Expandable spiral threaded apparatus and method for anchoring a downhole tool to a casing, and method for assembling the apparatus

Abstract

The apparatus for anchoring a downhole tool to a casing includes a spiral threaded engagement and a raised spiral threaded engagement between a slip device and first and second cones. The first cone is moved closer to the second cone within the slip device to expand the slip device from an initial diameter in a run-in configuration to an extended diameter in a set configuration. The initial diameter corresponds to the spiral threaded engagement, and the extended diameter corresponds to the raised spiral threaded engagement. The spiral threaded engagement of the first cone is in the opposite spiral direction to the spiral threaded engagement of the second cone. There are multiple locking systems incorporated to prevent premature expansion and reverse rotating the cones from the slip device. The invention includes both the method of assembling the apparatus and the method of using the apparatus to anchor to a casing.

We claim: 
     
         1 . An apparatus for anchoring a downhole tool to a casing, comprising:
 a first cone having a first spiral threaded outer cone surface, said first spiral threaded outer cone surface being threaded in a first spiral direction;   a second cone having a second spiral threaded outer cone surface, said second spiral threaded outer cone surface being threaded in a second spiral direction, said first spiral direction being opposite said second spiral direction; and   a slip device having an outer slip surface and an inner slip surface,   
       wherein said inner slip surface being comprised a first spiral threaded inner slip surface and a second spiral threaded inner slip surface, 
       wherein said first cone faces toward said second cone within said slip device, 
       wherein said slip device has a run-in configuration with an initial diameter, said first spiral threaded inner slip surface being in spiral threaded engagement with said first spiral threaded outer cone surface in said run-in configuration, said second spiral threaded inner slip surface being in spiral threaded engagement with said second spiral threaded outer cone surface in said run-in configuration, and said first cone being positioned at an initial distance from said second cone within said slip device in said run-in configuration, 
       wherein said slip device has a set configuration with an extended diameter, said first cone being positioned closer to said second cone than said initial distance within said slip device in said set configuration, said first spiral threaded inner slip surface being in raised spiral threaded engagement with said first spiral threaded outer cone surface in said set configuration, and said second spiral threaded inner slip surface being in raised spiral threaded engagement with said second spiral threaded outer cone surface in said set configuration, and 
       wherein said extended diameter is greater than said initial diameter. 
     
     
         2 . The apparatus for anchoring, according to  claim 1 , wherein said outer slip surface is comprised of a gripping means. 
     
     
         3 . The apparatus for anchoring, according to  claim 1 , wherein said outer slip surface is spaced further from said first spiral threaded outer cone surface in said raised spiral threaded engagement than in said spiral threaded engagement, and
 wherein said outer slip surface is spaced further from said second spiral threaded outer cone surface in said raised spiral threaded engagement than in said spiral threaded engagement.   
     
     
         4 . The apparatus for anchoring, according to  claim 1 , further comprising:
 a locking means for said first cone and said second cone.   
     
     
         5 . The apparatus for anchoring, according to  claim 4 , wherein said locking means is comprised of a plurality of shear screws,
 wherein at least one first shear screw of said plurality of shear screws is removably positioned on said first cone, and   wherein at least one second shear screw of said plurality of shear screws is removably positioned on said second cone.   
     
     
         6 . The apparatus for anchoring, according to  claim 1 , wherein said slip device is comprised of a barrel body, said barrel body being comprised of a plurality of ribs, each rib of said plurality of ribs being connected to an adjacent rib of said plurality of ribs. 
     
     
         7 - 12 . (canceled) 
     
     
         13 . A method for assembling an apparatus for anchoring a downhole tool, comprising the steps of:
 inserting a first cone into a slip device, said first cone having a first spiral threaded outer cone surface being threaded in a first spiral direction; and   inserting a second cone into said slip device opposite said first cone, said second cone having a second spiral threaded outer cone surface being threaded in a second spiral direction, said first spiral direction being opposite said second spiral direction so as to set said slip device in a run-in configuration with an initial diameter, said slip device having an outer slip surface and an inner slip surface, said inner slip surface being comprised a first spiral threaded inner slip surface and a second spiral threaded inner slip surface, said first spiral threaded outer cone surface being in spiral threaded engagement with said first spiral threaded inner slip surface, said second spiral threaded outer cone surface being in spiral threaded engagement with said second spiral threaded inner slip surface,   
       wherein the step of inserting said first cone is comprised of rotating said first spiral threaded outer cone surface into a spiral threaded engagement with said first spiral threaded inner slip surface, 
       wherein the step of inserting said second cone is comprised of rotating said second spiral threaded outer cone surface into a spiral threaded engagement with said second spiral threaded inner slip surface, 
       wherein said first cone faces toward said second cone within said slip device, and 
       wherein said first cone is positioned at an initial distance from said second cone within said slip device in said run-in configuration. 
     
     
         14 . The method for assembling, according to  claim 13 , further comprising the step of:
 installing a locking means for said first cone and said second cone, said locking means being comprised of a plurality of shear screws.   
     
     
         15 . The method for assembling, according to  claim 14 , wherein the method of installing said lock means comprises the steps of:
 removably positioning at least one first shear screw of said plurality of shear screws on said first cone; and   removably positioning at least one second shear screw of said plurality of shear screws on said second cone.   
     
     
         16 . The method for assembling, according to  claim 13 , further comprising the step of:
 mounting a first rotation locking key on said first cone so as to prevent rotation of said first spiral threaded inner slip surface relative to said first spiral threaded outer cone surface; and   mounting a second rotation locking key on said second cone so as to prevent rotation of said second spiral inner slip surface relative to said second spiral outer cone surface.   
     
     
         17 . The method for assembling, according to  claim 16 ,
 wherein said slip device being comprised of a barrel body, said barrel body being comprised of a plurality of ribs, each rib of said plurality of ribs being connected to an adjacent rib of said plurality of ribs,   wherein said first rotation locking key is positioned between a first rib of said plurality of ribs and a corresponding first adjacent rib of said plurality of ribs, and   wherein said second rotation locking key is positioned between a second rib of said plurality of ribs and a corresponding second adjacent rib of said plurality of ribs.   
     
     
         18 . A method of anchoring the downhole tool to a casing within a borehole, the method comprising the steps of:
 deploying the downhole tool with said slip device in said run-in configuration, according to the method for assembling of  claim 15 , into the casing;   locating the downhole tool at a desired location in the casing; and   positioning said first cone closer to said second cone than said initial distance within said slip device so as to place said slip device in a set configuration with an extended diameter, said extended diameter being greater than said initial diameter and holding the downhole tool at said desired location.   
     
     
         19 . The method for anchoring, according to  claim 18 , wherein said first spiral inner slip surface is in raised threaded engagement with said first spiral outer cone surface in said set configuration, and wherein said second spiral inner slip surface is in raised threaded engagement with said second spiral outer cone surface in said set configuration. 
     
     
         20 . The method for anchoring, according to  claim 18 , further comprising the steps of:
 spacing outer slip surface further from said first spiral outer cone surface in said raised threaded engagement than in said run-in configuration; and   spacing said outer slip surface further from said second spiral outer cone surface in said raised threaded engagement than in said run-in configuration.