US3568142A
Expired / Lapsed
US
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Multiple frequency surveying system
Assignee: Pan American Petroleum Corp
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Filing: 1967-01-16
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Granted: 1971-03-02
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Expires: 1987-01-16
Abstract
Abstract A seismic surveying method utilizes a vibratory source emitting a succession of differing frequency sine waves. Received waves after suitable amplification are passed through a group of narrow filters which separate the various frequency components. After suitable time delays, these components are recombined to present a record similar to that obtained from an explosive single source.
Inventors
- 👤 Ralph A Landrum Jr
- 👤 John L Shanks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:10
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/28; G01V2210/00; G01V2210/20
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
208 words
A process for seismic surveying including the steps of: 1. generating a seismic signal at a location, said signal comprising a substantially continuous succession of sets of waves, each set being made up substantially of a plurality of cycles of at least approximately a sine wave of a single frequency, the period of at least some of said sets differing from each other, each of said sets succeeding the preceding set within a time not greater than the duration of said succeeding set, whereby said signal propagates through the earth, reflecting from interfaces; 2. receiving seismic waves due to said signal at a plurality of points removed from said location, including reflected waves, to produce a received signal corresponding to each of said points; 3. narrowly filtering each said received signal by a plurality of filters each tuned to the fundamental frequency only of one of said sets of waves in said succession and appropriately delaying each such signal by a preselected time interval such that one-half cycle of each of said sets from a single reflection is in phase; 4. combining the outputs of the delayed and filtered signals; and 5. producing a visual record in accordance with the combined outputs of the delayed and filtered signals.
Claim 2
Dependent Claim
208 words
A process for seismic surveying including the steps of: 1. generating a seismic signal at a location, said signal comprising a substantially continuous succession of sets of waves, each set being made up substantially of a plurality of cycles of at least approximately a sine wave of a single frequency, the period of at least some of said sets differing from each other, each of said sets succeeding the preceding set within a time not greater than the duration of said succeeding set, whereby said signal propagates through the earth, reflecting from interfaces; 2. receiving seismic waves due to said signal at a plurality of points removed from said location, including reflected waves, to produce a received signal corresponding to each of said points; 3. narrowly filtering each said received signal by a plurality of filters each tuned to the fundamental frequency only of one of said sets of waves in said succession and appropriately delaying each such signal by a preselected time interval such that one-half cycle of each of said sets from a single reflection is in phase; 4. combining the outputs of the delayed and filtered signals; and 5. producing a visual record in accordance with the combined outputs of the delayed and filtered signals.
Claim 3
Dependent Claim
30 words
receiving seismic waves due to said signal at a plurality of points removed from said location, including reflected waves, to produce a received signal corresponding to each of said points;
Claim 4
Dependent Claim
30 words
receiving seismic waves due to said signal at a plurality of points removed from said location, including reflected waves, to produce a received signal corresponding to each of said points;
Claim 5
Dependent Claim
50 words
A process in accordance with claim 1, in which the time duration of each sine wave in said succession is at least approximately inversely proportional to the attenuation of seismic waves of this frequency in the earth, and the amplitude of all sine waves in said succession is substantially constant.
Claim 6
Dependent Claim
61 words
A process in accordance with claim 1, in which the time duration of each set in said succession is substantially equal, the amplitude of all sine waves in said succession is substantially constant, and the number of said sets at a particular frequency is at least approximately inversely proportional to the attenuation of seismic waves of this frequency in the earth.
Claim 7
Dependent Claim
55 words
narrowly filtering each said received signal by a plurality of filters each tuned to the fundamental frequency only of one of said sets of waves in said succession and appropriately delaying each such signal by a preselected time interval such that one-half cycle of each of said sets from a single reflection is in phase;
Claim 8
Dependent Claim
55 words
narrowly filtering each said received signal by a plurality of filters each tuned to the fundamental frequency only of one of said sets of waves in said succession and appropriately delaying each such signal by a preselected time interval such that one-half cycle of each of said sets from a single reflection is in phase;
Claim 9
Dependent Claim
10 words
combining the outputs of the delayed and filtered signals; and
Claim 10
Dependent Claim
10 words
combining the outputs of the delayed and filtered signals; and
Claim 11
Dependent Claim
71 words
A process in accordance with claim 1, in which the time duration of each set in said succession is substantially equal, the amplitude of all sine waves in said succession is at least approximately inversely proportional to the attenuation of seismic waves of this frequency in the earth, and the frequency of each of said sets is related to the next lower frequency in said sets by a common integral number.
Claim 12
Dependent Claim
24 words
A process in accordance with claim 1 in which each of said sets of waves after the first follows immediately after the preceding set.
Claim 13
Dependent Claim
16 words
producing a visual record in accordance with the combined outputs of the delayed and filtered signals.
Claim 14
Dependent Claim
16 words
producing a visual record in accordance with the combined outputs of the delayed and filtered signals.
Claim 15
Dependent Claim
81 words
A process in accordance with claim 1, in which the time duration of each set in said succession is substantially equal, the amplitude of all sine waves in said succession is substantially constant, the frequency of each of said sets is related to the next lower frequency in said sets by a common integral nuMber, and in the combining step the initial polarity of at least about half of said sets is opposite from that of the rest of said sets.
Claim 16
Dependent Claim
31 words
A process in accordance with claim 4, in which each said preselected time interval is chosen such that said one-half cycle is substantially a center half cycle of each said set.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |