Patent US3997338A successfully refreshed from Google Patents.
US3555409A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic susceptibility logging system with transmitter and receiver null coils
Assignee: Texaco Inc
•
Filing: 1969-10-06
•
Granted: 1971-01-12
•
Expires: 1989-10-06
Abstract
Abstract A BOREHOLE LOGGING TOOL THAT INCLUDES AIR CORE TRANSMITTER AND RECEIVER COILS PLUS AUXILIARY AIR CORE NULLING COILS. A COMPENSATED MAGNETIC INDUCTION CIRCUIT IS EMPLOYED FOR NULLING A MAJOR PORTION OF THE RECEIVER COIL SIGNALS, IN ORDER THAT THE CHANGES CAUSED BY MAGNETIC PROPERTY CHANGE IN THE SURROUNDING BOREHOLE, MAY BE READILY DETECTED. THE AUXILIARY NULLING COILS ARE PANCAKE SHAPED AND ARE LOCATED OUTSIDE THE FIELDS OF THE TRANSMITTER AND RECEIVER COILS. BUT THEY ARE LOCATED ON THE LOGGING TOOL SO THAT THEY ARE SUBJECT TO THE SAME AMBIENT CONDITIONS AS ARE THE TRANSMITTER AND RECEIVER COILS.
Inventors
- 👤 George R Atwood
- 👤 Donald J Dowling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:28
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/26; G01V3/28
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |