Patent US4381591A successfully refreshed from Google Patents.
Patent US3136942A successfully refreshed from Google Patents.
US3136942A
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US
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Electrical well logging methods and apparatus having a focussed electrode system including plural survey current electrodes
Assignee: Schlumberger Well Surveying Corp
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Filing: 1959-06-16
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Granted: 1964-06-09
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Expires: 1979-06-16
Abstract
No abstract record available.
Inventors
- 👤 Nick A Schuster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:29
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/20; G01V3/24
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
75 words
IN APPARATUS FOR INVESTIGATING EARTH FORMATIONS TRAVERSED BY A BOREHOLE, THE COMBINATION COMPRISING: MEANS FOR SIMULTANEOUSLY EMITTING FIRST AND SECOND SURVEY CURRENTS AT TWO VERTICALLY SPACED APART POINTS IN A BOREHOLE; MEANS FOR EMITTING FOCUSSING CURRENT ADJACENT SAID POINTS FOR DIRECTING THE SURVEY CURRENTS INTO THE ADJACENT EARTH FORMATIONS; AND MEANS RESPONSIVE TO THE FLOW OF BOTH OF SAID SURVEY CURRENTS FOR PROVIDING AN INDICATION OF THE EARTH FORMATION RESISTIVITY GRADIENT INTERMEDIATE SAID TWO POINTS.
References Cited (Backward Citations)
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US2669689A
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US2712630A
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US2786178A
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US2823349A
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US2961600A
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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) | 1967-06-09 | 1967-12-09 | 1968-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-06-09 | 1971-12-09 | 1972-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-06-09 | 1975-12-09 | 1976-06-09 | $7700.00 | Window Closed / Lapsed |