Abstract: A search is made down each trace of a seismic record at the approximate period of the multiple events to find a trace segment which most resembles a selected later segment of the same trace. An autocorrelation procedure is initially employed to determine the approximate period of the multiples and a crosscorrelation procedure is then employed to determine the time alignment of the two segments which produces maximum correspondence between the two segments. The degree of correspondence is determined by a "least-squares-fit" procedure. A portion of the earlier segment is subtracted from the later segment. The amount of the earlier segment to be subtracted is determined by the degree of correspondence. The procedure is incremented along the trace until the entire trace has been processed. Each trace is handled in the described manner until the entire record has been processed.

Abstract: Disclosed is a method of processing geological seismic reflection data to compensate for lateral variations in the attenuation effect which the weathered layer has on the reflected seismic energy waves as they approach an array of detectors at the surface. Absolute amplitudes of the waves are summed for each trace throughout a test window at the depth to be explored. The amplitudes are normalized by taking the ratio of each sum to the sum of the absolute amplitudes obtained throughout a standard window, in the corresponding trace. In a particular embodiment disclosed, the test window scans each trace in increments, and the absolute amplitude sum obtained at each position is normalized to the standard window in that trace. The ratios thus obtained, when plotted, reveal the positions of large-amplitude reflecting strata without weathered-layer distortion.

Abstract: An illustrative embodiment of the present invention includes methods for Seismic Data Processing which may be used to enhance the signal/noise ratio of seismic signals taken by use of the Common Depth Point or Hundred Percent Coverage survey techniques. The methods preserve time alignment and amplitude of the signals while effectively removing the noise therefrom. Small portions of the record centered at a selected time on a selected trace are processed to extract the coherent signal component from the reference trace as determined by comparison with other spacewise adjacent traces. Output records comprising the enhanced signal data and the noise data are produced.

Abstract: A method of enhancing a "gather" formed of a plurality of unmoved out common depth point (CDP) data traces. The gather is formed of a plurality of seismic traces arranged in a display in which time varies along the horizontal axis and distance between source and detector (range) varies along the vertical axis. The gather is incrementally processed by cross correlating trace segments within a defined area or search window. To this end, the center trace within the window is selected as a reference trace which is multiplied by a taper function and cross correlated with the other traces in the window to provide a coherent trace and a separate noise trace, both of which are produced in the output. The window is shifted on the gather and the procedure is repeated until every trace has been processed. In the cross correlation technique, the trace segments in the window are examined along a derived hyperbolic curve.