Measurements Of Shear-Wave Azimuthal Anisotropy With Cross-Dipole Logs

Abstract

Three methods for analyzing azimuthal anisotropy from cross-dipole logs are applied to data from the Powder River Basin in Wyoming. These techniques are based on the phenomena of flexural wave splitting in anisotropic materials and are analogous to the techniques used for VSP data processing. The four-component cross-dipole logging data obtained with a Schumberger tool from a vertically-fractured section of 56 m at a depth of 3550 m are processed with three different techniques. The results demonstrate that the non-orthogonal rotation method works best for the data. The results from the linear transform and polar energy spectrum methods are acceptable. The linear transform processing takes much less computing time, while the polar energy spectrum method is computationally-intensive.