Residual moveout analysis and velocity determination for parametric media

Abstract

For the case that a prestack depth migration has been performed with inaccurate velocities, it is shown that second order approximations to the wavefront can be used to predict the residual moveout of downward continued gathers. The relevant corrections can be estimated by using standard analysis techniques. A one parameter correction scheme is suggested in which tabular values derived from the data of the prestack depth migration are employed to estimate the residual moveout. The estimated corrections can be used to imcrease the signal to noise ratio of the migrated data and to improve the velocity model. Applications for parametric velocity laws are demonstrated with promising results.