VARIABLE RANGE 3 D PRESTACK DEPTH MIGRATION BY PHASE SHIFT PLUS CORRECTION

The theory and practice prove that prestack depth migration is the most accurate imaging method of seismic wavefield at present. Based on 2 D prestack depth migration and the creation of migration velocity model , the authors have studied and realized the method and software of variable range 3 D prestack depth migration . The migration imaging range is determined according to the structural attitude of 3 D velocity model , and the variable range 3 D prestack depth migration is done on the CSP gathers by phase shift plus correction . The migrated structural feature is more distinct. The method is a kind of full wave equation migration and is characterized by the high wavefield imaging precision and good adaptation to the models.