Abstract: 3-D migration is a key step during 3-D data processing. Besides the migratoin method, another important factor that influenced the effect of it is 3-D migration velocity field which is provided with interactive system as a new method for rebuilding it. At present, "Tectonostratigraphic method" has been usually used to many domestic explored areas for building the field. However, this paper shows that "tectonostratigraphic method" is complicated for operation and have a lot of work to do, not suitable for processing velocitics picked from complexing structure and overthrust block districts. The paper presents the methods and steps of building 3-D migration velocity field with “Slice Method” on INTERBASE system of CGG. It is indicated practically that this new method is easy for operation,a good adaptability and effective for the velocity processing.

Key words: 3-D migration velocity field, Velocity slice, Dipcorrection, Networking, Filtering