Methods of fracturing subterranean zones with less pumping

Abstract

Methods of fracturing subterranean zones with less pumping are provided. The methods basically comprise the steps of providing an aqueous fracturing fluid comprised of a brine having a density in the range of from about 9 to about 19 pounds per gallon, pumping the aqueous fracturing fluid into the subterranean zone at a rate and pressure sufficient to fracture the subterranean zone and recovering the aqueous fracturing fluid from the subterranean zone.

1 . A method of fracturing a subterranean zone penetrated by a well bore comprising the steps of: 
 (a) providing an aqueous fracturing fluid that comprises a brine having a density in the range of from about 9 to 19 pounds per gallon;    (b) pumping said aqueous fracturing fluid into said subterranean zone at a rate and pressure sufficient to fracture said subterranean zone; and    (c) recovering said aqueous fracturing fluid from said subterranean zone.    
     
     
         2 . The method of  claim 1  wherein said brine is selected from the group consisting of calcium chloride brine, calcium bromide brine, sodium bromide brine, sodium chloride brine, potassium formate brine, cesium formate brine, zinc chloride brine, zinc bromide brine, and mixtures thereof.  
     
     
         3 . The method of  claim 1  wherein said brine is calcium chloride brine.  
     
     
         4 . A method of fracturing a subterranean zone penetrated by a well bore comprising the steps of: 
 (a) providing a viscous aqueous fracturing fluid that comprises a brine having a density in the range of from about 9 to about 19 pounds per gallon and a gelling agent;    (b) pumping said viscous aqueous fracturing fluid into said subterranean zone at a rate and pressure sufficient to fracture said subterranean zone; and    (c) recovering said aqueous fracturing fluid from said subterranean zone.    
     
     
         5 . The method of  claim 4  wherein said brine is selected from the group consisting of calcium chloride brine, calcium bromide brine, sodium bromide brine, sodium chloride brine, potassium formate brine, cesium formate brine, zinc chloride brine, zinc bromide brine, and mixtures thereof.  
     
     
         6 . The method of  claim 4  wherein said brine is calcium chloride brine.  
     
     
         7 . The method of  claim 4  wherein said gelling agent is selected from the group consisting of hydroxyethylcellulose, guar, xanthan and succinoglycan.  
     
     
         8 . The method of  claim 4  wherein said gelling agent is xanthan.  
     
     
         9 . The method of  claim 4  wherein said gelling agent is present in said aqueous fracturing fluid in an amount in the range of from about 0.1% to about 2% by weight of said brine therein.  
     
     
         10 . The method of  claim 4  wherein said aqueous fracturing fluid further comprises a cross-linking agent for cross-linking said gelling agent.  
     
     
         11 . The method of  claim 10  wherein said cross-linking agent is selected from the group consisting of sodium borate decahydrate, zirconium oxychloride, calcium salts, aluminum salts, magnesium salts, iron compounds, iodine compounds and baron compounds.  
     
     
         12 . The method of  claim 10  wherein said cross-linking agent is sodium borate decahydrate.  
     
     
         13 . The method of  claim 10  wherein said cross-linking agent is present in said aqueous fracturing fluid in an amount in the range of from about 0.1% to about 66% by weight of said gelling agent therein.  
     
     
         14 . The method of  claim 4  wherein said aqueous fracturing fluid further comprises a proppant material.  
     
     
         15 . The method of  claim 14  wherein said proppant material is selected from the group consisting of graded sand, sintered bauxite, walnut hulls, and glass beads.  
     
     
         16 . The method of  claim 14  wherein said proppant material is graded sand.  
     
     
         17 . The method of  claim 14  wherein at least part of said proppant material is coated with a hardenable resin composition.  
     
     
         18 . The method of  claim 14  wherein said proppant material is present in said aqueous fracturing fluid in an amount in the range of from about 1 to about 18 pounds per gallon of said fracturing fluid.  
     
     
         19 . The method of  claim 4  wherein said aqueous fracturing fluid further comprises a delayed breaker for effecting a controlled reduction in viscosity of said aqueous fracturing fluid.  
     
     
         20 . The method of  claim 19  wherein said delayed breaker is selected from the group consisting of sodium perborate, potassium periodate, sodium persulfate, t-butyl hydroperoxide, sodium bromate, lithium hypochlorite, sodium hypochlorite and sodium chlorite.  
     
     
         21 . The method of  claim 19  wherein said delayed breaker is sodium perborate.  
     
     
         22 . The method of  claim 19  wherein said delayed breaker is present in said aqueous fracturing fluid in an amount in the range of from about 0.01% to about 5% by weight of gelling agent therein.  
     
     
         23 . A method of fracturing a subterranean zone penetrated by a well bore comprising the steps of: 
 (a) providing a viscous aqueous fracturing fluid that comprises calcium chloride brine having a density in the range of from about 9 to about 19 pounds per gallon, a xanthan gelling agent present in said viscous fracturing fluid in an amount in the range of from about 0.1% to about 2% by weight of said brine therein, a graded sand proppant material present in said viscous fracturing fluid in an amount in the range of from about 1 pound to about 18 pounds per gallon of said viscous fracturing fluid, and a sodium perborate delayed breaker present in said viscous aqueous fracturing fluid in an amount in the range of from about 0.01% to about 5% by weight of said gelling agent therein;    (b) pumping said viscous aqueous fracturing fluid into said subterranean zone at a rate and pressure sufficient to fracture said subterranean zone; and    (c) recovering said aqueous fracturing fluid from said subterranean zone.    
     
     
         24 . The method of  claim 23  wherein said aqueous fracturing fluid further comprises a cross-linking agent comprising sodium perborate tetrahydrate present in said aqueous fracturing fluid in an amount in the range of from about 0.01% to about 5% by weight of said gelling agent therein.