Two-step inversion of P-wave data for horizontal transverse isotropy

Abstract

Seismic inversion, one of the most significant technologies for seismic reservoir characterization, provides the most detailed view of underground structure and rock properties. Over the past few decades, many different inversion techniques, from post-stack inversion to pre-stack inversion, have been greatly improved, especially the azimuth anisotropy inversion, in which the transversely isotropic model with a horizontal symmetry axis (HTI media) has been extensively used in seismological studies of fractured reservoirs.The inversion of P-wave data in HTI media is normally carried out with azimuthally-dependent P-wave normalmoveout (NMO) velocities (Contreras et al., 1999), and can be used to estimate the crack density and orientation. In this paper, a parameter estimation technique is originally proposed for HTI media, which is based on Rüger equation, and the Thomsen-style anisotropic coefficients responsible for P-wave reflection coefficient can be obtained directly by two-step inversion of reflection P-wave data acquired over HTI formations.