When is anti-aliasing needed in Kirchhoff migration? |
The operator aliasing has been somewhat contained by limiting the migration aperture to in Figure 3b; however, the seafloor event still has a precursor, the top of the salt dome is still poorly imaged, and there is more coherent noise than in Figure 2b.
Gulfaper
Figure 3. (a) Kirchhoff migration without any aperture limitation or anti-aliasing. The effect of operator aliasing is noticeable at the seafloor where migration velocity is slow and where there is significant operator dip. At later times, the migration velocity is fast and there is not much operator dip, so there is no operator aliasing. (b) Kirchhoff migration of Gulf of Mexico data with aperture limitation. Limiting the aperture reduces some, but not all, of the operator aliasing at the seafloor. |
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Figure 4. Close up of (a) the anti-aliased migration, and (b) the standard Kirchhoff migration without anti-aliasing. The seafloor operator aliasing artifacts and the dipping artifacts are marked. |
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When is anti-aliasing needed in Kirchhoff migration? |