Patent US2481339A successfully refreshed from Google Patents.
US2481339A
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Drilling fluid composition
Assignee: Shell Development Co
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Filing: 1947-07-01
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Granted: 1949-09-06
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Expires: 1967-07-01
Abstract
No abstract record available.
Inventors
- 👤 Charles S Penfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:15
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/003
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1952-09-05 | 1953-03-07 | 1953-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-09-05 | 1957-03-07 | 1957-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-09-05 | 1961-03-07 | 1961-09-06 | $7700.00 | Window Closed / Lapsed |