Geophysical Systems Corporation

Lincoln A Martin

William F Fenley, Jr

In a seismic recording and processing system in which a line of sources and a separate line of receivers are provided and each of the source operations from each of the source points is recorded on all receiver points. A method is described for determining the differential static correction between each adjacent pair of source points in terms of the differences in travel times from each pair of source points, to all pairs of receiver points. This is provided even though the lines of source points and receiver points may be parallel to or at angles to each other, and the spacings of source points and receiver points in their separate lines may be the same or different.

Method of determining weathering corrections in seismic operations

A system and method for carrying out seismic operations with low energy sources, which involves operating the source at spaced points along a seismic spread, the source points are spaced far enough apart so that their seismic waves originate at different points and travel by different paths to the geophones. The geophone outputs cannot be time stacked. The geophone signals are amplified at constant gain and digitized to 1 bit. If the low energy source is a vibratory source, the 1 bit signals are correlated with a 1 bit version of the sweep signal. The resulting correlograms are digitized to 1 bit and C.D.P. stacked and displayed. If the low energy source is impulsive, the 1 bit amplified signals are C.D.P. stacked and displayed. In C.D.P. stacking, the determination of optimum velocity can be carried out by 1 bit processing.

Method and apparatus for determination of optimum velocity in processing

The method of determining the magnitude of the differential static correction between adjacent records in seismic record processing, that involves the steps of: recording a first multi-trace record responsive to a first seismic wave generated at a first source point; recording a second corresponding multi-trace record responsive to a second seismic wave at a second source point, which is adjacent to the first source point; correlating a first trace of the first record with the corresponding first trace of the second record, and determining the first time difference between the two first traces of said two records; repeating the correlation step and determining the time differences for a plurality of N pairs of traces; adding all of the N time differences and dividing the sum by N to find the net difference in static correction between the first and second source points.

A system and method for carrying out seismic operations with low energy sources, which involves operating the source at spaced points along a seismic spread, the source points are spaced far enough apart so that their seismic waves originate at different points and travel by different paths to the geophones. The geophone outputs cannot be time stacked. The geophone signals are amplified at constant gain and digitized to 1 bit. If the low energy source is a vibratory source, the 1 bit signals are correlated with a 1 bit version of the sweep signal. The resulting correlograms are digitized to 1 bit and then C.D.P. stacked and displayed. If the low energy source is impulsive, the 1 bit amplified signals are C.D.P. stacked and displayed.

Method and apparatus for processing seismic signals from low energy

A method of carrying out vibratory seismic operations with the object of minimizing correlation noise lobes, comprising, repeating a vibratory source a plurality of times each with a different sweep, having different terminal frequencies, correlating each received signal with its corresponding sweep, and stacking the resultant correlograms. The range in terminal frequencies for the plurality of sweeps should preferably be in the range of one octave or more. Another method of operation is to vary the time durations of the successive sweeps, preferably over a range of 2 to 1, and correlating the received signals and sweeps, and then stacking. In a third method of operation both the time durations and the terminal frequencies are varied. The successive repetitions of the source can be at the same source point and the results straight stacked, or they can be at different independent source points and the results CDP stacked.

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Altadena, CA, United States of America

Lincoln A Martin