Inclusion of spatial sampling and migration artifacts in AVO/Az analysis using Kirchhoff approximation

Hassan Khaniani, Daniel O. Trad

We quantify the uncertainty of linearized Amplitude Variation with Offset/Azimuth (AVO/Az) analysis of seismic P-P wave in a Horizontal Transverse Isotropic (HTI) model. We use Kirchhoff scattering and imaging operators to modify analytical values of AVO/Az based on the numerical artefacts produced by poor sampling and deficiencies of the operators to reproduce true amplitude migration. To compensate for errors due to numerical artefacts of sampling and migration, we present a multiparameter inversion for azimuthal parameters based on the reconstruction of total waveforms by representation on numerical dictionaries obtained by optimization. The computational operator for modeling the dictionaries is based on a 3D Kirchhoff scattering formulation, while the migration operator is based on Prestack Time Migration (PSTM). All operators consider the footprints of acquisition and migration operator in the estimation of AVO/Az characteristics of dictionaries. The amplitude and traveltime kernels during modeling are based on the linearized reflection coefficients of the HTI medium and the Double Square Root (DSR) equation of PSTM respectively. We show that the inclusion of the artifacts of acquisition and processing in the numerical estimation of AVO/Az values improves the accuracy of conventional analytical curve fitting. The Kirchhoff operator is a target oriented algorithm, which reduces the computation time of modeling and migration at specific target layers.