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The regular cube was then datumed to just
above the water-bottom to avoid spending precious migration time on
downward continuation through the water layer. Figure
shows a comparison of one CMP 3D gather before (left) and after
datuming (right). Notice
that datuming not only saves time but also allows a significant reduction of
the data because the offsets decrease as the recording surface is ``moved''
closer to the reflectors, making the positions of sources and receivers closer.
Notice also that the holes in both offsets and CMPs have been healed by the
propagation.
datum_comp
Figure 9 Comparison of a 3D CMP gather before (left)
and after datuming (right).
Next: Common-Azimuth Migration
Up: Preprocessing
Previous: Data infill
Stanford Exploration Project
4/6/2006