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US3501201A
Expired / Lapsed
US
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Method of producing shale oil from a subterranean oil shale formation
Assignee: Shell USA Inc
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Filing: 1968-10-30
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Granted: 1970-03-17
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Expires: 1988-10-30
Abstract
No abstract record available.
Inventors
- 👤 Philip J Closmann
- 👤 Ronald P Nordgren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:11
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/28; E21B43/16; E21B43/24; E21B43/2405; E21B43/281
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) | 1973-03-16 | 1973-09-15 | 1974-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-03-16 | 1977-09-15 | 1978-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-03-16 | 1981-09-15 | 1982-03-17 | $7700.00 | Window Closed / Lapsed |