Mechanical anisotropy in the Woodford Shale, Permian Basin: Origin, magnitude, and scale

Abstract

The rock mechanical properties of shales are critical to how they perform as reservoirs, determining both their tendency to develop natural fractures and their response to hydraulic stimulation. These mechanical properties are, in turn, manifestations of composition, fabric and porosity, and fluid saturations. Such properties also dictate the seismic response of shales, as well as their signature on many well logs. It has long been recognized, or perhaps assumed, that shales are relatively homogeneous in the plane parallel to bedding and relatively heterogeneous in the direction perpendicular to bedding.