US3825067A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of aqueous solutions of polyacrylamides suitable for supplemented recovery of petroleum
Assignee: Marathon Oil Co
•
Filing: 1972-12-29
•
Granted: 1974-07-23
•
Expires: 1992-12-29
Abstract
Abstract Polyacrylamide gel or polyacrylamide powder is added to water and the pH is adjusted to within the range of from about 7 to about 14, e.g., with NaOH. The mixture is then heated to from about 20* to about 100*C. to form an aqueous solution having good efficiency in the recovery of petroleum from formations.
Inventors
- 👤 C Vestal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:53
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/20; C; C09; C09K; C09K8/00; C09K8/58; C09K8/588
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
17 words
A process according to claim 1 wherein said polyacrylamide is in the form of a dry powder.
Claim 2
Dependent Claim
16 words
A process according to claim 1 wherein said polyacrylamide is in the form of a gel.
Claim 3
Dependent Claim
72 words
A process according to claim 3 wherein said polyacrylamide gel is prepared by: a. dissolving acrylamide monomer in deoxygenated water substantially free from divalent cations, b. adjusting the pH to about 7 by addition of buffer compounds, c. adding free radical initiator to the resulting buffered acrylamide-water mixture, d. maintaining the resulting mixture in a substantially quiescent state for a period of time sufficient to permit the formation of said polyacrylamide gel.
Claim 4
Dependent Claim
29 words
A process according to claim 4 wherein said free radical initiator is selected from the group consisting of: triethanolamine, ammonium persulfate, and sodium bisulfite and mixtures of the foregoing.
Claim 5
Dependent Claim
18 words
A process according to claim 5 wherein said free radical initiator comprises both ammonium persulfate and sodium bisulfite.
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) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |