Common-Azimuth Migration

In order to choose the key migration parameters such as depth step, number of frequencies and especially the minimum amount of padding of negative subsurface offsets needed to accommodate the migration of the multiples, I ran some tests using common-azimuth migration (, ). Figure 14 shows the inline dimensions (CMP and offset) of an SODCIG after common-azimuth migration. Notice that the multiples have been mapped to the negative subsurface offsets and to shallower depths, consistent with the results of Chapter .

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Figure 14. Common-azimuth migration. Panel (a) is the migrated inline section at CMP-Y=662.5 m, zero inline subsurface offset and -25 m crossline subsurface offset. Panel (b) is the inline subsurface offset gather at CMP-X=8400 m, CMP-Y=662.5 m and -25 m crossline subsurface offset. Notice in panel (b) how the multiple migrated towards the negative subsurface offsets.