Method and apparatus for reaming well bore surfaces nearer the center of drift

Abstract

An apparatus to increase a diameter of a well bore includes a drill pipe that includes a first end, a second end spaced apart from the first end, and a longitudinal axis. A first reamer is coupled to the drill pipe, the first reamer including a first plurality of teeth and a first reamer axis spaced radially apart from the longitudinal axis of the drill pipe. At least a second reamer is coupled to the drill pipe and spaced longitudinally apart from the first reamer. The at least a second reamer includes a second plurality of teeth and a second reamer axis spaced radially apart from the longitudinal axis of the drill pipe, the second reamer axis being angularly offset from the first reamer axis such that a drift diameter of the apparatus is smaller than a drill diameter of the apparatus.

1 . An apparatus configured to be positioned in at least one of a drill string and a bottom hole assembly and adapted to increase a diameter of a well bore as the apparatus is rotated, comprising:
 a drill pipe that includes a first end, a second end spaced apart from the first end, and a longitudinal axis that is aligned with a longitudinal axis of at least one of the drill string and the bottom hole assembly;   a first reamer coupled to the drill pipe, the first reamer including:
 a first plurality of teeth; 
 a first reamer axis spaced radially apart from the longitudinal axis of the drill pipe; and 
   at least a second reamer coupled to the drill pipe and spaced longitudinally apart from the first reamer, the at least a second reamer including:
 a second plurality of teeth; 
 a second reamer axis spaced radially apart from the longitudinal axis of the drill pipe, the second reamer axis being angularly offset from the first reamer axis such that a drift diameter of the apparatus is smaller than a drill diameter of the apparatus. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the first reamer axis and the second reamer axis are each a fixed distance from the longitudinal axis of the drill pipe. 
     
     
         3 . The apparatus of  claim 1 , wherein the second reamer axis is 180 degrees apart from the first reamer axis relative to the longitudinal axis of the drill pipe. 
     
     
         4 . The apparatus of  claim 1 , wherein at least one of the first reamer and the at least a second reamer further comprises at least one groove formed in a surface of the first reamer and the at least a second reamer. 
     
     
         5 . The apparatus of  claim 4 , wherein a long axis of the groove, when viewed in profile, intersects at an acute angle the longitudinal axis of the drill pipe as the longitudinal axis extends downhole. 
     
     
         6 . The apparatus of  claim 1 , wherein the first plurality of teeth form a first plurality of sets of teeth, wherein each set of the first plurality of sets of teeth is separated from an adjacent set of teeth by a groove formed in a surface of the first reamer. 
     
     
         7 . The apparatus of  claim 1 , wherein the second plurality of teeth form a second plurality of sets of teeth, wherein each set of the second plurality of sets of teeth is separated from an adjacent set of teeth by a groove formed in a surface of the second reamer. 
     
     
         8 . The apparatus of  claim 7 , wherein each set of the first plurality of sets of teeth defines a blade. 
     
     
         9 . The apparatus of  claim 8 , wherein each set of the second plurality of sets of teeth defines a blade. 
     
     
         10 . The apparatus of  claim 8 , wherein a width of the groove is greater than a width of the blade. 
     
     
         11 . The apparatus of  claim 1 , wherein a center of at least a first tooth of the at least a second plurality of teeth is spaced at a different circumferential location than a center of at least a first tooth of the first plurality of teeth. 
     
     
         12 . The apparatus of  claim 1 , wherein a first plane extending through a center of each tooth of the first plurality of teeth, when viewed in profile, intersects at an acute angle the longitudinal axis of the drill pipe as the longitudinal axis extends downhole. 
     
     
         13 . The apparatus of  claim 1 , wherein at least the first plurality of teeth covers approximately fifty percent of the circumference of at least one of the first reamer and the at least a second reamer. 
     
     
         14 . The apparatus of  claim 1 , wherein the first plurality of teeth are arranged along a spiral path along a surface of the first reamer. 
     
     
         15 . The apparatus of  claim 1 , wherein the second plurality of teeth are arranged along a spiral path along a surface of the first reamer. 
     
     
         16 . The apparatus of  claim 1 , wherein at least one tooth of at least one of the first plurality of teeth and the second plurality of teeth is formed of one of carbide and diamond. 
     
     
         17 . A method of increasing a drill diameter of a wellbore, comprising:
 coupling the apparatus of  claim 1  to a drill string and to a bottom hole assembly;   positioning the apparatus in the wellbore;   rotating the apparatus.