Drill Bit with Angulary Offset Centerlines

Abstract

A drill bit for use in horizontal directional drilling. In a preferred embodiment the drill bit has a connector section having a first axis of rotation. The connector section is used to connect the drill bit to a beacon housing for thrust and rotation therewith. A bit body is disposed next to the connector section and slopes from the connector section to a front nose section. The front nose section has a frontwardly facing surface that supports a plurality of cutting teeth. The front nose section and the bit body comprise a second axis of rotation about which the front nose section and the bit body are rotated. The first axis of rotation and the second axis of rotation are angularly offset at an offset angle of between four degrees and ten degrees.

1 . A drilling bit for use in directional drilling, the bit comprising:
 a connector section having a first axis of rotation;   a front nose section having a frontwardly facing surface;   a bit body which slopes from the connector section to the front nose section;   wherein the front nose section and the bit body comprise a second axis of rotation about which the front nose section and hit body are rotated; and   a steering face disposed on a side of the bit body and sloped from the connector section to the front nose section and disposed at an oblique angle relative to the second axis of rotation;   wherein the first axis of rotation and the second axis of rotation are angularly offset at an offset angle of between four degrees and ten degrees.   
     
     
         2 . The bit of  claim 1  further comprising a plurality of spaced rock cutting teeth mounted on the frontwardly facing surface of the nose section. 
     
     
         3 . The bit of  claim 1  wherein the offset angle is approximately six degrees. 
     
     
         4 . The bit of  claim 2  wherein the plurality of spaced apart rock cutting teeth are rotatable relative to the bit body. 
     
     
         5 . The bit of  claim 1  wherein the nose section includes an arcuate front brow at a position opposite the steering face, wherein the brow extends radially outwardly, and the frontwardly facing surface of the bit comprises an arcuate front face of the brow. 
     
     
         6 . The bit of  claim 1  wherein the steering face comprises a rise over run ratio of between 2:1 and 4:1. 
     
     
         7 . The bit of  claim 6  wherein the rise over run ratio is approximately three to one. 
     
     
         8 . The bit of  claim 5  wherein the bit body comprises a deflection surface at a position opposite the brow and deflects the bit in a direction opposite the side of the bit body on which the deflection surface is disposed. 
     
     
         9 . The bit of  claim 1  wherein the first axis of rotation is collinear with a centerline of the connector section. 
     
     
         10 . A horizontal directional drilling system comprising:
 a drive machine:   a drill string connected to the drive machine and operable in response to rotation and thrust forces from the drive machine;   a downhole tool assembly connected to a downhole end of the drill string, the downhole tool assembly comprises a beacon assembly and a drill bit, the drill bit comprises:
 a connector section having a first axis of rotation; 
 a front nose section having a frontwardly facing surface; 
 a bit body which slopes from the connector section to the front nose section; 
 wherein the front nose section and the bit body comprise a second axis of rotation about which the front nose section and bit body are rotated; 
 a steering face disposed on a side of the bit body and sloped from the connector section to the front nose section and disposed at an oblique angle relative to the second axis of rotation; and 
 wherein the first axis of rotation and the second axis of rotation are angularly offset at an offset angle of between four degrees and ten degrees. 
   
     
     
         11 . The horizontal directional drilling system of  claim 10  wherein the drill bit further comprises a plurality of spaced rock cutting teeth mounted on the frontwardly facing surface of the nose section. 
     
     
         12 . The horizontal directional drilling system of  claim 10  wherein the offset angle is approximately six degrees. 
     
     
         13 . The horizontal directional drilling system of  claim 10  wherein the oblique angle is acute. 
     
     
         14 . The horizontal directional drilling system of  claim 10  wherein the nose section comprises an arcuate front brow at a position opposite the steering face, wherein the brow extends radially outwardly, and the frontwardly facing surface of the bit comprises an arcuate front face of the brow. 
     
     
         15 . The horizontal directional drilling system of  claim 10  wherein the steering face comprises a rise over run ratio of between two to one and four to one. 
     
     
         16 . The horizontal directional drilling system of  claim 15  wherein the rise over run ratio is approximately three to one. 
     
     
         17 . The horizontal directional drilling system of  claim 10  comprising:
 a radially extending brow formed on the nose section at a position opposite the steering face; and 
 a plurality of rock cutting teeth mounted on the frontwardly facing surface of the nose section and rotatable relative to the bit body. 
 
     
     
         18 . The horizontal directional drilling system of  claim 11  wherein the rock cutting teeth comprise a cutting diameter of 6.4 inches when the bit is rotated about the first axis of rotation. 
     
     
         19 . The horizontal directional drilling system of  claim 10  wherein the first axis of rotation is collinear with a centerline of the connector section. 
     
     
         20 . The bit of  claim 1  wherein the oblique angle is acute.