Hydraulic Whipstock Anchor

Abstract

A whipstock anchor is hydraulically set and locked in the set position. Release occurs with a pull induced component failure that relieves hydraulic pressure that allows the slips to retract. Release can occur with a remotely actuated circuit that burns a retainer for a piston whose movement opens a vent or initiates a chemical reaction to undermine a lock ring. Movement of a single cone or opposed cones extends the slips. The cone angles being different (cone angles do not have to be different, it is preferred to have the slip angles different) adds a skew to the slips and positions the top of the whipstock against the tubular top in a horizontal run. A bottom cap is removable to convert to setting by set down weight or to attach a hydraulically operated packer below the slips. Slips can be extended with radial movement of pistons.

We claim: 
     
         1 . An anchored borehole tool assembly, comprising:
 a borehole tool;   an anchor housing featuring at least one radially extendible slip actuated by at least one piston selectively operated by hydraulic pressure provided into said housing;   said housing further comprising a pressure retaining device to hold said at least one slip extended by holding hydraulic pressure applied to said housing.   
     
     
         2 . The assembly of  claim 1 , wherein:
 said hydraulic pressure in said housing is relieved with failure of a component in said housing allowing said slip to be retracted.   
     
     
         3 . The assembly of  claim 1 , wherein:
 said hydraulic pressure in said housing is relieved with opening a vent valve in said housing allowing said slip to be retracted.   
     
     
         4 . The assembly of  claim 1 , wherein:
 said hydraulic pressure in said housing is relieved with undermining at least one locking member for said at least one slip in said housing allowing said slip to be retracted.   
     
     
         5 . The assembly of  claim 4 , wherein:
 said at least one locking member is undermined by opening a valve to release a fluid to reach said at least one locking member.   
     
     
         6 . The assembly of  claim 5 , wherein:
 said valve is signaled to open from a remote location without borehole intervention.   
     
     
         7 . The assembly of  claim 6 , wherein:
 said valve comprises a selectively retained piston, whereupon said remote signal a restraint on said piston is removed such that piston movement opens a fluid reservoir to said at least one locking member to undermine said at least one locking member with said fluid.   
     
     
         8 . The assembly of  claim 1 , wherein:
 said piston moves axially for radial extension of said slip.   
     
     
         9 . The assembly of  claim 8 , wherein:
 said hydraulic pressure in said housing is relieved with opening a vent valve in said housing allowing said slip to be retracted.   
     
     
         10 . The assembly of  claim 9 , wherein:
 said valve is signaled to open from a remote location without borehole intervention.   
     
     
         11 . The assembly of  claim 10 , wherein:
 said valve comprises a selectively retained piston, whereupon said remote signal a restraint on said piston is removed allowing said piston to open a vent passage so that said at least one slip can retract into said housing.   
     
     
         12 . The assembly of  claim 3 , wherein:
 said valve is signaled to open from a remote location without borehole intervention.   
     
     
         13 . The assembly of  claim 12 , wherein:
 said valve comprises a selectively retained piston, whereupon said remote signal a restraint on said piston is removed allowing said piston to open a vent passage so that said at least one slip can retract into said housing.   
     
     
         14 . The assembly of  claim 13 , wherein:
 said at least one piston is spring biased to a position where said at least one slip is retracted.   
     
     
         15 . The assembly of  claim 7 , wherein:
 said at least one piston is spring biased to a position where said at least one slip is retracted.   
     
     
         16 . The assembly of  claim 11 , wherein:
 said at least one piston is spring biased to a position where said at least one slip is retracted.   
     
     
         17 . The assembly of  claim 1 , wherein:
 said at least one piston is selectively mechanically operated for extension of said at least one slip by exposing said at least one piston with removal of a cover on said housing.   
     
     
         18 . The assembly of  claim 1 , wherein:
 removal of a cover on said housing adapts said housing to accept a packer assembly for hydraulic operation using the hydraulic pressure in said housing that operates said at least one slip.   
     
     
         19 . The assembly of  claim 1 , wherein:
 a mandrel is surrounded by said at least one piston;   movement of said piston relative to said mandrel is locked with a locking member against reverse movement of said at least one piston;   said mandrel having a decreased dimension portion that breaks or fails in response to a tensile force on said tool transmitted to one end of said mandrel with an opposing end of said mandrel retained by said at least one slip resisting said tensile force through said at least one piston and said locking member;   said breaking or failing of said decreased dimension portion of said mandrel allows a portion of said mandrel to move away from said at least one slip for retraction of said at least one slip.   
     
     
         20 . The assembly of  claim 1 , wherein:
 said at least one slip comprises a plurality of pistons disposed for movement in opposite directions toward said at least one slip with each piston locked against reverse movement away from said at least one slip.   
     
     
         21 . The assembly of  claim 1 , wherein:
 said tool has a first longitudinal axis and said slips have a second longitudinal axis that is skewed with respect to said first longitudinal axis such that extension of said at least one slip cocks an end of said tool toward a wall of the borehole.   
     
     
         22 . The assembly of  claim 1 , wherein:
 said at least one slip comprises a plurality of circumferentially spaced slips each of said slips having opposed end tapers that slide on opposing ramps, wherein said tapers have the same angle with said opposing ramps at different angles or said tapers have the different angles with said opposing tapers having the same angle such that extension of said slips cocks an end of said tool toward a wall of the borehole.   
     
     
         23 . The assembly of  claim 9 , wherein:
 said tool comprises a whipstock;   said valve is opened with intervention of a retrieval tool for said whipstock.   
     
     
         24 . The assembly of  claim 9 , wherein:
 said signal comprises acoustic, electromagnetic, mud pulse or vibration.   
     
     
         25 . An anchored borehole tool assembly, comprising:
 a borehole tool;   an anchor housing featuring a plurality of radially extendible slips actuated by at least one piston selectively operated by hydraulic pressure provided into said housing;   wherein radial extension of said slips skews the axis of at least said borehole tool with respect to an axis of the borehole.   
     
     
         26 . The assembly of  claim 22 , wherein:
 said slips having different widths on opposed sides of a retainer to insure the proper installation orientation.   
     
     
         27 . The assembly of  claim 1 , wherein:
 said at least one slip comprises a plurality of circumferentially spaced slips;   said slips are axially offset to skew said anchor housing upon radial extension of said slips.   
     
     
         28 . The assembly of  claim 25 , wherein:
 said piston moves axially for radial extension of said slips.   
     
     
         29 . The assembly of  claim 25 , wherein:
 a mandrel is surrounded by said at least one piston;   movement of said piston relative to said mandrel is locked with a locking member against reverse movement of said at least one piston;   said mandrel having a decreased dimension portion that breaks or fails in response to a tensile force on said tool transmitted to one end of said mandrel with an opposing end of said mandrel retained by said slips resisting said tensile force through said at least one piston and said locking member;   said breaking or failing of said decreased dimension portion of said mandrel allows a portion of said mandrel to move away from said slips for retraction of said slips.   
     
     
         30 . The assembly of  claim 25 , wherein:
 said tool has a first longitudinal axis and said slips have a second longitudinal axis that is skewed with respect to said first longitudinal axis such that extension of said slips cocks an end of said tool toward a wall of the borehole.   
     
     
         31 . The assembly of  claim 25 , wherein:
 said slips are circumferentially spaced such that each of said slips comprises opposed end tapers that slide on opposing ramps, wherein said tapers have the same angle with said opposing ramps at different angles or said tapers have the different angles with said opposing tapers having the same angle such that extension of said slips cocks an end of said tool toward a wall of the borehole.   
     
     
         32 . The assembly of  claim 31 , wherein:
 said slips having different widths on opposed sides of a retainer to insure the proper installation orientation.   
     
     
         33 . The assembly of  claim 28 , wherein:
 two said radially extendable slips are axially offset to skew said anchor housing upon radial extension of said slips.   
     
     
         34 . The assembly of  claim 27 , wherein:
 said piston includes ramp surfaces that are axially offset to engaged tapered surfaces on two said radially extendible slips to skew said anchor housing upon radial extension of said slips.   
     
     
         35 . The assembly of  claim 33 , wherein:
 said anchor housing includes ramp surfaces that are axially offset to engaged tapered surfaces on two radially extendible slips to skew said anchor housing upon radial extension of said slips.