US4091358A — Seismic detecting means for obtaining maximum sig…

Claim 1

Independent Claim 156 words

In a method for delineating subsurface formations for use in seismic exploration of water-covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: dividing said array into a plurality of detector groups having parallel connected outputs, said array comprised of a central detector group and a plurality of groups located to either side of said central group; summing the output of selected numbers of detector groups located adjacent the central detector group with the central detector group output; and recording simultaneously the output signal from the central detector group and the summed seismic signal from said central detector group and said selected numbers of detector groups located adjacent the central detector group.

Claim 2

Dependent Claim 156 words

In a method for delineating subsurface formations for use in seismic exploration of water-covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: dividing said array into a plurality of detector groups having parallel connected outputs, said array comprised of a central detector group and a plurality of groups located to either side of said central group; summing the output of selected numbers of detector groups located adjacent the central detector group with the central detector group output; and recording simultaneously the output signal from the central detector group and the summed seismic signal from said central detector group and said selected numbers of detector groups located adjacent the central detector group.

Claim 3

Dependent Claim 43 words

The method of claim 1 wherein the output of each detector group located to one side of said central detector group is connected in parallel with the output of the detector group similarly located to the other side of said central detector group.

Claim 4

Dependent Claim 134 words

In a method for delineating subsurface formations for use in seismic exploration of water covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: summing the output signals of pluralities of said seismic detectors so as to form composite signals representative of the seismic energy detected along differing segmental lengths of said array; recording simultaneously the composite signals representative of the seismic energy detected along said differing segmental lengths of said array; and selecting an array segmental length for seismic analysis that enhances seismic data signal-to-noise ratio and minimizes distortion.

Claim 5

Dependent Claim 134 words

In a method for delineating subsurface formations for use in seismic exploration of water covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: summing the output signals of pluralities of said seismic detectors so as to form composite signals representative of the seismic energy detected along differing segmental lengths of said array; recording simultaneously the composite signals representative of the seismic energy detected along said differing segmental lengths of said array; and selecting an array segmental length for seismic analysis that enhances seismic data signal-to-noise ratio and minimizes distortion.

Claim 6

Dependent Claim 36 words

The method of claim 3 wherein the array segmental length selected for seismic analysis is the maximum length recorded over which the highest seismic signal frequency of interest has a phase correlation within one half cycle.

Claim 7

Dependent Claim 85 words

The method of claim 4 wherein the array segmental length is determined from the formula: ##EQU5## where: L = array segmental length, ft. v = average velocity of the seismic wave, ft. sec. -1 b = cycle breadth of maximum seismic frequency of interest, sec. φ = average emergence angle of the seismic wave α = dip angle of the reflecting horizon x = distance from seismic source to center of the array, ft. d = depth from which the seismic signal is reflected, ft.

Claim 8

Dependent Claim 64 words

The method of claim 5 wherein said maximum segmental length is determined for a plurality of vertical segments of subsurface formations and "d" is the depth of the top of a given vertical formation segment, and "α" is assumed to be zero degrees, further including: redetermining said maximum array segmental lengths if seismic analysis discloses subsurface horizons having dip angles other than zero degrees.

Claim 9

Dependent Claim 216 words

In a method for delineating subsurface formations for use in seismic exploration of water-covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable, and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: dividing said array into a plurality of detector groups having parallel connected outputs, comprised of a central detector group and a plurality of groups located to either side of said central group; connecting the output of each detector group located to one side of said central group in parallel with the output of the detector group similarly located to the other side of said central detector group; summing selected numbers of the outputs of said detector groups located adjacent the central group with the output of said central group so as to form a plurality of composite seismic signals representative of the seismic energy detected along selected segmented lengths of said array prior to the recording of seismic data; recording simultaneously the plurality of composite seismic signals so formed; and selecting an array segmented length for seismic analysis that enhances signal-to-noise ratio of said seismic signal and minimizes distortion.

Claim 10

Dependent Claim 216 words

In a method for delineating subsurface formations for use in seismic exploration of water-covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable, and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: dividing said array into a plurality of detector groups having parallel connected outputs, comprised of a central detector group and a plurality of groups located to either side of said central group; connecting the output of each detector group located to one side of said central group in parallel with the output of the detector group similarly located to the other side of said central detector group; summing selected numbers of the outputs of said detector groups located adjacent the central group with the output of said central group so as to form a plurality of composite seismic signals representative of the seismic energy detected along selected segmented lengths of said array prior to the recording of seismic data; recording simultaneously the plurality of composite seismic signals so formed; and selecting an array segmented length for seismic analysis that enhances signal-to-noise ratio of said seismic signal and minimizes distortion.

Claim 11

Dependent Claim 36 words

The method of claim 7 wherein the array segmental length selected for seismic analysis is the maximum length recorded over which the highest seismic signal frequency of interest has a phase correlation within one half cycle.

Claim 12

Dependent Claim 87 words

The method of claim 8 wherein the array segmental length is determined from the formula: ##EQU6## where: L = array segmental length, ft. v = average velocity of the seismic wave, ft. sec. -1 b = cycle breadth of the maximum seismic frequency of interest, sec. φ = average emergence angle of the seismic wave α = dip angle of the reflecting horizon x = distance from the seismic source to center of the array, ft. d = depth from which the seismic signal is reflected, ft.

Claim 13

Dependent Claim 65 words

The method of claim 9 wherein said maximum array segmental length is determined for a plurality of vertical segments of subsurface formations and "d" is the depth of the top of a given vertical formation segment, and "α" is assumed to be zero degrees, further including: redetermining said maximum array segmental lengths if seismic analysis discloses subsurface horizons having dip angles other than zero degrees.

Claim 14

Dependent Claim 169 words

In a method of delineating subsurface formations for use in seismic exploration of water-covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: dividing said array into a plurality of detector groups, said array comprised of a central detector group and a plurality of groups located to either side of said central group; interconnecting the detectors within each group to produce a composite seismic signal representative of the seismic energy detected by the detectors comprising each group; and recording simultaneously the composite seismic signal from the central detector group on a first recording channel and a seismic signal comprising a summation of the composite seismic signals from the two detector groups located to either side and adjacent said central group on a second recording channel.

Claim 15

Dependent Claim 169 words

In a method of delineating subsurface formations for use in seismic exploration of water-covered locations of the earth wherein seismic energy is generated by a seismic source, a portion of the seismic energy is detected by seismic detectors spaced along an elongated cable and comprising at least one seismic array, and the output signals from said seismic detectors are recorded for later seismic analysis, the improvement comprising: dividing said array into a plurality of detector groups, said array comprised of a central detector group and a plurality of groups located to either side of said central group; interconnecting the detectors within each group to produce a composite seismic signal representative of the seismic energy detected by the detectors comprising each group; and recording simultaneously the composite seismic signal from the central detector group on a first recording channel and a seismic signal comprising a summation of the composite seismic signals from the two detector groups located to either side and adjacent said central group on a second recording channel.

Claim 16

Dependent Claim 95 words

The method of claim 11 wherein said array is divided into a central detector group and at least two detector groups on one side of said central detector group and at least two detector groups on the other side of said central detector group, further comprising: recording on a third recording channel a seismic signal comprising a summation of the composite seismic signals from the two detector groups located to either side of the two detector groups adjacent said central detector group simultaneously with the recording of the signals on the first and second channels.

Claim 17

Dependent Claim 26 words

The method of claim 11 wherein the summation signal recorded on said second recording channel further comprises the composite seismic signal from the central detector group.

Claim 18

Dependent Claim 61 words

The method of claim 12 wherein the summation signal recorded on said second recording channel further comprises the composite seismic signal from the central detector group and the summation signal recorded on said third recording channel further comprises the composite seismic signal from the central detector group and the two detector groups located to either side and adjacent said central group.

Claim 19

Dependent Claim 126 words

Apparatus for conducting seismic exploration of water-covered areas of the earth's surface comprising: an elongated cable having a multiplicity of seismic detectors at spaced apart locations along said cable formed into at least one array and said detectors forming said array are divided into a plurality of detector groups, the seismic detectors within each group being electrically interconnected to produce a composite seismic signal representative of the seismic energy detected by the seismic detectors comprising the group; and means for generating simultaneously for recording by a seismic recorder, a first seismic signal representative of the seismic energy detected by a first detector group and a second seismic signal representative of the seismic energy detected by said first detector group and selected numbers of additional detector groups.

Claim 20

Dependent Claim 126 words

Apparatus for conducting seismic exploration of water-covered areas of the earth's surface comprising: an elongated cable having a multiplicity of seismic detectors at spaced apart locations along said cable formed into at least one array and said detectors forming said array are divided into a plurality of detector groups, the seismic detectors within each group being electrically interconnected to produce a composite seismic signal representative of the seismic energy detected by the seismic detectors comprising the group; and means for generating simultaneously for recording by a seismic recorder, a first seismic signal representative of the seismic energy detected by a first detector group and a second seismic signal representative of the seismic energy detected by said first detector group and selected numbers of additional detector groups.

Claim 21

Dependent Claim 26 words

The apparatus of claim 15 wherein said selected numbers of additional detector groups comprise two detector groups positioned adjacently on each side of said first group.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1981-05-22	1981-11-21	1982-05-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1985-05-22	1985-11-21	1986-05-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1989-05-22	1989-11-21	1990-05-23	$7700.00	Window Closed / Lapsed

Seismic detecting means for obtaining maximum signal enhancement

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