Hydraulically Actuated Tool

Abstract

Disclosed is a downhole tool and method of use. The tool has a sleeve assembly slideable within the body between a first position and a second position. A master hydraulic reservoir is defined between the sleeve assembly and the body to a first end of a control portion. A bleed conduit extends between the master hydraulic reservoir and a slave hydraulic system defined, at least in part, by the body. An electromechanical control valve across the bleed conduit is configured to regulate fluid flow along the bleed conduit. When the sleeve moves between the first and second positions, the volume of the master hydraulic reservoir and the slave hydraulic system each change; and the combined volumes of the master hydraulic reservoir and the slave hydraulic system is substantially constant. The volume change can be used to effect control over downhole tool functionality.

1 . A downhole tool, comprising:
 a body having a through bore and a control portion;   a sleeve assembly slideable within the body between a first position and a second position;   a master hydraulic reservoir defined between the sleeve assembly and the body to a first end of the control portion, and   wherein the control portion has a bleed conduit extending between the master hydraulic reservoir and a slave hydraulic system defined, at least in part, by the body; and having an electromechanical control valve across the bleed conduit configured to regulate fluid flow along the bleed conduit;   wherein, when the sleeve moves between the first and second positions, a volume of the master hydraulic reservoir and a volume of the slave hydraulic system changes; and   wherein the combined volumes of the master hydraulic reservoir and the slave hydraulic system is substantially constant.   
     
     
         2 . The downhole tool of  claim 1 , wherein the slave hydraulic system comprises at least one of an actuation chamber and wherein the, or each, actuation chamber has an actuation element. 
     
     
         3 . The downhole tool of  claim 2 , wherein the, or each, at least one actuation chamber is defined, at least in part, by the actuation element. 
     
     
         4 . The downhole tool of  claim 2 , wherein the, or each, actuation element is movable within or in relation to a cavity or an aperture defined by the body. 
     
     
         5 . The downhole tool of  claim 4 , wherein the, or each, actuation element is slideable within the cavity or the aperture. 
     
     
         6 . The downhole tool of  claim 4 , further comprising:
 a seal between the actuation element and the cavity or the aperture.   
     
     
         7 . The downhole tool of  claim 2 , wherein the actuation element is moveable radially. 
     
     
         8 . The downhole tool of  claim 2 , wherein the actuation element has a deployable tooling element; or
 wherein the actuation element is operably coupled to a deployable tooling element.   
     
     
         9 . The downhole tool of  claim 8 , wherein the deployable tooling element, or an outer portion thereof, comprises;
 a cleaning formation;   a milling formation;   a casing anchor;   a packer, comprising a resiliently deformable or an inflatable formation for sealing against a casing wall; and   a wiper plug, for engaging with a casing wall and retaining fluid flow or pressure in one direction past the tool.   
     
     
         10 . The downhole tool of  claim 8 , wherein the deployable tooling element is moveable between a retracted position and an extended position, effected by movement of the sleeve assembly between the first and second positions. 
     
     
         11 . The downhole tool of  claim 1 , wherein the slave hydraulic system has a primary slave hydraulic reservoir and has one, or more than one, actuation chamber in fluid communication with the primary slave hydraulic reservoir. 
     
     
         12 . (canceled) 
     
     
         13 . The downhole tool of  claim 11 , wherein the primary slave hydraulic reservoir fluidly communicates with the bleed conduit and wherein the, or each, actuation chamber is in fluid communication with the primary slave hydraulic reservoir via a connecting conduit or channel. 
     
     
         14 .- 16 . (canceled) 
     
     
         17 . The downhole tool of  claim 1 , wherein the tool further comprises a control system configured to open and close the electromechanical control valve. 
     
     
         18 . The downhole tool of  claim 1 , wherein the sleeve assembly is slideable between the first and second positions under the action of hydraulic pressure. 
     
     
         19 . The downhole tool of  claim 1 , wherein the sleeve assembly is resiliently biased towards one or other of the first and second positions by a resilient biasing member. 
     
     
         20 .- 21 . (canceled) 
     
     
         22 . A method of moving a sliding sleeve assembly of a downhole tool between a first position and a second position, wherein a master hydraulic reservoir is defined between the sleeve assembly and a body of the tool to a first end of a control portion of the body, and the control collar portion comprises a bleed conduit extending between the master hydraulic reservoir slave hydraulic system;
 the method, comprising the steps of:   generating a hydrostatic pressure differential between the through bore and an outside of the tool; and/or generating a dynamic pressure differential in the through bore across the tool or across a flow restriction defined by the sleeve assembly;   opening a control valve disposed in the bleed conduit;   flowing hydraulic fluid between the master hydraulic reservoir and the slave hydraulic system along the bleed conduit via the control valve; and   closing the control valve to hydraulically lock the sleeve assembly in the first or second position.   
     
     
         23 . The method of  claim 22 , further comprising the step of:
 changing the volume of the master hydraulic chamber and the slave hydraulic system,   wherein the combined volume of the master hydraulic chamber and the slave hydraulic system is substantially constant.   
     
     
         24 . (canceled) 
     
     
         25 . The method of  claim 23 , further comprising the step of:
 flowing fluid into or out of one or more actuation chambers, when the control valve is open, to thereby move an actuation element.   
     
     
         26 . The method of  claim 25 , wherein moving an actuation element comprises moving a deployable tooling element between a retracted position to an extended position. 
     
     
         27 . The method of  claim 25 , further comprising, the step of:
 increasing or decreasing the volume of the slave hydraulic system by moving an actuation element or elements.   
     
     
         28 . (canceled) 
     
     
         29 . The method of  claim 22 , further comprising the step of:
 issuing a control signal or signals to open and/or close the control valve.