Well treatment fluid and methods with oxidized chitosan-based compound
First Claim
1. A method of treating a subterranean formation penetrated by a wellbore comprising the steps of:
- (a) forming a well treatment fluid comprising;
(i) water;
(ii) an oxidized chitosan-based compound having the property of being soluble in water at greater than about 2 wt % while maintaining a viscosity of less than about 1000 cp; and
(iii) a water-soluble compound having carbonyl groups; and
(b) contacting the subterranean formation with the well treatment fluid.
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Abstract
The present invention provides a well treatment fluid that contains water, an oxidized chitosan-based compound, and a water-soluble compound having carbonyl groups, wherein the oxidized chitosan-based compound has the property of being soluble in water up to about 2 wt % while maintaining a viscosity of less than about 1000 cp. The water used for the well treatment fluid is selected from the group consisting of fresh water, seawater, natural brine, formulated brine, 2% KCl solution, and any mixtures in any proportion thereof. The present invention also provides a method of treating a subterranean formation penetrated by a wellbore comprising the steps of: (a) forming the well treatment fluid, and (b) contacting the subterranean formation with the fluid.
154 Citations
38 Claims
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1. A method of treating a subterranean formation penetrated by a wellbore comprising the steps of:
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(a) forming a well treatment fluid comprising;
(i) water;
(ii) an oxidized chitosan-based compound having the property of being soluble in water at greater than about 2 wt % while maintaining a viscosity of less than about 1000 cp; and
(iii) a water-soluble compound having carbonyl groups; and
(b) contacting the subterranean formation with the well treatment fluid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A well treatment fluid for use in a well, the well treatment fluid comprising:
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(a) water;
(b) an oxidized chitosan-based compound comprising oxidized chitosan and having the property of being soluble in water at greater than about 2 wt % while maintaining a viscosity of less than about 1000 cp; and
(c) a water-soluble compound having carbonyl groups comprising an acrylamide-based polymer. - View Dependent Claims (25, 26, 27, 28)
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24. A well treatment fluid for use in a well, the well treatment fluid comprising:
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(a) water;
(b) an oxidized chitosan-based compound comprising oxidized chitosan and having the property of being soluble in water at a pH in the range of about 4 to about 7 and at STP at greater than about 2 wt % and up to about 10 wt %, while maintaining a viscosity of less than about 1000 cp; and
(c) a water-soluble compound having carbonyl groups comprising an acrylamide-based polymer.
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29. A well treatment fluid for use in a well, the well treatment fluid comprising:
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(a) water;
(b) an oxidized chitosan-based compound comprising oxidized chitosan and having the property of being soluble in water at greater than about 2 wt % while maintaining a viscosity of less than about 1000 cp; and
(c) a water-soluble compound having carbonyl groups comprising an oxidized starch. - View Dependent Claims (31, 32, 33)
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30. A well treatment fluid for use in a well, the well treatment fluid comprising:
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(a) water;
(b) an oxidized chitosan-based compound comprising oxidized chitosan and having the property of being soluble in water at a pH in the range of about 4 to about 7 and at STP at greater than about 2 wt % and up to about 10 wt %, while maintaining a viscosity of less than about 1000 cp; and
(c) a water-soluble compound having carbonyl groups comprising an oxidized starch.
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34. A well treatment fluid for use in a well, the well treatment fluid comprising:
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(a) water;
(b) an oxidized chitosan-based compound having the property of being soluble in water at greater than about 2 wt % while maintaining a viscosity of less than about 1000 cp; and
(c) a water-soluble compound having carbonyl groups comprising an acrylamide-based polymer. - View Dependent Claims (35, 36, 37, 38)
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Specification