US4517101A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reduced biodegradability in a polymer flood process
Assignee: Cities Service Co
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Filing: 1983-08-22
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Granted: 1985-05-14
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Expires: 2003-08-22
Abstract
Abstract In a polymer flood, where bacterial contamination frequently causes a loss in viscosity of the polymer, the viscosity of the polymer solution is maintained by the use of a xanthan polymer modified by methylation of a portion of the subunit sugar residues of the xanthan base.
Inventors
- 👤 David Williams
- 👤 Douglas M. Munnecke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:03
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/84; C09K8/86; C09K8/88; C09K8/90; C09K8/905; C08; C08B; C08B37/00; C08B37/0006; C08B37/0024; C08B37/0033; Y; Y10; Y10S; Y10S435/00; Y10S435/8215; Y10S435/822; Y10S435/91; Y10S507/00; Y10S507/904; Y10S507/935; Y10S507/936
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
39 words
In an enhanced oil recovery process, a method for modifying xanthan gum polymers to make them more resistant to bacterial enzymatic degradation, comprising (a) methylating a xanthan gum polymer in an aqueous solution, and (b) recovering the methylated polymer.
Claim 2
Dependent Claim
39 words
In an enhanced oil recovery process, a method for modifying xanthan gum polymers to make them more resistant to bacterial enzymatic degradation, comprising (a) methylating a xanthan gum polymer in an aqueous solution, and (b) recovering the methylated polymer.
Claim 3
Dependent Claim
32 words
A process of enhanced oil recovery of a micellar polymer flood type wherein the biodegradability of the polymer is suppressed by the use of a methylated xanthan gum in the polymer flood.
Claim 4
Dependent Claim
32 words
A process of enhanced oil recovery of a micellar polymer flood type wherein the biodegradability of the polymer is suppressed by the use of a methylated xanthan gum in the polymer flood.
Claim 5
Dependent Claim
117 words
The method of claim 1, wherein (a) the xanthan gum polymer is in the form of an aqueous solution with a polymer concentration of from about 0.5 to about 3 grams per liter, (b) the xanthan gum polymer solution temperature is from about 5° C. to about 25° C., (c) the pH of the xanthan gum polymer solution is maintained at a value of from about 10 to about 12, (d) a methylating agent is added to the xanthan gum polymer solution in amounts of from about 2 to about 4 g/g polymer, over a period of 5 minutes per liter of polymer solution, and (e) the methylated xanthan gum polymer is precipitated from solution and separated.
Claim 6
Dependent Claim
21 words
The method of claim 3, wherein (a) the methylating agent is dimethyl sulfate, and (b) the precipitating agent is isopropyl alcohol.
Claim 7
Dependent Claim
53 words
The process of claim 2, wherein (a) the methylated xanthan gum polymer is injected into the formation, in the form of an aqueous solution, at a concentration of from about 500 to about 2000 ppm., and (b) at least a portion of the available hydroxyl groups of the xanthan gum polymer are methylated.
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) | 1988-05-13 | 1988-11-12 | 1989-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-13 | 1992-11-12 | 1993-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-13 | 1996-11-12 | 1997-05-14 | $7700.00 | Window Closed / Lapsed |