3-D prestack datuming in midpoint and offset coordinates

Sean Crawley

sean@sep.stanford.edu

ABSTRACT

3-D seismic surveys are designed to have even sampling in midpoints, but often have irregular sampling in offset. For instance, marine surveys tend towards poor sampling and small aperture in the crossline offset direction, owing to the necessity of towing streamers. Integral operators which work on 3-D prestack data must deal with the problems that arise from 3-D prestack geometry in order to be useful; a straightforward generalization of a 2-D operator is likely to consume a great many CPU cycles to produce suboptimal output. Prestack Kirchhoff datuming can be made more effective in 3-D by reformulating it in midpoint and offset coordinates, and choosing an antialiasing strategy to take advantage of the resulting limitation of the time dip of events.