Dispersion of guided waves in thin anisotropic waveguides

Abstract

SUMMARY This paper shows that: if appropriate source mechanisms and frequency bands can be selected, thin layers in sedimentary reservoirs may act as seismic waveguides, and guided waves may be useful for reservoir characterization in cross-hole surveys; and that the dispersion of such guided waves is sensitive to crack saturations and crack orientations, and could contain important information about the level of saturation in specific thin layers in enhanced oil recovery operations. In the first part of the paper, we extend a technique, previously used for calculating the dispersion of surface waves in a plane-layered anisotropic half-space, to calculating the dispersion of guided waves in the interior of a multilayered anisotropic solid. In the second part, we demonstrate the effects of anisotropy by calculating synthetic guided waves in a thin gas-sand layer displaying crack-induced anisotropy.