Eccentric sleeve for directional drilling systems

Abstract

A drill bit includes a bit body configured to rotate about a bit rotational axis and a sleeve coupled to the bit body. The sleeve is coupled to the bit body on an uphole portion of the bit body. The sleeve has a smaller diameter than the bit body and is aligned at the edge of the circumference of the bit body.

What is claimed is: 
     
         1 . A drill bit comprising:
 a bit body configured to rotate about a bit rotational axis;   a first sleeve coupled to the bit body at an uphole portion of the bit body, the first sleeve:
 having a smaller diameter than the bit body; and 
 having a portion aligned with a first edge portion of the bit body, the first edge portion located on the circumference of the bit body. 
   
     
     
         2 . The drill bit of  claim 1  wherein the first sleeve is configured to form a fulcrum point for directional drilling at least once during a revolution of the bit body during formation of a wellbore. 
     
     
         3 . The drill bit of  claim 2 , wherein the first sleeve is further configured to contact a portion of the wellbore at a first point on the circumference of the first sleeve, and the fulcrum point is formed at the portion of the first sleeve contacting the wellbore. 
     
     
         4 . The drill bit of  claim 3 , wherein the first sleeve is further configured to form a gap between the wellbore and a second point on the first sleeve, the second point approximately one-hundred-eighty degrees along the circumference of the first sleeve from the first point. 
     
     
         5 . The drill bit of  claim 1  wherein:
 the first sleeve comprises a first geometrical axis, the first geometrical axis located parallel to the bit rotational axis; and 
 the first geometrical axis and the bit rotational axis are separated by a first distance. 
 
     
     
         6 . The drill bit of  claim 5 , wherein the first sleeve is mass balanced around the bit rotational axis. 
     
     
         7 . The drill bit of  claim 1 , further comprising a second sleeve, the second sleeve:
 having a smaller diameter than the bit body; and   having a portion aligned with a second edge portion of the bit body, the second edge portion on the circumference of the bit body.   
     
     
         8 . The drill bit of  claim 7 , wherein:
 the first sleeve is further configured to form a fulcrum point for directional drilling a wellbore at least once during a revolution of the bit body; and   the second sleeve is further configured to form the fulcrum point for directional drilling at least once during a revolution of the bit body.   
     
     
         9 . The drill bit of  claim 8 , wherein:
 the first sleeve is further configured to contact a portion of the wellbore at a first point on the circumference of the first sleeve;   the second sleeve is further configured to contact the portion of the wellbore at a first point on the circumference of the second sleeve; and   the fulcrum point is formed at the portion of the first sleeve contacting the wellbore and at the portion of the second sleeve contacting the wellbore during a revolution of the drill bit.   
     
     
         10 . The drill bit of  claim 9 , wherein during contact by the first sleeve with the wellbore, the second sleeve is configured to form a gap, the gap formed between the wellbore and the second sleeve, the gap located at the portion of the wellbore in contact with the first sleeve. 
     
     
         11 . The drill bit of  claim 7 , wherein the first sleeve and the second sleeve are coupled together. 
     
     
         12 . The drill bit of  claim 7 , wherein the first sleeve and the second sleeve are spaced equidistantly from each other along the circumference of the bit body from each other. 
     
     
         13 . The drill bit of  claim 7 , wherein the first sleeve and the second sleeve are spaced approximately one-hundred-eighty degrees from each other along the circumference of the bit body. 
     
     
         14 . The drill bit of  claim 7 , wherein:
 the second sleeve comprises a second geometrical axis, the second geometrical axis parallel with the bit rotational axis;   the second geometrical axis and the bit rotational axis are separated by a second distance; and   the first distance and the second distance are approximately equal.   
     
     
         15 . The drill bit of  claim 7 , wherein the first sleeve and the second sleeve rotate around the bit rotational axis. 
     
     
         16 . The drill bit of  claim 7 , further comprising a third sleeve, the third sleeve:
 having a smaller diameter than the bit body; and   aligned at the edge of the circumference of the bit body.   
     
     
         17 . The drill bit of  claim 16 , wherein:
 the first sleeve is configured to form a fulcrum point for directional drilling a wellbore at least once during a revolution of the bit body;   the second sleeve is configured to form the fulcrum point for directional drilling at least once during a revolution of the bit body; and   the third sleeve is configured to form the fulcrum point for directional drilling at least once during a revolution of the bit body   
     
     
         18 . The drill bit of  claim 17 , wherein:
 the first sleeve is further configured to contact a portion of the wellbore at a first point on the circumference of the first sleeve;   the second sleeve is further configured to contact the portion of the wellbore at a first point on the circumference of the second sleeve;   the third sleeve is further configured to contact the portion of the wellbore at a first point on the circumference of the third sleeve; and   the fulcrum point is formed at the portion of the first sleeve contacting the wellbore, at the portion of the second sleeve contacting the wellbore, and at the portion of the third sleeve contacting the wellbore during a revolution of the drill bit.   
     
     
         19 . The drill bit of  claim 18 , wherein during contact by the first sleeve with the wellbore:
 the second sleeve is configured to form a first gap, the first gap formed between the wellbore and the second sleeve, the first gap located at the portion of the wellbore in contact with the first sleeve; and   the third sleeve is configured to form a second gap, the second gap formed between the wellbore and the third sleeve, the second gap located at the portion of the wellbore in contact with the first sleeve.   
     
     
         20 . The drill bit of  claim 16 , wherein the first sleeve, the second sleeve, and the third sleeve are spaced approximately one-hundred-twenty degrees from each other along the circumference of the bit body. 
     
     
         21 . The drill bit of  claim 16 , wherein:
 the second sleeve comprises a second geometrical axis, the second geometrical axis located parallel to the bit rotational axis;   the second geometrical axis and the bit rotational axis are separated by a second distance;   the third sleeve comprises a third geometrical axis, the third geometrical axis located parallel to the bit rotational axis;   the third geometrical axis and the bit rotational axis are separated by a third distance; and   the first distance, the second distance and the third distance are approximately each equal to each other.   
     
     
         22 . A downhole drilling tool operable to form a wellbore comprising:
 a bit body configured to remove material to form a portion of the wellbore; and   a first eccentric sleeve coupled to the bit body at un uphole portion of the bit body.   
     
     
         23 . The downhole drilling tool of  claim 22 , wherein:
 the bit body is configured to rotate around a bit rotational axis;   the first eccentric sleeve comprises a geometrical axis located parallel to the bit rotational axis; and   the geometrical axis of the eccentric sleeve is offset from the bit rotational axis.   
     
     
         24 . The downhole drilling tool of  claim 22 , further comprising one or more second eccentric sleeves. 
     
     
         25 . The downhole drilling tool of  claim 24 , wherein:
 the bit body is configured to rotate around a bit rotational axis;   each eccentric sleeve comprises a geometrical axis located parallel to the bit rotational axis;   the geometrical axis of each eccentric sleeve is offset from the bit rotational axis.   
     
     
         26 . The downhole drilling tool of  claim 22  wherein:
 the bit body is configured to rotate around a bit rotational axis; 
 the first eccentric sleeve is configured to contact a portion of a wellbore formed by the downhole drilling tool; and 
 the downhole drilling tool is configured to form a fulcrum point for directional drilling at the portion of the first sleeve contacting the wellbore at least once during a revolution of the bit body. 
 
     
     
         27 . The downhole drilling tool of  claim 22  wherein the first eccentric sleeve is mass balanced around a bit rotational axis of the bit body. 
     
     
         28 . The downhole drilling tool of  claim 22  wherein the first eccentric sleeve is configured to form a gap between the wellbore and the first sleeve at a second point approximately one-hundred-eighty degrees from the first point. 
     
     
         29 . A drilling tool, comprising:
 a bit body configured to rotate about a bit rotational axis;   a first sleeve coupled to the bit body at an uphole portion of the bit body, the first sleeve:
 having a smaller diameter than the bit body; and 
 having a portion aligned with a first edge portion of the bit body, the first edge portion located on the circumference of the bit body. 
   
     
     
         30 . The drilling tool of  claim 29 , wherein the first sleeve is configured to:
 form a fulcrum point for directional drilling at least once during a revolution of the bit body during formation of a wellbore; and   contact a portion of the wellbore at a first point on the circumference of the first sleeve, and the fulcrum point is formed at the portion of the first sleeve contacting the wellbore.   
     
     
         31 . The drilling tool of  claim 29 , wherein the first sleeve is further configured to form a gap between the wellbore and a second point on the first sleeve, the second point located approximately one-hundred-eighty degrees from the first point. 
     
     
         32 . The drilling tool of  claim 29 , further comprising a second sleeve, the second sleeve:
 having a smaller diameter than the bit body; and   having a portion aligned with a second edge portion of the bit body, the second edge portion located on the circumference of the bit body.   
     
     
         33 . The drilling tool of  claim 32 , further comprising a third sleeve, the second sleeve:
 having a smaller diameter than the bit body; and   having a portion aligned with a third edge portion of the bit body, the third edge portion located on the circumference of the bit body.   
     
     
         34 . The drilling tool of  claim 33 , wherein:
 the first sleeve is configured to form a fulcrum point for directional drilling a wellbore at least once during a revolution of the bit body;   the second sleeve is configured to form the fulcrum point for directional drilling at least once during a revolution of the bit body; and   the third sleeve is configured to form the fulcrum point for directional drilling at least once during a revolution of the bit body.   
     
     
         35 . The drilling tool of  claim 33 , wherein the first sleeve, the second sleeve, and the third sleeve are spaced approximately one-hundred twenty degrees from each other along the circumference of the bit body.