Patent US4210869A successfully refreshed from Google Patents.
US4210869A
Expired / Lapsed
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Rotating telluric field measurements
Assignee: Mobil Oil AS
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Filing: 1979-04-02
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Granted: 1980-07-01
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Expires: 1999-04-02
Abstract
Abstract In magneto-telluric geophysical exploration, the earth's electric telluric field in two orthogonal directions is determined. Electrodes are positioned on the earth's surface so that measured potentials between adjacent electrodes measures the earth's telluric field in known directions. These measurements are converted to signals representing the earth's telluric field in two specified orthogonal directions. The measurements are made between electrodes spaced along a cable which is laid on the ocean floor.
Inventors
- 👤 Goethe M. Groenendyke, deceased
- 👤 Gustave L. Hoehn, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:16
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/08; G01V3/082
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
173 words
In magneto-telluric geophysical exploration, the system for determining the earth's electric telluric field in two orthogonal directions comprising: (a) means for measuring the earth's telluric field along a first horizontal line in a first known direction and for producing a first telluric signal representative thereof, (b) means for measuring the earth's telluric field along a second horizontal line in a second known direction and producing a second telluric signal representative thereof, (c) means for producing a pair of signals representative of the values of said first and second telluric signals along a third predetermined horizontal line and for combining said pair of signals to provide a signal representative of the earth's electric telluric field along said third horizontal line, and (d) means for producing a pair of signals representative of the values of said first and second telluric signals along a fourth horizontal line orthogonal to said third horizontal line and for combining said pair of signals to provide a signal representative of the earth's electric telluric field along said fourth horizontal line.
Claim 2
Dependent Claim
173 words
In magneto-telluric geophysical exploration, the system for determining the earth's electric telluric field in two orthogonal directions comprising: (a) means for measuring the earth's telluric field along a first horizontal line in a first known direction and for producing a first telluric signal representative thereof, (b) means for measuring the earth's telluric field along a second horizontal line in a second known direction and producing a second telluric signal representative thereof, (c) means for producing a pair of signals representative of the values of said first and second telluric signals along a third predetermined horizontal line and for combining said pair of signals to provide a signal representative of the earth's electric telluric field along said third horizontal line, and (d) means for producing a pair of signals representative of the values of said first and second telluric signals along a fourth horizontal line orthogonal to said third horizontal line and for combining said pair of signals to provide a signal representative of the earth's electric telluric field along said fourth horizontal line.
Claim 3
Dependent Claim
43 words
The system recited in claim 1 wherein the means for measuring the earth's telluric field along said first and second horizontal lines comprises at least three electrodes positioned on the earth's surface with at least one electrode being displaced from a straight line.
Claim 4
Dependent Claim
21 words
The system recited in claim 2 wherein one of said electrodes is common to both said first and second horizontal lines.
Claim 5
Dependent Claim
32 words
The system recited in claim 3 for use in marine geophysical exploration and which further comprises: a cable for lying on the ocean bottom with said electrodes being spaced along said cable.
Claim 6
Dependent Claim
33 words
The system recited in claim 4 further comprising: means for transmitting from each electrode a signal establishing the location of that electrode so that the directions of said horizontal lines can be established.
Claim 7
Dependent Claim
29 words
The system of claim 1 wherein said means for producing pairs of signals representative of the telluric signals along said third and fourth horizontal lines are variable gain amplifiers.
Claim 8
Dependent Claim
13 words
The system of claim 6 wherein said variable gain amplifiers are operational amplifiers.
Claim 9
Dependent Claim
30 words
The system of claim 6 wherein said means for combining said pairs of signals representative of the earth's telluric field along said third and fourth horizontal lines are summing amplifiers.
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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) | 1983-07-01 | 1983-12-31 | 1984-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-01 | 1987-12-31 | 1988-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-01 | 1991-12-31 | 1992-07-01 | $7700.00 | Window Closed / Lapsed |