US3704990A
Expired / Lapsed
US
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Process for recovering oil from heterogeneous reservoirs
Assignee: Union Oil Company of California
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Filing: 1971-06-04
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Granted: 1972-12-05
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Expires: 1991-06-04
Abstract
Abstract A process for recovering oil from heterogeneous petroleum reservoirs in which there is successively injected into the reservoir through one or more injection wells (1) an aqueous solution of a water-soluble polymer dissolved in substantially salt-free water, (2) a solvent miscible with the reservoir oil, and (3) an aqueous drive fluid; and wherein oil is recovered from one or more production wells spaced apart in the reservoir from the injection well. The polymer is selected to obtain mobility reduction in the more permeable zones without causing plugging of these zones.
Inventors
- 👤 Amir M Sarem
- 👤 Leroy W Holm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:07
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/58; C09K8/588
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
33 words
The method defined in claim 1 wherein said water-soluble polymer is an acrylic acid-acrylamide copolymer, an acrylic acid-acrylamide-diacetone acrylamide terpolymer, a polyacrylamide, a partially hydrolyzed polyacrylamide, hydroxyethyl cellulose, carboxymethyl cellulose, polyoxyethylene, or polysaccharide.
Claim 2
Dependent Claim
21 words
The method defined in claim 1 wherein said aqueous solution contains from about 0.01 to 0.2 weight percent of said polymer.
Claim 3
Dependent Claim
23 words
The method defined in claim 1 wherein about 0.005 to 0.15 reservoir pore volume of said aqueous solution is injected into the reservoir.
Claim 4
Dependent Claim
51 words
The method defined in claim 1 wherein said polymer is an acrylic acid-acrylamide copolymer, partially hydrolyzed polyacrylamide, or acrylic acid-acrylamide-diacetone acrylamide terpolymer characterized by a resistance factor of between about 6 and 25 for a 0.05 weight percent solution thereof in an aqueous 3 percent solution of sodium chloride at 25*C.
Claim 5
Independent Claim
98 words
A method for recovering petroleum from a heterogeneous subterranean petroleum reservoir penetrated by at least one injection well and one production well spaced apart in the reservoir, which comprises: injecting 0.005 to 0.15 reservoir pore volume of an aqueous solution consisting essentially of a water-soluble polymer and water through said injection well and into said reservoir; next injecting 0.01 to 0.15 reservoir pore volume of a displacement fluid that is miscible with the reservoir oil; thereafter injecting an aqueous flooding medium to drive the miscible displacement fluid towards said production well; and recovering oil from said production well.
Claim 6
Dependent Claim
33 words
The method defined in claim 6 wherein said water-soluble polymer is an acrylic acid-acrylamide copolymer, an acrylic acid-acrylamide-diacetone acrylamide terpolymer, a polyacrylamide, a partially hydrolyzed polyacrylamide, hydroxyethyl cellulose, carboxymethyl cellulose, polyoxyethylene, or polysaccharide.
Claim 7
Dependent Claim
21 words
The method defined in claim 6 wherein said aqueous solution contains from about 0.01 to 0.15 weight percent of said polymer.
Claim 8
Dependent Claim
52 words
The method defined in claim 6 wherein said polymer is an acrylic acid-acrylamide copolymer, partially hydrolyzed polyacrylamide, or acrylic acid-acrylamide-diacetone acrylamide terpolymer characterized by a resistance factor of between about 6 and 25 for a 0.05 weight percent solution thereof in an aqueous 3 percent solution of sodium chloride at 25* C.
Claim 9
Dependent Claim
17 words
The method defined in claim 6 wherein said water contains less than about 50 ppm dissolved salts.
Claim 10
Dependent Claim
18 words
The method defined in claim 6 wherein said displacement fluid is a soluble oil or a water-in-oil microemulsion.
Claim 11
Dependent Claim
30 words
The method defined in claim 6 wherein an initial portion of the aqueous flooding medium is increased in viscosity by the addition of a small amount of a water-soluble polymer.
Claim 12
Independent Claim
148 words
A method for recovering oil from a heterogeneous subterranean petroleum reservoir penetrated by at least one injection well and one production well spaced apart in the reservoir, which comprises: injecting through the injection well and into the reservoir 0.01 to 0.15 reservoir pore volume of an aqueous solution consisting essentially of a substantially salt-free water having dissolved therein 0.01 to 0.15 weight percent of a water-soluble acrylic acid-acrylamide copolymer, a partially hydrolyzed polyacrylamide, or an acrylic acid-acrylamide-diacetone acrylamide terpolymer characterized by a resistance factor of between about 6 and 25 for a 0.05 weight percent solution thereof in an aqueous 3 percent solution of sodium chloride at 25* C.; next injecting 0.01 to 0.15 reservoir pore volume of soluble oil or water-in-oil microemulsion; next injecting 0.1 to 0.50 reservoir pore volume of a thickened aqueous flooding medium; thereafter injecting flood water; and recovering oil from said production well.
Claim 13
Dependent Claim
39 words
The method defined in claim 13 wherein said polymer is characterized by a resistance factor of between about 10 to 20 for a 0.05 weight percent solution thereof in an aqueous 3 percent solution of sodium chloride at 25*.
Claim 14
Dependent Claim
45 words
The method defined in claim 13 wherein said soluble oil is comprised of a mixture of about 45 to 90 percent liquid hydrocarbon, 4 to 30 percent of a surface active agent, 1 to 8 percent stabilizing agent, and less than about 10 percent water.
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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) | 1975-12-05 | 1976-06-05 | 1976-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-05 | 1980-06-05 | 1980-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-05 | 1984-06-05 | 1984-12-05 | $7700.00 | Window Closed / Lapsed |