US3726796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling fluid and method
Assignee: Kelco Co
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Filing: 1971-06-03
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Granted: 1973-04-10
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Expires: 1991-06-03
Abstract
Abstract OIL BASE DRILLING FLUIDS AND WATER-IN-OIL EMULSION DRILLING FLUIDS CONTAINING QUATERNARY AMMONIUM SALTS OF CELLULOSE SULFATE HAVING A DEGREE OF SUBSTITUTION OF ABOUT 2 OR MORE AND A VISCOSITY AT A ONE-PERCENT CONCENTRATIONS IN AQUEOUS MEDIA IN EXCESS OF 20 CPS. METHOD FOR DRILLING WELLS BY CIRCULATING A DRILLING FLUID,AS DEFINED ABOVE, IN CONTACT WITH A SUBSURFACE FORMATION.
Inventors
- 👤 R Schweiger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:02
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/32; C09K8/36; Y; Y10; Y10S; Y10S507/00; Y10S507/91; Y10S516/00; Y10S516/01; Y10S516/03; Y10S516/05; Y10S516/902
Claims Analysis
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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) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |