Anchor

Abstract

An anchor and a method for limiting the movement of a tubing string within a wellbore are provided. The anchor comprises a mandrel, a slip body assembly, a drag block assembly, and a mechanism for transitioning the anchor between a release position and a set position. The mechanism is operable by relative movement between the drag block assembly and the mandrel. The anchor is transitionable between the release position and the set position by rotating the mandrel less than half a full turn relative to the drag block assembly.

I claim: 
     
         1 . An anchor comprising:
 a mandrel;   a slip body assembly carried on the mandrel, the slip body assembly comprising at least one first slip;   a drag block assembly carried on the mandrel, the drag block assembly comprising at least one second slip, at least one drag block, and a mechanism for transitioning the anchor between a release position and a set position, the mechanism is operable by relative movement between the drag block assembly and the mandrel; and   a cone carried on the mandrel and disposed between the slip body assembly and the drag block assembly, for causing radially outward projection of the at least one first slip and the at least one second slip,   the anchor is transitionable between the release position and the set position by rotating the mandrel less than half a full turn relative to the drag block assembly.   
     
     
         2 . The anchor of  claim 1 , wherein the rotation is substantially a quarter turn. 
     
     
         3 . The anchor of  claim 1 , wherein the rotation is to the right. 
     
     
         4 . The anchor of  claim 3 , further comprising moving the mandrel axially for a distance relative to the drag block assembly, and rotating the mandrel less than half a full turn to the left relative to the drag block assembly. 
     
     
         5 . The anchor of  claim 1 , wherein the mechanism comprises a pin attached to the mandrel; and a slot having a connector slot, a first recess at one end of the connector slot, and a second recess at the other end of the connector slot, and the pin is positionable in the slot and engageable with the recesses. 
     
     
         6 . The anchor of  claim 5 , wherein the first recess and the second recess extend away from the axis of the connector slot on one side of the connector slot. 
     
     
         7 . The anchor of  claim 5 , wherein the first recess and the second recess each have a return nook. 
     
     
         8 . The anchor of  claim 7 , wherein the return nooks face each other. 
     
     
         9 . The anchor of  claim 5 , wherein the slot is a C-shaped slot. 
     
     
         10 . The anchor of  claim 5 , wherein the pin engages the first recess when the anchor is in the set position, and the pin engages in the second recess when the anchor is in the release position. 
     
     
         11 . The anchor of  claim 5 , wherein any torque resulting from the rotation is dissipated when the pin is engaged with one of the recesses. 
     
     
         12 . The anchor of  claim 4 , wherein the mechanism comprises a pin attached to the mandrel; and a slot having a connector slot, a first recess at one end of the connector slot, and a second recess at the other end of the connector slot, and the pin is positionable in the slot and engageable with the recesses; and
 wherein the pin is movable from the first recess to the connector slot by the rotation of the mandrel to the right; the pin is movable along the connector slot by the axial movement of the mandrel; and the pin is movable from the connector slot to the second recess by the rotation of the mandrel to the left.   
     
     
         13 . The anchor of  claim 1 , wherein the mandrel connectable to a tubing string. 
     
     
         14 . The anchor of  claim 1 , wherein the slip body assembly further comprises a spring. 
     
     
         15 . The anchor of  claim 1 , wherein the slip body assembly and the drag block assembly each have a bore, and the mandrel extends through the bores. 
     
     
         16 . The anchor of  claim 1 , further comprising drag block springs disposed under the at least one drag block for urging the drag block radially outwardly away from the mandrel. 
     
     
         17 . The anchor of  claim 1 , wherein at least one of the at least one drag block, the at least one first slip, and the at least one second slip has a textured outer surface. 
     
     
         18 . The anchor of  claim 1 , wherein the cone is frustoconical in shape. 
     
     
         19 . The anchor of  claim 1 , wherein the slip body assembly further comprises a releasing slip. 
     
     
         20 . A method for limiting the movement of a tubing string in a wellbore having inner wall, comprising:
 positioning an anchor in the wellbore, the anchor comprising a mandrel having connected thereto the tubing string, and having a set-release mechanism and at least one slip engageable with the inner wall; and   activating the set-release mechanism by rotating the mandrel less than half a full turn to the right, thereby engaging the at least one slip with the inner wall and transitioning the anchor from a release position to a set position.   
     
     
         21 . The method of  claim 20 , wherein the step of activating further comprises:
 picking up the tubing string; slacking off the tubing string; and releasing the rotation.   
     
     
         22 . The method of  claim 20 , wherein the set-release mechanism comprises a pin and a slot, the pin being positionable in the slot, and the slot having a first recess at one end and a second recess at the other end. 
     
     
         23 . The method of  claims 21 , wherein the set-release mechanism comprises a pin and a slot, the pin being positionable in the slot, and the slot having a first recess at one end and a second recess at the other end; and wherein the steps of picking up, rotating, slacking off and releasing move the pin from the first recess to the second recess. 
     
     
         24 . The method of  claim 20 , wherein the at least one slip is engaged by sliding on to a cone and projecting radially outwardly. 
     
     
         25 . A method of releasing an anchor from a wellbore having an inner surface, the anchor having a mandrel connected to a tubing string, a set-release mechanism, and at least one slip engaged with the inner surface, comprising:
 activating the set-release mechanism by rotating the mandrel less than half a full turn to the right, thereby disengaging the at least one slip from the inner surface.   
     
     
         26 . The method of  claim 25 , wherein the step of activating further comprises:
 slacking off the tubing string; and picking up the tubing string.   
     
     
         27 . The method of  claim 25 , wherein the set-release mechanism comprises a pin and a slot, the pin being positionable in the slot, and the slot having a first recess at one end and a second recess at the other end. 
     
     
         28 . The method of  claims 26 , wherein the set-release mechanism comprises a pin and a slot, the pin being positionable in the slot, and the slot having a first recess at one end and a second recess at the other end; and wherein the steps of slacking off, rotating, and picking up move the pin from the first recess to the second recess, and the movement of the pin to the second recess triggers the disengaging of the at least one slip. 
     
     
         29 . The method of  claim 25 , wherein the anchor further comprises an emergency release mechanism.