Moveout inversion of wide-azimuth data in the presence of velocity lenses*

摘要: Moveout analysis of wide-azimuth reflection data seldom takes into account lateral velocity variations on the scale spreadlength. However, lenses in overburden can cause significant laterally-varying errors moveout parameters. Here, we derive an analytic expression for NMO ellipse stratified media with variation and show that correction heterogeneity is controlled by second derivatives interval vertical traveltime. This equation provides a quick estimate contribution substantially mitigates lens-induced distortions effective ellipses. To remove influence nonhyperbolic inversion data, propose prestack algorithm involves computation traveltime distortion each recorded trace. The method designed horizontally-layered but handle laterally heterogeneous target layers dipping or curved interfaces. Synthetic tests confirm our accurately removes lens-related shifts significantly reduces azimuthally varying developed methods should increase robustness seismic processing surveys, especially those acquired fracture-characterization purposes.