Some geomechanical properties of montney shale

Abstract

Some geomechanical properties of the Montney shale were investigated experimentally in this study. From the Brazilian and point load strength tests, the tensile strength in the horizontal direction was dominated by the bond strength of the intact structure (6 -15.3 MPa), whereas that in the vertical direction was controlled by the existing natural beddings (0.7-2.8 MPa). Compressive strength, compressive elastic modulus in the vertical direction and the Poisson' s ratio were measured from the unconfined compressive strength test as 99 MPa, 25 GPa, and 0.1, respectively. Tensile and compressive elastic moduli in the horizontal direction were measured from Brazilian test as 31 GPa and 40 GPa, respectively. From the shear test results, the cohesion was found as 2 MP a and the peak friction angle was about 40°. From this study it was found that the pre-existing planes of weakness play a major role in failure and anisotropic behavior of the Montney shale.