The Impact of Constitutive Laws on Wellbore Stability: A General Review

Abstract

Summary This paper is focused on soft deep rocks that can induce strong well-bore-stability problems. In the first part, it is shown that these rocks generally exhibit plastic-type behaviors. In the second part two elasto-plastic models (Cam-Clay and Laderock) are briefly presented. In the third part, these constitutive laws are applied to wellbore stability through analytical solutions or finite element codes. Finally, in the fourth part, a case history is discussed in detail. We insist on the difficulty to properly define the boundary conditions of the problem (in-situ stresses and virgin pore pressure) and on the subjectivity of the criterion translating the boundary wellbore problem in stability recommendations. Some keys for future research are proposed.