Abstract：If the seismic reflections in a given partial time—space domain need to be migrated to their correct locations, we can achieve this by migrating them only in the partial time space domain, without necessity of whole time space domain. Their only difference lies in the velocity used, so that operation range of migration can be shortened greatly. The application of this partial migration method to the residual velocity migration of constant velocity prestack migration section can completely remove the disconnection, caused by velocity variation, of dipping reflection horizons in prestack section. What is more, less velocity points and less computation can be taken in prestack migration. Residual velocity migration in this way needs reduced computation in wave field imaging, hence making the constant velocity prestack migration turn into a practical processing technique which brings good result and high efficiency.
