Exploration system for cross-steering and stacking seismic data using a sawtooth traverse of shot points centrally spaced between at least a pair of linear detector spreads

A seismic exploration method where seismic impulses are generated successively, one pulse at each of a plurality of source point locations along a sawtooth asymmetrical shot point line, having a stepped segment defining an offset spacing distance (d), between adjacent source point locations, and where seismic waves resulting from each of said impulses are detected by at least two detector spreads each containing a plurality of detectors spaced at a series of in-line detector locations, adjacent spreads being offset from each other a distance D, which is related to said source point spacing distance (d) by a ratio of 2:1 or greater than one which comprises:

• i. statically and dynamically correcting detected seismic signals so as to produce a series of corrected traces, said series of corrected traces containing sets of common traces associated with common centerpoints of a two-dimensional grid of centerpoints formed between particular source point location and detector spread location pairs, and cross-sets of traces associated with cross-line of centerpoints of said grid, at least one trace of cross-set of traces being a product of a source-detector pair having a substantially different horizontal spacing than at least one other source-detector pair of other cross-traces associated with said same set of cross-traces;
• ii. stacking said sets of common traces to produce stacked traces which improve the portrayal of multifold areal surface structural conditions;
• and
• iii. beam-steering said stacked traces to produce subsets of cross-directional traces having improved directional content as well as primary-to-multiple ratios.

A seismic exploration method where seismic impulses are generated successively, one pulse at each of a plurality of source point locations along at least two parallel lines offset from each other a distance D, and where seismic waves resulting from each of said impulses are detected by a plurality of detectors positioned along a sawtooth asymmetrical line, having a stepped segment defining an adjacent offset spacing distance (d), between adjacent offset detector locations, and where each distance D is related to said detector offset spacing distance (d) by a ratio of 2:1 or greater which comprises:

• i. statically and dynamically correcting detected seismic signals so as to produce a series of corrected traces, said series of corrected traces containing sets of common traces associated with common centerpoints of a two-dimensional grid of centerpoints formed between particular source point location and detector spread location pairs and cross-sets of traces associated with cross-lines of centerpoints of said grid, at least one trace of each set of common traces being a product of a source-detector pair having a substantially different horizontal spacing than at least one other source-detector pair of other traces associated with said same set of common traces;
• ii. stacking said sets of common traces to produce stacked traces having improved primary-to-multiple ratios which improve the portrayal of multifold areal surface structural conditions;
• and
• iii. beam-steering said stacked traces to produce subsets of cross-directional traces having improved directional content as well as signal-to-noise ratios.