Washpipe stabilization system

Abstract

The invention relates to washpipe assemblies for use in well bores and provides a washpipe assembly ( 2 ) comprising a washover shoe ( 10 ) attached to a washpipe ( 18 ), wherein a washpipe stabiliser ( 22 ) is provided on the washpipe ( 18 ) so that, when in use, deflection of the washover shoe ( 10 ) from a desired position is substantially prevented. The washpipe assembly of the present invention has the advantage over the prior art assemblies of providing means for supporting the washpipe off the wall of a well bore or well bore casing ( 52 ), and thereby reducing the torque required to rotate the washover string and the tendency of the washover shoe ( 10 ) to deviate from its preferred path down the well bore.

1 . A washpipe assembly for use in a well bore, the washpipe assembly comprising a washover shoe attached to a washpipe, wherein the washpipe stabiliser is provided on the washpipe so that, when in use, deflection of the washover shoe from a desired position is substantially prevented.  
     
     
         2 . A washpipe assembly as claimed in    claim 1   , wherein the washover shoe is a cylinder defining a bore, the cylinder of the washover shoe being provided with cutting members mounted on the lower end portion thereof.  
     
     
         3 . A washpipe assembly as claimed in    claim 2   , wherein the bore of the washover shoe is adapted to receive equipment located within the well bore.  
     
     
         4 . A washpipe assembly as claimed in any of the preceding claims, wherein the washpipe is an elongate cylinder defining a bore.  
     
     
         5 . A washpipe assembly as claimed in    claim 4   , wherein the bore of the washpipe is adapted to received equipment located within the well bore.  
     
     
         6 . A washpipe assembly as claimed in any of the preceding claims, wherein the stabiliser is provided as a plurality of blade members projecting from an exterior surface of the washpipe.  
     
     
         7 . A washpipe assembly as claimed in    claim 6   , wherein each blade member is arranged in a helix about the washpipe.  
     
     
         8 . A washpipe assembly as claimed in    claim 6    or    7   , wherein the stabiliser incorporates five blade members.  
     
     
         9 . A washpipe assembly as claimed in any of    claims 6    to    8   , wherein the blade members are provided with a cutting edge.  
     
     
         10 . A washpipe assembly as claimed in any of the preceding claims, wherein the stabiliser is provided on a portion of the washpipe adjacent the washover shoe.  
     
     
         11 . A washpipe assembly substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.