Symmetry allowed use of one-quadrant of the normal plane. The casing and cement were modeled with quadrilateral elements. Grid size was refined later to examine element-size effects. 1 shows the refined grid. Material properties for the cement were determined by triaxial-experimental results.
FEM results agree with radial and circumferential stresses published in the literature.
Two types of loading were considered. One was a 10,000-psi pressure increase and the second was a 3600F temperature increase. Both were applied instantaneously at the inner casing wall. The vertical stress in the z direction at 15,427 ft is 15,427 psi. Horizontal stresses in the x and y directions were assumed to be 3,900 psi and 1,950 psi, respectively, to reflect the far-field stress conditions in the rock.