Well Wall Gripping Element

Abstract

A gripping element for incorporation into a track of a downhole tractor. The gripping element may be configured with an arcuate or curved surface in order to roughly match the arcuate nature of a well through which the downhole tractor is advanced. Due to the matching arcuate surfaces of the gripping element and the wall of the well, problems associated with uneven wear on the tracks may be avoided. Furthermore, damage to the well wall may be minimized as a result of the substantially matching surfaces of the well wall and the track made up of such gripping elements. Additionally, the gripping element may be made up of primarily a monolithic body in order to avoid challenges presented by some segmented body configurations.

1 . A driving mechanism for interfacing a well wall with a gripping element, said gripping element having an arcuate surface selected based on an arcuate character of the well wall, wherein an interfacing of the gripping element with the well wall causes the driving mechanism to move relative to the well wall. 
   
   
       2 . The driving mechanism of  claim 1  wherein said gripping element comprises at least one tooth at said arcuate surface for the interfacing. 
   
   
       3 . The driving mechanism of  claim 1  wherein said gripping element comprises a body that is one of a monolithic and a segmented variety. 
   
   
       4 . The driving mechanism of  claim 3  further comprising:
 a rotable pin through said body; and   rollers secured at ends of said rotable pin.   
   
   
       5 . The driving mechanism of  claim 1  wherein said gripping element is of a y-shaped configuration comprising a male region and a female region. 
   
   
       6 . The driving mechanism of  claim 5  wherein each said region further comprises more than one tooth at a surface thereof. 
   
   
       7 . The driving mechanism of  claim 1 , wherein the driving mechanism is a downhole tractor and said gripping element forms a portion of a track on the downhole tractor. 
   
   
       8 . The driving mechanism of  claim 7  wherein said track is a first track, the downhole tractor further comprising between about 1 and about 3 additional tracks. 
   
   
       9 . The driving mechanism of  claim 7  wherein said downhole tractor further comprises a central housing comprising:
 an expansion mechanism for engaging said track with the well wall.   
   
   
       10 . The driving mechanism of  claim 9  further comprising an extension coupled to said central housing for accommodating a downhole tool. 
   
   
       11 . A downhole tractor for use within a well and comprising a gripping element having a monolithic body with an arcuate surface configured based on an arcuate character of a wall of the well, the downhole tractor to effect an interface between the arcuate surface and the wall, which causes the downhole tractor to move relative to the well wall. 
   
   
       12 . The downhole tractor of  claim 11  wherein the arcuate surface is substantially continuous across a width of the gripping element. 
   
   
       13 . The downhole tractor of  claim 11  wherein the arcuate surface is configured to contact the wall through between about 50% and about 97% of the interface. 
   
   
       14 . A gripping element for use on a track of a downhole tractor, the gripping element comprising an arcuate surface to interface a well wall, said arcuate surface substantially matching an arcuate shape of the well wall. 
   
   
       15 . The gripping element of  claim 14  wherein said arcuate surface displays a radius that is within about one inch of a radius of the well wall. 
   
   
       16 . The gripping element of  claim 14 , wherein the arcuate shape of the well wall is in the form of a diameter, said diameter chosen from the group consisting of about 6.5 inches, about 8.5 inches and about 10.5 inches, and wherein said arcuate surface of the gripping element is in the form or a radius, said radius chosen from the group consisting of about 3.25 inches, about 4.25 inches and about 5.25 inches. 
   
   
       17 . A downhole tractor comprising:
 a chain for engaging a well wall and rotating thereagainst to propel the downhole tractor with respect to the well wall, wherein the chain comprises:   a plurality of links, wherein each link comprises at least one tooth formed in an arcuate shape selected based on an arcuate character of the well wall.   
   
   
       18 . The downhole tractor of  claim 17 , wherein the plurality of links contains interconnecting links such that a width of the chain contains no more than two interfacing junctions between connected links.