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| When is anti-aliasing needed in Kirchhoff migration? | |
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Operator aliasing most often occurs when operator moveout across adjacent
traces exceeds the time sampling rate. Cycle skips can occur
when the operator is
aliased. For a moveout curve with slope , and data with a spatial
Nyquist frequency of , temporal frequencies above
are aliased.
In terms of the mesh spacing and operator slope ,
operator aliasing will occur for all frequencies above , where
is given by:
|
(1) |
Defining the maximum stepout as
, the
highest dip frequency in the data is given by
|
(2) |
When the stepout is captured by the mesh
spacing,
, and
, the
highest unaliased dip frequency is equal to the
Nyquist frequency
. In areas of
economic interest, steep dips are often
present in the data and .
Anti-aliasing is called for when the frequency content of the data, ,
falls between
|
(3) |
This situation is illustrated in Figure 1.
spectrum
Figure 1. Operator aliasing, event dip, and
frequency content of the data.
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| When is anti-aliasing needed in Kirchhoff migration? | |
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Next: GULF OF MEXICO SALT
Up: Bevc and Lumley: Anti-aliasing?
Previous: Introduction
2015-03-26