Measuring the Anisotropic Dynamic and Static Moduli of the Duvernay Shale

We measure the anisotropic static and dynamic moduli of a calcareous shale from the Duvernay unconventional hydrocarbon reservoir. The full set of the five stiffness, following the assumed Transverse Isotropy for earth materials, needed to describe the complete elastic behaviour of the test sample are obtained by measuring the acoustic wave velocities on a sample cut into the shape of prism allowing Piezoelectric wafers to be attached to its surface and receive/emit waves in different angles. Measurements are taken at different confining pressures up to 180 MPa. Static loading tests are performed on the cylindrical plugs cored at different angles using the Hoek Cell. We observed that Young's modulus at the direction parallel to the direction of symmetry axis (E3) is highly pressure-dependent for both dynamic (20 – 30 GPa) and static (12 – 37 GPa) measurements. Lesser pressure dependence is observed for the dynamic (34–36 GPa) and static (~26 GPa) E1,2 . Static and dynamic Poisson's ratios demonstrate pressure dependence too. Generally speaking, the static moduli are more prone to pressure change compared with their dynamic counterparts.