Abstract:
On the basis of first-order quasi-P wave equations in transversely isotropic media with a vertical symmetry axis (VTI), high-order finite-difference schemes in staggered-grid for reverse-time extrapolation were derived. The stability condition and the perfectly matched layer (PML) absorbing boundary condition for the equations were also provided. Prestack reverse-time depth migration of quasi-P wave equations in VTI media using maximum amplitude method of down-going wave-field and normalized cross-correlation imaging conditions was carried out. Numerical experiments of anisotropic Marmousi model show that prestack reverse-time depth migration of quasi-P wave equations in VTI media has no dip restriction or lateral velocity variation restriction, and has good imaging effect for complex models. Reversetime migration imaging condition using normalized cross-correlation has better imaging ability. Additionally, the contrast between the imaging results of anisotropic and isotropic reversetime migration profiles proves that theoretically better imaging results can be obtained using anisotropic migration scheme for P-wave data acquired in anisotropic regions.