Triaxial Deformation of the Goldwyer Gas Shale at In Situ Stress Conditions—Part I: Anisotropy of Elastic and Mechanical Properties

Abstract The evolution of shale’s mechanical properties with confining pressure, temperature, and mineral composition directly influences fracture closure besides the effect in situ stress variation across lithologies. We are first to perform experimental study characterize Goldwyer gas shale formation located Canning Basin, Western Australia. have performed constant strain rate multistage triaxial tests at condition (confining pressure ≤ 22 MPa) on 15 samples shales variable minerology, organic content, heterogeneity. Deformation were conducted room temperature drained conditions cylindrical cored parallel (horizontal) perpendicular (vertical) bedding plane. Both compressive strength ( σ TCS ) static young’s modulus E show a strong sensitivity mineralogy, while only shows directional dependency, i.e., h > v . internal friction coefficient µ i plane is 0.72 ± 0.12, it 0.58 0.17 orthogonal direction. significantly lower when larger fractions weak constituents present (clays or matter). observe that Young’s most vertical best approximated by Reuss’s bound, whereas horizontal Hill’s average Voigt Reuss bounds. prospective G-III unit (depth 1510 m) semi-brittle brittle, making suitable for future development.