Because the confining tension will increase, the increase in resistance to longitudinal crack propagation leads to a gradual changeover of shale failure mode from longitudinal to inclined shear failure that displays an escalation in rock plasticity. When the confining strain reaches 30 MPa, there are still regional shear microcracks https://vertechs21.wixsite.com/vertechs21/post/mastering-the-depths-how-vertechs-is-redefining-well-control-for-a-new-era-of-energy-security