Novel bits and cutting structures

Abstract

This invention provides an improved cutting element for downhole cutting tools including a support element and a beveled shearing element disposed on the support element and a drill bit including the cutting element; a cutting element including a support element and a shearing element disposed on the support element, wherein the shearing element includes TSP, a sharpened cutting edge, and at least one blended edge that forms part of an interface with the support element and a drill bit including the cutting element. Cutting inserts including an insert body and the shearing elements disclosed above are provided. Also provided are methods for forming the cutting elements and drill bit inserts and a method for drilling mixed earth formations using the improved downhole cutting tools of the present invention.

1 . A cutting element disposed on a downhole cutting tool, comprising: 
 a support element; and    a beveled shearing element disposed on the support element, wherein the beveled shearing element comprises thermally stable polycrystalline diamond.    
   
   
       2 . A cutting element disposed on a downhole cutting tool, comprising: 
 a support element;    a shaped shearing element disposed on the support element, wherein the shaped shearing element is disposed proximal to a leading edge of the downhole cutting tool; and    a retaining element overlaying at least a portion of the shaped shearing element.    
   
   
       3 . The cutting element of  claim 2 , wherein the shaped shearing element comprises at least one beveled edge.  
   
   
       4 . The cutting element of  claim 2 , wherein the shaped shearing element comprises at least one rounded edge.  
   
   
       5 . The cutting element of  claim 2 , wherein the shaped shearing element comprises at least one tapered surface.  
   
   
       6 . The cutting element of  claim 2 , wherein the shaped shearing element comprises at least one rounded cutting edge.  
   
   
       7 . The cutting element of  claim 2 , wherein the shaped shearing element comprises at least one beveled cutting edge.  
   
   
       8 . The cutting element of  claim 2 , wherein the shaped shearing element comprises at least one non-planar cutting face geometry selected from the group consisting of concave, convex, saddle shaped, chiseled, and beveled.  
   
   
       9 . The cutting element of  claim 2 , wherein the shaped shearing element comprises at least one selected from the group consisting of polycrystalline diamond, thermally stable polycrystalline diamond, a silicon carbide polycrystalline diamond composite, and a silicon carbide thermally stable polycrystalline diamond composite.  
   
   
       10 . The cutting element of  claim 2 , wherein the retaining element is formed integrally with the support element.  
   
   
       11 . The cutting element of  claim 2 , wherein the retaining element is at least one selected from the group consisting of a cubic boron nitride composite, a tungsten carbide composite and a diamond-impregnated material.  
   
   
       12 . A cutting element disposed on a downhole cutting tool, comprising: 
 a support element;    a shearing element disposed on the support element, wherein the shearing element comprises; 
 thermally stable polycrystalline diamond;  
 a sharpened cutting edge proximal to a leading edge of the downhole cutting tool; and  
 at least one blended edge, wherein the at least one blended edge forms part of an interface with the support element.  
   
   
   
       13 . The cutting element of  claim 12 , wherein the shearing element comprises a composite of silicon carbide and thermally stable polycrystalline diamond.  
   
   
       14 . The cutting element of  claim 12 , wherein the cutting element further comprises a retaining element overlaying at least a portion of the shearing element.  
   
   
       15 . The cutting element of  claim 12 , wherein the shearing element further comprises at least one tapered surface.  
   
   
       16 . The cutting element of  claim 12 , wherein the shearing element further comprises at least one perturbation on at least one surface of the shearing element.  
   
   
       17 . The cutting element of  claim 12 , wherein the shearing element comprises a non-planar cutting face geometry selected from the group consisting of concave, convex, saddle shaped, chiseled, and beveled.  
   
   
       18 . A drill bit for drilling earth formations comprising: 
 a bit body having at least one support element disposed thereon; and    a shearing element disposed on the at least one support element, wherein the shearing element comprises; 
 thermal stable polycrystalline diamond;  
 a sharpened cutting edge proximal to a leading edge of the downhole cutting tool; and  
 at least one blended edge, wherein the at least one blended edge forms part of an interface with the at least one support element.  
   
   
   
       19 . The drill bit of  claim 18 , wherein the shearing element further comprises at least one tapered surface.  
   
   
       20 . The drill bit of  claim 18 , wherein the shearing element further comprises at least one perturbation on at least one surface of the shearing element.  
   
   
       21 . A drill bit for drilling earth formations comprising: 
 a bit body;    a plurality of inserts disposed on the bit body, wherein at least one of the plurality of inserts comprises an insert body and a shaped shearing element disposed on the insert body; and    a retaining element overlaying at least a portion of the shaped shearing element.    
   
   
       22 . The bit of  claim 21 , wherein the shaped shearing element comprises at least one beveled cutting edge.  
   
   
       23 . The drill bit of  claim 21 , wherein the shaped shearing element comprises at least one rounded cutting edge.  
   
   
       24 . The drill bit of  claim 21 , wherein the shaped shearing element comprises at least one selected from the group consisting of cubic boron nitride, polycrystalline diamond, and thermally stable polycrystalline diamond.  
   
   
       25 . The drill bit of  claim 21 , wherein the bit body comprises a diamond-impregnated material.  
   
   
       26 . A drill bit comprising: 
 a bit body;    a plurality of inserts disposed on the bit body, wherein at least one of the plurality of inserts comprises an insert body and a shearing element disposed on the insert body, wherein the shearing element comprises; 
 thermally stable polycrystalline diamond;  
 a sharpened cutting edge located proximal a leading edge of the drill bit; and  
 at least one blended edge, wherein the at least one blended edge forms part of an interface with the insert body.  
   
   
   
       27 . The drill bit of  claim 26 , wherein the shearing element further comprises at least one tapered surface.  
   
   
       28 . The drill bit of  claim 26 , wherein the shearing element is tapered toward the insert body.  
   
   
       29 . The drill bit of  claim 26 , wherein the shearing element further comprises at least one perturbation on at least one surface of the shearing element.  
   
   
       30 . The drill bit of  claim 26 , wherein the bit body comprises a diamond-impregnated material.  
   
   
       31 . The drill bit of  claim 26 , wherein the insert body comprises a tungsten carbide composite.  
   
   
       32 . The drill bit of  claim 26 , wherein the insert body comprises a diamond-impregnated material.  
   
   
       33 . The drill bit of  claim 32 , wherein the diamond-impregnated insert body comprises thermally stable polycrystalline diamond.  
   
   
       34 . The drill bit of  claim 32 , wherein the shearing element is disposed on the diamond-impregnated insert body post-infiltration.  
   
   
       35 . A method of forming a diamond-impregnated insert having a shearing portion, the method comprising: 
 forming a diamond-impregnated insert body;    forming a beveled shearing portion; and    bonding the beveled shearing portion to the diamond-impregnated insert body.    
   
   
       36 . The method of  claim 35 , wherein the diamond-impregnated insert body is formed by a hot press process.  
   
   
       37 . The method of  claim 36 , wherein the hot press process is performed with a powder material in a mold, the powder material being selected to form the diamond-impregnated insert body.  
   
   
       38 . A method of forming an insert having a shearing portion, the method comprising: 
 forming an insert body;    forming a shearing portion, wherein the shearing portion comprises, 
 a sharpened cutting face located proximal a leading edge of the diamond-impregnated insert; and  
 at least one blended edge, wherein the at least one blended edge forms part of an interface with the insert body; and  
 bonding the shearing portion to the diamond-impregnated insert body to form the diamond-impregnated insert.  
   
   
   
       39 . A composite cutting element for a drill bit comprising: 
 an abrasive body having a mixture of ultra-hard material and a less abrasive resistant matrix material cemented together; and    a shearing element disposed on the abrasive body.