US2221353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for treating oil wells
Assignee: Shell Development Co
•
Filing: 1939-03-27
•
Granted: 1940-11-12
•
Expires: 1959-03-27
Abstract
No abstract record available.
Inventors
- 👤 Donald A Limerick
- 👤 Howard C Lawton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:31
CPC Classifications
E; E21; E21B; E21B36/00; C; C09; C09K; C09K8/00; C09K8/52; C09K8/524; Y; Y10; Y10S; Y10S507/00; Y10S507/927; Y10S507/929; Y10S507/931
Claims Analysis
Total Claims: 0
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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) | 1943-11-12 | 1944-05-13 | 1944-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-11-12 | 1948-05-13 | 1948-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-11-12 | 1952-05-13 | 1952-11-12 | $7700.00 | Window Closed / Lapsed |