Quantitative Structural Effects in Layered Media, an Application of Anisotropic Dynamic Ray Tracing to AVAZ Studies

Advances in 3D seismic acquisition and processing are providing new tools for the analysis of fractured zones. Studying the amplitude variation as a function of azimuth is one of the current methods to determine the anisotropic parameters. Based on recent studies conducted with field data, several questions remain, notably the validity of the Amplitude versus Azimuth (AVAZ) analysis of the datasets when the seismic processing is based on some large simplifications of the real situation. In this paper, we apply an anisotropic dynamic ray tracing to 3D isotropic and Horizontal Transversely Isotropic (HTI) models to perform a feasibility study and to analyze the uncertainties related to geometrical spreading compensation. We compare the error introduced by a standard geometrical compensation with the anisotropic variation due to HTI reservoir. This study demonstrates, even in case of moderate structured subsurface, the full true amplitude PSTM or PSDM workflow providing the exact geometrical spreading compensation should be performed to study the anisotropic amplitude.