Crosslinked alginate-based gels for matrix conformance
First Claim
1. A method for modifying the fluid flow profile in a subterranean formation having a heterogeneous permeability distribution, the method comprising:
- a) forming a composition comprising an aqueous solution of an alginate polysaccharide having a molecular weight between about 80,000 Daltons and about 200,000 Daltons, the polysaccharide being present in an amount up to about 10 percent by weight, a crosslinking agent selected from the group consisting of Group IIA cations, Fe2+, Fe3+, Al3+, Mn2+, Zn2+, dialdehydes, diamines, and mixtures thereof, the crosslinking agent being present in an amount ranging from about 0.0001M to about 0.05M, and a modifier present in an amount up to about 5 percent by weight and selected from the group consisting of synthetic polymers consisting of polyvinyl alcohols, neutral polycarboxylic acids, polyacrylamides, and mixtures thereof, the solution capable of forming a gel;
b) injecting the composition into a subterranean formation; and
c) allowing the composition to form a gel.
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Abstract
A composition of matter for matrix conformance formed from an aqueous solution of an alginate polysaccharide and a method of forming an alginate polysaccharide gel. A Group IIA cation, Fe2+, Fe3+, Al3+, Mn2 +, Zn2+, a dialdehyde, or a diamine may be used to crosslink the resulting alginate gel. The gel may also comprise a modifier, such as a polyvinyl alcohol, a polycarboxylic acid, or a polyacrylamide. The rate and extent of crosslinking are controlled by varying the alginate molecular weight, the alginate concentration, or the type and concentration of crosslinker, or by adding a sequestering agent such as EDTA or citrate.
51 Citations
23 Claims
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1. A method for modifying the fluid flow profile in a subterranean formation having a heterogeneous permeability distribution, the method comprising:
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a) forming a composition comprising an aqueous solution of an alginate polysaccharide having a molecular weight between about 80,000 Daltons and about 200,000 Daltons, the polysaccharide being present in an amount up to about 10 percent by weight, a crosslinking agent selected from the group consisting of Group IIA cations, Fe2+, Fe3+, Al3+, Mn2+, Zn2+, dialdehydes, diamines, and mixtures thereof, the crosslinking agent being present in an amount ranging from about 0.0001M to about 0.05M, and a modifier present in an amount up to about 5 percent by weight and selected from the group consisting of synthetic polymers consisting of polyvinyl alcohols, neutral polycarboxylic acids, polyacrylamides, and mixtures thereof, the solution capable of forming a gel; b) injecting the composition into a subterranean formation; and c) allowing the composition to form a gel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification