Anhydride-modified chitosan, method of preparation thereof, and fluids containing same
AssigneeVenture Chemicals, Inc.
InventorsJack C. Cowan, Roy F. House, Tammy L. Rodrigue
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Abstract
The invention provides an organic diacid anhydride-modified chitosan and a method of preparing the same under high shear conditions which eliminates the use of solvents and excessive amounts of aqueous liquids. Also provided are organic diacid anhydride-modified chitosans containing an inorganic basic material which enhances the aging stability thereof. The invention also provides fluids useful in various well drilling and servicing operations comprising an alkaline aqueous liquid containing an organic diacid anhydride-modified chitosan, as well as a method of drilling wells therewith.
Claims15
The method of preparing an anhydride-modified chitosan comprising mixing under high shear conditions chitosan, an organic diacid anhydride, and water, wherein the concentration of the chitosan is from about 30% to about 65% by weight, the concentration of the anhydride is from about 10% to about 30% by weight and the concentration of water is from about 20% to about 40% by weight.
An anhydride-modified chitosan-containing composition comprising chitosan, an organic diacid anhydride, water, and optionally a basic material, wherein the weight ratio of anhydride to chitosan is from about 0.2 to 1 to about 1 to 1, wherein the weight ratio of water to chitosan is from about 0.33 to 1 to about 1.33 to 1, and wherein the weight ratio of the basic material to chitosan is from about 0 to 1 to about 1.67 to 1.
Dependencies are inferred from the claim text.