Experimental Research On Mechanical Property Of Shale In Lower Silurian Longmaxi Southeast Chongqing

We tested for porosity and permeability of shale in Lower Silurian Longmaxi southeast Chongqing. The samples tested in our studies are with different angles between core drilling and the direction of bedding plane. And the compressive strength, tensile strength and hardness are tested in the experiment. The results indicate that the mechanical properties show significant difference when the angle between core drilling direction and layers changes. Under uniaxial loading, the uniaxial compressive strength of shale increases with the increase of the bedding angle linearly. The failure surface extending direction is consistent with the bedding angle, when the angle between bedding direction and the axis of core is less than 45 degrees. While the angle ranges from 60 degrees to 90 degrees, the major failure surface direction is inconsistent with the bedding angle, though a part of the cracks may go with the bedding angle. The tensile strength of our samples is between 2.8720Mpa and 10.4900Mpa, and the indentation hardness ranges from 556.62MPa to 1842.98Mpa, which is widely dispersed. The mechanical properties of shale are clearly anisotropic, and our study provides a reference for wellbore stability design in shale.