Downhole tool

Abstract

A method of locating a tubing string in a bore, the method comprising the steps: providing a device defining a restriction-engaging member; locating the device on the lower end of a tubing string; and then running the tubing string into the bore until the member engages a restriction in the bore and the device and the tubing is prevented from advancing further by the restriction. The member is then re-configured to permit further advancement of the device and tubing relative to the restriction and the device and tubing moved a predetermined distance relative to the restriction to position the tubing at a desired location in the bore.

We claim:  
     
         1 . A method of locating a tubing string in a bore having a restriction therein, the method comprising the steps: 
 (a) providing a device defining a restriction-engaging member;    (b) running the tubing string into the bore until the member engages a restriction in the bore and the device and tubing are prevented from advancing further by the restriction;    (c) re-configuring the member to permit further advancement of the device and tubing relative to the restriction; and    (d) moving the device a predetermined distance relative to the restriction to position the tubing at a desired location in the bore.    
     
     
         2 . The method of  claim 1 , comprising re-configuring the member by radially retracting the member.  
     
     
         3 . The method of  claim 1 , comprising re-configuring the member by positively retracting the member.  
     
     
         4 . The method of  claim 1 , comprising re-configuring the member by application of a predetermined force thereto.  
     
     
         5 . The method of  claim 4 , comprising re-configuring the member by application of a predetermined downward weight thereto.  
     
     
         6 . The method of  claim 4 , comprising releasing a shear coupling.  
     
     
         7 . The method of  claim 1 , further comprising the step of maintaining the member in a retracted configuration.  
     
     
         8 . The method of  claim 7 , comprising restraining the member in the retracted configuration.  
     
     
         9 . The method of  claim 1 , wherein following step (b), landing devices are incorporated in the tubing string and, carrying out step (d) lands out the string.  
     
     
         10 . The method of  claim 9 , further comprising pulling the tubing string back out prior to incorporating the landing devices in the tubing string.  
     
     
         11 . The method of  claim 9 , wherein the landing devices are incorporated in the tubing string without pulling back the tubing string.  
     
     
         12 . Apparatus for use in locating a tubing string in a bore with reference to an existing bore restriction, the apparatus comprising: a device adapted to be run into a bore on a lower end of a tubing string, the device comprising a radially extending member adapted to land out on a bore restriction and adapted to be selectively retracted to permit passage of the device and the associated tubing string beyond the restriction.  
     
     
         13 . The apparatus of  claim 12 , wherein the member is adapted to be retracted by application of a predetermined weight thereto.  
     
     
         14 . The apparatus of  claim 13 , wherein the member is initially retained in a restriction-engaging position by a releasable coupling.  
     
     
         15 . The apparatus of  claim 14 , wherein the coupling is in the form of a shear member.  
     
     
         16 . The apparatus of  claim 12 , further comprising means for maintaining the member in a retracted configuration.  
     
     
         17 . The apparatus of  claim 16 , wherein said means for maintaining the member in the retracted configuration comprises spring biassed sleeves located above and below the member.  
     
     
         18 . The apparatus of  claim 12 , wherein the member comprises a plurality of fingers.