Application

We computed angle gathers using equation (2) from a common-azimuth migrated SEG-EAGE salt dataset. Figure shows a depth slice taken at a depth of 580 meters. Figure shows two ADCIGs taken at an in-line location of 8,350 meters and a cross-line location of 5,250 meters. The ADCIG on the left was computed using the 2-D relationship (equation (1)) for the transformation to angle domain. The ADCIG on the right was computed using the correct 3-D relationship (equation (2)). The $\cos \delta$ term corrects the ADCIG for the top of the salt reflection ($z\simeq$ 580 meters) that dips at approximately 50 degrees in the cross-line direction. Notice that the bottom of the salt reflection (z$\simeq$ 2,100 meters) in unaffected by the $\cos \delta$ term because it is flat.

 

depth_slice Figure 2 Depth slice cut through the common-azimuth image of the SEG-EAGE salt dataset at a depth of 580 meters. The crossing point of the grid lines indicates the location of the ADCIGs shown in Figure .

 

comp_2d_vs_3d Figure 3 ADCIGs taken at in-line location of 8,350 meters and cross-line location of 5,250 meters: a) computed using the 2-D relationship for the transformation to angle domain (equation (1)). b) computed using the correct 3-D relationship (equation (2)).