As being the confining stress improves, the increase in resistance to longitudinal crack propagation ends in a gradual transition of shale failure method from longitudinal to inclined shear failure that demonstrates an escalation in rock plasticity. When the confining strain reaches thirty MPa, there are still area shear microcracks https://wellcontrolprocedures44219.wikitron.com/2435777/top_guidelines_of_rock_mechanics_in_wellbore_stability