Compositions and methods for delayed crosslinking in hydraulic fracturing fluids

Abstract

Disclosed herein are compositions and methods for delaying crosslinking in injectable compositions for hydraulic fracturing and related applications. The compositions and methods are effective in injectable compositions comprising or substantially excluding dissolved reactive species. The compositions and methods provide delayed crosslinking at high temperatures and pressures, such as those encountered by hydraulic fracturing compositions injected into subterranean environments. Compositions include injectable solutions comprising a competing agent that is the reaction product of a dialdehyde having 2 to 4 carbon atoms with a non-polymeric cis-hydroxyl compound. Also provided are methods of making and using delayed-crosslinking compositions comprising crosslinker compositions containing zirconium complexes and the competing agents.

What is claimed is: 
     
         1 . An injectable solution comprising:
 a crosslinkable polymer;   a competing agent comprising a reaction product of a dialdehyde having 2 to 4 carbon atoms with a non-polymeric cis-hydroxyl compound; and   a produced water, wherein the injectable solution is adapted for injection thereof into a subterranean reservoir.   
     
     
         2 . The injectable solution of  claim 1 , wherein the dialdehyde is glyoxal, the cis-hydroxyl compound is sorbitol, and the crosslinkable polymer is selected from guar gum, carboxymethyl hydroxypropyl guar, or a combination thereof. 
     
     
         3 . The injectable solution of  claim 1 , wherein the produced water has a total dissolved solids content of about 1 wt % to about 35 wt %. 
     
     
         4 . The injectable solution of  claim 1 , further comprising an additional component selected from a gel breaker, a demulsifier, a clay stabilizer, a biocide, a scale inhibitor, one or more surfactants, a pH adjuster, or a mixture of two or more thereof. 
     
     
         5 . The injectable solution of  claim 1 , wherein the dialdehyde and the non-polymeric cis-hydroxyl compound are in about a 3:1 to about a 1:3 molar ratio. 
     
     
         6 . The injectable solution of  claim 1 , wherein the produced water comprises about 10 ppm to 500 ppm boron present as dissolved reactive boron species. 
     
     
         7 . The injectable solution of  claim 6  further comprising a source of dissolved reactive boron selected from a sparingly soluble borate, boric acid, borate oxyanion, or a combination of two or more thereof. 
     
     
         8 . The injectable solution of  claim 6 , wherein the molar ratio of dissolved reactive boron species to competing agent in the injectable solution is about 5:1 to 1:20. 
     
     
         9 . The injectable solution of  claim 6 , wherein the pH of the injectable solution is about 5 to 7. 
     
     
         10 . The injectable solution of  claim 6 , wherein the pH of the injectable solution is about 8.5 to 13. 
     
     
         11 . The injectable solution of  claim 1 , further comprising a reaction product obtained by combining a solution of a zirconium tetraalkoxide and an alkanolamine composition comprising an alkanolamine, wherein the molar ratio of the zirconium tetraalkoxide to the alkanolamine is about 1:9. 
     
     
         12 . The injectable solution of  claim 11 , wherein the alkanolamine is triethanolamine, wherein the solution of zirconium tetraalkoxide is a solution of zirconium tetra(n-propoxide) in n-propanol, and wherein the molar ratio of the zirconium tetra(n-propoxide) to the competing agent is about 5:1 to about 1:20. 
     
     
         13 . A method of making an injectable solution, the method comprising:
 combining a dialdehyde having 2 to 4 carbons and a non-polymeric cis-hydroxyl compound in an aqueous solution to form a competing agent solution comprising a competing agent; and   combining a crosslinkable polymer and the competing agent in produced water to form the injectable solution, the produced water containing about 10 ppm to 500 ppm boron as dissolved reactive boron species.   
     
     
         14 . The method of  claim 13 , further comprising injecting the injectable solution into the subterranean reservoir, and recovering a hydrocarbon from the reservoir. 
     
     
         15 . The method of  claim 13 , wherein the dialdehyde is glyoxal, the non-polymeric cis-hydroxyl compound is sorbitol, and the crosslinkable polymer is selected from guar gum or carboxymethyl hydroxypropyl guar. 
     
     
         16 . The method of  claim 13 , wherein the combining the crosslinkable polymer and the competing agent in produced water consists essentially of combining the crosslinkable polymer and the competing agent solution in produced water, wherein the injectable solution after the combining has a pH of about 5 to about 7, and wherein the method further comprises adding to the injectable solution having a pH of about 5 to about 7 a pH adjusting agent in an amount sufficient to raise the pH of the injectable solution to about 8.5 to 13. 
     
     
         17 . The method of  claim 16 , further comprising adding to the injectable solution a source of dissolved reactive boron selected from a sparingly soluble borate, boric acid, borate oxyanion, or a combination thereof. 
     
     
         18 . The method of  claim 16 , wherein about 30 seconds to 5 minutes after the combining the crosslinkable polymer and the competing agent solution in the produced water, the injectable solution reaches a viscosity of at least about 100 cP at 65° C. when measured at 100 s −1 . 
     
     
         19 . The method of  claim 13 , wherein the combining the crosslinkable polymer and the competing agent in produced water to form the injectable solution consists essentially of combining the crosslinkable polymer and a delayed-crosslinking composition in produced water, and wherein the method further comprises:
 adjusting the pH of the competing agent solution to maintain a pH of about 6.0 to about 6.5;   combining a zirconium tetraalkoxide and an alkanolamine in a solvent to form a crosslinker composition, wherein the combining is carried out at a temperature between about 15° C. and about 46° C. and the molar ratio of zirconium tetraalkoxide to the alkanolamine is about 1:9;   maintaining the crosslinker composition at a temperature of from about 35° C. to about 40° C. for 90 to 150 minutes; and   combining the competing agent solution and the crosslinker composition to form the delayed-crosslinking composition.   
     
     
         20 . The method of  claim 19 , wherein about 30 seconds to 5 minutes after combining the crosslinkable polymer and the delayed crosslinking composition in the produced water, the injectable solution reaches a viscosity of from about 100 cP to about 10,000 cP at 163° C. when measured at 100 s −1 .