A Gulf of Mexico example

This dataset has been intensively used for testing multiple attenuation techniques (The Leading Edge, January 1999). Figure shows the velocity model that is used for the migration ().

 

velgom
Figure 12 Velocity field for the Gulf of Mexico 2-D line.

For this data set I did not separate primaries from multiples as required by the theory. As an approximate solution, I decided to mute everything above the first surface-related multiple for the up-going wavefield. Therefore the down-going wavefield is made of the complete shot and the up-going wavefield is made of the complete shot minus the primaries above the first surface-related multiple (Figure ).

 

gom_ud_mult500
Figure 13 Left: The source function with primaries and multiples. Right: Same as the source function but with a mute above the first surface-related multiple.

The migration results are displayed in Figure . Figures a and b show the migration results for primaries and multiples respectively. The two migrations produce similar results. Despite the approximations made, the multiple migration gives a very accurate image of the salt body and of the sediments.

 

gom_comp
Figure 14 (a) Migration of the primaries. (b) Migration of the multiples. The two images are comparable. The salt body is clearly visible in the multiple migration result.