In one aspect of the present invention, a rotary drag drill bit has a body intermediate a shank and a working face. The working face has a plurality of blades converging towards a center of the working face and diverging towards a gauge of the working face. A carbide section is fixed to the working face and positioned within a pocket disposed within an inverted cone of the working face. The carbide section has a distal end exposed within the working face.
1. A rotary drag drill bit, comprising:
a body intermediate a shank and a working face;
the working face comprising a plurality of blades converging toward a center of the working face and diverging toward a gauge of the working face;
a carbide section fixed to the working face and positioned within a pocket disposed within an inverted cone of the working face; and
the carbide section comprising a distal end exposed within the working face;
wherein the carbide section is disposed about a jack element coaxial with an axis of rotation of the drill bit, the jack element extending out of an opening formed in the working face.
2. The drill bit of claim 1 , wherein at least one cutting element is brazed to a distal portion of the carbide section.
3. The drill bit of claim 1 , wherein the carbide section is brazed or shrink-fit within the pocket formed in the working face.
4. The drill bit of claim 1 , wherein the drill bit body is made of steel.
5. The drill bit of claim 1 , wherein the drill bit body is made of matrix.
6. The drill bit of claim 1 , wherein a steel sleeve is intermediate the carbide section and a wall of the pocket.
7. The drill bit of claim 1 , wherein the carbide section forms a portion of a cone section of at least one blade of the plurality of blades.
8. The drill bit of claim 7 , the at least one blade comprises a slope transition formed by the cone section of the blade and the carbide section.
9. The drill bit of claim 8 , wherein the carbide section comprises a larger cone angle than the cone section of the blade.
10. The drill bit of claim 1 , wherein a portion of the carbide section protrudes from the working face.
11. The drill bit of claim 10 , wherein the protruding portion of the carbide section comprises a length of 0.25 to 2 inches.
12. The drill bit of claim 1 , wherein a portion of the carbide section is set back into the working face.
13. The drill bit of claim 1 , wherein at least one nozzle is disposed within a portion of the carbide section.
14. The drill bit of claim 1 , wherein carbide section tapers to a point.
15. The drill bit of claim 1 , wherein the inverted cone is formed by the plurality of blades and comprises a slope transition formed by at least two contiguous substantially flat sections with different cone angles; and
a radially proximal flat section comprising a larger cone angle than a radially distal flat section.
16. The drill bit of claim 15 , wherein a plurality of cutting elements is arrayed along any portion of the at least one blade including the cone portion, nose portion, flank portion, gauge portion, or combinations thereof.
17. The drill bit of claim 15 , wherein the radially proximal cone angle comprises an angle between 30 and 60 degrees with respect to a horizontal plane of the working face.
18. The drill bit of claim 15 , wherein the radially distal cone angle comprises an angle between 5 and 25 degrees with respect to a horizontal plane of the working face.