Zero-Offset Stolt and Gazdag Migration

The wave-equation evidence for plumes in the previous section relied upon the Kirchhoff migration technique, which is very closely related to our geometrical constructions. It is of interest to see whether the plume shape appears when other types of time migration are used. Thus we present Stolt and Gazdag phase-shift migration images of the point diffractor in Figure 8 and Figure 9 respectively. Both the Stolt and Gazdag results were obtained using a constant RMS well velocity having the same value as in Figure 7. Notice that in both cases we obtain plume shapes that are in good agreement with our geometrical constructions and with the Kirchhoff result of Figure 7.

 

stolth
Figure 8 Stolt migration with the common-tangent construction overlaid.

 

gazdag
Figure 9 Gazdag phase-shift migration with the common-tangent construction overlaid.