Successful subsalt imaging in the Gulf of Mexico depends critically on three aspects of the imaging<br>process; the building of an accurate sediment velocity model, defining the geometry of the salt body or<br>bodies, and successful application of 3D poststack and prestack depth migration algorithms. Even if the<br>target subsalt dips are moderate, steep dip imaging is often necessary for defining the geometry of the<br>salt bodies, parts of which may have significant dip. In addition, even though energy that propagates<br>through salt may be dip-limited because of the sharp velocity contrast between sediment and salt, energy<br>that propagates laterally from outside salt may also contribute to the flanks of subsalt reflectors with<br>steep dip. In such areas careful processing to preserve dips is necessary, with the ultimate goal being a<br>subsalt image that is as interpretable subsalt as it is outboard of salt. Here we discuss several<br>techniques for optimizing steep-dip salt and subsalt imaging, including iterative prestack depth migration<br>and velocity updating for sediment velocities, iterative prestack and poststack depth migrations for salt<br>boundary definition, proper interpretation of the salt boundary, and optimal application of a Kirchhoff<br>algorithm for final imaging. These techniques are illustrated with examples from an area of significant<br>complexity in the Gulf of Mexico.


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