An advanced methodology for predicting wellbore stability in chalk

In the past few decades, due to the need of constructing complex geometry boreholes (deviated, horizontal wellbores, radial drilled laterals) that are noncolinear with the principal stress directions, the traditional approach to the problem of borehole stability has been revisited. Traditionally, the stability of a well is determined using models based on linear elasticity; however, this approach does not provide realistic evaluation of stability as with elastoplastic models. With the improved understanding of the micromechanisms of the rock microstructe failure subjected to a tangential stress around the wellbore, advanced models that incorporate softening of the strength are developed.