US4274488A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cosurfactant in preflush for surfactant flood system
Assignee: Phillips Petroleum Co
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Filing: 1979-08-31
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Granted: 1981-06-23
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Expires: 1999-08-31
Abstract
Abstract In a post-primary oil recovery process involving the sequential addition of a saline preflush, a surfactant system comprising a surfactant, a cosurfactant and brine, the improvement comprising the addition of cosurfactant to the preflush. If desired, cosurfactant can also be added to a subsequent injected mobility buffer. The resulting system gives extraordinarily high recovery of oil.
Inventors
- 👤 James H. Hedges
- 👤 Gilbert R. Glinsmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:22
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/58; C09K8/584
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
124 words
A process for recovering oil from a subterranean oil-bearing reservoir comprising the steps of: (a) injecting into said reservoir through at least one injection well a preflush comprising water, an electrolyte, and 0.1 to 10 weight percent cosurfactant based on the total weight of said preflush; (b) thereafter injecting into said reservoir through at least one injection well an aqueous surfactant system comprising water, electrolyte, surfactant and cosurfactant, which surfactant system is characterized by forming a microemulsion by mixing with oil corresponding to that in said reservoir which microemulsion is immiscible with said oil; (c) thereafter injecting into said reservoir through at least one injection well a drive fluid thus forcing said oil toward at least one recovery well; and (d) recovering said oil.
Claim 2
Dependent Claim
124 words
A process for recovering oil from a subterranean oil-bearing reservoir comprising the steps of: (a) injecting into said reservoir through at least one injection well a preflush comprising water, an electrolyte, and 0.1 to 10 weight percent cosurfactant based on the total weight of said preflush; (b) thereafter injecting into said reservoir through at least one injection well an aqueous surfactant system comprising water, electrolyte, surfactant and cosurfactant, which surfactant system is characterized by forming a microemulsion by mixing with oil corresponding to that in said reservoir which microemulsion is immiscible with said oil; (c) thereafter injecting into said reservoir through at least one injection well a drive fluid thus forcing said oil toward at least one recovery well; and (d) recovering said oil.
Claim 3
Dependent Claim
35 words
A method according to claim 1 wherein said electrolyte is present in said preflush in a concentration within the range of 5,000 to 25,000 parts by weight per million parts by weight of said preflush.
Claim 4
Dependent Claim
15 words
A method according to claim 1 wherein said electrolyte of said preflush comprises sodium chloride.
Claim 5
Dependent Claim
31 words
A method according to claim 1 wherein said cosurfactant is an alcohol having a solubility within the range of 0.5 to 20 grams per 100 grams of water at room temperature.
Claim 6
Dependent Claim
23 words
A method according to claim 1 wherein said cosurfactant is selected from the group consisting of 2-butanol, 2-pentanol, n-butanol, tertiary pentanol, and isopentanol.
Claim 7
Dependent Claim
30 words
A method according to claim 1 wherein said cosurfactant is present in an amount within the range of 1.5 to 4.5 weight percent based on the weight of said preflush.
Claim 8
Dependent Claim
39 words
A method according to claim 6 wherein said electrolyte in said preflush is sodium chloride and is present in an amount within the range of 5,000 to 25,000 parts by weight per million parts by weight of said preflush.
Claim 9
Dependent Claim
22 words
A method according to claim 7 wherein said cosurfactant of said preflush is the same as the cosurfactant of the surfactant system.
Claim 10
Dependent Claim
105 words
A method according to claim 8 wherein said surfactant system comprises: water; an electrolyte present in a concentration within the range of 5,000 to 25,000 parts by weight per million parts by weight of water; 1 to 7 weight percent based on the weight of said water of a petroleum sulfonate surfactant having an average equivalent weight within the range of 375 to 500; and an alcohol cosurfactant selected from the group consisting of 2-butanol, isobutanol, 2-pentanol, n-butanol, tertiary pentanol, and isopentanol, said cosurfactant being present in an amount within the range of 1 to 7 weight percent based on the weight of said water.
Claim 11
Dependent Claim
34 words
A method according to claim 9 wherein a mobility buffer is injected into said subterranean oil-bearing formation subsequent to said injection of said surfactant system and prior to said injection of said drive fluid.
Claim 12
Dependent Claim
13 words
A method according to claim 10 wherein said mobility buffer contains a cosurfactant.
Claim 13
Dependent Claim
18 words
A method according to claim 10 wherein neither said mobility buffer nor said drive fluid contain a cosurfactant.
Claim 14
Dependent Claim
21 words
A method according to claim 1 comprising in addition introducing a preflush containing no cosurfactant ahead of said preflush of (a).
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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) | 1984-06-22 | 1984-12-22 | 1985-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-22 | 1988-12-22 | 1989-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-22 | 1992-12-22 | 1993-06-23 | $7700.00 | Window Closed / Lapsed |