Non-damaging fluid-loss pill and method of using the same

Abstract

A fluid-loss pill that includes a brine solution and an effective amount of a viscoelastic surfactant is disclosed. The viscoelastic surfactant preferably includes at least one compound selected from the family of compounds described by where R 1 , R 2 , R 3 , R 4 and R 5 are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R 1 contains 16-26 carbon atoms, R 2 contains 2-10 carbon atoms, R 3 , R 4 and R 5 contains 1-6 carbon atoms. Methods of treating a well that include injecting fluid-loss pill into a well to control lost-circulation or to kill a well.

What is claimed is:  
     
         1 . A fluid loss control, lost-circulation pill comprising: 
 An aqueous solution; and    A viscoelastic surfactant added in an effective amount to provide an increase of viscosity at near-static reservoir conditions.    
     
     
         2 . The fluid loss pill of  claim 1  wherein the viscoelastic surfactant comprises at least one compound selected from the family of compounds described by  
       
         
           
           
               
               
           
         
       
       where R 1 , R 2 , R 3 , R 4  and R 5  are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R 1  contains 16-26 carbon atoms, R 2  contains 2-10 carbon atoms, R 3 , R 4  and R 5  contains 1-6 carbon atoms.  
     
     
         3 . The fluid loss pill of  claim 1  wherein the aqueous solution is a brine having a density of at least 11.5 pgg.  
     
     
         4 . The fluid loss pill of  claim 1 , wherein the viscoelastic surfactant comprises an erucylamidopropyl betaine.  
     
     
         5 . The fluid loss pill of  claim 1 , wherein the viscoelastic surfactant an oleylamidopropyl betaine  
     
     
         6 . The fluid loss pill of  claim 1 , wherein the viscoelastic surfactant blend comprises about 2% to about 30% by volume of the fluid loss pill.  
     
     
         7 . The fluid loss pill of  claim 6 , wherein the viscoelastic surfactant comprises about 5% to about 20% by volume of the fluid loss pill.  
     
     
         8 . The fluid loss pill of  claim 7 , wherein the viscoelastic surfactant comprises about 10% to 15% of the fluid loss pill.  
     
     
         9 . The fluid loss pill of  claim 1 , further comprising a cosurfactant selected among the class of benzene sulfonate described by  
       
         
           
           
               
               
           
         
       
     
     
         10 . The fluid loss pill of  claim 1 , further comprising particulates selected among acid or chelant soluble particulates, resins, graded starches and polymers.  
     
     
         11 . The fluid loss pill of  claim 10 , wherein the fluid loss pill comprises calcium carbonate as acid soluble bridging particulates.  
     
     
         12 . A method of controlling loss circulation in a well comprising injecting a fluid loss pill comprising: 
 An aqueous solution; and    A viscoelastic surfactant added in an effective amount to provide an increase of viscosity at near-static reservoir conditions.    
     
     
         13 . The method of  claim 12  wherein the viscoelastic surfactant comprises at least one compound selected from the family of compounds described by  
       
         
           
           
               
               
           
         
       
       where R 1 , R 2 , R 3 , R 4  and R 5  are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R 1  contains 16-26 carbon atoms, R 2  contains 2-10 carbon atoms, R 3 , R 4  and R 5  contains 1-6 carbon atoms.  
     
     
         14 . The method of  claim 12  wherein the aqueous solution is a brine having a density of at least 11.5 pgg.  
     
     
         15 . The method of  claim 12 , wherein the viscoelastic surfactant comprises an erucylamidopropyl betaine.  
     
     
         16 . The method of  claim 12 , wherein the viscoelastic surfactant an oleylamidopropyl betaine  
     
     
         17 . The method of  claim 12 , wherein the viscoelastic surfactant is used in conjunction with a polymer, linear or crosslinked to build viscosity and also to develop a filtercake.  
     
     
         18 . The method of  claim 12 , wherein the viscoelastic surfactant blend comprises about 2% to about 30% by volume of the fluid loss pill.  
     
     
         19 . The method of  claim 12 , wherein the pill further comprises a cosurfactant selected among the class of benzene sulfonate described by  
       
         
           
           
               
               
           
         
       
     
     
         20 . The method of  claim 12 , wherein the pill further comprises particulates selected among acid or chelant soluble particulates, resins, graded starches and polymers.  
     
     
         21 . A method of killing a well comprising injecting a fluid loss pill comprising: 
 An aqueous solution; and    A viscoelastic surfactant added in an effective amount to provide an increase of viscosity at near-static reservoir conditions.    
     
     
         22 . The method of  claim 21  wherein the viscoelastic surfactant comprises at least one compound selected from the family of compounds described by  
       
         
           
           
               
               
           
         
       
       where R 1 , R 2 , R 3 , R 4  and R 5  are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R 1  contains 16-26 carbon atoms, R 2  contains 2-10 carbon atoms, R 3 , R 4  and R 5  contains 1-6 carbon atoms.  
     
     
         23 . The method of  claim 21  wherein the aqueous solution is a brine having a density of at least 11.5 pgg.  
     
     
         24 . The method of  claim 21 , wherein the viscoelastic surfactant comprises an erucylamidopropyl betaine.  
     
     
         25 . The method of  claim 21 , wherein the viscoelastic surfactant an oleylamidopropyl betaine  
     
     
         26 . The method of  claim 21 , wherein the viscoelastic surfactant is used in conjunction with a polymer, linear or crosslinked to build viscosity and also to develop a filtercake.  
     
     
         27 . The method of  claim 21 , wherein the viscoelastic surfactant blend comprises about 2% to about 30% by volume of the fluid loss pill.  
     
     
         28 . The method of  claim 21 , wherein the pill further comprises a cosurfactant selected among the class of benzene sulfonate described by  
       
         
           
           
               
               
           
         
       
     
     
         29 . The method of  claim 21 , wherein the pill further comprises particulates selected among acid or chelant soluble particulates, resins, graded starches and polymers.  
     
     
         30 . A method of pre-conditioning a well in a high-permeable reservoir prior to performing the injection of a polymer-base fluid comprising injecting a fluid loss pill 
 An aqueous solution; and    A viscoelastic surfactant added in an effective amount to provide an increase of viscosity at near-static reservoir conditions.    to minimize to the volume of polymer invasion into the formation before the formation of the polymer-containing filter cake.    
     
     
         31 . The method of  claim 30  wherein the viscoelastic surfactant comprises at least one compound selected from the family of compounds described by  
       
         
           
           
               
               
           
         
       
       where R 1 , R 2 , R 3 , R 4  and R 5  are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R 1  contains 16-26 carbon atoms, R 2  contains 2-10 carbon atoms, R 3 , R 4  and R 5  contains 1-6 carbon atoms.  
     
     
         32 . The method of  claim 30  wherein the aqueous solution is a brine having a density of at least 11.5 pgg.  
     
     
         33 . The method of  claim 30 , wherein the viscoelastic surfactant blend comprises about 2% to about 30% by volume of the fluid loss pill.  
     
     
         34 . The method of  claim 30 , wherein the pill further comprises a cosurfactant selected among the class of benzene sulfonate described by  
       
         
           
           
               
               
           
         
       
     
     
         35 . The method of  claim 30 , wherein the pill further comprises particulates selected among acid or chelant soluble particulates, resins, graded starches and polymers.  
     
     
         36 . A method of packing a well comprising the placement of solids comprising the use of a fluid comprising 
 An aqueous solution; and    A viscoelastic surfactant added in an effective amount to provide an increase of viscosity at near-static reservoir conditions.    
     
     
         37 . The method of  claim 36  wherein the viscoelastic surfactant comprises at least one compound selected from the family of compounds described by  
       
         
           
           
               
               
           
         
       
       where R 1 , R 2 , R 3 , R 4  and R 5  are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R 1  contains 16-26 carbon atoms, R 2  contains 2-10 carbon atoms, R 3 , R 4  and R 5  contains 1-6 carbon atoms.  
     
     
         38 . The method of  claim 36  wherein the aqueous solution is a brine having a density of at least 11.5 pgg.  
     
     
         39 . The method of  claim 36  wherein the step of placing solids comprises the step of proppants placement.  
     
     
         40 . The method of  claim 39  wherein the step of packing is performed on a sand control screen.