US4573533A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for using thermally stable mobility control agents for harsh environmental reservoirs
Assignee: Wyeth Holdings LLC
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Filing: 1984-06-21
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Granted: 1986-03-04
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Expires: 2004-06-21
Abstract
Abstract Copolymers of 2-acrylamido-2-methylpropane sulfonic acid or its salts are used to maintain the viscosity of aqueous solutions thereof in the presence of divalent salt containing-waters during the enhanced recovery of petroleum from sub-terranean petroleum-bearing deposits.
Inventors
- 👤 Roderick G. Ryles
- 👤 Albert G. Robustelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:31
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/58; C09K8/588; Y; Y10; Y10S; Y10S507/00; Y10S507/935; Y10S507/936
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
104 words
In a method for recovering petroleum from a sub-terranean petroleum-bearing deposit which comprises injecting an aqueous polymer solution into the area of said deposit through at least one input well to cause said petroleum to flow from said area for collection through at least one output well, the improvement which comprises maintaining and controlling the viscosity of said solution by utilizing, in the substantial absence of oxygen, a water-soluble copolymer containing from about 30-70 mole percent of 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof and from about 70-30 mole percent of an acrylic monomer, the temperature at the petroleum-bearing deposit being at least 60° C.
Claim 2
Dependent Claim
104 words
In a method for recovering petroleum from a sub-terranean petroleum-bearing deposit which comprises injecting an aqueous polymer solution into the area of said deposit through at least one input well to cause said petroleum to flow from said area for collection through at least one output well, the improvement which comprises maintaining and controlling the viscosity of said solution by utilizing, in the substantial absence of oxygen, a water-soluble copolymer containing from about 30-70 mole percent of 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof and from about 70-30 mole percent of an acrylic monomer, the temperature at the petroleum-bearing deposit being at least 60° C.
Claim 3
Dependent Claim
14 words
A method according to claim 1 wherein said aqueous solution contains a divalent salt.
Claim 4
Dependent Claim
21 words
A method according to claim 2 wherein said divalent salt is present at a concentration of at least about 100 ppm.
Claim 5
Dependent Claim
19 words
A method according to claim 2 wherein said divalent salt is a calcium or magnesium salt or mixture thereof.
Claim 6
Dependent Claim
12 words
A method according to claim 1 wherein said acrylic monomer is acrylamide.
Claim 7
Dependent Claim
13 words
A method according to claim 1 wherein said acrylic monomer is sodium acrylate.
Claim 8
Dependent Claim
32 words
A method according to claim 1 wherein said copolymer contains from about 40-70 mole percent of 2-acrylamido-2-methylpropane sulfonic acid or salt thereof and from about 60-30 mole percent of an acrylic monomer.
Claim 9
Dependent Claim
22 words
A method according to claim 7 wherein the temperature at the petroleum-bearing deposit ranges from about 60° C. to about 120° C.
Claim 10
Dependent Claim
12 words
A method according to claim 7 wherein said acrylic monomer is acrylamide.
Claim 11
Dependent Claim
13 words
A method according to claim 7 wherein said acrylic monomer is sodium acrylate.
Claim 12
Dependent Claim
22 words
A method according to claim 7 wherein the temperature at the petroleum-bearing deposit ranges from about 70° C. to about 90° C.
References Cited (Backward Citations)
US3679000A
Cited
US3800877A
Cited
US3858652A
Cited
US3945929A
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US3953341A
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US4458753A
Cited
EP0115836A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-03 | 1989-09-02 | 1990-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-03 | 1993-09-02 | 1994-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-03 | 1997-09-02 | 1998-03-04 | $7700.00 | Window Closed / Lapsed |