A Study of Numerical Simulations of Mixed-mode Fracture Propagation in Rock

Fracture propagation, especially for fractures emanating from inclined wellbores and closed natural fracture often involves Mode I, Mode II and at times Mode III fracture pattern. When an embedded inclined 3D fracture is subjected to compression, the fracture tips are restrained by the surrounding materials so that it does not propagates as predicted by 2D fracture models. In this paper, threedimensional mixed-mode fracture growth from an initially embedded circular crack is studied using two numerical approaches. The virtual multidimensional internal bond (VMIB) and damage mechanics have been implemented within a finite element method along with an element partition algorithm (EPM) to simulate 3D crack growth. The VMIB approach has been utilized to simulate multiple cracks. The damage approach has shown to be effective when considering rock heterogeneity and thermal stresses and thus is also considered in this work.