Flooding operations employing chlorine dioxide

1. A method comprising:

introducing a treatment fluid comprising a first polymer gel into a subterranean formation to generate a production fluid comprising an aqueous portion and a hydrocarbon portion;

treating at least the aqueous portion of the production fluid with chlorine dioxide to provide an additional hydrocarbon portion from the aqueous portion; and

adjusting the viscosity of the treated aqueous portion prior to introducing the treated aqueous portion back into the subterranean formation;

wherein adjusting the viscosity comprises forming a second polymer gel, wherein to reach a target viscosity of the second polymer gel an amount of polymer used to form the second polymer gel is reduced by about 25% to about 75%, relative to an untreated aqueous portion, when residual chlorine dioxide from the treating step is present during the adjusting step.

2. The method of claim 1 , further comprising a step of introducing a pre-treatment fluid in the subterranean formation prior to introducing the treatment fluid, wherein the pre-treatment fluid comprises an oxidant.

3. The method of claim 1 , wherein the treatment fluid is introduced distal to a wellbore.

4. The method of claim 1 , wherein the treatment fluid is introduced through a portion of the wellbore.

5. The method of claim 1 , further comprising separating solids from the treated aqueous portion.

6. The method of claim 1 , further comprising performing a flooding operation selected from the group consisting of a gas flood, a caustic flood, a surfactant flood, a foam flood, a steam flood, a carbon dioxide flood, and a water flood.

7. The method of claim 1 , wherein the polymer gel comprises a water-soluble polymer selected from the group consisting of a polyacrylate, a polyacrylamide, a cellulose, a xanthan gum, a guar gum, a diutan, a wellan, a glucan, a glycan, a dextran, an alginate, a curdlan, a pullulan, and combinations thereof and derivatives thereof.

8. The method of claim 1 , wherein the polymer gel comprises a water-soluble polymer selected from the group consisting of polyacrylamide, partially hydrolyzed polyacrylamide, sulfonated polyacrylamide, methyl cellulose, hydroxyethylcellulose, hydroxypropyl cellulose, carboxymethylcellulose, carboxymethylhydroxyethylcellulose, sulfonated carboxymethylcellulose, sulfonated carboxymethylhydroxyethylcellulose, sulfonated hydroxyethylcellulose, sulfonated methylhydroxypropylcellulose, sulfonated methylcellulose, sulfonated ethylcellulose, sulfonated propylcellulose, sulfonated ethylcarboxymethylcellulose, sulfonated methylethylcellulose, sulfonated hydroxypropylmethylcellulose, guar, hydroxypropylguar, succinoglycan, scleroglucan, and combinations thereof.

9. The method of claim 1 , wherein the treatment fluid further comprises chlorine dioxide.

10. The method of claim 9 , wherein the amount of chlorine dioxide in the treatment fluid is in a range from about 10 parts per million to about 3,000 mg/L.

11. The method of claim 1 , wherein the treatment fluid comprises an aqueous base comprising production water.

12. The method of claim 1 , wherein the treatment fluid further comprises an additive selected from the group consisting of a corrosion inhibitor, a pH control additive, a surfactant, a salt, a breaker, a fluid loss control additive, a scale inhibitor, an asphaltene inhibitor, a paraffin inhibitor, a biocide, a crosslinker, a fluid stabilizer, a chelant, a foaming agent, a defoamer, an emulsifier, a demulsifier, an iron control agent, an alcohol solvent, a mutual solvent, an oxygen scavenger, a particulate diverter, a gas, a friction reducer, an activator, a retarder, and combinations thereof.

13. The method of claim 1 , further comprising the step of removing the production fluid from the wellbore prior to the treating step.

14. The method of claim 1 , wherein an amount of chlorine dioxide used in the treating step is in a range from about 25 mg/L to about 500 mg/L.

15. The method of claim 1 , wherein the additional hydrocarbons are present in the aqueous portion up to about 20% by weight of the aqueous portion and the treating step reduces hydrocarbon content in the aqueous portion to less than about 2.5%.

16. The method of claim 15 , wherein the treating step reduces hydrocarbon content in the aqueous portion to less than about 0.25%.

17. The method of claim 1 , wherein the second polymer gel is different from the first polymer gel.

18. A method comprising:

introducing a treatment fluid into a subterranean formation under conditions of a polymer flooding operation, the treatment fluid comprising:

a polymer gel comprising a water-soluble polymer;

a polymer gel-preserving amount of chlorine dioxide; and

an aqueous base fluid; and

generating a production fluid comprising an aqueous portion and a hydrocarbon portion, the method further comprising:

treating at least the aqueous portion of the production fluid with chlorine dioxide to provide an additional hydrocarbon portion from the aqueous portion; and

adjusting the viscosity of the treated aqueous portion prior to introducing the treated aqueous portion back into the subterranean formation, wherein adjusting the viscosity comprises forming a second polymer gel, wherein to reach a target viscosity of the second polymer gel an amount of polymer used to form the second polymer gel is reduced by about 25% to about 75%, relative to an untreated aqueous portion, when residual chlorine dioxide from the treating step is present during the adjusting step.