Drill pipe with roller assembly

Abstract

A drill pipe assembly includes a tubular body and a roller assembly for reducing friction between the drill pipe and the inner wall of a wellbore. The tubular body includes a substantially cylindrical body outer surface defining roller pockets. Alternatively, the drill pipe assembly may have a sleeve that fits concentrically and rotatably around the tubular body, with the sleeve outer surface defining the roller pockets. Each roller pocket has a roller assembly that includes an axle having opposed ends retained by the tubular body or the sleeve. A roller is retained by and rotates on each axle, partially disposed in the roller pocket and partially projecting outwardly from the outer surface.

What is claimed is: 
     
         1 . A drill pipe assembly installable between an up-hole component and a down-hole component of a drill string insertable in a wellbore, the drill string defining an axial direction and a transverse direction perpendicular thereto, the drill pipe assembly comprising:
 (a) a tubular body comprising:
 an up-hole end adapted for connection to the up-hole component, and a down-hole end adapted for connection to the down-hole component; 
 an inner surface defining an inner bore extending axially between the up-hole end and the down-hole end; 
 a substantially cylindrical body outer surface defining a plurality of inwardly extending roller pockets; 
   (b) for each of the plurality of roller pockets, a corresponding roller assembly comprising:
 an axle having opposed ends each retained by the tubular body; and 
 a roller retained by the axle for rotating axially relative to the tubular body, partially disposed within the roller pocket and partially projecting outwardly from the body outer surface. 
   
     
     
         2 . The drill pipe assembly of  claim 1  wherein the plurality of roller pockets are arranged in at least one row circumferential around the body outer surface. 
     
     
         3 . The drill pipe assembly of  claim 2  wherein the at least one row comprises a plurality of rows axially spaced apart from each other. 
     
     
         4 . The drill pipe assembly of  claim 3  wherein one of the roller pockets is circumferentially offset from one of the roller pockets in one of the adjacent rows. 
     
     
         5 . The drill pipe assembly of  claim 1  wherein:
 the body outer surface further defines an access pocket circumferentially adjacent to one of the plurality of roller pockets and having an inwardly extending side wall; 
 the body defines an aperture extending between an inwardly extending side wall of the one of the plurality of roller pockets and the side wall of the access pocket; and 
 the axle is retained by the tubular body within the aperture. 
 
     
     
         6 . The drill pipe assembly of  claim 5  wherein the access pocket circumferentially adjacent to the one of the plurality of roller pockets is circumferentially adjacent to another one of the plurality of roller pockets. 
     
     
         7 . The drill pipe assembly of  claim 1  wherein the roller has a barrel shape with a curvature closely matching the curvature of the body outer surface in a transverse plane. 
     
     
         8 . A drill pipe assembly installable between an up-hole component and a down-hole component of a drill string insertable in a wellbore, the drill string defining an axial direction and a transverse direction perpendicular thereto, the drill pipe assembly comprising:
 (a) a tubular body comprising:
 an up-hole end adapted for connection to the up-hole component, and a down-hole end adapted for connection to the down-hole component; 
 an inner surface defining an inner bore extending axially between the up-hole end and the down-hole end; 
 a substantially cylindrical body outer surface; 
   (b) a sleeve disposed concentrically around the tubular body between the up-hole end and the down-hole end, and comprising a substantially cylindrical sleeve outer surface defining a plurality of inwardly extending roller pockets;   (c) for each of the plurality of roller pockets, a corresponding roller assembly comprising:
 an axle having opposed ends each retained by the sleeve; and 
 a roller retained by the axle for rotating axially relative to the tubular body, partially disposed within the roller pocket and partially projecting outwardly from the sleeve outer surface. 
   
     
     
         9 . The drill pipe assembly of  claim 8  wherein the sleeve comprises a first portion and a second portion releasably securable to the first portion, wherein each of the portions has a semi-annular shape in a transverse plane. 
     
     
         10 . The drill pipe assembly of  claim 8  wherein the body outer surface and the sleeve outer surface comprise abutting edges that are flush with each other. 
     
     
         11 . The drill pipe assembly of  claim 10  wherein the sleeve is disposed concentrically around a reduced portion of the tubular body having an outer diameter less than the outer diameter of the body outer surface. 
     
     
         12 . The drill pipe assembly of  claim 8  wherein the sleeve is rotatable around the tubular body. 
     
     
         13 . The drill pipe assembly of  claim 12  wherein the tubular body defines at least one aperture for fluid communication between the inner bore and an annular space between the tubular body and the sleeve. 
     
     
         14 . The drill pipe assembly of  claim 8  wherein the plurality of roller pockets are arranged in at least one row circumferential around the sleeve outer surface. 
     
     
         15 . The drill pipe assembly of  claim 14  wherein the at least one row comprises a plurality of rows axially spaced apart from each other. 
     
     
         16 . The drill pipe assembly of  claim 15  wherein one of the roller pockets is circumferentially offset from one of the roller pockets in one of the adjacent rows. 
     
     
         17 . The drill pipe assembly of  claim 8  wherein:
 the sleeve outer surface further defines an access pocket circumferentially adjacent to one of the plurality of roller pockets and having an inwardly extending side wall; 
 the body defines an aperture extending between an inwardly extending side wall of the one of the plurality roller pockets and the side wall of the access pocket; and 
 the axle is retained by the sleeve within the aperture. 
 
     
     
         18 . The drill pipe assembly of  claim 17  wherein the access pocket circumferentially adjacent to the one of the plurality of roller pockets is circumferentially adjacent to another one of the plurality of roller pockets. 
     
     
         19 . The drill pipe assembly of  claim 8  wherein the roller has a barrel shape with a curvature closely matching the curvature of the sleeve outer surface in a transverse plane. 
     
     
         20 . A sleeve assembly installable on a tubular body having an uphole end for connection to an up-hole component of a drill string and a down-hole end for connection to a down-hole component of a drill string, the drill string insertable in a wellbore and defining an axial direction and a transverse direction perpendicular thereto, the sleeve assembly comprising:
 (a) a sleeve disposable concentrically around the tubular body between the up-hole end and the down-hole end of the tubular body, and comprising a substantially cylindrical sleeve outer surface defining a plurality of inwardly extending roller pockets;   (b) for each of the plurality of roller pockets, a corresponding roller assembly comprising:
 an axle having opposed ends each retained by the sleeve; and 
 a roller retained by for rotating axially relative to the tubular body, partially disposed within the roller pocket and partially projecting outwardly from the sleeve outer surface.