US3528914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling fluid and method for increasing drilling rate
Assignee: Shell USA Inc
•
Filing: 1966-12-14
•
Granted: 1970-09-15
•
Expires: 1986-12-14
Abstract
No abstract record available.
Inventors
- 👤 Henry C H Darley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:50
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/26; C09K8/28
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US3276887A
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US3310125A
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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) | 1973-09-14 | 1974-03-16 | 1974-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-09-14 | 1978-03-16 | 1978-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-09-14 | 1982-03-16 | 1982-09-15 | $7700.00 | Window Closed / Lapsed |