Phase-Shift Migration and the Anisotropic Acoustic Wave Equation

C021 Phase-Shift Migration and the Anisotropic Acoustic Wave Equation R.A. Bale* (CGGVeritas) SUMMARY The acoustic TI approximation is used to enable modelling or migration in the presence of transverse isotropy without resorting to the full elastic wave equation that is theoretically required. Unfortunately use of the acoustic TI equation in finite difference modelling gives rise to spurious S-wave events. Some workers have resorted to weak anisotropy approximations or artificial isotropic layers to avoid these artefacts. Here it is shown that this is unnecessary if a phase-shift extrapolation method is used instead of finite difference. EAGE 69 th Conference & Exhibition