US4005749A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oil recovery by surfactant waterflooding
Assignee: Mobil Oil AS
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Filing: 1975-11-11
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Granted: 1977-02-01
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Expires: 1995-11-11
Abstract
Abstract A surfactant waterflooding process for the recovery of oil from subterranean oil reservoirs in which a water-soluble polyalkylene oxide is employed as a sacrificial agent in order to retard adsorption of the surfactant. An aqueous pretreatment slug is injected which contains a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200. Thereafter an aqueous slug containing a surfactant exhibiting a lower molecular weight than that of the polyalkylene oxide sacrificial agent is injected. The surfactant slug may also contain a polyalkylene oxide sacrificial agent as described above. In this case, concentration of sacrificial agent in the surfactant slug normally is lower than the concentration in the pretreatment slug.
Inventors
- 👤 Silvia C. Birk
- 👤 Samuel H. Collins
- 👤 Peggy M. Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:11
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/84; C09K8/86; C09K8/88; C09K8/885; C09K8/58; C09K8/584
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
127 words
In the recovery of oil from a subterranean oil reservoir penetrated by spaced injection and production systems, the method comprising: a. injecting into said reservoir via said injection system an aqueous pretreatment slug containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200 selected from the group consisting of polyethylene glycols, polypropylene glycols, interpolymers of polypropylene glycols and polyethylene glycols, and mixtures thereof, b. thereafter introducing into said reservoir via said injection system an aqueous surfactant slug containing a surfactant having a lower molecular weight than the molecular weight of said polyalkylene oxide, c. introducing into said reservoir via said injection system an aqueous flooding medium to displace reservoir oil to said production system, and d. recovering oil from said production system.
Claim 2
Dependent Claim
127 words
In the recovery of oil from a subterranean oil reservoir penetrated by spaced injection and production systems, the method comprising: a. injecting into said reservoir via said injection system an aqueous pretreatment slug containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200 selected from the group consisting of polyethylene glycols, polypropylene glycols, interpolymers of polypropylene glycols and polyethylene glycols, and mixtures thereof, b. thereafter introducing into said reservoir via said injection system an aqueous surfactant slug containing a surfactant having a lower molecular weight than the molecular weight of said polyalkylene oxide, c. introducing into said reservoir via said injection system an aqueous flooding medium to displace reservoir oil to said production system, and d. recovering oil from said production system.
Claim 3
Dependent Claim
44 words
The method of claim 1 wherein said surfactant slug contains a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200 selected from the group consisting of polyethylene glycols, polypropylene glycols, interpolymers of polypropylene glycols and polyethylene glycols, and mixtures thereof.
Claim 4
Dependent Claim
152 words
In the recovery of oil from a subterranean oil reservoir penetrated by spaced injection and production systems, the method comprising: a. injecting into said reservoir via said injection system an aqueous pretreatment slug containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200, b. thereafter introducing into said reservoir via said injection system an aqueous surfactant slug containing a surfactant having a lower molecular weight than the molecular weight of said polyalkylene oxide, said surfactant slug also containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200 and in a concentration within the range of 0.05-0.5 weight percent and lower than the concentration of said polyalkylene oxide sacrificial agent in said pretreatment slug, c. introducing into said reservoir via said injection system an aqueous flooding medium to displace reservoir oil to said production system, and d. recovering oil from said production system.
Claim 5
Dependent Claim
152 words
In the recovery of oil from a subterranean oil reservoir penetrated by spaced injection and production systems, the method comprising: a. injecting into said reservoir via said injection system an aqueous pretreatment slug containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200, b. thereafter introducing into said reservoir via said injection system an aqueous surfactant slug containing a surfactant having a lower molecular weight than the molecular weight of said polyalkylene oxide, said surfactant slug also containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200 and in a concentration within the range of 0.05-0.5 weight percent and lower than the concentration of said polyalkylene oxide sacrificial agent in said pretreatment slug, c. introducing into said reservoir via said injection system an aqueous flooding medium to displace reservoir oil to said production system, and d. recovering oil from said production system.
Claim 6
Dependent Claim
114 words
In the recovery of oil from a subterranean oil reservoir penetrated by spaced injection and production systems, the method comprising: a. injecting into said reservoir via said injection system an aqueous pretreatment slug containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200, b. thereafter introducing into said reservoir via said injection system an aqueous surfactant slug containing a multifunctional anionic-nonionic surfactant system and comprising a surfactant having a lower molecular weight than the molecular weight of said polyalkylene oxide, c. introducing into said reservoir via said injection system an aqueous flooding medium to displace reservoir oil to said production system, and d. recovering oil from said production system.
Claim 7
Dependent Claim
114 words
In the recovery of oil from a subterranean oil reservoir penetrated by spaced injection and production systems, the method comprising: a. injecting into said reservoir via said injection system an aqueous pretreatment slug containing a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200, b. thereafter introducing into said reservoir via said injection system an aqueous surfactant slug containing a multifunctional anionic-nonionic surfactant system and comprising a surfactant having a lower molecular weight than the molecular weight of said polyalkylene oxide, c. introducing into said reservoir via said injection system an aqueous flooding medium to displace reservoir oil to said production system, and d. recovering oil from said production system.
Claim 8
Dependent Claim
18 words
The method of claim 4 wherein the anionic component of said multifunctional surfactant system comprises an amide-linked sulfonate.
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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) | 1980-02-01 | 1980-08-02 | 1981-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-01 | 1984-08-02 | 1985-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-01 | 1988-08-02 | 1989-02-01 | $7700.00 | Window Closed / Lapsed |