Prestack Migration Velocity Analysis: Determination of Interval Velocities
, by Kamal Al-Yahya

The velocity analysis method presented in this paper uses
iterative prestack migration.
In each iteration, the field profiles are migrated with a velocity
model and the error in the velocity model is estimated from the
curvature of events in common receiver gathers.
The velocity obtained from the curvature of an event is
averaged over all depths above that event.
The average velocities are used to estimate interval velocities
which are constrained to exclude unreasonable velocity models.
This sequence (migration, calculation of residual velocity, and updating
the velocity model) is repeated until convergence is achieved.
I processed field data using this method and obtained
reasonable results after two iterations.