Patent US3481398A successfully refreshed from Google Patents.
US3481398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permeabilizing by acidizing oil shale tuffaceous streaks in and oil recovery therefrom
Assignee: Shell USA Inc
•
Filing: 1967-02-28
•
Granted: 1969-12-02
•
Expires: 1987-02-28
Abstract
No abstract record available.
Inventors
- 👤 Michael Prats
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:30
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/20; C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2804145A
Cited
US3075463A
Cited
US3246693A
Cited
US3297090A
Cited
US3284281A
Cited
US3346048A
Cited
US3322194A
Cited
US3352355A
Cited
US3346044A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-12-01 | 1973-06-02 | 1973-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-12-01 | 1977-06-02 | 1977-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-12-01 | 1981-06-02 | 1981-12-02 | $7700.00 | Window Closed / Lapsed |