Elastic-plastic solutions for analyzing wellbore stability

Abstract

Selecting a good practical prediction method of wellbore instability has extensively become an important issue in order to overcome the resulting instability problems during drilling. Therefore, the aim of this paper is to simulate the actual stresses around wellbore using elastoplastic rock behavior in order to describe the actual cases of wellbore instability problems. Description of stress state around wellbore is presented. Common failure criteria are also presented. Selection of the most applicable equations for description of stress state using elastoplastic rock behavior. Experimental data are used to calculate the cylindrical stresses surrounding the drilling hole wall at various diameters. Furthermore, a sensitivity analysis is done to test changing the radial stress with overbalance support and wellbore radius.