Migration velocity analysis in depth-ray domaia

Velocity model updating is key in the iteration flow of prestack depth migration modeling. Model updating is depended on migration velocity analysis.It is present that the method on migration velocity analysis with depth-ray parameter CIGs (Common Image Gather) based on wave field extrapolation theory and common angle image condition. The method is flattening CIGs event (i.e.the image quality is the best) using to velocity scan technology, is extracting velocity update. The interactive velocity analysis is along with structure stratum or gathers depth.It is test to migration velocity analysis on two modes as Marmousi model data.The result shows that extracting velocity update on this method is almost consistent with migration analysis beforehand.