Method for mounting a casing shoe on a drilling appatatus

Abstract

A method for mounting a casing shoe ( 4 ) around a cylindrical drilling apparatus ( 2 ), which shoe is used by drilling and pulled in the ground on drilling, whereby shoe ( 4 ) and drilling apparatus ( 2 ) can in the installed position rotate with respect to one another and move a certain distance axially with respect to one another, when shoulder ( 8 ) in the shoe is in transverse groove ( 9 ) on the periphery of the drilling apparatus and the groove is determining the length of the axial motion. The cylindrical shoe ( 2 ) is shrunk in order to make its diameter smaller around a spot in drilling apparatus ( 2 ) smaller than the outer diameter (Du), until through shrinking the outer diameter of the shoe has become smaller than the outer diameter (Du) of the drilling apparatus.

1 . A method for mounting a casing shoe ( 4 )around a cylindrical drilling apparatus ( 2 ), which shoe is used by drilling and pulled into the ground on drilling, whereby shoe ( 4 ) and drilling apparatus ( 2 ) can in the installed position rotate with respect to one another and move a certain distance axially with respect to one another, when shoulder ( 8 ) in the shoe is in transverse groove ( 9 ) on the periphery of the drilling apparatus and the groove determing the length of the axial motion, characterized in that at least a part of cylindrical shoe ( 2 ) is shrunk in order to make its diameter smaller around a spot in the drilling apparatus smaller than the outer diameter (Du) of drilling apparatus ( 2 ) on which there is the transverse groove ( 9 ), until the outer diameter of the shoe has through shrinking become smaller than the outer diameter (Du) of the drilling apparatus and/or the formed shoulder is in groove ( 9 ).  
     
     
         2 . A method according to  claim 1  characterized in that shoe ( 4 ) including shoulder ( 8 ) retain their shape during shrinking.  
     
     
         3 . A method according to  claim 1  and  2  characterized in that shoe ( 4 ) is shrunk by means of many clamping jaws ( 10 ) formed to correspond to the shoe ( 4 ) outer surface.  
     
     
         4 . A method according to  claim 1  and  2  characterized in that the shoe is shrunk in forcing the shoe into a tool ( 5 ) that has a diminishing conical portion ( 6 ).  
     
     
         5 . A method according to any of the previous claims  1 - 4  characterized in that in order to carry out the shrinking stage, into groove ( 9 ) a detachable ring assembly ( 3 ) is placed, which steers the shoe ( 4 ) shoulder ( 8 ) to become shrunk in the backmost edge of groove ( 9 ) with respect to the drilling direction.  
     
     
         6 . A method according to  claim 5  characterized in that on using the ring assembly ( 3 ) the drilling apparatus with shoe ( 4 ) is pushed into conical tool ( 5 ) until the shoe size is shrunk to the diameter size needed.