Methods and Compositions for the Controlled Crosslinking and Viscosifying of Well Servicing Fluids Utilizing Mixed Borate Hydrocarbon-Based Suspensions

Abstract

Disclosed are treating fluid compositions for use in subterranean workover and hydrocarbon recovery operations, as well as methods of treating subterranean formations penetrated by a wellbore utilizing the treating fluid. The treating fluid compositions contain a first, aqueous liquid, and a crosslinkable organic polymer that is at least partly soluble in the liquid. The treating fluid further contains a borate crosslinking agent solution containing a primary, un-refined borate and a secondary, refined borate, the borate solution being present as a crosslinking agent upon addition to the first fluid admixture so as to crosslink the organic polymer and increase the viscosity and/or accelerate the crosslink time of the treating fluid.

What is claimed is: 
     
         1 . A treating fluid composition comprising:
 a polymer solution, comprising:
 an aqueous fluid; 
 a crosslinkable organic polymer having a solubility in the aqueous fluid; 
 a viscosifier; and 
 an alkaline buffer; and 
   a borate crosslinking composition, comprising:
 a low-aromatic content hydrocarbon fluid; 
 an un-refined borate crosslinking agent; and 
 a refined borate crosslinking agent, wherein the treating fluid composition has a pH of greater than pH 8. 
   
     
     
         2 . The treating fluid composition of  claim 1 , wherein the aqueous fluid comprises substantially any aqueous fluid that does not adversely react with the constituents of the treating fluid, the subterranean formation, and the fluids present therein. 
     
     
         3 . The treating fluid composition of  claim 1 , wherein the aqueous fluid is selected from the group consisting of fresh water, natural brines, and artificial brines. 
     
     
         4 . The treating fluid composition of  claim 3 , wherein the artificial brines are selected from the group consisting of potassium halide solutions, sodium halide solutions, and cesium halide solutions. 
     
     
         5 . The treating fluid composition of  claim 1 , wherein the crosslinkable, organic polymer is guar or guar derivatives, galactomannan gum, cellulose, hydroxyethylcellulose, hydroxypropyl cellulose, carboxymethylcellulose, carboxymethylhydroxyethyl cellulose, xanthan gum, diutan, scleroglucan, carrageenan, polyacrylamide, and polyacrylate. 
     
     
         6 . The treating fluid composition of  claim 1 , wherein the alkaline buffer comprises alkaline compounds. 
     
     
         7 . The treating fluid composition of  claim 6 , wherein the alkaline compounds comprise one or more selected from the group consisting of ammonium, alkali metal (Group 1) hydroxides, carbonates and bicarbonates, and alkaline earth metal (Group 2) hydroxides, carbonates, and bicarbonates. 
     
     
         8 . The treating fluid composition of  claim 6 , wherein the alkaline compounds are selected from the group consisting of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, and potassium bicarbonate. 
     
     
         9 . The treating fluid composition of  claim 1 , wherein the un-refined borate crosslinking agent contains about 5 wt. % or more of boron. 
     
     
         10 . The treating fluid composition of  claim 1 , wherein the un-refined borate crosslinking agent is selected from the group consisting of ulexite, colemanite, probertite, and mixtures thereof. 
     
     
         11 . The treating fluid composition of  claim 1 , wherein the refined borate crosslinking agent is a metal octaborate material. 
     
     
         12 . The treating fluid composition of  claim 11 , wherein the metal octaborate is disodium octaborate tetrahydrate. 
     
     
         13 . The treating fluid composition of  claim 1 , wherein the low-aromatic content hydrocarbon fluid has less than about 0.5% aromatics. 
     
     
         14 . The treating fluid composition of  claim 1 , wherein the low-aromatic content hydrocarbon fluid is a hydrotreated light petroleum distillate with a CCS kinematic viscosity of less than about 2 cSt at 40° F.