The Separation of Irregular Multiples Based on the Focal Transform

Summary With the deeper seismic exploration for complex structures, the data processing becomes more difficult owing to the complex data, for example, data containing both strong surface-related multiples and internal multiples, which is called ‘irregular multiples’ in this paper. Most of the accurate methods for multiple separation assume that the multiples are regular interferences. Separation of surface-related multiples requires inexistence of internal multiples, and separation of internal multiples requires elimination of surface-related multiples. Otherwise, the multiples cannot be accurately predicted. Besides, there is little research on the separation of surface-related multiples and internal multiples simultaneously through a single method based on wave theory. Considering that the focal transform can easily realize order reduction and elevation of the reflections, a method for separation of irregular multiples based on focal transform is proposed. According to the analysis on energy distribution of different kinds of reflections in focal domain, a workflow of simultaneous separation of primaries, surface-related multiples and internal multiples is presented and synthetic example is used to verify the effectiveness. This method breaks through the assumption in traditional methods, and the accurately separated surface-related multiples and internal multiples can be used further to get more information of the complex structures.