Nanoclay Assisted High Temperature Crosslinked Fracturing Fluids

1 . A fracturing fluid comprising a mixture of:

an aqueous copolymer composition comprising a copolymer, the copolymer comprising acrylamide monomer units, or acrylic acid monomer units, or both, or salts thereof;

a crosslinker comprising a metal; and

a friction reducing additive, wherein the friction reducing additive comprises a nanoclay.

2 . The fracturing fluid of claim 1 , wherein the copolymer comprises 2-acrylamido-2-methylpropane-sulfonic acid monomer units or salts thereof.

3 . The fracturing fluid of claim 1 , wherein the fracturing fluid comprises 1 to 20 pounds of the nanoclay per thousand gallons of the fracturing fluid (0.12 kg/kL to 2.4 kg/kL).

4 . The fracturing fluid of claim 1 , wherein the fracturing fluid comprises about 2 pounds of the nanoclay per thousand gallons of the fracturing fluid.

5 . The fracturing fluid of claim 1 , wherein the nanoclay comprises a phyllosilicate structure with a thickness of about 1 nanometer (nm).

6 . The fracturing fluid of claim 1 , wherein a weight ratio of the metal to the copolymer is in a range of 0.01 to 0.8.

7 . The fracturing fluid of claim 1 , wherein a weight ratio of the metal to the copolymer is in a range of 0.2 to 0.6.

8 . The fracturing fluid of claim 2 , wherein the copolymer comprises 1 mol % to 25 mol % of the 2-acrylamido-2-methylpropanesulfonic acid monomer units.

9 . The fracturing fluid of claim 8 , wherein the copolymer comprises about 15 mol % of the 2-acrylamido-2-methylpropanesulfonic acid monomer units.

10 . The fracturing fluid of claim 1 , comprising at least one of a gel stabilizer, a clay stabilizer, a viscosity breaker, a proppant, and a pH adjusting agent.

11 . The fracturing fluid of claim 10 , comprising the pH adjusting agent, wherein a pH of the fracturing fluid is in a range of 3 to 6.5.

12 . The fracturing fluid of claim 1 , comprising between 50 mg/L and 50,000 mg/L of total dissolved solids.

13 . The fracturing fluid of claim 1 , wherein a concentration of the metal in the fracturing fluid is in a range of 0.001 wt % to 0.24 wt %.

14 . The fracturing fluid of claim 1 , wherein the fracturing fluid comprises 20 to 50 pounds of the copolymer per thousand gallons (2.4 kilogram/kiloliter, kg/kL to 6.0 kg/kL) of the fracturing fluid.

15 . The fracturing fluid of claim 1 , wherein, after crosslinking, the fracturing fluid has a viscosity of at least 300 cP for at least 80 minutes when subjected to a shear rate of 100 s −1 at a temperature in a range of 300° F. to 400° F.

16 . The fracturing fluid of claim 1 , wherein a viscosity of the fracturing fluid measured at 100 s −1 is reduced by greater than 30% by adding 2 pounds per thousand gallons of the nanoclay to the fracturing fluid (0.24 kg/kL).

17 . A method of treating a subterranean formation, the method comprising:

introducing a fracturing fluid into the subterranean formation, the fracturing fluid comprising:

an aqueous copolymer composition comprising a copolymer, the copolymer comprising acrylamide monomer units, or acrylic acid monomer units, or both, or salts thereof;

a crosslinker comprising a metal; and

a friction reducing additive, wherein the friction reducing additive comprises a nanoclay, wherein the fracturing fluid comprises greater than 1 pounds per thousand gallons (pptg) (0.12 kg/kL) of the nanoclay; and

crosslinking the fracturing fluid in the subterranean formation to yield a crosslinked fracturing fluid.

18 . The method of claim 17 , wherein the copolymer comprises 2-acrylamido-2-methylpropane-sulfonic acid monomer units.

19 . The method of claim 17 , wherein a weight ratio of the metal to the copolymer is in a range of 0.01 to 0.8.

20 . The method of claim 17 , comprising adding the nanoclay as a dry powder after hydrating the copolymer.

21 . The method of claim 17 , wherein a concentration of the metal in the fracturing fluid is in a range of 0.001 wt % to 0.24 wt %.

22 . The method of claim 17 , wherein the fracturing fluid comprises 20 to 50 pounds of the crosslinker to of the copolymer.

23 . The method of claim 22 , wherein the crosslinker comprises zirconium, the fracturing fluid comprises 25 pounds of the copolymer per thousand gallons of the fracturing fluid (3.0 kg/kL), a weight ratio of the zirconium to the copolymer is in a range of about 0.2 to about 0.4, the copolymer comprises 15 mol % of the 2-acrylamido-2-methylpropane-sulfonic acid monomer units, and the crosslinked fracturing fluid maintains a viscosity of at least 300 cP for up to 150 minutes when the crosslinked fracturing fluid is subjected to a shear rate of 100 s −1 at a temperature of 300° F. (149° C.).

24 . The method of claim 23 , wherein the crosslinked fracturing fluid comprises a viscosity breaker, and the crosslinked fracturing fluid maintains a viscosity of at least 300 cP for up to 100 minutes and has a viscosity of less than 10 cP after 360 minutes when the crosslinked fracturing fluid is subjected to a shear rate of 100 s −1 at a temperature of 300° F. (149° C.).

25 . A fracturing fluid comprising a mixture of:

an aqueous copolymer composition comprising a copolymer, the copolymer comprising 2-acrylamido-2-methylpropanesulfonic acid, acrylamide, and acrylic acid monomer units, or a salt thereof, and wherein the copolymer comprises 1 mol % to 55 mol % of the 2-acrylamido-2-methylpropanesulfonic acid monomer units;

a crosslinker comprising a metal; and

a friction reducing additive, wherein the friction reducing additive comprises a nanoclay, wherein the nanoclay comprises particles less than about 25 micrometers in size.

26 . The fracturing fluid of claim 25 , wherein the nanoclay comprises a hydrophilic bentonite.

27 . The fracturing fluid of claim 25 , wherein the nanoclay comprises a sheet structure sheet structure having a thickness of about 1 nanometer (nm) and a width between about 50-150 nm in one dimension.