In complex mountainous areas,the large variation of elevation has a bad effect on velocity analysis and model building and
results in inaccurate migration.In order to remove the effects of poor imaging focusing and avoid building depth-domain
velocity model under the low signal-to-noise ratio,a pre-stack time migration scheme for rugged topography was proposed.The
main procedures of this scheme include imaging datum construction,velocity model update based on imaging datum and
prestack time migration for rugged topography.The purpose of building image surface is trying to make the obtained velocity
model coinciding with the actual velocity model.The convergence of velocity model benefits from the velocity model update
based on imaging surface.Meanwhile,by using this scheme,the actual shot-receiver relationship can be obtained to improve
focusing ability of time migration.The real data examples at mountainous area in Western China illustrate that high-quality
sections were achieved with obviously-improved resolution,clear breakpoints and break sections,which provides good basic
data for subsequent interpretation.
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