Magnetic Slip Retention for Downhole Tool

Abstract

A downhole tool, such as a packer or liner hanger, has a mandrel on which slips are disposed for engaging a surrounding tubular downhole. When the tool is being run in or out of the hole, at least one magnetic component magnetically retains the slip adjacent the mandrel so the slip can be held away from the surrounding tubular. When the tool is set downhole, the initial magnetic retention can be broken, and the slips can be moved away from the mandrel to engage the surface of the surrounding tubular.

1 . A downhole tool, comprising:
 a portion of the downhole tool having a first magnetic component; and   a slip disposed on the downhole tool, at least a portion of the slip being movable from a first position adjacent the downhole tool to a second position away from the downhole tool for engaging a surrounding surface,   the slip having a second magnetic component magnetically opposed to the first magnetic element and magnetically retaining the slip in the first position.   
     
     
         2 . The tool of  claim 1 , wherein the downhole tool is selected from the group consisting of a packer, a liner hanger, a plug, and a tubing stop. 
     
     
         3 . The tool of  claim 1 , wherein the downhole tool comprises a mandrel having the first magnetic component. 
     
     
         4 . The tool of  claim 1 , wherein the downhole tool comprises a cage having the first magnetic component. 
     
     
         5 . The tool of  claim 1 , wherein the first and second magnetic components comprise permanent magnets with repulsing polarities. 
     
     
         6 . The tool of  claim 1 , further comprising a spring disposed on the downhole tool and biasing the slip toward the first position. 
     
     
         7 . The tool of  claim 1 , further comprising one or more rings engaging the slip and disposed about the downhole tool, the one or more rings biasing the slip toward the first position. 
     
     
         8 . The tool of  claim 1 , further comprising additional means for retaining the slip in the first position. 
     
     
         9 . A downhole tool, comprising:
 a tool body having a first magnetic component;   an activation body disposed on the tool body; and   a slip disposed on the tool body, at least a portion of the slip being movable by the activation body from a first position adjacent the tool body to a second position away from the tool body for engaging a surrounding surface,   the slip having a second magnetic component magnetically opposed to the first magnetic component and magnetically retaining the slip in the first position.   
     
     
         10 . The tool of  claim 9 , wherein the downhole tool is selected from the group consisting of a packer, a liner hanger, a plug, and a tubing stop. 
     
     
         11 . The tool of  claim 9 , wherein the tool body comprises a mandrel having the first magnetic component. 
     
     
         12 . The tool of  claim 9 , wherein the tool body comprises a mandrel having the slip disposed adjacent thereto and comprises a cage disposed on the mandrel adjacent the slip, the cage having the second magnetic component. 
     
     
         13 . The tool of  claim 9 , wherein the first and second magnetic components comprise permanent magnets with repulsing polarities. 
     
     
         14 . The tool of  claim 9 , further comprising a spring disposed on the tool body and biasing the slip toward the first position. 
     
     
         15 . The tool of  claim 9 , further comprising one or more rings engaging the slip and disposed about the downhole tool, the one or more rings biasing the slip toward the first position. 
     
     
         16 . The tool of  claim 9 , further comprising additional means for retaining the slip in the first position until moved by the activation body. 
     
     
         17 . A downhole tool, comprising:
 an activation body disposed on the downhole tool;   a slip disposed on the downhole tool, at least a portion of the slip being movable by the activation body from a first position adjacent the downhole tool to a second position away from the downhole tool for engaging a surrounding surface; and   means for magnetically retaining the slip in the first position until moved by the activation body toward the second position, the means for magnetically retaining the slip comprising means for magnetically repelling the slip from a portion of the downhole tool.   
     
     
         18 . The tool of  claim 17 , wherein the downhole tool is selected from the group consisting of a packer, a liner hanger, a plug, and a tubing stop. 
     
     
         19 . The tool of  claim 17 , wherein the portion of the downhole tool from which the slip is magnetically repelled comprises means for mechanically engaging the slip in the second position. 
     
     
         20 . The tool of  claim 17 , further comprising means for biasing the slip toward the first position.