Subterranean formation treating fluid concentrates, treating fluids and methods

Abstract

Subterranean formation treating fluid concentrates, treating fluids and methods are provided by the present invention. The treating fluid concentrates are basically comprised of water and a substantially fully hydrated depolymerized polymer. The treating fluids which are formed by adding water to the treating fluid concentrates are basically comprised of water, a substantially fully hydrated depolymerized polymer and a crosslinking agent for crosslinking the hydrated depolymerized polymer.

What is claimed is:  
     
         1 . A subterranean formation treating fluid concentrate comprised of: 
 water; and    a substantially fully hydrated depolymerized polymer having a polydispersity ratio of from 1 to about 12.    
     
     
         2 . The concentrate of  claim 1  wherein said water is selected from the group consisting of fresh water, unsaturated salt water and saturated salt water.  
     
     
         3 . The concentrate of  claim 1  wherein said substantially fully hydrated depolymerized polymer is a depolymerized guar derivative polymer selected from the group consisting of hydroxypropylguar, carboxymethylhydroxypropylguar, carboxymethylguar, hydroxyethyl cellulose, grafted hydroxyethyl cellulose, carboxymethyl cellulose and carboxymethylhydroxyethyl cellulose.  
     
     
         4 . The concentrate of  claim 1  wherein said substantially fully hydrated depolymerized polymer is depolymerized hydroxypropylguar.  
     
     
         5 . The concentrate of  claim 1  wherein said substantially fully hydrated depolymerized polymer is present in said concentrate in an amount greater than about 6% by weight of said water therein.  
     
     
         6 . The concentrate of  claim 1  wherein said substantially fully hydrated depolymerized polymer is present in said concentrate in an amount in the range of from about 6% to about 20% by weight of said concentrate.  
     
     
         7 . The concentrate of  claim 1  wherein said substantially fully hydrated depolymerized polymer is present in said concentrate in an amount in the range of from about 12% to about 30% by weight of said concentrate.  
     
     
         8 . The concentrate of  claim 1  which further comprises a pH adjusting compound for adjusting the pH of the treating fluid which is formed with said concentrate selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, fumaric acid, formic acid, acetic acid, acetic anhydride and hydrochloric acid.  
     
     
         9 . The concentrate of  claim 8  wherein said pH adjusting compound is sodium hydroxide.  
     
     
         10 . The concentrate of  claim 8  wherein said pH adjusting compound is present in said concentrate in an amount in the range of from about 0% to about 0.3% by weight of said water therein.  
     
     
         11 . The concentrate of  claim 1  which further comprises a buffer selected from the group consisting of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium diacetate, potassium diacetate, sodium phosphate, potassium phosphate, sodium dihydrogen phosphate and potassium dihydrogen phosphate.  
     
     
         12 . The concentrate of  claim 11  wherein said buffer is sodium carbonate.  
     
     
         13 . The concentrate of  claim 11  wherein said buffer is present in said concentrate in an amount in the range of from about 0.5% to about 10% by weight of said water therein.  
     
     
         14 . The concentrate of  claim 1  which further comprises a surfactant for preventing the formation of emulsions between the treating fluid which is formed with said concentrate and subterranean formation fluids selected from the group consisting of alkyl sulfonates, alkyl aryl sulfonates such as the salts of dodecylbenzene sulfonic acid, alkyltrimethylammonium chloride, branched alkyl ethoxylated alcohols, phenol-formaldehyde nonionic resin blends, cocobetaines, dioctyl sodium sulfosuccinate, imidazolines, alpha olefin sulfonates, linear alkyl ethoxylated alcohols and trialkyl benzylammonium chloride.  
     
     
         15 . The concentrate of  claim 14  wherein said surfactant is a salt of dodecylbenzene sulfonic acid.  
     
     
         16 . The concentrate of  claim 14  wherein said surfactant is present in said concentrate in an amount in the range of from about 0.01% to about 1% by weight of said water therein.  
     
     
         17 . The concentrate of  claim 1  which further comprises a clay stabilizer selected from the group consisting of potassium chloride, sodium chloride, ammonium chloride, tetramethyl ammonium chloride and temporary clay stabilizers.  
     
     
         18 . The concentrate of  claim 17  wherein said clay stabilizer is potassium chloride.  
     
     
         19 . The concentrate of  claim 17  wherein said clay stabilizer is present in said concentrate in an amount in the range of from about 2% to about 20% by weight of said water therein.  
     
     
         20 . An improved subterranean formation treating fluid prepared by: 
 mixing water with a concentrate of a substantially fully hydrated depolymerized polymer having a polydispersity ratio of from 1 to about 12; and    a crosslinking agent for crosslinking said substantially fully hydrated depolymerized polymer.    
     
     
         21 . The treating fluid of  claim 22  wherein said water is selected from the group consisting of fresh water, unsaturated salt water and saturated salt water.  
     
     
         22 . The treating fluid of  claim 20  wherein said substantially fully hydrated depolymerized polymer is a substantially fully hydrated depolymerized guar derivative polymer selected from the group consisting of 
 hydroxypropylguar, carboxymethylhydroxypropylguar, carboxymethylguar, hydroxyethyl cellulose, grafted hydroxyethyl cellulose, carboxymethyl cellulose and carboxymethylhydroxyethyl cellulose.  
 
     
     
         23 . The treating fluid of  claim 20  wherein said substantially fully hydrated depolymerized polymer is substantially fully hydrated depolymerized hydroxypropylguar.  
     
     
         24 . The treating fluid of  claim 20  wherein said substantially fully hydrated depolymerized polymer is present in said treating fluid in an amount in the range of from about 0.2% to about 5% by weight of said water therein.  
     
     
         25 . The treating fluid of  claim 20  wherein said crosslinking agent is selected from the group consisting of boron compounds, compounds that supply zirconium IV ions, compounds that supply titanium IV ions, aluminum compounds and compounds that supply antimony ions.  
     
     
         26 . The treating fluid of  claim 20  wherein said crosslinking agent is a boron compound.  
     
     
         27 . The treating fluid of  claim 20  wherein said crosslinking agent is present in said treating fluid in an amount in the range of from about 50 ppm to about 5000 ppm.  
     
     
         28 . The treating fluid of  claim 20  which further comprises a proppant material selected from the group consisting of resin coated or uncoated sand, sintered bauxite, ceramic materials and glass beads.  
     
     
         29 . The treating fluid of  claim 28  wherein said proppant material is present in said treating fluid in an amount in the range of from about 1 to about 24 pounds of proppant material per gallon of said treating fluid.  
     
     
         30 . The treating fluid of  claim 20  which further comprises a tackifying compound for controlling fines or proppant migration within the subterranean formation  
     
     
         31 . The treating fluid of  claim 20  which further comprises a pH adjusting compound for elevating the pH of the treating fluid selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide.  
     
     
         32 . The treating fluid of  claim 30  wherein said pH adjusting compound is present in said treating fluid in an amount in the range of from about 0% to about 0.3% by weight of said water therein.  
     
     
         33 . The treating fluid of  claim 20  which further comprises a buffer selected from the group consisting of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium diacetate, potassium diacetate, sodium phosphate, potassium phosphate, sodium dihydrogen phosphate and potassium dihydrogen phosphate.  
     
     
         34 . The treating fluid of  claim 33  wherein said buffer is sodium carbonate.  
     
     
         35 . The treating fluid of  claim 33  wherein said buffer is present in said treating fluid in an amount in the range of from about 0% to about 0.3% by weight of said water therein.  
     
     
         36 . The treating fluid of  claim 20  which further comprises a surfactant for preventing the formation of emulsions between said treating fluid and subterranean formation fluids selected from the group consisting of alkyl sulfonates, alkyl aryl sulfonates such as the salts of dodecylbenzene sulfonic acid, alkyltrimethylammonium chloride, branched alkyl ethoxylated alcohols, phenol-formaldehyde nonionic resin blends, cocobetaines, dioctyl sodium sulfosuccinate, imidazolines, alpha olefin sulfonates, linear alkyl ethoxylated alcohols and trialkyl benzylammonium chloride.  
     
     
         37 . The treating fluid of  claim 36  wherein said surfactant is a salt of dodecylbenzene sulfonic acid.  
     
     
         38 . The treating fluid of  claim 36  wherein said surfactant is present in said treating fluid in an amount in the range of from about 0% to about 0.1% by weight of said water therein.  
     
     
         39 . The treating fluid of  claim 20  which further comprises a clay stabilizer selected from the group consisting of potassium chloride, sodium chloride, ammonium chloride, tetramethyl ammonium chloride and temporary clay stabilizers.  
     
     
         40 . The treating fluid of  claim 39  wherein said clay stabilizer is potassium chloride.  
     
     
         41 . The treating fluid of  claim 39  wherein said clay stabilizer is present in said treating fluid in an amount in the range of from about 0.5% to about 10% by weight of said water therein.  
     
     
         42 . The treating fluid of  claim 20  which further comprises a fluid loss control agent selected from the group consisting of silica flour, starches, waxes and resins.  
     
     
         43 . The treating fluid of  claim 42  wherein said fluid loss control agent is present in said treating fluid in an amount in the range of from about 0% to about 1% by weight of said water therein.  
     
     
         44 . The treating fluid of  claim 20  which further comprises a delayed delinker for causing said treating fluid to revert to a thin fluid selected from the group consisting of lactone delinkers, ester delinkers, encapsulated acid delinkers, slowly soluble acid generating delinkers, oxidizers that produce acids upon reaction, and water reactive metals.  
     
     
         45 . The treating fluid of  claim 44  wherein said delayed delinker is present in said treating fluid in an amount in the range of from about 0% to about 1% by weight of said water therein.  
     
     
         46 . The treating fluid of  claim 20  which further comprises a delayed breaker for causing said treating fluid to revert to a thin fluid selected from the group of oxidizers, encapsulated oxidizers and enzyme breakers consisting of sodium persulfate, potassium persulfate, ammonium persulfate, magnesium peroxide, sodium chlorite, sodium bromate, alpha and beta amylases, amyloglucosidase, invertase, maltase, cellulase and hemicellulase.  
     
     
         47 . The treating fluid of  claim 46  wherein said delayed breaker is present in said treating fluid in an amount sufficient to break said treating fluid and cause it to revert to a thin fluid.  
     
     
         48 . A recyclable subterranean formation treating fluid prepared by: 
 mixing with an aqueous treatment fluid recovered from a subterranean formation treatment containing depolymerized polymer additional water, a concentrate of a substantially fully hydrated depolymerized polymer to adjust the depolymerized polymer concentration to a desired level in the subterranean formation treating fluid and a crosslinking agent for crosslinking said substantially fully hydrated depolymerized polymer in said treating fluid.