US3638728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Secondary oil recovery process with incremental injection of surfactant slugs
Assignee: Shell USA Inc
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Filing: 1970-03-11
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Granted: 1972-02-01
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Expires: 1990-03-11
Abstract
Abstract An improved method for recovering oil from underground formations by prior to waterflooding, treating said formations with at least two chemical slugs each containing a synergistic mixture of particular surfactants namely sulfonate-sulfate mixture wherein one slug is compatible with water of high salinity and hardness and the other slug is compatible with the floodwater which optionally can contain a thickener.
Inventors
- 👤 Harold J Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:51
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/58; C09K8/584; E; E21; E21B; E21B43/00; E21B43/16; E21B43/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
21 words
The method of claim 1 wherein the sulfonate is a petroleum sulfonate and the oxyalkylated surfactant is a polyethoxylated alcohol sulfate.
Claim 2
Dependent Claim
26 words
The method of claim 2 where in the petroleum sulfonate is na oil-soluble Na petroleum sulfonate and the oxyalkylated surfactant is a sulfated polyethoxylated primary alcohol.
Claim 3
Dependent Claim
19 words
The method of claim 3 wherein the sulfated alcohol has from three to six ethoxy groups in the molecule.
Claim 4
Dependent Claim
14 words
The method of claim 4 wherein he drive water is water containing a thickener.
Claim 5
Dependent Claim
11 words
The method of claim 5 wherein the thickener is a polyacrylamide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |