Amplitude-Preserving Imaging Condition for Scattering-Based RTM in Acoustic VTI Media

Abstract

Conventional seismic imaging methods rely on reflected waves to obtain the interfaces of geologic variations and the normal-incidence reflectivity at the interfaces. However, the scattering phenomena affect the imaging quality, especially in anisotropic media. Most of the current techniques which neglect the scattering effects are insufficient to acquire accurate images. To correct such scattering effects and reduce the image artifacts, we have derived a new, scattering-based, amplitude-preserving imaging condition with anisotropic background assumption in acoustic vertical transverse isotropic (VTI) media. In addition, we present a correlation-type representation for this imaging condition to avoid the problem of being divided by small numbers during reverse-time migration (RTM). Based on this proposed imaging condition, the amplitude of imaging result has the specific physical meaning of the velocity perturbation, and can be retrieved by RTM accurately. Numerical experiments on synthetic data show that our inverse-scattering imaging condition can produce more accurate amplitudes on images than cross-correlation imaging condition.