US3581824A
Expired / Lapsed
US
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Oil recovery process using an ionic polysaccharide thickening agent
Assignee: Mobil Oil AS
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Filing: 1969-12-17
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Granted: 1971-06-01
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Expires: 1989-12-17
Abstract
Abstract This specification discloses an oil recovery process involving the injection of an aqueous liquid containing an ionic polysaccharide thickening agent which is subject to agglomeration in the presence of divalent cations. This liquid, which exhibits a relatively low divalent cation concentration, is preceded by an aqueous liquid having a relatively high divalent cation concentration. As the first injected liquid moves through the reservoir, divalent cations are adsorbed onto the reservoir surfaces. These cations then are desorbed from the reservoir surfaces into the liquid containing the thickening agent in order to cause agglomeration thereof. This agglomeration results in partial plugging of the reservoir preferentially within the more permeable zones thereof in order to improve the sweep efficiency of the recovery process.
Inventors
- 👤 Billy G Hurd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:20
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/84; C09K8/86; C09K8/88; C09K8/90; C09K8/905
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
67 words
The method of claim 1 wherein the aqueous liquid of step (a) is introduced into said reservoir in an amount within the range of 5 to 10 percent of the pore volume of said recovery zone and the aqueous liquid of step (b) is introduced into said reservoir in an amount within the range of 1 to 20 percent of the pore volume of said recovery zone.
Claim 2
Dependent Claim
28 words
The method of claim 1 wherein said aqueous liquid injected in step (a) exhibits a monovalent cation concentration lower than the monovalent cation concentration of said formation water.
Claim 3
Dependent Claim
33 words
The method of claim 3 wherein the aqueous liquid injected in step (b) contains monovalent cations in a concentration greater than the monovalent cation concentration of the aqueous liquid injected in step (a).
Claim 4
Dependent Claim
39 words
The method of claim 1 further comprising intermediate steps (a) and (b) introducing into said reservoir via said injection system an aqueous buffer liquid of a divalent cation concentration lower than that of the liquid injected in step (a).
Claim 5
Dependent Claim
51 words
The method of claim 5 wherein said liquid injected in step (a) exhibits a monovalent cation concentration lower than the monovalent cation concentration of said formation water and said buffer liquid and liquid injected in step (b) exhibit higher monovalent cation concentrations than that of the liquid injected in step (a).
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein said thickening agent is an ionic polysaccharide produced by fermentation of carbohydrates by bacteria of the genus Xanthomonas.
Claim 7
Dependent Claim
14 words
The method of claim 7 wherein said thickening agent is the ionic polysaccharide B-1459.
Claim 8
Dependent Claim
134 words
In the recovery of oil from a subterranean oil reservoir exhibiting a base exchange capacity and penetrated by spaced injection and production systems defining a recovery zone of said reservoir, the method comprising: a. injecting into said reservoir via said injection system an aqueous liquid containing divalent cations in a concentration within the range of 0.5 to 5 weight percent, b. introducing into said reservoir via said injection system an aqueous liquid of a divalent ion concentration lower than that of the liquid injected in step (a) and within the range of 0 to 0.5 weight percent and containing an ionic polysaccharide which is subject to agglomeration in the presence of said divalent ions, c. introducing a driving fluid into said reservoir via said injection system, and d. recovering oil from said production system.
Claim 9
Dependent Claim
24 words
The method of claim 9 wherein said thickening agent is an ionic polysaccharide produced by fermentation of carbohydrates by bacteria of the genus Xanthomonas.
Claim 10
Dependent Claim
14 words
The method of claim 10 wherein said thickening agent is the ionic polysaccharide B-l459.
Claim 11
Dependent Claim
48 words
The method of claim 11 wherein the liquid injected in step (a) exhibits a monovalent cation concentration within the range of 0 to 0.5 weight percent and the liquid injected in step (b) exhibits a higher monovalent cation concentration within the range of 0.5 to 2.5 weight percent.
Claim 12
Dependent Claim
77 words
The method of claim 12 further comprising intermediate steps (a) and (b) introducing into said reservoir via said injection syStem an aqueous buffer liquid of a divalent cation concentration lower than that of the liquid injected in step (a) and within the range of 0 to 0.5 percent by weight and of a monovalent cation concentration greater than that of the liquid injected in step (a) and within the range of 0.5 to 2.5 percent by weight.
Claim 13
Dependent Claim
53 words
The method of claim 13 wherein the liquid of step (a), the buffer liquid, and the liquid of step (b) are introduced into said reservoir in amounts within the ranges, respectively, of 5 to 10 percent, 0.001 to 0.1 percent, and 1 to 20 percent of the pore volume of said recovery zone.
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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) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |