Drill bits and tools for subterranean drilling

Abstract

A drill bit that includes a boss extending rotationally forward of at least one blade thereof in a gage region of a bit body for increasing stability and reducing impact shock caused by a lateral imbalance force acting on the bit while drilling a subterranean formation is disclosed. The boss includes a circumferential bearing surface that rotationally precedes a circumferential bearing surface of the at least one blade. A drill bit that includes a boss having a nozzle port extending therein is also disclosed.

1 . A drill bit comprising:
 a bit body having a longitudinal axis, and a face extending to a gage region;   at least one blade extending longitudinally and radially outward over the face and having a plurality of cutting elements disposed thereon; and   a boss coupled to and extending forward of the at least one blade in a direction of intended bit rotation about the longitudinal axis, the boss including a circumferential bearing surface in the gage region.   
   
   
       2 . The drill bit of  claim 1 , wherein the at least one blade includes a circumferential bearing surface in the gage region. 
   
   
       3 . The drill bit of  claim 1 , wherein the at least one blade comprises a plurality of blades circumferentially separated by junk slots. 
   
   
       4 . The drill bit of  claim 3 , further including additional blades, at least one of the additional blades being without a boss associated therewith. 
   
   
       5 . The drill bit of  claim 1 , further including additional blades each having a plurality of cutting elements disposed thereon, wherein at least some of the cutting elements disposed on the blades are configured, positioned and oriented to provide a lateral imbalance force upon rotation of the bit body about the longitudinal axis when drilling a formation under weight on bit, the lateral imbalance force being circumferentially directed substantially toward the circumferential bearing surface. 
   
   
       6 . The drill bit of  claim 5 , wherein the at least one blade includes a circumferential bearing surface in the gage region and the lateral imbalance force is substantially centered over a combined extent of the boss bearing surface and the at least one blade bearing surface. 
   
   
       7 . The drill bit of  claim 1 , wherein the boss further includes a land and a nozzle port therein, the land being substantially orthogonal to the longitudinal axis of the bit body. 
   
   
       8 . The drill bit of  claim 7 , further comprising a nozzle coupled to the nozzle port. 
   
   
       9 . The drill bit of  claim 8 , wherein the nozzle is aimed toward a rotationally leading blade surface of the at least one blade. 
   
   
       10 . The drill bit of  claim 8 , wherein the nozzle is aimed directionally inward from longitudinal axis extending from substantially the gage region of the blade. 
   
   
       11 . A drill bit comprising:
 a bit body having a longitudinal axis and a face extending to a gage region;   a plurality of blades extending longitudinally and radially outward over the face, the plurality of blades including at least a first blade and a second blade, the second blade rotationally trailing the first blade about the longitudinal axis;   an open fluid course between the first blade and the second blade extending to a junk slot in the gage region of the bit body; and   a boss coupled to the second blade in the gage region of the bit body, the boss extending into the open fluid course.   
   
   
       12 . The drill bit of  claim 11 , wherein each of the plurality of blades includes a boss coupled thereto. 
   
   
       13 . The drill bit of  claim 11 , wherein at least one blade of the plurality of blades is without a boss coupled thereto. 
   
   
       14 . The drill bit of  claim 11 , wherein the boss includes a circumferential bearing surface preceding the second blade. 
   
   
       15 . The drill bit of  claim 14 , further comprising a plurality of cutting elements coupled to each of the plurality of blades, at least some of the plurality of cutting elements, in combination configured, positioned and oriented to provide lateral imbalance force upon rotational movement of the bit body about the longitudinal axis under weight on bit when drilling a formation, the lateral imbalance force being generally directed toward the circumferential bearing surface. 
   
   
       16 . The drill bit of  claim 15 , wherein the second blade including a circumferential bearing surface in the gage region and the lateral imbalance force is generally directed to the boss bearing surface and the second blade bearing surface. 
   
   
       17 . The drill bit of  claim 11 , wherein the boss further includes a plateau and a nozzle port extending therein, the plateau being generally orthogonal to the axis of the bit body, and further comprising a nozzle coupled to the nozzle port. 
   
   
       18 . The drill bit of  claim 17 , wherein the nozzle is aimed toward a rotationally leading blade surface of the second blade. 
   
   
       19 . A drill bit comprising:
 a bit body having a longitudinal axis and a face extending to a gage region;   a plurality of blades extending longitudinally and radially outward over the face of the bit body to the gage region; and   a boss extending forward from a rotationally leading blade surface of at least one blade of the plurality of blades substantially in the gage region, the boss including a land and a nozzle port extending therein, the land being substantially orthogonal to the axis of the bit body; and   a nozzle coupled to the nozzle port.   
   
   
       20 . The drill bit of  claim 19 , wherein each of the plurality of blades includes a boss.