Emulsions, treatment fluids and methods for treating subterranean formations
Emulsions, treatment fluids and methods for treating subterranean formations are provided, wherein the emulsions comprise water, a water-immiscible liquid, one or more polymers, one or more ethoxylated amine compounds and optionally, one or more organic or inorganic salts. The emulsions are particularly suitable for use in harsh brine conditions.
1. An emulsion comprising:
a) water;
b) a water-immiscible liquid;
c) greater than about 10% by weight one or more polymers;
d) about 2% to about 5% by weight one or more ethoxylated amine compounds selected from compounds of Formula I:
wherein R 1 is H, alkyl, aryl, C(═O)-alkyl, or C(═O)-aryl; and X and Y are each independently 1-20;
e) about 0.5% to about 5% by weight one or more inverting surfactants having an HLB value of greater than 10, wherein the one or more ethoxylated amine compounds have been combined with the one or more inverting surfactants to form an inverting surfactant composition;
f) and at least about 0.5% of one or more organic or inorganic salts.
2. The emulsion of claim 1 , wherein the one or more of the polymers is an acrylamide-containing polymer.
3. The emulsion of claim 1 , wherein the one or more polymers comprises acrylamide or partially hydrolyzed acrylamide and one or more monomers selected from the group consisting of acrylic acid and salts thereof.
4. The emulsion of claim 1 , further comprising about 1% to about 5% by weight of one or more emulsifying surfactants.
5. The emulsion of claim 1 , wherein the one or more inverting surfactants is selected from the group consisting of polyoxyethylene sorbitol tetraoleate; polyethylene glycol monooleate; ethoxylated alcohols, ethoxylated octyl and nonyl phenols; ethoxylated nonyl phenol formaldehyde resin; polyethylene oxide esters of fatty acids and dioctyl esters of sodium sulfosuccinate.
6. The emulsion of claim 1 , further comprising a proppant.
7. A treatment fluid comprising an emulsion of claim 1 and additional water; wherein the one or more polymers are present in the treatment fluid in an amount of about 0.01% to about 1% by weight of the treatment fluid.
8. The treatment fluid of claim 3 , further comprising a proppant.
9. A method of treating a subterranean formation, comprising: providing a treatment fluid comprising an emulsion of claim 1 ; and introducing the treatment fluid into a subterranean formation.
10. The method of claim 9 , further comprising adding a proppant to the treatment fluid.
11. A method of fracturing a subterranean formation, comprising:
(i) providing an emulsion of claim 1 ;
(ii) mixing the emulsion with additional water or brine to form a treatment fluid, wherein the one or more polymers are present in the treatment fluid in an amount of about 0.01% to about 1% by weight of the treatment fluid; and
(iii) introducing the treatment fluid into a subterranean formation at or above a pressure sufficient to create one or more fractures in the subterranean formation.
12. The method of claim 11 , wherein the treatment fluid comprises brine.
13. The method of claim 11 , wherein the treatment fluid further comprises a proppant.
14. A method for improving or lowering the freezing point of a treatment fluid comprises:
(i) providing an emulsion of claim 1 ; and
(ii) inverting the emulsion in a treatment fluid containing brine;
wherein the emulsion has an improvement in freezing point, when compared to a similar emulsion that does not contain the one or more ethoxylated amine compounds.
15. The method of claim 14 , wherein the treatment fluid further comprises a proppant.