Percussion drill bit and method of drilling a borehole

Abstract

A percussion drill bit includes a bit body having a central axis and a bit face. A plurality of inserts is disposed on the bit face. A plurality of gauge row inserts is disposed on a periphery of the bit face. At least some one of the plurality of gauge row inserts is enhanced with a super hard material and oriented on the periphery of the bit face at an angle between about 36 degrees and about 40 degrees relative to the central axis of the bit body.

1 . A percussion drill bit, comprising: 
 a bit body having a central axis;    a bit face;    a plurality of inserts disposed on the bit face    a plurality of gauge row inserts disposed on a periphery of the bit face, wherein at least one of the plurality of gauge row inserts is enhanced with a super hard material and oriented on the periphery of said bit face at an angle between about 36 degrees and about 40 degrees relative to the central axis of the bit body.    
   
   
       2 . The percussion drill bit of  claim 1 , wherein at least one of the plurality of gauge row inserts is bullet-shaped.  
   
   
       3 . The percussion drill bit of  claim 1 , wherein at least one of the plurality of gauge row inserts is semi-spherical.  
   
   
       4 . A method of designing a percussion drill bit comprising a bit body having a central axis and a bit face, the method comprising: 
 modeling a gauge row insert comprising a wear pattern;    performing finite element analysis (“FEA”) on the modeled gauge row insert, wherein the modeled gauge row insert is oriented at a first angle relative to the central axis of the bit body;    repeating the performed FEA with the modeled gauge row insert at a second angle relative to the central axis of the bit body;    selecting an angle for a plurality of gauge row inserts from the performed FEA.    
   
   
       5 . The method of  claim 4 , wherein the wear pattern is a cat eye pattern.  
   
   
       6 . The method of  claim 4 , wherein the first angle and the second angle are between about 36 degrees and about 40 degrees relative to the central axis of the bit body.  
   
   
       7 . A percussion drill bit designed using the method of  claim 4.