Analysis of stress-induced wellbore breakouts in an arbitrarily oriented tectonic stress field

A detailed study is presented of a case of stress induced wellbore breakouts observed where none of the principal axes of the tectonic stresses coincides with a wellbore axis. The observed depth and azimuth of breakout occurrence were compared with theoretical predictions based on the elastic stress field induced around a wellbore in a generalized 3-D stress field. The stress field had previously been studied using 3-D hydrofrac stress measurement. Results show that, when the uniaxial compressive strength of the rock is known, the depth and azimuth of breakout occurrence can be used as a reliable method to confirm the tectonic stress magnitudes determined by hydraulic fracturing.