Patent US5068043A successfully refreshed from Google Patents.
US5068043A
Expired / Lapsed
US
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Preformed surfactant-optimized aqueous alkaline flood
Assignee: Shell USA Inc
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Filing: 1989-08-09
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Granted: 1991-11-26
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Expires: 2009-08-09
Abstract
Abstract An aqueous alkaline flood for recovering oil from a reservoir containing acidic oil is improved by adding to the injected aqueous alkaline solution both a stoichiometric excess of the alkaline material and a kind and amount of preformed cosurfactant material that increases the salinity of that solution so that, in contact with the oil in the reservoir, it will form a surfactant system having a salinity requirement which minimizes the interfacial tension between it and the oil.
Inventors
- 👤 David R. Thigpen
- 👤 Jimmie B. Lawson
- 👤 Richard C. Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:58
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/58; C09K8/584; Y; Y10; Y10S; Y10S507/00; Y10S507/935; Y10S507/936
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
184 words
In a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system, the improvement comprising: 1) selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is greater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; 2) combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system havng a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and 3) injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.
Claim 2
Dependent Claim
184 words
In a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system, the improvement comprising: 1) selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is greater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; 2) combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system havng a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and 3) injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein the amount of the preformed cosurfactant is about 0.3 weight percent based on the aqueous alkaline solution.
Claim 4
Dependent Claim
30 words
The process of claim 2 wherein the alkaline material is present in the aqueous alkaline solution in a concentration of the equivalent of about 0.8 percent by weight sodium hydroxide.
Claim 5
Dependent Claim
24 words
The process of claim 3 wherein the sodium chloride is present in concentration of about 1.2 percent by weight of the aqueous alkaline solution
Claim 6
Dependent Claim
17 words
The process of claim 1 in which the aqueous alkaline solution further comprises a polymeric water-thickening agent.
Claim 7
Dependent Claim
15 words
The process of claim 1, in which the preformed cosurfactant is a polyalkoxyalcohol sulfate surfactant.
Claim 8
Dependent Claim
18 words
The process of claim 1 in which the aqueous alkaline solution further comprises a xanthan gum water-thickening agent.
Claim 9
Dependent Claim
22 words
The process of claim 1 in which the preformed cosurfactant is a polyoxyalcohol sulfate surfactant and the alkaline material includes sodium carbonate.
Claim 10
Dependent Claim
18 words
The process of claim 8 in which the aqueous alkaline solution further comprises a xanthan gum water-thickening polymer.
Claim 11
Dependent Claim
15 words
The process of claim 1 in which the preformed cosurfactant is an internal olefin sulfonate.
Claim 12
Dependent Claim
20 words
The process of claim 10 in which the internal olefin sulfonate cosurfactant contains from about 17 to 25 carbon atoms.
Claim 13
Dependent Claim
178 words
A process for recovering oil from an acidic oil reservoir by injecting an aqueous solution of alkaline material, which solution is capable of reacting with the oil to form petroleum acid soaps, the improvement comprising: formulating the aqueous solution to be injected to be substantially free of multivalent cations and to contain (a) an amount of alkaline material equivalent to about 0.8 wt percent or more alkali metal hydroxide, and a preformed cosurfactant, which cosurfactant is an amphiphlic compound, is soluble in both the injected aqueous solution and the reservoir oil while being more soluble in the aqueous solution than are the petroleum soaps which are formed from the oil (1) and has a greater solubility ratio than the solubility ratio of the petroleum acid soaps where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil, and (2) is contained within the injected solution in a concentration of about 0.3 wt percent; and injecting said solution into the reservoir to displace oil toward a fluid production location.
Claim 14
Dependent Claim
178 words
A process for recovering oil from an acidic oil reservoir by injecting an aqueous solution of alkaline material, which solution is capable of reacting with the oil to form petroleum acid soaps, the improvement comprising: formulating the aqueous solution to be injected to be substantially free of multivalent cations and to contain (a) an amount of alkaline material equivalent to about 0.8 wt percent or more alkali metal hydroxide, and a preformed cosurfactant, which cosurfactant is an amphiphlic compound, is soluble in both the injected aqueous solution and the reservoir oil while being more soluble in the aqueous solution than are the petroleum soaps which are formed from the oil (1) and has a greater solubility ratio than the solubility ratio of the petroleum acid soaps where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil, and (2) is contained within the injected solution in a concentration of about 0.3 wt percent; and injecting said solution into the reservoir to displace oil toward a fluid production location.
Claim 15
Dependent Claim
18 words
The process of claim 12 in which the aqueous solution of alkaline material includes a polymeric water-thickening agent.
Claim 16
Dependent Claim
15 words
The process of claim 12 in which the preformed cosurfactant is a polyalkoxyalcohol sulfate surfactant.
Claim 17
Dependent Claim
21 words
The process of claim 12 in which the aqueous solution of alkaline material includes a xanthan gum or polyacrylamide water-thickening agent.
Claim 18
Dependent Claim
22 words
The process of claim 12 in which the preformed cosurfactant is a polyoxyalcohol sulfate surfactant and the alkaline material includes sodium carbonate.
Claim 19
Dependent Claim
22 words
The process of claim 16 in which the aqueous solution of alkaline material includes a xanthan gum or a polyacrylamide water-thickening polymer.
Claim 20
Dependent Claim
15 words
The process of claim 12 in which the preformed cosurfactant is an internal olefin sulfonate.
Claim 21
Dependent Claim
20 words
The process of claim 18 in which the internal olefin sulfonate cosurfactant contains from about 17 to 25 carbon atoms.
Claim 22
Dependent Claim
160 words
An aqueous alkaline solution for displacing an acidic oil within a subterranean reservoir comprisng: an aqueous alkaline solution which is substantially free of multivalent cations and contains solutes which comprise about 0.3 weight percent of an internal olefin sulfonate cosurfactant, which cosurfactant is (a) soluble in both said aqueous alkaline solution and reservoir oil, and (b) has a higher solubility ratio than reaction products of the aqueous alkaline solution and the acid components of the reservoir oil where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; and alkaline material in an amount equivalent to about 0.8 wt percent or more of alkali metal hydroxide and such that the solution is capable of reacting with the reservoir oil, within the reservoir, to form a surfactant system having a salinity which is about equal to the optimum for minimizing the interfacial tension between that surfactant system and the reservoir oil.
Claim 23
Dependent Claim
160 words
An aqueous alkaline solution for displacing an acidic oil within a subterranean reservoir comprisng: an aqueous alkaline solution which is substantially free of multivalent cations and contains solutes which comprise about 0.3 weight percent of an internal olefin sulfonate cosurfactant, which cosurfactant is (a) soluble in both said aqueous alkaline solution and reservoir oil, and (b) has a higher solubility ratio than reaction products of the aqueous alkaline solution and the acid components of the reservoir oil where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; and alkaline material in an amount equivalent to about 0.8 wt percent or more of alkali metal hydroxide and such that the solution is capable of reacting with the reservoir oil, within the reservoir, to form a surfactant system having a salinity which is about equal to the optimum for minimizing the interfacial tension between that surfactant system and the reservoir oil.
Claim 24
Dependent Claim
19 words
The composition of claim 20 in which said cosurfactant contains from about 17 to 25 carbon atoms per molecule.
Claim 25
Dependent Claim
26 words
The composition of claim 20 in which said alkaline material is selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, and ammonium hydroxide.
Claim 26
Dependent Claim
25 words
The composition of claim 20 in which said cosurfactant consists essentially of an internal olefin sulfonate containing about 20 to 24 carbon atoms per molecule.
Claim 27
Dependent Claim
24 words
The composition of claim 20 in which said cosurfactant consists essentially of internal olefin sulfonates containing about 17 to 20 carbon atoms per molecule.
Claim 28
Dependent Claim
31 words
The composition of claim 20 in which said cosurfactant consists essentially of a mixture of internal olefin sulfonates containing, respectively, 17 to 20 and 20 and 24 carbon atoms per molecule.
Claim 29
Dependent Claim
154 words
An aqueous alkaline solution for displacing an acidic oil within a subterranean reservoir, the solution comprising: a) an amount of an alkaline material which exceeds that required to neutralize the acidity of the reservoir oil; b) about 0.3 percent by weight of at least one internal olefin sulfonate cosurfactant, the cosurfactant being i) soluble in both the aqueous alkaline solution and the reservoir oil, and ii) has a higher solubility ratio than reaction product of the acidic components of the reservoir oil and the alkaline material where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; and c) sodium chloride, wherein the solution is capable of reacting with the reservoir oil within the reservoir to form a surfactant system having a salinity which is about the salinity which is optimum for minimizing the interfacial tension between the surfactant system and the reservoir oil.
Claim 30
Dependent Claim
154 words
An aqueous alkaline solution for displacing an acidic oil within a subterranean reservoir, the solution comprising: a) an amount of an alkaline material which exceeds that required to neutralize the acidity of the reservoir oil; b) about 0.3 percent by weight of at least one internal olefin sulfonate cosurfactant, the cosurfactant being i) soluble in both the aqueous alkaline solution and the reservoir oil, and ii) has a higher solubility ratio than reaction product of the acidic components of the reservoir oil and the alkaline material where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; and c) sodium chloride, wherein the solution is capable of reacting with the reservoir oil within the reservoir to form a surfactant system having a salinity which is about the salinity which is optimum for minimizing the interfacial tension between the surfactant system and the reservoir oil.
Claim 31
Dependent Claim
24 words
The aqueous alkaline solution of claim 26 wherein the cosurfactant is present in the solution in a concentration of about 0.3 percent by weight.
Claim 32
Dependent Claim
19 words
The composition of claim 27 in which said cosurfactant contains from about 17 to 25 carbon atoms per molecule.
Claim 33
Dependent Claim
26 words
The composition of claim 27 in which said alkaline material is selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, and ammonium hydroxide.
Claim 34
Dependent Claim
26 words
The composition of claim 27 in which said cosurfactant consists essentially of an internal olefin sulfonate containing from about 20 to 24 carbon atoms per molecule.
Claim 35
Dependent Claim
25 words
The composition of claim 27 in which said cosurfactant consists essentially of internal olefin sulfonates containing from about 17 to 20 carbon atoms per molecule.
Claim 36
Dependent Claim
31 words
The composition of claim 27 in which said cosurfactant consists essentially of a mixture of internal olefin sulfonates containing, respectively, 17 to 20 and 20 to 24 carbon atoms per molecule.
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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) | 1994-11-25 | 1995-05-27 | 1995-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-25 | 1999-05-27 | 1999-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-25 | 2003-05-27 | 2003-11-26 | $7700.00 | Window Closed / Lapsed |