Removing S‐wave noise in TTI reverse time migration

Abstract

Anisotropy is intrinsically an elastic phenomenon. The widely‐used acoustic anisotropic wave equation results in significant shear wave presence in both modeling data and reverse time migration images. In this abstract, we discuss two approaches to reduce the S‐wave noise in migration. The first is based on an elastic anisotropic wave equation with non‐zero S‐wave velocity to attenuate S‐wave noise. The second approach uses a supplementary routine to remove the S‐waves after wavefield modeling in each time step. Impulse responses and a simple 2D TTI example show that both methods reduce S‐wave energy significantly and lead to a cleaner image than those based on the conventional acoustic anisotropic wave equation.