Tool and method for locking and releasing a plug

Abstract

A tool for locking and releasing a plug in a hydrocarbon well includes a sleeve having at least one pocket for receiving the plug's pin element, and at least one locking element which can be moved between a release position in which the pocket is open, and a locking position in which the pocket is closed. When locking the tool to the plug, the tool is moved in the hydrocarbon well to facilitate positioning of the pin element in abutment with the locking element, further movement bringing the locking element into an open position for receiving the pin element in the pocket, and the locking element is brought into a locking position such that the plug's pin element is locked in the pocket. When releasing the tool from the plug, fluid means are used for movement of the locking element into a release position.

1 . A tool for locking and releasing a plug in a hydrocarbon well, wherein the plug has at least one pin element, and wherein the tool comprises;
 a sleeve with at least one pocket for receiving the plug's pin element;   at least one locking element that can be moved between a release position in which the pocket is open, and a locking position in which the pocket is closed; and   when locking the tool to the plug, the tool is moved in the hydrocarbon well to facilitate positioning of the pin element in abutment with the locking element, wherein further movement of the tool moves the locking element into an open position for receiving the pin element in the pocket, and the locking element is brought into a locking position such that the plug's pin element is locked in the pocket; and   when releasing the tool from the plug, fluid means are used for movement of the locking element into a release position for release of the plug's pin element from the pocket.   
     
     
         2 . The tool according to  claim 1 , wherein the locking element is provided with at least one spring, wherein the spring is in an unloaded position when the locking element is in the locking position. 
     
     
         3 . The tool according to  claim 1 , wherein the locking element is connected to at least one sleeve-like part enclosing a movable sleeve which encloses an inner bore, the inner bore and the movable sleeve having openings for fluid communication between the inner bore and a piston face formed in an axial space in the sleeve-like part. 
     
     
         4 . The tool according to  claim 1 , wherein the sleeve has an oblique guide portion for insertion of the pin element into the pocket. 
     
     
         5 . The tool according to  claim 1 , wherein the pocket is provided with at least one oblique side face. 
     
     
         6 . The tool according to  claim 3 , wherein the sleeve-like part can be moved axially, and where there is provided a cavity in connection with the movable sleeve, which cavity is suitable for fluid communication with the inner bore through the openings, and where an applied weight on the tool is able to move the movable sleeve in order to permit fluid communication between the cavity and the axial space through the openings. 
     
     
         7 . A method for releasing the plug according to  claim 2 , wherein the plug comprises a sleeve-like part which is in abutment with the at least one spring at one end and connected to the locking element at the other end, and where the plug's pin element is released from the pocket by applying a fluid pressure which acts on a piston face in the sleeve-like part such that the sleeve-like part is moved, and the at least one spring is thereby compressed and moves the locking element into the release position. 
     
     
         8 . A method according to  claim 7 , wherein the sleeve-like part encloses an axially movable sleeve which encloses an inner bore, in that a weight is applied to the tool and moves the movable sleeve so as to allow fluid to migrate between the inner bore, via openings to a cavity, and further from the cavity through openings into an axial space in towards the piston face in the sleeve-like part and, in that the force from the fluid which is exerted against the piston face is sufficient to compress the at least one spring, and move the locking element into the release position. 
     
     
         9 . A method for locking the plug according to  claim 2 , wherein the plug's at least one pin element, upon movement of the tool, moves the at least one locking element into an open position whilst the at least one spring is compressed, and where the pin element is inserted into the pocket, after which each spring, with the connected locking element, returns to its unloaded position and the locking element is moved to the locking position.