Technical Paper

Linking Preferred Orientation of Shale Minerals to their Elasticity

Written by: Venkatesh Anantharamu and Lev Vernik

The elastic velocity and anisotropy of shales are significantly affected by the orientation distribution of clay minerals including mica. A lot of research has been done on elastic properties of clay and clay aggregates with varying degree of the platelet preferred orientation. However, our understanding regarding the properties are still limited. In this study, we use both experimental and empirical rock physics models (RPM) for conventional shale to constrain elastic properties of muscovite and illite. The orientation distribution data from the published literature is used to relate the maximum platelet pole density to the median orientation angle . We then propose a heuristic approach to model anisotropic elastic moduli and P- and S-wave velocities of zero-porosity clay (matrix) aggregates as a function of the median orientation angle.