High energy cutting elements and bits incorporating the same

Abstract

High energy cutting elements and bits incorporating the same are provided. The cutting elements have at least a portion of their cutting layers which will be exposed to high temperatures during drilling formed from a PCBN material capable of operating at temperatures of at least 1000° C.

1 . A shear cutting element comprising:
 a substrate;   a cutting layer over the substrate comprising at least a portion comprising PCBN for contacting a formation during drilling, wherein said at least a portion comprising PCBN has a thermal gradient in the range from about 200 to 2000° C./mm.   
   
   
       2 . The cutting element as recited in  claim 1  wherein said entire cutting layer is a PCBN cutting layer. 
   
   
       3 . The cutting element as recited in  claim 2  wherein the cutting element further comprises a PCD layer interposed between the PCBN layer and the substrate. 
   
   
       4 . The cutting element as recited in  claim 3  wherein the PCD layer is completely encapsulated by the PCBN layer and the substrate. 
   
   
       5 . The cutting element as recited in  claim 1  wherein the cutting layer further comprises another portion comprising an ultra hard material adjacent to the at least a portion comprising PCBN. 
   
   
       6 . The cutting element as recited in  claim 5  wherein the ultra hard material is PCD. 
   
   
       7 . The cutting element as recited in  claim 1  wherein said cutting layer comprises a plurality of portions comprising PCBN. 
   
   
       8 . The cutting element as recited in  claim 1  wherein said cutting layer is formed from a plurality of PCBN layers bonded together. 
   
   
       9 . A bit as recited in  claim 8  wherein said at least a portion comprising PCBN is part of one of said plurality of layers. 
   
   
       10 . The cutting element as recited in  claim 1  wherein said at least a portion comprising PCBN has a strength of at least 100 ksi. 
   
   
       11 . The cutting element as recited in  claim 1  wherein said at least a portion comprising PCBN has a strength in the range of 100 ksi to 200 ksi. 
   
   
       12 . The cutting element as recited in  claim 1  wherein the cutting layer comprises an ultra hard material portion, wherein said at least a portion comprising PCBN forms a cutting edge of the cutting layer. 
   
   
       13 . The cutting element as recited in  claim 12  wherein the cutting layer comprises a periphery, wherein said at least a portion comprising PCBN extends only along a portion of said periphery. 
   
   
       14 . The cutting element as recited in  claim 12  wherein said at least a portion comprising PCBN forms a peripheral portion of the cutting layer surrounding said ultra hard material portion. 
   
   
       15 . The cutting element as recited in  claim 14  wherein said at least a portion comprising PCBN extends to the substrate. 
   
   
       16 . The cutting element as recited in  claim 12  wherein said at least a portion comprising PCBN is spaced apart from the substrate. 
   
   
       17 . The cutting element as recited in  claim 16  wherein said ultra hard material portion is sandwiched between the substrate and said at least a portion comprising PCBN. 
   
   
       18 . The cutting element as recited in  claim 12  wherein said at least a portion comprising PCBN extends to the substrate. 
   
   
       19 . The cutting element as recited in  claim 1  wherein said at least a portion comprising PCBN comprises greater than 90% by PCBN. 
   
   
       20 . A shear cutting element comprising:
 a substrate;   a cutting layer over the substrate comprising at least a portion comprising a thermally stable ultra hard material for contacting a formation during drilling, wherein said at least a portion has a thermal gradient in the range from about 200 to 2000° C./mm.   
   
   
       21 . The cutting element as recited in  claim 20  wherein said thermally stable ultra hard material comprises PCBN.