Effect of Eccentricity on Breakout Propagation around Noncircular Boreholes

Investigating the shear failure caused by concentration of compressive stress around noncircular boreholes is important both in field and laboratory. This article deals with numerical analysis elliptical under a nonisotropic situ using Mogi–Coulomb nonlinear criterion. The purpose presented model to simulate progressive (breakout) borehole investigate impact eccentricity on stability depth width area. According obtained results, breakout V-shaped formed along minimum principal stress. As increases, final dimension becomes smaller; other words, increase ellipticity strengthens against failure. However, as at tip increases. Another finding study conducted this significant relationship between failure, which makes idea estimating horizontal stresses dimensions seriously doubtful. Also, interesting result that factor for different eccentricities same end breakout.