Wellbore Stress Distribution Produced by Moisture Adsorption

Summary For this study, we evaluated the stress distribution produced by moisture adsorption around a wellbore by applying the mechanics of deformable solids. This paper shows that the moisture-adsorption process is governed by a diffusion equation and that the equations governing the moisture-induced stresses around the hole are similar to those equations used in thermoelasticity. A computational method is developed for calculating the stress distribution around the borehole, and the experimental procedure for obtaining the material constants needed in the computation is presented. This paper also studies the effect of borehole pressure on the stress distribution around the hole. Results show that the magnitude and distribution of stresses around the borehole are very sensitive to the adsorption characteristics and the moisture-induced modulus change of the material.