Downhole Tool Roller Device With Cylindrical Bearing Mechanism

Abstract

Roller devices for passively or actively aiding in the conveyance of a toolstring through a well. The well may be of tortuous architecture and include a host of different corrosives. However, the roller devices are equipped with a cylindrical bearing based mechanism such as a journal bearing. Thus, these devices may be substantially less prone to exposure to corrosives. For example, they may be provided in a substantially monolithic circumferential form more readily shielded and/or isolated from such direct exposure.

What is claimed is: 
     
         1 . A roller device for incorporation into a housing of a downhole toolstring to aid conveyance thereof through a well, the device comprising:
 a body with an exposed surface for contacting a wall of the well during the conveyance through the well; and   a cylindrical bearing based mechanism for disposal at an underside of said body opposite the exposed surface.   
     
     
         2 . The roller device of  claim 1  wherein said cylindrical bearing based mechanism comprises a journal bearing. 
     
     
         3 . The roller device of  claim 2  wherein said journal bearing is substantially circumferentially monolithic. 
     
     
         4 . The roller device of  claim 2  wherein said journal bearing comprises:
 a first journal piece; and 
 a second journal piece adjacent said first with an isolated slip interface therebetween. 
 
     
     
         5 . The roller device of  claim 1  wherein said cylindrical bearing based mechanism comprises a cylindrical roller bearing for radial and axial slip. 
     
     
         6 . A downhole tool for incorporation into a toolstring and for conveyance through a well, the tool comprising:
 a housing; and   a roller device accommodated by said housing for contacting a wall of the well during the conveyance therethrough, the device comprising a cylindrical bearing based mechanism to allow rolling thereof during the contacting of the wall.   
     
     
         7 . The tool of  claim 6  wherein said roller device is of a diameter larger than the toolstring. 
     
     
         8 . The tool of  claim 6  wherein the toolstring is between about 50 feet and 150 feet in length. 
     
     
         9 . The tool of  claim 8  wherein the well includes a bend to a non-vertical section. 
     
     
         10 . The tool of  claim 6  wherein said roller device is one of exteriorly disposed relative said housing, at least partially recessed into said housing and extended from said housing. 
     
     
         11 . The tool of  claim 10  wherein the roller device is a first roller device, the tool further comprising a second roller device at an opposite side of said housing relative the first roller device. 
     
     
         12 . The tool of  claim 11  further comprising a formation disturbing implement at said housing between said roller devices, said roller devices exteriorly disposed and to provide a foothold at a wall of the well for substantially perpendicular orientation of said implement relative the wall. 
     
     
         13 . The tool of  claim 12  wherein said formation disturbing implement is a sampling implement for attaining substantially sealed engagement with the wall during sampling due to the perpendicular orientation. 
     
     
         14 . The tool of  claim 11  wherein the roller devices are dual-sided and extended from said housing to promote a degree of centralization of the tool in the well. 
     
     
         15 . A method of conveying a toolstring through a well, the method comprising:
 deploying the toolstring into the well over a well access line;   employing a roller device for assistance in aiding conveyance of the toolstring to a target location in the well; and   utilizing a cylindrical bearing based mechanism of the roller device during said employing thereof for conveyance assistance.   
     
     
         16 . The method of  claim 15  wherein deploying of the toolstring is a coiled tubing deployment and the well access line is coiled tubing. 
     
     
         17 . The method of  claim 15  further comprising performing an application with a tool of the toolstring at the target location. 
     
     
         18 . The method of  claim 17  wherein the application is a formation sampling application. 
     
     
         19 . The method of  claim 18  further comprising substantially perpendicularly orienting a formation sampling implement of the tool relative a wall of the well for the application with the roller device. 
     
     
         20 . The method of  claim 15  further comprising enhancing centralization of the tool in the well with the roller device during the conveyance through the well.