Comparison of different traveltime approximations for VTI media in context of poststack diffraction imaging

Abstract

Diffractions carry valuable information about local discontinuities and small scale objects in the subsurface. They are still not commonly used in the process of geological interpretation. Many diffraction imaging techniques have been developed and applied for isotropic media while relatively few techniques have been developed for anisotropic media. Ignoring anisotropy can result in low resolution images with wrongly positioned or spurious diffrators. In this article, we propose to take anisotropy into account in 2D poststack domain by considering P-wave non-hyperbolic diffraction traveltime approximations for VTI media, previously developed for reflection seismology. Accuracy of final images are directly connected to the accuracy diffraction traveltime approximations. We also quantified the accuracy of six different approximations, including normal moveout approximation, by application to 2D synthetic data examples.