System And Method For Preserving A Hydraulic Packer

Abstract

A technique facilitates use of a hydraulically actuated packer in a high temperature, downhole environment. The packer is actuated by directing pressurized fluid to the packer and routing the fluid to an actuation region of the packer to provide the force for setting the packer. A thermal isolation member is positioned in the packer along the pressurized fluid flow path and activates upon exposure to heat. Once the thermal isolation member is fully activated, flow is blocked along the pressurized fluid flow path which prevents return flow of pressurized fluid.

1 . A system, comprising:
 a packer expandable by application of hydraulic pressure downhole, the packer comprising:
 a mandrel having an internal flow passage and a radial port extending through a wall of the mandrel to the internal flow passage; 
 a cylinder positioned around the mandrel to create a cavity exposed to the radial port; 
 a piston system slidably mounted in the cylinder and exposed to the cavity; 
 an expandable member operatively engaged with the piston system; and 
 a thermal isolation member positioned at the radial port to automatically block flow through the radial port when the thermal isolation member is exposed to sufficient heat. 
   
     
     
         2 . The system as recited in  claim 1 , wherein the piston system comprises at least one piston having an elastomeric seal positioned to form a seal with an internal surface of the cylinder. 
     
     
         3 . The system as recited in  claim 1 , wherein the expandable member comprises a packer seal element. 
     
     
         4 . The system as recited in  claim 1 , wherein the expandable member comprises a plurality of packer slips. 
     
     
         5 . The system as recited in  claim 1 , wherein the thermal isolation member is retained in the radial port with a snap ring. 
     
     
         6 . The system as recited in  claim 1 , wherein the thermal isolation member is retained in the radial port with a ported, threaded member. 
     
     
         7 . The system as recited in  claim 1 , wherein the thermal isolation member comprises a material having a greater thermal expansion coefficient than a surrounding mandrel material. 
     
     
         8 . The system as recited in  claim 1 , wherein the thermal isolation member comprises an aluminum material. 
     
     
         9 . The system as recited in  claim 1 , wherein the thermal isolation member comprises a shape memory alloy. 
     
     
         10 . A method, comprising:
 constructing a hydraulically actuated packer with an actuation piston exposed to an actuating fluid via an inlet passage; and   positioning a thermal isolation member at the inlet passage to automatically block flow through the inlet passage by expanding when exposed to sufficient heat.   
     
     
         11 . The method as recited in  claim 10 , further comprising:
 delivering the hydraulically actuated packer downhole into a wellbore; and   actuating the hydraulically actuated packer by delivering the actuating fluid through the inlet passage.   
     
     
         12 . The method as recited in  claim 10 , wherein constructing the hydraulically actuated packer comprises constructing the hydraulically actuated packer with a packer seal element expandable via the actuation piston. 
     
     
         13 . The method as recited in  claim 10 , wherein constructing the hydraulically actuated packer comprises constructing the actuation piston with a plurality of packer slips expandable via the actuation piston. 
     
     
         14 . The method as recited in  claim 10 , wherein positioning the thermal isolation member comprises positioning the thermal isolation member in the inlet passage between an interior and an exterior of a packer mandrel. 
     
     
         15 . The method as recited in  claim 10 , wherein positioning the thermal isolation member comprises positioning a shape memory alloy thermal isolation member. 
     
     
         16 . The method as recited in  claim 10 , wherein positioning the thermal isolation member comprises positioning a metal thermal isolation member having a greater thermal expansion coefficient than the surrounding material through which the inlet passage is formed. 
     
     
         17 . A system for use in a well, comprising a well completion comprising a packer, the packer having a fluid passage for receiving a fluid under pressure to actuate the packer, the packer further comprising a thermal isolation member deployed along the fluid passage, the thermal isolation member reacting to heat in a manner that blocks return flow along the fluid passage. 
     
     
         18 . The system as recited in  claim 17 , wherein the packer comprises an actuating piston which can be moved by the fluid under pressure to set the packer at a desired location in a wellbore. 
     
     
         19 . The system as recited in  claim 18 , wherein once the thermal isolation member blocks return flow along the fluid passage, the piston is not able to move. 
     
     
         20 . The system as recited in  claim 17 , wherein the thermal isolation member expands to block the fluid passage upon exposure to sufficient heat. 
     
     
         21 . The system as recited in  claim 17 , wherein the thermal isolation member is formed from a shape memory alloy. 
     
     
         22 . A method, comprising:
 moving a hydraulic packer downhole into a wellbore;   setting the packer by directing a high pressure fluid into a packer actuation region; and   blocking return flow of fluid from the packer actuation region with a thermally activated isolation member.   
     
     
         23 . The method as recited in  claim 22 , wherein blocking return flow of fluid comprises blocking return flow with the thermally activated isolation member formed of a material that expands upon exposure to sufficient heat. 
     
     
         24 . The method as recited in  claim 22 , wherein blocking return flow of fluid comprises blocking return flow with the thermally activated isolation member formed as a plug deployed in a fluid port.