Drill bits for drilling subterranean boreholes and methods for making same

Abstract

A method for manufacturing a fixed cutter drill bit for drilling an earthen formation, the drill bit including a bit body, the method including (a) preparing a powdered metal matrix mixture including 5.0 wt % to 20.0 wt % of a plurality of large size particles having mesh sizes ranging from 80 mesh to 200 mesh. The plurality of large size particles consist essentially of a plurality of crushed cast tungsten carbide (WC) particles, a plurality of macrocrystalline WC particles, a plurality of spherical cast WC particles, a plurality of tungsten (W) particles, or a combination thereof. The powdered metal matrix mixture also includes at least 50.0 wt % of a plurality of medium size particles having mesh sizes ranging from 200 mesh to 325 mesh. The plurality of medium size particles consist essentially of a plurality of spherical cast WC particles. The powdered metal matrix mixture further includes a plurality of small size particles having mesh sizes ranging from 325 mesh to 600 mesh. The plurality of small size particles consist essentially of (i) a plurality of small size metal or metal alloy particles, and (ii) a plurality of small size macrocrystalline WC particles, a plurality of small size carburized WC particles, a plurality of small size spherical cast WC particles, a plurality of small size W particles, or a combination thereof. The powdered metal matrix mixture still further includes 5.0 wt % to 20.0 wt % of the plurality of small size macrocrystalline WC particles, the plurality of small size carburized WC particles, the plurality of small size spherical cast WC particles, or the combination thereof. The powdered metal matrix mixture also includes 0.0 wt % to 10.0 wt % of the plurality of small size W particles and 0.0 wt % to 7.0 wt % of the plurality of small size metal or metal alloy particles. In addition, the method includes (b) placing the powdered metal matrix mixture in a mold after (a). Further, the method includes (c) positioning an infiltration alloy on top of the powdered metal matrix mixture in the mold after (b). Still further, the method includes (d) heating the mold, the powdered metal matrix mixture in the mold, and the infiltration alloy after (c) to melt the metal or metal alloy particles and melt the infiltration alloy. Moreover, the method includes (e) infiltrating the powdered metal matrix mixture with the melted metal or metal alloy and the melted infiltration alloy during (d). The method also includes (f) cooling the mold, the melted metal or metal alloy, and the melted infiltration alloy to solidify the melted metal or metal alloy and solidify the melted infiltration alloy after (e) to form the bit body.

What is claimed is: 
     
         1 . A method for manufacturing a fixed cutter drill bit for drilling an earthen formation, the drill bit having a central axis and including a bit body, a plurality of circumferentially-spaced blades extending from the bit body, a plurality of cutter elements mounted to a cutter supporting surface of each blade, the method comprising:
 (a) preparing a powdered metal matrix mixture comprising:
 5.0 wt % to 20.0 wt % of a plurality of large size particles having mesh sizes ranging from 80 mesh to 200 mesh, wherein the plurality of large size particles consist essentially of a plurality of crushed cast tungsten carbide (WC) particles, a plurality of macrocrystalline WC particles, a plurality of spherical cast WC particles, a plurality of tungsten (W) particles, or a combination thereof; 
 at least 50.0 wt % of a plurality of medium size particles having mesh sizes ranging from 200 mesh to 325 mesh, wherein the plurality of medium size particles consist essentially of a plurality of spherical cast WC particles; 
 a plurality of small size particles having mesh sizes ranging from 325 mesh to 600 mesh, wherein the plurality of small size particles consist essentially of (i) a plurality of small size metal or metal alloy particles, and (ii) a plurality of small size macrocrystalline WC particles, a plurality of small size carburized WC particles, a plurality of small size spherical cast WC particles, a plurality of small size W particles, or a combination thereof; 
 5.0 wt % to 20.0 wt % of the plurality of small size macrocrystalline WC particles, the plurality of small size carburized WC particles, the plurality of small size spherical cast WC particles, or the combination thereof; 
 0.0 wt % to 10.0 wt % of the plurality of small size W particles; and 
 0.0 wt % to 7.0 wt % of the plurality of small size metal or metal alloy particles; 
   (b) placing the powdered metal matrix mixture in a mold after (a);   (c) positioning an infiltration alloy on top of the powdered metal matrix mixture in the mold after (b);   (d) heating the mold, the powdered metal matrix mixture in the mold, and the infiltration alloy after (c) to melt the metal or metal alloy particles and melt the infiltration alloy;   (e) infiltrating the powdered metal matrix mixture with the melted metal or metal alloy and the melted infiltration alloy during (d); and   (f) cooling the mold, the melted metal or metal alloy, and the melted infiltration alloy to solidify the melted metal or metal alloy and solidify the melted infiltration alloy after (e) to form the bit body.   
     
     
         2 . The method of  claim 1 , wherein the plurality of small size metal or metal alloy particles comprise nickel (Ni) particles, iron (Fe) particles, steel alloy particles, or a combination thereof. 
     
     
         3 . The method of  claim 2 , wherein the plurality of small size metal or metal alloy particles are Ni particles. 
     
     
         4 . The method of  claim 3 , wherein the plurality of large size particles consist essentially of the plurality of crushed cast WC particles, the plurality of spherical cast WC particles, the plurality of macrocrystalline WC particles, or a combination thereof. 
     
     
         5 . The method of  claim 4 , wherein the plurality of small size particles consist essentially of (i) the plurality of small size metal or metal alloy particles, and (ii) the plurality of small size macrocrystalline WC particles. 
     
     
         6 . The method of  claim 5 , wherein the powdered metal matrix mixture comprises:
 8.0 wt % to 12.0 wt % of the plurality of large size particles;   at least 70.0 wt % of the plurality of medium size particles; and   8.0 wt % to 12.0 wt % of the plurality of small size macrocrystalline WC particles, the plurality of small size carburized WC particles, the plurality of small size spherical cast WC particles, or the combination thereof.   
     
     
         7 . The method of  claim 1 , wherein the powdered metal matrix mixture comprises:
 about 10.0 wt % of the plurality of large size particles, wherein the plurality of large size particles consist essentially of the plurality of crushed cast WC particles, the plurality of macrocrystalline WC particles, the plurality of spherical cast WC particles, or a combination thereof;   about 76.0 wt % of the plurality of medium size particles; and   about 14.0 wt % of the plurality of small size particles.   
     
     
         8 . The method of  claim 7 , wherein the plurality of small size particles consist essentially of the plurality of small size macrocrystalline WC particles and a plurality of small size Ni particles. 
     
     
         9 . The method of  claim 8 , wherein the powdered metal matrix mixture comprises:
 about 10.0 wt % of the plurality of small size macrocrystalline WC particles; and   about 4.0 wt % of the plurality of small size Ni particles.   
     
     
         10 . The method of  claim 1 , further comprising (g) mounting a plurality of cutter elements to each of a plurality of blades of the bit body. 
     
     
         11 . The method of  claim 1 , wherein the plurality of large size particles comprises the plurality of special cast WC particles, the plurality of small size particles comprises the plurality of small size spherical cast WC particles, or a combination thereof. 
     
     
         12 . A bit body for a drill bit for drilling a borehole in earthen formations, the bit body comprising:
 5.0 wt % to 20.0 wt % of a plurality of large size particles having mesh sizes ranging from 80 mesh to 200 mesh, wherein the plurality of large size particles consist essentially of a plurality of crushed cast WC particles, a plurality of macrocrystalline WC particles, a plurality of spherical cast WC particles, a plurality of tungsten (W) particles, or a combination thereof;   at least 50 wt % of a plurality of medium size particles having mesh sizes ranging from 200 mesh to 325 mesh, wherein the plurality of medium size particles consist essentially of a plurality of spherical cast WC particles; and   a plurality of small size particles having mesh sizes ranging from 325 mesh to 600 mesh, wherein the plurality of small size particles consist essentially of (i) a plurality of small size metal or metal alloy particles, and (ii) a plurality of small size macrocrystalline WC particles, a plurality of small size carburized WC particles, a plurality of small size spherical cast WC particles, a plurality of small size W particles, or a combination thereof.   
     
     
         13 . The bit body of  claim 12 , wherein the plurality of small size metal or metal alloy particles comprise a plurality of nickel (Ni) particles, a plurality of iron (Fe) particles, a plurality of steel alloy particles, or a combination thereof. 
     
     
         14 . The bit body of  claim 13 , wherein the plurality of small size metal or metal alloy particles consist essentially of the plurality of Ni particles. 
     
     
         15 . The bit body of  claim 12 , wherein the plurality of large size particles consist essentially of the plurality of crushed cast WC particles or the plurality of macrocrystalline WC particles. 
     
     
         16 . The bit body of  claim 15 , wherein the plurality of small size particles consist essentially of (i) the plurality of small size metal or metal alloy particles, and (ii) the plurality of small size macrocrystalline WC particles. 
     
     
         17 . The bit body of  claim 16 , further comprising:
 8.0 wt % to 12.0 wt % of the plurality of large size particles;   at least 70.0 wt % of the plurality of medium size particles; and   8.0 wt % to 12.0 wt % of the plurality of small size particles.   
     
     
         18 . The bit body of  claim 12 , further comprising:
 about 10 wt % of the plurality of large size particles, wherein the plurality of large size particles consist essentially of the plurality of crushed cast WC particles, the plurality of macrocrystalline WC particles, the plurality of spherical cast WC particles, or a combination thereof;   about 76 wt % of the plurality of medium size particles; and   about 14% of the plurality of small size particles.   
     
     
         19 . The bit body of  claim 18 , wherein the plurality of small size particles consist essentially of the plurality of small size macrocrystalline WC particles and a plurality of small size Ni particles. 
     
     
         20 . The bit body of  claim 19 , further comprising:
 about 10 wt % of the plurality of small size macrocrystalline WC particles;   about 4 wt % of the plurality of small size Ni particles.   
     
     
         21 . The bit body of  claim 12 , wherein the plurality of large size particles comprises the plurality of special cast WC particles, the plurality of small size particles comprises the plurality of small size spherical cast WC particles, or a combination thereof.