The Irregular Surface Velocity Modeling And Migration

China's western exploration area has the characteristics of complex surface and complex underground structure,which is the hotspot of current seismic exploration.In dealing with the seismic data of this exploration area,the precise velocity model is the prerequisite and basis for high precision migration to get good results.As for the problems that the migration floating surface and the velocity model caused by the undulating surface in the conventional process are not accurate,they are solved by two aspects.On the one hand,we use floating surface which is close to the surface as the reference surface for prestack depth migration.On the other hand,the near-surface velocity model and the middle-deep velocity model are spliced to establish a full-speed model with accurate near-surface velocity information.The main processing steps include pre-processing,joint velocity modeling and irregular surface prestack depth migration,and as the basis for the establishment of a set for the fluctuation of the surface shift imaging process.The results of the mathematical model test verify the effectiveness of the method and processing flow.At the same time,after the actual two-dimensional seismic data processing,the migration profile has improved significantly.Therefore,the method and process in the actual data also has some practicality,which can also provide a technical strategy and ideas for bottlenecks of the current western exploration complex structure velocity modeling and migration.