Clean Viscosified Treatment Fluids and Associated Methods

Abstract

Treatment fluids comprising an aqueous base fluid, a compliant cellulosic viscosifying agent, a crosslinking agent, and a protective ligand are provided. The present invention provides methods of using the treatment fluids in subterranean formations. One example of a suitable method includes providing a fracturing fluid comprising an aqueous base fluid, a compliant cellulosic viscosifying agent, a crosslinking agent, and a protective ligand and introducing the fracturing fluid into at least a portion of a subterranean formation at a rate and pressure sufficient to create or enhance at least one or more fractures in the subterranean formation.

1 . A method comprising:
 providing a treatment fluid having a first viscosity comprising:
 an aqueous base fluid, 
 a compliant cellulosic viscosifying agent, 
 a crosslinking agent, and 
 a protective ligand; and 
   placing the treatment fluid in a subterranean formation.   
     
     
         2 . The method of  claim 1  wherein the treatment fluid forms a crosslinked gel having a second viscosity, the second viscosity being higher than the first viscosity prior to being placed in the subterranean formation. 
     
     
         3 . The method of  claim 1  wherein the treatment fluid forms a crosslinked gel having a second viscosity, the second viscosity being higher than the first viscosity after being placed in the subterranean formation. 
     
     
         4 . The method of  claim 1  wherein the compliant cellulosic viscosifying agent is a carboxylated viscosifying agent selected from the group consisting of a carboxyethylcellulose, a carboxymethylcellulose, a carboxymethylhydroxyethylcellulose, and any combination thereof. 
     
     
         5 . The method of  claim 1  wherein the crosslinking agent is a compound capable of supplying a metal ion selected from the group consisting of: a zirconium ion, an iron ion, a titanium ion, an aluminum ion, a chromium ion, an antimony ion, and any combination thereof. 
     
     
         6 . The method of  claim 4  wherein the crosslinking agent comprises a compound capable of supplying an aluminum ion and wherein treatment fluid has a pH in the range of from about 3.5 to about 5. 
     
     
         7 . The method of  claim 1  wherein the protective ligand is an acid selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, butyric acid, isobutyric acid, malonic acid, succinic acid, malic acid, tartaric acid, citric acid, ethylenediaminetetraacetic acid, sulfuric acid and any combination thereof. 
     
     
         8 . The method of  claim 1  wherein the treatment fluid is placed in the subterranean formation as part of a subterranean operation selected from the group consisting of a drilling operation, a fracturing operation, a completion operation, and a workover operation. 
     
     
         9 . The method of  claim 1  wherein the subterranean formation comprises a bottom hole temperature of up to and including about 275° F. 
     
     
         10 . A method comprising:
 providing a fracturing fluid having a first viscosity comprising:
 an aqueous base fluid, 
 a compliant cellulosic viscosifying agent, 
 a crosslinking agent, 
 and a protective ligand; and 
   introducing the fracturing fluid into at least a portion of a subterranean formation at a rate and pressure sufficient to create or enhance at least one or more fractures in the subterranean formation.   
     
     
         11 . The method of  claim 10  wherein the fracturing fluid forms a crosslinked gel having a second viscosity, the second viscosity being higher than the first viscosity prior to being placed in the subterranean formation. 
     
     
         12 . The method of  claim 10  wherein the fracturing fluid forms a crosslinked gel having a second viscosity, the second viscosity being higher than the first viscosity after being placed in the subterranean formation. 
     
     
         13 . The method of  claim 10  wherein the compliant cellulosic viscosifying agent is a carboxylated viscosifying agent selected from the group consisting of a carboxyethylcellulose, a carboxymethylcellulose, a carboxymethylhydroxyethylcellulose, and any combination thereof. 
     
     
         14 . The method of  claim 10  wherein the crosslinking agent is a compound capable of supplying a metal ion selected from the group consisting of: a zirconium ion, an iron ion, a titanium ion, an aluminum ion, a chromium ion, an antimony ion, and any combination thereof. 
     
     
         15 . The method of  claim 10  wherein the protective ligand is an acid selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, butyric acid, isobutyric acid, malonic acid, succinic acid, malic acid, tartaric acid, citric acid, sulfuric acid, ethylenediaminetetraacetic acid, and any combination thereof. 
     
     
         16 . The method of  claim 10  wherein the subterranean formation comprises a bottom hole temperature of up to and including about 275° F. 
     
     
         17 . A method comprising:
 providing a treatment fluid having a pH in the range of about 3.5 to about 5 comprising:
 an aqueous base fluid, 
 a cellulosic, carboxylated viscosifying agent, 
 an aluminum crosslinking agent, and 
 a protective ligand; and 
   placing the treatment fluid in a subterranean formation.   
     
     
         18 . The method of  claim 10  wherein the compliant cellulosic viscosifying agent is a carboxylated viscosifying agent selected from the group consisting of a carboxyethylcellulose, a carboxymethylcellulose, a carboxymethylhydroxyethylcellulose, and any combination thereof. 
     
     
         19 . The method of  claim 10  wherein the crosslinking agent is a compound capable of supplying a metal ion selected from the group consisting of: a zirconium ion, an iron ion, a titanium ion, an aluminum ion, a chromium ion, an antimony ion, and any combination thereof. 
     
     
         20 . The method of  claim 17  wherein the protective ligand is an acid selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, butyric acid, isobutyric acid, malonic acid, succinic acid, malic acid, tartaric acid, citric acid, sulfuric acid, ethylenediaminetetraacetic acid, and any combination thereof.