On the mechanical stability of inclined wellbores

Abstract

Knowledge of the in-situ stress field can be used in the planning of stable inclined wells. By adopting optimum wellbore drilling direction with respect to the azimuth of the major horizontal principal stress and deviation angle from the vertical, in which the shear stress anisotropy around the wellbore wall is minimized, it is shown that such well alignments are more stable mechanically than vertical wells in various tectonic stress environments, using a new model for compressive rock failure and the assumption that the rock properties can be described as linearly elastic and isotropic.