Extending common-azimuth migration

Louis Vaillant and Biondo Biondi

louis@sep.stanford.edu, biondo@sep.stanford.edu

ABSTRACT

We present a review of common-azimuth prestack depth migration theory and propose a new extension to the original method. In common-azimuth migration theory, source and receiver raypaths are constrained to lie on the same plane at each depth level. By using data with a broader range of cross-line offsets, we increase the number of raypaths examined and consider more information. Consequently, our extended common-azimuth migration is theoretically better able to model lateral velocity variations due to real
3-D structures and is more compatible with the standard marine acquisition geometry, in which cross-line offsets are concentrated in a narrow band. We first discuss the theory of the process, and then introduce computational issues leading to future implementation.