摘要
Scattering theory and Kirchhoff pre-stack time migration methods are the theory basis of pre-stack time migration and velocity analysis methods on common scattering point(CSP) gathers.The concept of equivalent offset proposed in the paper provides a new approach for pre-stack migration and velocity analysis.This paper first derives a new kind of single-square-root travel-time equation,and a method to obtain CSP gathers,and summarize the advantage of CSP gathers compared to CMP gathers.And then the paper develops a CSP gathers method to 3D geometry data.Through the processing to 3D model and field data,it is clear that the quality of semblances and the imaging on CSP methods are better than those of CMP gathers.