Matrix body fixed cuter bits

Abstract

A drill bit that includes a bit body having a plurality of blades extending radially therefrom, at least a portion of the plurality of blades comprises a first matrix region comprising a plurality of first carbide particles separated by a first binder phase, each of the first carbide particles comprising a mixture of WC and W 2 C, and wherein the first matrix region has less than about 5 percent by volume, based on the total volume of the first matrix region, of complex metal carbides dispersed in the first binder phase; and at least one cutting element for engaging a formation disposed on at least one of the plurality of blades.

What is claimed: 
     
         1 . A method of forming a matrix bit body, comprising:
 loading a first matrix powder comprising a plurality of first carbide particles into a mold cavity, the plurality of first carbide particles comprising a core of a mixture of WC and W 2 C and a shell of WC; and   heating and infiltrating the mold contents with an infiltration binder.   
     
     
         2 . The method of  claim 1 , further comprising loading a second matrix powder comprising a plurality of second carbide particles into the mold cavity. 
     
     
         3 . The method of  claim 2 , wherein the plurality of second carbide particles comprise at least one of cemented tungsten carbide, cast tungsten carbide, macrocrystalline tungsten carbide, carburized tungsten carbide, or combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein the first carbide particles have a particle size distribution of ±20% or less of a median particle size. 
     
     
         5 . The method of  claim 1 , wherein a mean particle size of the first carbide particles ranges from 50 to 840 microns. 
     
     
         6 . The method of  claim 1 , wherein the first carbide particles have an average particle size of at least about 100 microns. 
     
     
         7 . The method of  claim 1 , wherein the first matrix powder further comprises at least one of cemented tungsten carbide, carburized tungsten carbide or macrocrystalline tungsten carbide. 
     
     
         8 . The method of  claim 1 , wherein the heating and infiltrating the mold further comprises forming a first matrix region, the first matrix region having a fracture toughness, K 1C , of greater than or equal to 25 ksi(in) 1/2 , a transverse rupture strength of greater than or equal to 110 ksi, and a mud erosion rate of less than or equal to 0.0003 in/hr. 
     
     
         9 . A method of forming a matrix bit body, comprising:
 loading a first matrix powder comprising a plurality of first carbide particles into a mold cavity, each of the first carbide particles comprising a mixture of W 2 C and WC;   heating the first matrix powder in the presence of a source of carbon under conditions sufficient to form a layer of WC on a surface of at least a portion of the plurality of first carbide particles; and   heating the mold contents under conditions sufficient to infiltrate the first matrix powder with an infiltration binder.   
     
     
         10 . The method of  claim 9 , wherein the source of carbon is provided from a portion of the inner surface of the mold cavity. 
     
     
         11 . The method of  claim 9 , wherein the source of carbon is provided from the first matrix powder which contains a carbon component. 
     
     
         12 . The method of  claim 9 , wherein the first matrix powder further comprises a plurality of first metal binder particles, the first metal binder particles comprising nickel. 
     
     
         13 . The method of  claim 9 , further comprising loading a second matrix powder comprising a plurality of second carbide particles into the mold cavity. 
     
     
         14 . The method of  claim 13 , wherein the plurality of second carbide particles comprise at least one of cemented tungsten carbide, cast tungsten carbide, macrocrystalline tungsten carbide, carburized tungsten carbide, or combinations thereof. 
     
     
         15 . The method of  claim 9 , wherein the first carbide particles have a particle size distribution of ±20% or less of a median particle size. 
     
     
         16 . The method of  claim 9 , wherein a mean particle size of the first carbide particles ranges from 50 to 840 microns. 
     
     
         17 . The method of  claim 9 , wherein the first carbide particles have an average particle size of at least about 100 microns. 
     
     
         18 . The method of  claim 9 , wherein the first matrix powder further comprises at least one of cemented tungsten carbide, carburized tungsten carbide or macrocrystalline tungsten carbide. 
     
     
         19 . The method of  claim 9 , wherein the heating the mold contents further comprises forming a first matrix region, the first matrix region having a fracture toughness, K 1C , of greater than or equal to 25 ksi(in) 1/2 , a transverse rupture strength of greater than or equal to 110 ksi, and a mud erosion rate of less than or equal to 0.0003 in/hr.