ELEMENTS OF MIGRATION AND VELOCITY ANALYSIS

Abstract

This paper describes a theory for combining migration and velocity analysis of seismic data and uses experimental model data to illustrate some of the practical problems. It is shown that adaptive weighting of the data, based on a measure of coherence, can be effective in suppressing false images and noisy backgrounds caused by finite migration apertures, finite sampling in space and time, and random noise in the data. Velocity analysis is presented as a “range finding” method in which images for two different constant offset profiles are brought into coincidence by using the correct velocity. The method is valid even in the presence of diffraction, dipping interfaces, or curved reflectors.