US2597085A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Employment of nonaqueous well drilling fluids
Assignee: NL Industries Inc
•
Filing: 1944-04-17
•
Granted: 1952-05-20
•
Expires: 1964-04-17
Abstract
No abstract record available.
Inventors
- 👤 Delmar H Larsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:34
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/32; Y; Y10; Y10S; Y10S507/00; Y10S507/91
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
39 words
AN OIL-BASE WELL-DRILLING FLUID CONTAINING A NATURAL ASPHALT OF A TYPE AND CHARACTER DISPERSIBLE IN OIL AND CHOSEN FROM THE GROUP CONSISTING OF GILSONITE, MANJAK, GLANCE PITCH AND GRAHAMITE, IN AN AMOUNT SUFFICIENT TO SUBSTANTIALLY REDUCE THE FILTRATION LOSS.
Claim 2
Dependent Claim
39 words
AN OIL-BASE WELL-DRILLING FLUID CONTAINING A NATURAL ASPHALT OF A TYPE AND CHARACTER DISPERSIBLE IN OIL AND CHOSEN FROM THE GROUP CONSISTING OF GILSONITE, MANJAK, GLANCE PITCH AND GRAHAMITE, IN AN AMOUNT SUFFICIENT TO SUBSTANTIALLY REDUCE THE FILTRATION LOSS.
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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) | 1955-05-20 | 1955-11-19 | 1956-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-05-20 | 1959-11-19 | 1960-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-05-20 | 1963-11-19 | 1964-05-20 | $7700.00 | Window Closed / Lapsed |