Lubricant for use in a wellbore

Abstract

The present invention provides methods and apparatus for reducing friction and preventing galling between surfaces in a wellbore. In one aspect of the invention, mating threads are coated with fullerene to reduce galling of the threads during make up and break down. In another aspect, a fullerene is used between surfaces of an expansion tool and a tubular to be expanded in order to reduce friction and prevent galling therebetween. Preferably, the fullerene is a spherically shaped carbon 60 molecule otherwise known as buckyball or C 60 . The fullerene coating provides an intermediate surface between two metal surfaces, thereby preventing galling between the two surfaces. In another aspect of the invention, the fullerene is placed between the roller of an expander tool and the surface of the tubular to be expanded in order to reduce friction and galling.

1 . A method for lubricating two contacting surfaces in a wellbore, comprising: 
 depositing a layer of fullerene on a first surface; and    causing the first surface to contact a second surface.    
     
     
         2 . The method of  claim 1 , wherein the second surface is coated with fullerene.  
     
     
         3 . The method of  claim 1 , wherein the fullerene is selected from the group consisting of C 60 , C 70 , C 76 , C 78 , C 84 , and combinations thereof.  
     
     
         4 . A method of lubricating a surface of a downhole component, comprising: 
 placing a layer of C 60  on the surface, whereby the surface will contact another surface in a wellbore and create friction therebetween.    
     
     
         5 . An expander tool for expanding a tubular, the tool comprising: 
 a body having a bore longitudinally formed therethrough; and    one or more roller members radially extendable from the body, wherein the one or more roller members include at least one coating comprising a fullerene.    
     
     
         6 . The expander tool of  claim 5 , wherein the one or more rollers extend due to fluid pressure applied from the bore to a piston surface formed on a roller housing.  
     
     
         7 . The expander tool of  claim 5 , wherein the fullerene comprises a carbon cage molecule.  
     
     
         8 . The expander tool of  claim 5 , wherein the fullerene is selected from the group consisting of C 60 , C 70 , C 76 , C 78 , C 84 , and combinations thereof.  
     
     
         9 . The expander tool of  claim 5 , wherein the coating further comprises a carrier component.  
     
     
         10 . The expander tool of  claim 9 , wherein the carrier component is selected from the group consisting of zirconium, ceramic, and combinations thereof.  
     
     
         11 . The expander tool of  claim 5 , wherein an inner surface of the tubular comprises the fullerene layer.  
     
     
         12 . The expander tool of  claim 11 , wherein the inner surface is expanded by the expander tool.  
     
     
         13 . The expander tool of  claim 5 , wherein the fullerene is deposited by sputtering.  
     
     
         14 . A method for expanding a first tubular into a second tubular in a wellbore, the first tubular and second tubular each having a top portion and a bottom portion, comprising: 
 positioning the first tubular within the wellbore;    running the second tubular to a selected depth within the wellbore such that the top portion of the second tubular overlaps with the bottom portion of the first tubular, wherein an inner surface of the top portion of the second tubular comprise a fullerene coating; and    expanding the top portion of the second tubular using an expander tool.    
     
     
         15 . The method of  claim 14 , wherein the expander tool comprises: 
 a body having a bore longitudinally formed therein; and    one or more roller members radially extendable from the body.    
     
     
         16 . The method of  claim 15 , wherein the one or more roller members comprise a fullerene.  
     
     
         17 . The method of  claim 15 , wherein the one or more rollers extend due to fluid pressure applied from the bore to a piston surface formed on a roller housing.  
     
     
         18 . The method of  claim 14 , wherein the fullerene comprises a carbon caged molecule.  
     
     
         19 . The method of  claim 14 , wherein the fullerene is selected from the group consisting of C 60 , C 70 , C 76 , C 78 , C 84 , and combinations thereof.  
     
     
         20 . The expander tool of  claim 14 , wherein the coating further comprises a carrier component.  
     
     
         21 . The expander tool of  claim 20 , wherein the carrier component is selected from the group consisting of zirconium, ceramic, and combinations thereof.  
     
     
         22 . The method of  claim 14 , wherein the first tubular and the second tubular each define a string of casing.  
     
     
         23 . The method of  claim 14 , wherein the expander tool comprises a cone shaped portion.  
     
     
         24 . The method of  claim 23 , wherein the cone shaped portion includes a fullerene coating.  
     
     
         25 . A method of connecting a first tubular and a second tubular, the first tubular having a threaded end for mating with a threaded end of the second tubular, comprising: 
 coating the threaded end of the first tubular, the coating comprising a fullerene layer; and    connecting the threaded end of the first tubular with the threaded end of the second tubular.    
     
     
         26 . The method of  claim 25 , wherein the fullerene comprises a carbon cage molecule.  
     
     
         27 . The method of  claim 25 , wherein the fullerene is selected from the group consisting of C 60 , C 70 , C 76 , C 78 , C 84 , and combinations thereof.  
     
     
         28 . The method of  claim 25 , wherein the coating further comprises a carrier component.  
     
     
         29 . The method of  claim 28 , wherein the carrier component is selected from the group consisting of zirconium, ceramic, and combinations thereof.  
     
     
         30 . The method of  claim 25 , wherein the first tubular and the second tubular comprise a metal selected from the group of stainless steel, carbon steel, corrosive resistant alloy, chrome, nickel, and combinations thereof.  
     
     
         31 . The method of  claim 25 , further comprising coating the threaded end of the second tubular, the coating comprising the fullerene layer.  
     
     
         32 . A method for expanding a tubular in a wellbore, comprising: 
 positioning the tubular within the wellbore;    placing an expander tool within the tubular at a location adjacent a portion of the tubular to be expanded, wherein at least one of the portion of the tubular and a portion of the expander tool comprise a fullerene coating disposed thereupon; and    expanding the tubular using the expander tool.    
     
     
         33 . The method of  claim 32 , wherein the expander tool is a cone-shaped member movable independently within the tubular and having an outer diameter larger than an inside diameter of the unexpanded tubular.  
     
     
         34 . The method of  claim 32 , wherein the expander tool includes at least one radially extendable member that is extendable with the application of fluid pressure to a backside thereof.