a simulation. XFEM, unlike Cohesive Zone Method (CZM), allows simulating nucleation and growth of a fracture along an arbitrary, solution-dependent path without re-meshing the material in the bulk. In this work, we have used 2D XFEM coupled with pore-pressure degrees of freedom to simulate a variety of boundary value problems related to fluid-driven (hydraulic) fractures in a permeable medium. Specifically, through these simulations, we investigate the influence of critical geomechanical and operational parameters on hydraulic fracturing, including (a) creation of fracture-tortuosity due to a misalignment between initial perforation and maximum u stress direction, (b) impact of u stress anisotropy on the near-wellbore fracture geometry, (c) deflection of fracture path due to a spatial pore-pressure gradient, (d) refracturing of an already existing hydraulic fracture, and (e) merging of a hydraulic fracture with a pre-existing natural fracture in the formation. For each of these cases, the predicted fracture geometry is compared with the respective experimental result available in the literature. The simulated and the measured fracture geometries are found to be in good agreement.