Migration velocity analysis of incomplete/irregular data using least squares Kirchhoff migration

Abdolnaser Yousefzadeh, John C. Bancroft and Gary F. Margrave

ABSTRACT

Kirchhoff least squares prestack migration (LSPSM) with the correct velocity information gives a higher resolution image than the standard Kirchhoff migration and produces less acquisition footprints.

This paper focuses on migration velocity analysis by measuring coherency on common image gathers and extends the method to LSPSM.

We show that when the data are sampled incompletely or irregularly, velocity analysis with semblance method on the migration offset domain CIGs, which is a robust tool for migration velocity analysis, can be extended to the LSPSM offset domain CIGs. The same result is achieved by using an unnormalized crosscorrelation (XC) on the shot domain CIGs. We show that the velocity extracted by this method is accurate enough to give a high resolution image in LSPSM and works well for the data reconstruction.

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