A PLANE MODEL FOR THE STRESS FIELD AROUND AN INCLINED,CASED AND CEMENTED WELLBORE

In-plane and out-of-plane analyses for the stress field around an internally pressurized, cased, cemented and remotely loaded circular hole have been developed in this report. Taking into account the well-known solution for a pressurized circular hole in an infinite medium, we have effected appropriate complex potentials for the steel ring and the cement annulus, such that continuity of stresses and displacements is maintained along the steel/cement and cement/rock interfaces and prescribed pressure is imposed along the open hole. Results indicate that the plane of the maximum tangential stress may rotate 90°, between the steel/cement and the cement/rock interfaces. A quantitative justification for the occurrence of such a rotation is presented, by considering the hole, the steel and the cement layers as a single ‘equivalent’ inclusion, bonded on the rock matrix.