Application of a geomechanical model to wellbore stability analysis: A case study X-well, bach ho field in Vietnam

Abstract

Selection of proper failure criterion is one of the most important task in analyzing wellbore stability analysis. While the Mohr-Coulomb criterion is still commonly used, its prediction of the safe mud weight supporting the wellbore wall is usually too high because this zone is predicted to yield without any shear failure around the borehole. The main purpose of the paper is to discuss pros and cons of some existing criteria such as Mohr-Coulomb, Hoek-Brown and modified Lade failure criterion. Then the allowable drilling mud pressures calculated by using these methods are compared with each other and with the field data. Two wellbores in two Bach Ho oilfields are considered as case studies in order to identify the criterion that is able to provide the closest agreement with the field data.