US4016932A
Expired / Lapsed
US
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Surfactant oil recovery method for use in high temperature formations containing water having high salinity and hardness
Assignee: Texaco Inc
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Filing: 1975-12-24
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Granted: 1977-04-12
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Expires: 1995-12-24
Abstract
Abstract Surfactant systems employing two or more surfactants, one anionic and one or more non-ionic surfactants such as polyethoxylated alkylaryl compounds or polyethoxylated alkyl or alkylaryl thiol, are useful in recovering oil from formations which also contain water having high salinities, e.g., salinities greater than about 40,000 parts per million, and which may also contain high concentrations of divalent ions such as calcium and/or magnesium, e.g., greater than about 3,000 parts per million calcium and magnesium. Polyethoxylated alcohols, alkyl phenols or polyethoxylated alkyl or alkylaryl thiols have well defined cloud points, and as a consequence thereof, if the formation temperature is much above the cloud point of the polyethoxylated compound, the surfactant fluid exhibits phase instability which degrades the oil recovery efficiency. Superior results are obtained if the ethoxylated surfactant is chosen to have a cloud point slightly above the formation temperature, and the concentration of divalent ions in the surfactant systems containing two or more surfactants, is maintained at high enough levels to prevent phase instability problems.
Inventors
- 👤 George Kalfoglou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:58
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/58; C09K8/592; C09K8/584; E; E21; E21B; E21B43/00; E21B43/16; E21B43/24; Y; Y10; Y10S; Y10S507/00; Y10S507/935; Y10S507/936
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
183 words
A method for recovering petroleum from a subterranean, permeable, petroleum-containing formation, which formation also contains water having a salinity from about 40,000 to about 120,000 parts per million total dissolved solids and a concentration of polyvalent ions including calcium and magnesium from about 3,000 to about 12,000 parts per million, said recovery method being of the type wherein an aqueous saline fluid containing at least two surfactants, one primary anionic surfactant selected from the group consisting of petroleum sulfonate, alkyl sulfonates, aliphatic sulfonates, and alkylaryl sulfonates, and at least one nonionic surfactant selected from the group consisting of polyethoxylated aliphatic compounds, polyethoxylated alkylaryl compounds, and polyethoxylated alkyl or alkylaryl thiols is injected into the formation to displace petroleum, wherein the improvement comprises: a. adjusting the average number of ethoxy groups per molecule of the nonionic surfactant to result in the nonionic surfactant's cloud point determined in an aqueous solution having salinity and polyvalent ion concentration about equal to the salinity and divalent ion concentration of the formation water, being from about 1° to about 20° F. greater than the temperature of the formation.
Claim 2
Independent Claim
183 words
A method for recovering petroleum from a subterranean, permeable, petroleum-containing formation, which formation also contains water having a salinity from about 40,000 to about 120,000 parts per million total dissolved solids and a concentration of polyvalent ions including calcium and magnesium from about 3,000 to about 12,000 parts per million, said recovery method being of the type wherein an aqueous saline fluid containing at least two surfactants, one primary anionic surfactant selected from the group consisting of petroleum sulfonate, alkyl sulfonates, aliphatic sulfonates, and alkylaryl sulfonates, and at least one nonionic surfactant selected from the group consisting of polyethoxylated aliphatic compounds, polyethoxylated alkylaryl compounds, and polyethoxylated alkyl or alkylaryl thiols is injected into the formation to displace petroleum, wherein the improvement comprises: a. adjusting the average number of ethoxy groups per molecule of the nonionic surfactant to result in the nonionic surfactant's cloud point determined in an aqueous solution having salinity and polyvalent ion concentration about equal to the salinity and divalent ion concentration of the formation water, being from about 1° to about 20° F. greater than the temperature of the formation.
Claim 3
Dependent Claim
39 words
A method as recited in claim 1 wherein the number of ethoxy groups associated with the nonionic surfactant is chosen so the cloud point is from about 5° to about 15° F. greater than the temperature of the formation.
Claim 4
Dependent Claim
16 words
A method as recited in claim 1 wherein the nonionic surfactant is an ethoxylated alkyl phenol.
Claim 5
Dependent Claim
16 words
A method as recited in claim 1 wherein the non-ionic surfactant is an ethoxylated aliphatic alcohol.
Claim 6
Dependent Claim
16 words
A method as recited in claim 1 wherein the non-ionic surfactant is an ehtoxylated alkyl thiol.
Claim 7
Dependent Claim
16 words
A method as recited in claim 1 wherein the non-ionic surfactant is an ethoxylated alkylaryl thiol.
Claim 8
Dependent Claim
21 words
A method as recited in claim 1 wherein the temperature of the formation is from about 80° to about 150° F.
Claim 9
Dependent Claim
24 words
A method as recited in claim 1 wherein the salinity of the surfactant fluid is about equal to the salinity of the formation water.
Claim 10
Dependent Claim
36 words
A method as recited in claim 1 wherein the surfactant solution also contains polyvalent ions including calcium and magnesium in a concentration at least as great as the concentration of polyvalent ions in the formation water.
Claim 11
Dependent Claim
32 words
A method as recited in claim 1 comprising the additional step of heating the surfactant fluid to a temperature about equal to the formation temperature prior to injecting it into the formation.
Claim 12
Dependent Claim
35 words
A method as recited in claim 1 wherein the average number of ethoxy groups per molecule of nonionic surfactant is chosen to yield a cloud point from 5° to 15° F. above the formation temperature.
Claim 13
Independent Claim
151 words
A method for recovering petroleum from a subterranean petroleum-containing permeable formation, said formation also containing water having a salinity from about 40,000 to about 120,000 parts per million total dissolved solids and from 3,000 to 12,000 parts per million divalent ions including calcium and magnesium, the formation temperature being from 100° to 150° F., comprising: a. introducing into the formation a saline surfactant-containing aqueous fluid having about the same salinity as the formation water, and containing an organic sulfonate anionic surfactant and a polyethoxylated nonionic surfactant, the average number of ethoxy groups per nonionic surfactant molecule being sufficient to cause the cloud point of the polyethoxylated nonionic surfactant in an aqueous solution having about the same salinity and divalent ion concentration as the formation water to be from 1° to 20° F. greater than the temperature of the formation; and b. recovering oil displaced by the surfactant solution from the formation.
Claim 14
Independent Claim
151 words
A method for recovering petroleum from a subterranean petroleum-containing permeable formation, said formation also containing water having a salinity from about 40,000 to about 120,000 parts per million total dissolved solids and from 3,000 to 12,000 parts per million divalent ions including calcium and magnesium, the formation temperature being from 100° to 150° F., comprising: a. introducing into the formation a saline surfactant-containing aqueous fluid having about the same salinity as the formation water, and containing an organic sulfonate anionic surfactant and a polyethoxylated nonionic surfactant, the average number of ethoxy groups per nonionic surfactant molecule being sufficient to cause the cloud point of the polyethoxylated nonionic surfactant in an aqueous solution having about the same salinity and divalent ion concentration as the formation water to be from 1° to 20° F. greater than the temperature of the formation; and b. recovering oil displaced by the surfactant solution from the formation.
Claim 15
Dependent Claim
38 words
A method as recited in claim 12 wherein the average number of ethoxy groups per nonionic surfactant molecule is sufficient to give the nonionic surfactant a cloud point from 5° to 15° F. greater than the formation temperature.
Claim 16
Dependent Claim
30 words
A method as recited in claim 12 wherein the surfactant solution is heated to a temperature about equal to the formation temperature prior to injecting the solution into the formation.
Claim 17
Dependent Claim
22 words
A method as recited in claim 12 wherein the surfactant solution also contains a sulfated or sulfonated ethoxylated aliphatic or alkylaryl compound.
Claim 18
Dependent Claim
21 words
A method as recited in claim 12 wherein the non-ionic surfactant is a polyethoxylated alkyl phenol or a polyethoxylated aliphatic alcohol.
Claim 19
Dependent Claim
18 words
A method as recited in claim 12 wherein the non-ionic surfactant is a polyethoxylated aliphatic or alkylaryl thiol.
Claim 20
Dependent Claim
14 words
A method as recited in claim 12 wherein the anionic surfactant is petroleum sulfonate.
Claim 21
Dependent Claim
24 words
A method as recited in claim 12 wherein the anionic surfactant is an alkyl or alkylaryl sulfonate having from 5 to 25 carbon atoms.
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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) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |