Numerical Modeling of Stress Distribution and Crack Trajectory near a Fault or a Natural Fracture

摘要

The trajectory of a crack emanating from a wellbore under hydraulic pressure is studied for the case when a fault influences the wellbore. The complex variable hypersingular boundary element method is shown to provide accurate results for the problem. In modeling the propagation of the crack, its pressure is assumed to be a constant and equal to the minimum value necessary for its initial propagation (with K_I =K_(IC)); therefore, K_I > K_(IC) beyond the initial propagation step. The crack trajectories are presented for the cases of an oblique and a steeply inclined fault. The changes in the tractions and the displacement discontinuities along the fault due to the approaching crack tip are presented; and the mutual influence of a propagating crack and a fault are discussed.