Wear indication apparatus and method

Abstract

Apparatus and method for monitoring the wear of a downhole tool, and providing indication of the degree of wear to an operator at the well surface. Rotating torque can exhibit a drop when wear of the cutting element matrix progresses to wear pads within the matrix. Other wear indicators can also be built into the cutting element matrix. Progression of wear down to the indicator can be directly measured at the well surface, or relayed to the surface via a downhole communication system.

1 . A system for monitoring wear of a downhole tool, comprising: 
 a working profile formed on a downhole tool, said working profile being adapted to perform work on a structure downhole in a well bore;    a wear resistant pad within said working profile, said wear resistant pad being initially protected from physical contact with said downhole structure by said working profile;    a torque sensor adapted to measure the torque required to rotate said downhole tool;    where said wear resistant pad is adapted to cause a drop in said torque upon sufficient progression of wear of said working profile to bring said downhole structure into contact with said wear resistant pad.    
   
   
       2 . The system recited in  claim 1 , further comprising an output device adapted to provide a signal of an alteration in said torque.  
   
   
       3 . The system recited in  claim 2 , wherein said output device comprises an operator interface.  
   
   
       4 . The system recited in  claim 3 , wherein said operator interface comprises a torque meter.  
   
   
       5 . The system recited in  claim 2 , wherein said output device comprises a control system interface adapted to provide an input signal into a control system.  
   
   
       6 . A method for monitoring wear of a downhole tool, comprising: 
 providing a wear resistant pad in a working profile of a downhole tool;    providing a torque sensor adapted to measure an operating parameter of said downhole tool;    operating said downhole tool to perform work downhole in a wellbore;    bearing weight with said wear resistant pad when wear of said working profile has progressed sufficiently to expose said wear resistant pad to contact with a downhole structure; and    sensing a drop in the torque required to rotate said downhole tool with said torque sensor.