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The methodologies described in this Chapter have several
fundamental limitations. Most importantly, they require an accurate
forward modeling operator: both the physics of wave propagation and the
true earth velocity must be accurately modeled.
While the physics of wave-propagation is well-understood, earth
velocity models are never completely true-to-life.
Another important caveat is that the wave-equation methods outlined
here require the data and models to be represented on a regular grid.
While we can choose our model-space, prestack seismic data is never
recorded on a perfectly regular grid. Before we can apply the
techniques described here, we need to regularize the data.
Chemingui (1999) and Fomel (2000) provide two
ways of achieving this goal.

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Stanford Exploration Project

5/27/2001