Wave equation preserved-amplitude prestack depth migration and AVO response

Key words:  prestack depth migration  preserved-amplitude migration  one-way wave equation  double-square-root  AVO

Abstract:

The high efficient and direct-viewing one-way wave equation, which was started from full acoustic wave equation， was derived by using one-way wavers preserved-amplitude decomposition based on strict decoupling theory. This kind of oneway wave equation is to do continuation for pressure components of seismic wavefield directly. The formula transformation from common-shot domain to common midpoint ( CMP) domain was achieved according to the theory of wavefield double downward continuation in prestack depth migration. Then the preserved-amplitude one-way wave equation defined by doublesquare-root equation was derived. So the amplitude error compensation as one part of migration can be realized during migration period. Furthermore, this method has a special function that can give true amplitudes as well as the correct locations at the same time. Under the condition of preserving true amplitudes, the common reflection point(CRP) gathers based on this method efficiently solve diffracted wave interference, reflection point dispersion and NMO problem connected with angle of dip. This method makes AVO response clearer and improves the precision of AVO analysis.