Common-offset-distance seismic trace filtering

Claim 1

In seismic exploration wherein a multiple coverage exploration technique is used to obtain seismic traces from source and receiver positions along a line of exploration, the machine implemented method of enhancing the signal-to-noise ratio of said seismic traces, comprising the steps of: (a) gathering said seismic traces into sets having common source-to-receiver offset distances, (b) summing the magnitudes of the absolute values of a selected number of contiguous seismic traces along a first selected orientation for the dip trajectory across the seismic traces of each of said sets to obtain a sum-of-magnitude signal at each of a plurality of first sampling points within a first time window, (c) summing the mutual products of the selected number of contiguous seismic traces along said first selected orientation for the dip trajectory of those portions of all possible trace pairs that lie within said first time window to obtain a cross-product signal for each of said plurality of first sampling points, (d) repeating steps (b) and (c) for a plurality of selected orientations for the dip trajectory, (e) incrementing said first time window along the time axis of said sets of traces and repeating steps (b)-(d) for each subsequent first time window position to obtain a plurality of sum-of-magnitude and cross-product signals, (f) multiplying the sum-of-magnitude and cross-product signals obtained from the same first time window position and the same selected orientation for the dip trajectory to obtain a plurality of merit function signals, (g) selecting the orientation for the dip trajectory associated with the largest value of the merit function signal for each first time window position as the initial dip estimate of the seismic reflection signal at the first sampling point that lies nearest the midpoint of the center trace within such first time window position, (h) smoothing the initial dip estimates for each of said sets of common-offset-distance traces to provide final dip estimates, the influence of erroneous dip estimates being thereby minimized, and (i) filtering said sets of common-offset-distance traces along the apparent dips of the seismic reflection signals as indicated by said final dip estimates.