US3760879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Petroleum recovery process utilizing formaldehyde-sulfite-reacted polyacrylamide
Assignee: Marathon Oil Co
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Filing: 1971-10-29
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Granted: 1973-09-25
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Expires: 1991-10-29
Abstract
Abstract Viscosity and screen factor of modified polyacrylamides for use in supplemented recovery of petroleum are increased by treatment with formaldehyde and either simultaneously or sequentially with sulfite or bisulfite to yield a high molecular weight partially hydrolyzed sulfomethylated polyacrylamide which is hydrophilic and exhibits high efficiency in petroleum recovery.
Inventors
- 👤 C Norton
- 👤 D Falk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:05
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/58; C09K8/588; Y; Y10; Y10S; Y10S507/00; Y10S507/935; Y10S507/936
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
46 words
The process of claim 1 wherein said aqueous solutions of unhydrolyzed polyacrylamide are contacted with said formaldehyde at a temperature of from about 0* to about 300* C. and wherein said unhydrolyzed polyacrylamide is contacted with said sulfite at from about 0* to about 300* C.
Claim 2
Dependent Claim
39 words
A process according to claim 1 wherein said unhydrolyzed polyacrylamide in first contacted with said formaldehyde for a time sufficient to substantially complete said reaction with said formaldehyde and wherein said unhydrolyzed methylolated polyacrylamide is thereafter contacted with sulfite.
Claim 3
Dependent Claim
20 words
A process according to claim 1 wherein said unhydrolyzed polyacrylamide is contacted with said formaldehyde and said sulfite substantially simultaneously.
Claim 4
Dependent Claim
149 words
A process according to claim 1 wherein the aqueous solution contains from about 50 to about 5,000 parts per million by weight of unhydrolyzed polyacrylamide, said unhydrolyzed polyacrylamide having a molecular weight in the range of from about 1 to about 100 million, the sulfite is selected from the group consisting of: alkali sulfiTes, alkaline earth sulfites, alkali bisulfites, alkaline earth bisulfites, ammonium sulfite, ammonium bisulfite, the pyrosulfites and metabisulfites corresponding to any of the foregoing and mixtures of any of the foregoing, and wherein there are present from about 0.01 to about 10.0 moles of formaldehyde and from about 0.01 to about 2.0 moles of sulfite per mole of acrylamide monomer unit in the polyacrylamide, and wherein the temperature is in the range of from about 0* to about 300* C., and the contact is maintained for a reaction time of from about 0.1 to about 100 hours.
Claim 5
Dependent Claim
131 words
A process according to claim 3 wherein the aqueous solution contains from about 50 to about 5,000 parts per million by weight of unhydrolyzed polyacrylamide, the sulfite is selected from the group consisting of: alkali sulfites, alkaline earth sulfites, alkali bisulfites, alkaline earth bisulfites, ammonium sulfite, ammonium bisulfite, the pyrosulfites and metabisulfites corresponding to any of the foregoing and mixtures of any of the foregoing, and wherein there are present from about 0.01 to about 10 moles of formaldehyde and from about 0.01 to about 2.0 moles of sulfite per mole of acrylamide monomer unit in the polyacrylamide, and wherein the temperature is in the range of from about 0* to about 300* C., and each contact is maintained for a reaction time of from about 0.1 to about 100 hours.
Claim 6
Dependent Claim
146 words
A process according to claim 5 in which the aqueous solution contains from about 100 to about 2,000 parts per million by weight of unhydrolyzed polyacrylamide, said unhydrolyzed polyacrylamide has a molecular weight in the range of from about 1 to about 100 million, there are present from about 0.1 to about 5.0 moles of formaldehyde and about 0.05 to about 1.0 mole of sulfite per mole of acrylamide monomer unit within the polyacrylamide, the pH during the contact with the formaldehyde is in the range of from about 8.0 to about 10.5, the pH during the contact with sulfite is in the range of from about 9.5 to about 13.5, the temperature during the contact with formaldehyde and with sulfite is in the range of from about 20* to about 200* C., and the reaction is carried out for about 0.5 to about 50 hours.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |