Magnetic tool for retrieving metal objects from a well bore when using coil tubing

Abstract

A magnetic tool for retrieval of metal debris from a well bore particularly adapted for use in coil tubing systems. The tool has a cylindrical body and a plurality of separate magnet assemblies mounted on the tool body. The magnet assemblies are separated by spacers, which define a secondary settling area for the metal objects attracted to the magnetic tool. Each magnet assembly has one or more magnet member encased in a protective sleeve

1 . An apparatus for retrieving metal objects from a wellbore, comprising: 
 a cylindrical tool body with a central opening therethrough; and    a plurality of spaced-apart magnet assemblies configured for positioning in a surrounding relationship over at least a portion of said tool body, said magnet assemblies defining a primary settling area for the metal objects; and    at least one spacer mounted between adjacent magnet assemblies, said spacer member defining a secondary settling area for the metal objects.    
   
   
       2 . The apparatus of  claim 1 , wherein each of said magnet assemblies has a generally ring-shaped cross-section.  
   
   
       3 . The apparatus of  claim 1 , wherein each of said magnet assemblies comprises a magnet member encased in a sleeve.  
   
   
       4 . The apparatus of  claim 3 , wherein said sleeve comprises a generally cylindrical main portion and opposing end portions having a generally frustoconical configuration.  
   
   
       5 . The apparatus of  claim 2 , wherein each of said magnet assemblies comprises a plurality of elongated magnet members circumferentially disposed about the tool body and extending in a generally parallel relationship to a central axis of the tool body.  
   
   
       6 . The apparatus of  claim 1 , wherein said at least one spacer has a generally tubular configuration.  
   
   
       7 . The apparatus of  claim 6 , wherein said at least one spacer comprises a plurality of elongated plates disposed in a circumferential relationship about said tool body and extending in a generally parallel relationship to a central axis of the tool body.  
   
   
       8 . The apparatus of  claim 6 , wherein an external diameter of said spacer is smaller than an external diameter of each of said magnet assemblies.  
   
   
       9 . The apparatus of  claim 1 , wherein each of said magnet assemblies and said spacer is detachably mounted on said tool body.  
   
   
       10 . The apparatus of  claim 1 , wherein said tool body is provided with an upper connector located above said magnet assemblies and a lower connector located below said magnet assemblies, said upper connector and said lower connector allowing connection of said tool body to a drill string lowered into the well bore.  
   
   
       11 . An apparatus for retrieving metal objects from a wellbore, comprising: 
 a cylindrical tool body with a central opening therethrough; and    at least a pair of spaced-apart magnet assemblies configured for positioning in a surrounding relationship over at least a portion of said tool body, said magnet assemblies defining a primary settling area for the metal objects; and    at least one tubular spacer mounted between said magnet assemblies in a surrounding relationship to said tool body, said spacer member defining a secondary settling area for the metal objects.    
   
   
       12 . The apparatus of  claim 11 , wherein an external diameter of said spacer member is smaller than an external diameter of each of said magnet assemblies.  
   
   
       13 . The apparatus of  claim 11 , wherein each of said magnet assemblies comprises a magnet member encased in a sleeve.  
   
   
       14 . The apparatus of  claim 13 , wherein said sleeve is formed from a non-corrosive material.  
   
   
       15 . The apparatus of  claim 13 , wherein said sleeve comprises a generally cylindrical main portion and opposing end portions having a generally frustoconical configuration.  
   
   
       16 . The apparatus of  claim 11 , wherein each of said magnet assemblies and said spacer is detachably mounted on said tool body.  
   
   
       17 . An apparatus for retrieving metal objects from a wellbore, comprising: 
 a cylindrical tool body with a central opening therethrough; and    at least a pair of spaced-apart magnet assemblies configured for positioning in a surrounding relationship over at least a portion of said tool body, said magnet assemblies defining a primary settling area for the metal objects, each of said magnet assemblies comprising a plurality of elongated magnet members secured in a surrounding relationship over at least a portion of said tool body and extending in a generally parallel relationship to a central axis of the tool body; and    at least one tubular spacer mounted between said magnet assemblies in a surrounding relationship to said tool body, said spacer member defining a secondary settling area for the metal objects.    
   
   
       18 . The apparatus of  claim 17 , wherein said at least one spacer comprises a plurality of elongated plates disposed in a circumferential relationship about said tool body and extending in a generally parallel relationship to a central axis of the tool body.