Downhole anchoring apparatus

Abstract

An anchoring apparatus for engaging a borehole surface includes an anchoring member, an actuator, a fluid chamber, and an intensifier piston within a housing. The intensifier piston includes a first end having a surface area greater than a second, the second end being in communication with the fluid chamber, such that application of pressure to the first end applies a second pressure, greater than the first, to fluid in the chamber, which is in turn applied to the actuator to extend the anchoring member toward the borehole surface with intensified force. A second intensifier piston and fluid chamber can be included and used to apply intensified pressure to the actuator to retract the anchoring member. A movable mandrel within the housing can be used to physically apply a physical force to one or both intensifier pistons in place of or in addition to fluid pressure.

What is claimed is: 
     
         1 . An anchoring apparatus for engaging a borehole surface, the apparatus comprising:
 a housing;   an anchoring member within the housing, wherein the anchoring member is movable between a retracted position within the housing and an extended position in which at least a portion of the anchoring member is positioned external to the housing for engaging the borehole surface;   an actuator in communication with the anchoring member and operable to move the anchoring member between the retracted position and the extended position;   a first fluid chamber within the housing and in communication with the actuator; and   a first intensifier piston comprising a first end in communication with a fluid source and a second end in communication with the first fluid chamber, wherein the first end of the first intensifier piston comprises a surface area greater than that of the second end of the first intensifier piston,   wherein fluid from the fluid source applies a first pressure to the first intensifier piston to move the first intensifier piston in a first direction, wherein movement of the first intensifier piston in the first direction applies a second pressure to fluid in the first fluid chamber, wherein the second pressure is greater than the first pressure, and wherein the second pressure applies force to the actuator to cause the actuator to urge the anchoring member toward the extended position.   
     
     
         2 . The apparatus of  claim 1 , further comprising a mandrel extending longitudinally through the housing, wherein the mandrel is vertically movable relative to the first intensifier piston, and wherein contact between the first end of the first intensifier piston and the mandrel, a member attached to the mandrel, or combinations thereof applies a force to urge the first intensifier piston in the first direction. 
     
     
         3 . The apparatus of  claim 1 , further comprising:
 a second fluid chamber within the housing and in communication with the actuator; and   a second intensifier piston comprising a first end in communication with a pressure source and a second end in communication with the second fluid chamber, wherein the first end of the second intensifier piston comprises a surface area greater than that of the second end of the second intensifier piston,   wherein pressure from the pressure source applies a third pressure to the second intensifier piston to move the second intensifier piston in a second direction, wherein movement of the second intensifier piston in the second direction applies a fourth pressure to fluid in the second fluid chamber, wherein the fourth pressure is greater than the third pressure, and wherein the fourth pressure applies force to the actuator to cause the actuator to urge the anchoring member toward the retracted position.   
     
     
         4 . The apparatus of  claim 3 , wherein the second fluid chamber comprises a volume greater than that of the first fluid chamber. 
     
     
         5 . The apparatus of  claim 3 , wherein the second direction is opposite the first direction. 
     
     
         6 . The apparatus of  claim 3 , wherein the pressure source comprises a mandrel extending logintudinally through the housing, wherein the mandrel is vertically movable relative to the second intensifier piston, and wherein contact between the first end of the second intensifier piston and the mandrel, a member attached to the mandrel, or combinations thereof applies a force to urge the second intensifier piston in the second direction. 
     
     
         7 . The apparatus of  claim 1 , further comprising a mandrel extending longitudinally through the housing, wherein the mandrel comprises an upper end and a lower end engaged with the housing, and wherein the upper end of the mandrel, the housing, or combinations thereof is adapted for engagement with a string, a tool, or combinations thereof. 
     
     
         8 . The apparatus of  claim 7 , wherein the upper end of the mandrel comprises a diameter greater than at least one other portion of the mandrel, wherein the mandrel is vertically movable relative to the first intensifier piston, wherein the diameter of the upper end is adapted to contact the first end of the first intensifier pistons to apply a force thereto. 
     
     
         9 . The apparatus of  claim 7 , wherein the lower end of the mandrel comprises a retainer engaged therewith, wherein the retainer is removably engaged with the housing via a connector, and wherein the mandrel is vertically movable relative to the housing upon application of a force thereto sufficient to disengage the connector from the housing. 
     
     
         10 . The apparatus of  claim 9 , further comprising:
 a second fluid chamber within the housing and in communication with the actuator; and   a second intensifier piston comprising a first end proximate to the lower retainer and a second end in communication with the second fluid chamber, wherein the first end of the second intensifier piston comprises a surface area greater than that of the second end of the second intensifier piston,   wherein the retainer comprises a diameter greater than that of the mandrel, and wherein contact between the retainer and the first end of the second intensifier piston applies a third pressure to the second intensifier piston to move the second intensifier piston in a second direction, wherein movement of the second intensifier piston in the second direction applies a fourth pressure to fluid in the second fluid chamber, wherein the fourth pressure is greater than the third pressure, and wherein the fourth pressure applies force to the actuator to cause the actuator to urge the anchoring member toward the retracted position.   
     
     
         11 . The apparatus of  claim 1 , wherein the anchoring member, the actuator, or combinations thereof is positioned relative to the housing such that movement of the anchoring member toward the extended position extends the anchoring member at a non-parallel angle relative to a longitudinal axis of the housing. 
     
     
         12 . The apparatus of  claim 11 , wherein the anchoring member, the actuator, or combinations thereof is positioned relative to the housing such that movement of the anchoring member toward the extended position extends the anchoring member generally perpendicular to the longitudinal axis of the housing. 
     
     
         13 . An anchoring apparatus for engaging a borehole surface, the apparatus comprising:
 a housing;   an anchoring member within the housing, wherein the anchoring member is movable between a retracted position within the housing and an extended position in which at least a portion of the anchoring member is positioned external to the housing for engaging the borehole surface;   an actuator in communication with the anchoring member and operable to move the anchoring member between the retracted position and the extended position;   a first fluid chamber within the housing and in communication with the actuator;   a first intensifier piston comprising a first end in communication with a fluid source and a second end in communication with the first fluid chamber, wherein the first end of the first intensifier piston comprises a surface area greater than that of the second end of the first intensifier piston;   a mandrel extending longitudinally through the housing, wherein the mandrel comprises an upper end proximate to the first intensifier piston and a lower end, and wherein the mandrel is vertically movable relative to the housing;   a second fluid chamber within the housing and in communication with the actuator;   a second intensifier piston comprising a first end in communication with the lower end of the mandrel and a second end in communication with the second fluid chamber, wherein the first end of the second intensifier piston comprises a surface area greater than that of the second end of the second intensifier piston,   wherein fluid from the fluid source applies a first pressure to the first intensifier piston to move the first intensifier piston in a first direction, wherein movement of the first intensifier piston in the first direction applies a second pressure to fluid in the first fluid chamber, wherein the second pressure is greater than the first pressure, and wherein the second pressure applies force to the actuator to cause the actuator to urge the anchoring member toward the extended position,   wherein contact between the lower end of the mandrel and the second intensifier piston applies a third pressure to the second intensifier piston to move the second intensifier piston in a second direction, wherein movement of the second intensifier piston in the second direction applies a fourth pressure to fluid in the second fluid chamber, wherein the fourth pressure is greater than the third pressure, and wherein the fourth pressure applies force to the actuator to cause the actuator to urge the anchoring member toward the retracted position.   
     
     
         14 . The apparatus of  claim 13 , wherein the mandrel passes through a bore in the first intensifier piston, wherein the upper end of the mandrel, a member attached to the upper end of the mandrel, or combinations thereof comprises a diameter greater than that of the bore, and wherein contact between the first end of the first intensifier piston and the upper end of the mandrel, the member attached to the upper end of the mandrel, or combinations thereof applies a force to urge the first intensifier piston in the first direction. 
     
     
         15 . The apparatus of  claim 13 , wherein the second fluid chamber comprises a volume greater than that of the first fluid chamber. 
     
     
         16 . The apparatus of  claim 13 , wherein the lower end of the mandrel comprises a retainer engaged therewith, wherein the retainer is removably engaged with the housing via a connector, and wherein the mandrel is vertically movable relative to the housing upon application of a force thereto sufficient to disengage the connector from the housing. 
     
     
         17 . The apparatus of  claim 16 , wherein the retainer comprises a diameter greater than that of the mandrel, and wherein contact between the retainer and the first end of the second intensifier piston applies the third pressure to the second intensifier piston. 
     
     
         18 . An anchoring apparatus for engaging a borehole surface, the apparatus comprising:
 a housing;   an actuator within the housing;   a first fluid chamber within the housing and in communication with the actuator; and   a first intensifier piston comprising a first end in communication with the first fluid chamber and a second end, wherein the second end of the first intensifier piston comprises a surface area greater than that of the first end of the first intensifier piston,   wherein application of a first pressure to the second end of the first intensifier piston moves the first intensifier piston, wherein movement of the first intensifier piston applies a second pressure to fluid in the first fluid chamber, wherein the second pressure is greater than the first pressure, and wherein the second pressure is applied to the actuator.   
     
     
         19 . The anchoring apparatus of  claim 18 , further comprising:
 a second fluid chamber within the housing and in communication with the actuator; and   a second intensifier piston comprising a first end in communication with the second fluid chamber and a second end, wherein the second end of the second intensifier piston comprises a surface area greater than that of the first end of the second intensifier piston,   wherein application of a third pressure to the second end of the second intensifier piston moves the second intensifier piston, wherein movement of the second intensifier piston applies a fourth pressure to fluid in the second chamber, wherein the fourth pressure is greater than the third pressure, and wherein the fourth pressure is applied to the actuator.   
     
     
         20 . The anchoring apparatus of  claim 19 , further comprising a mandrel within the housing, wherein the mandrel is vertically movable relative to at least one of the first intensifier piston and the second intensifier piston, and wherein the mandrel is adapted to contact the first intensifier piston to apply the first pressure thereto, to contact the second intensifier piston to apply the third pressure thereto, or combinations thereof.