Plane Wave Reverse Time Migration in VTI Media using Green's Function

Abstract

We propose an efficient and accurate plane wave reverse time migration (RTM) imaging condition using frequency domain plane wave Green’s functions. The proposed imaging condition can be applied in anisotropic media, as well as in isotropic media. Based on the discrete Fourier transform (DFT), a procedure is developed to extract frequency plane wave Green’s functions from time domain wave fields that include anisotropy. The rapid expansion method (REM) is implemented for the decoupled P wave equation in an acoustic vertical transversely isotropic (VTI) medium to compute time wave fields. Only plane wave Green’s functions need to be computed for imaging, which leads to a fast migration scheme. Furthermore, the proposed imaging condition can generate ray-parameter common image gathers (CIGs). Therefore, the migration approach can be a useful tool for anisotropic parameter analysis. The proposed method is demonstrated to be efficient and effective through one synthetic example.