Downhole cutting tool and method of making

Abstract

A downhole cutting tool includes, a body, a first contoured cutting element in operable communication with the body, and at least one contingency contoured cutting element in operable communication with the first contoured cutting element and the body. A contour of the at least one contingency contoured cutting element substantially matches a contour of the first contoured cutting element, and the at least one contingency contoured cutting element is maintainable in reserve and positioned to substitute for the first contoured cutting element if the first contoured cutting element becomes detached.

1 . A downhole cutting tool comprising:
 a body;   a first contoured cutting element in operable communication with the body; and   at least one contingency contoured cutting element in operable communication with the first contoured cutting element and the body, a contour of the at least one contingency contoured cutting element substantially matching a contour of the first contoured cutting element, the at least one contingency contoured cutting element being maintainable in reserve and positioned to trail rotationally behind the first contoured cutting element while cutting to substitute for the first contoured cutting element if the first contoured cutting element becomes detached.   
   
   
       2 . The downhole cutting tool of  claim 1 , wherein the first contoured cutting element is attached to at least one of the body and the at least one contingency contoured cutting element. 
   
   
       3 . The downhole cutting tool of  claim 2 , wherein attachment of the first contoured cutting element to the at least one of the body and the at least one contingency contoured cutting element is by one of bonding, brazing, welding and gluing. 
   
   
       4 . The downhole cutting tool of  claim 2 , wherein material employed to attach the first contoured cutting element to the at least one of the body and the at least one contingency contoured cutting element is more ductile than at least one of the first contoured cutting element and the at least one contingency contoured cutting element. 
   
   
       5 . The downhole cutting tool of  claim 2 , wherein attachment of the first contoured cutting element to at least one of the body and the at least one contingency contoured cutting element is configured to fail prior to fracture of the first contoured cutting element. 
   
   
       6 . The downhole cutting tool of  claim 2 , wherein detachment of the first contoured cutting element from at least the body and the at least one contingency contoured cutting element stops a fracture in the first contoured cutting element from propagating into the at least one contingency contoured cutting element. 
   
   
       7 . The downhole cutting tool of  claim 1 , wherein the at least one contingency contoured cutting element is attached to the body. 
   
   
       8 . The downhole cutting tool of  claim 1 , wherein the first contoured cutting element and the at least one contingency contoured cutting element are oriented in at least one stack. 
   
   
       9 . The downhole cutting tool of  claim 1 , wherein a size of the first contoured cutting element limits a loss of volume of the downhole cutting tool associated with each detachment event. 
   
   
       10 . The downhole cutting tool of  claim 1 , wherein the first contoured cutting element includes a contoured cutting edge. 
   
   
       11 . The downhole cutting tool of  claim 1 , wherein the at least one of the first contoured cutting element and the at least one contingency cutting element are one of hard metal, ceramic and diamond. 
   
   
       12 . The downhole cutting tool of  claim 11 , wherein the hard metal is carbide. 
   
   
       13 . (canceled) 
   
   
       14 . A method of making a downhole cutter device comprising:
 substantially matching a contoured cutting edge of at least one contingency contoured cutting element with a contoured cutting edge of a first contoured cutting element; and   attaching the at least one contingency contoured cutting element adjacent the first contoured cutting element positioned to trail rotationally behind the first contoured cutting element while cutting such that the at least one contingency contoured cutting element substitutes for the first contoured cutting element if the first contoured cutting element becomes detached.   
   
   
       15 . The method of making a downhole cutter device of  claim 14 , wherein the attaching is by one of bonding, brazing, welding and gluing. 
   
   
       16 . The method of making a downhole cutter device of  claim 14 , wherein the attaching is designed to fail at loads less than would cause fracture of the first contoured cutting element. 
   
   
       17 . A downhole cutter comprising:
 a plurality of cutting elements having substantially matched contoured cutting edges positioned perimetrically adjacent to one another; and   a bonding material having greater ductility than the plurality of cutting elements bonding the plurality of cutting elements to one another in an arrangement such that detachment of one of the plurality of cutting elements reveals another of the substantially matched contoured cutting edges that substitutes for a contoured cutting edge of the detached cutting element.   
   
   
       18 . The downhole cutter of  claim 17 , wherein the downhole cutter is configured to allow detachment of one of the plurality of cutting elements under load prior to fracture of the one of the plurality of cutting elements. 
   
   
       19 . (canceled) 
   
   
       20 . The downhole cutting tool of  claim 1 , further comprising:
 a second contoured cutting element in operable communication with the body; and   at least one contingency contoured cutting element in operable communication with the second contoured cutting element and the body, a contour of the at least one contingency contoured cutting element substantially matching a contour of the second contoured cutting element, the at least one contingency contoured cutting element being maintainable in reserve and positioned and displaced from the second contoured cutting element in a rotational direction of motion of the cutting elements while cutting to substitute for the second contoured cutting element if the second contoured cutting element becomes detached, and the detachability of the first contoured cutting element and the second contoured cutting element are independent from one another.   
   
   
       21 . The downhole cutting tool of  claim 20 , wherein independent detachment of the first contoured cutting element from the second contoured cutting element limits a volume of the downhole cutting tool that becomes detached during a detachment event.