... variations in tangential stress that typically develop around the circumference of a bore hole. During primary depletion and possible subsequent repressurization, in-situ reservoir stresses will change, and these new stresses affect critical conditions at the borehole wall. The vertical, overburden stress...

..., failure may not occur because the strengthening effect of 2 (or SHmax), the stress along the borehole axis, would allow increasing the tangential stresses to 11,000 psi to 12,000 psi and still remain elastic (for the same Pp). This is illustrated in Figure 6 where the two failure criteria are compared...

... not much with maximum tangential stress on a wellbore4,5,6. For the three- dimensional problem, the structure is treated as a transversely isotropic media in which permeability, strength, and elasticity are isotropic in a plane and different in the direction normal to the plane. However, the rock mass...