Quantifying Footprint: Objective measurements of acquisition footprint.

Gary F. Margrave

A method is presented to numerically estimate the degree of seismic acquisition footprint in a 3D seismic volume. Operating on time (or depth) slices, the method first constructs digital representations of the source and receiver grids and then these grids are crosscorrrelated with a chosen time slice. For orthogonal source and receiver grids, the procedure is especially simple since only correlation lags orthogonal to the source or receiver lines need be examined. Footprint causes a periodicity in the crosscorrelations whose period is the ratio between the line spacing and the image bin dimension. In a series of examples using real data, it is observed that the grid correlation measurement is much more sensitive than mere visual assessment to detect footprint. This is especially useful for comparing the effectiveness of alternative methods of footprint suppression.