Hydraulically locked tool

Abstract

A tool with a hydraulic lock mechanism may include a body defining a flow tube and a chamber. An expandable member may be coupled to the body. A first valve may be located between the chamber and the flow tube to control the flow of fluid into the chamber from the flow tube. A second valve may located between the chamber and an external environment to control the flow of fluid from the chamber into the external environment. The first and second valves may trap fluid within the chamber to maintain the tool in an active position. A piston may be connected to the expandable member and may move in response to pressurization of the chamber. At one position, the piston may cause the expandable member to extend to a radially outward position. At another position, the piston may cause the expandable member to retract to a radially inward position.

What is claimed is: 
     
         1 . A downhole tool for reaming a wellbore, comprising:
 a body having an inner surface that defines a bore, the body further having a chamber defined therein;   an expandable member movably coupled to the body;   a moveable element movably coupled to the body and configured to move to cause the expandable member to move between a retracted position and a deployed position; and   at least one valve providing fluid communication between the bore and the chamber, the at least one valve being configured to facilitate pressurizing the chamber to move the expandable member toward the deployed position and to facilitate releasing pressure in the chamber to allow the expandable member to move toward the retracted position.   
     
     
         2 . The downhole tool of  claim 1 , the at least one valve including a check valve configured to facilitate fluid flow:
 from the bore to the chamber and to restrict flow from the chamber to the bore; or   from the chamber to an external environment and to restrict flow from the external environment to the chamber.   
     
     
         3 . The downhole tool of  claim 1 , further comprising:
 a bias element configured to apply a force to the expandable member to move the expandable member toward the retracted position.   
     
     
         4 . The downhole tool of  claim 1 , the moveable element being located at least partially within the chamber and configured to apply a force to the expandable member to move the expandable member toward the deployed position. 
     
     
         5 . The downhole tool of  claim 1 , the at least one valve including a first valve configured to open to allow fluid to enter the chamber from the bore when a differential pressure across the first valve is greater than an opening pressure setpoint of the first valve. 
     
     
         6 . The downhole tool of  claim 1 , further comprising:
 a controller coupled to the at least one valve and configured to:
 open the at least one valve; 
 close the at least one valve; 
 adjust an opening pressure setpoint of the at least one valve; or adjust a closing pressure setpoint of the at least one valve. 
   
     
     
         7 . A tool comprising:
 a body having a flow tube and chamber therein;   a cutter block coupled to the body;   a first valve selectively connecting the chamber and the flow tube in fluid communication;   a second valve selectively connect the chamber and an external environment in fluid communication; and   a piston coupled to the cutter block, the piston being movable between first and second positions in response to pressurization of the chamber, the first position corresponding to a position in which the cutter block is extended in a radially outward position and a the second position corresponding to a position in which the cutter block is retracted in a radially inward position.   
     
     
         8 . The tool of  claim 7 , further comprising:
 a bias element that biases the piston toward the second position.   
     
     
         9 . The tool of  claim 7 , further comprising:
 a controller coupled to the first and second valves, the controller being configured to receive downlink signals and control the first and second valves in response to the downlink signals.   
     
     
         10 . The tool of  claim 7 , the chamber having a radially outward boundary defined at least in part by the body and a radially inward boundary defined at least in part by the flow tube. 
     
     
         11 . A method of operating a downhole tool, the method comprising:
 tripping a drill string into a wellbore, the drill string being coupled to a downhole tool;   providing a supply fluid to the downhole tool;   transitioning the downhole tool into an active state while off a bottom of the wellbore and in response to the supply fluid being at a first pressure;   reducing a pressure of the supply fluid to a second pressure that is below the first pressure; and   maintaining the downhole tool in the active state while reducing the pressure of the supply fluid to the second pressure by maintaining a quantity of fluid in the downhole tool at or above the first pressure.   
     
     
         12 . The method of  claim 11 , wherein reducing the pressure of the supply fluid to the second pressure includes providing less than 10 L/m of the supply fluid into the wellbore while maintaining the downhole tool in the active state. 
     
     
         13 . The method of  claim 11 , wherein maintaining the downhole tool in the active state includes hydraulically locking the downhole tool in the active state. 
     
     
         14 . The method of  claim 11 , wherein transitioning the downhole tool into the active state includes actuating a first valve, and wherein reducing the pressure of the supply fluid to the second pressure includes closing the first valve to maintain the quantity of fluid at or above the first pressure. 
     
     
         15 . The method of  claim 11 , further comprising:
 transitioning the downhole tool into an inactive state by at least one of:
 increasing a pressure of the quantity of fluid to a third pressure that is above the first pressure; 
 decreasing a pressure of fluid external to the downhole tool; or 
 using a controller responsive to downlink signals from a surface of the wellbore. 
   
     
     
         16 . The method of  claim 15 , the downhole tool being configured to release the quantity of fluid when at the third pressure, and wherein increasing the pressure of the quantity of fluid includes applying a mechanical force to the drill string, the mechanical force causing an expandable member to exert a force on the quantity of fluid and increase the pressure to the third pressure. 
     
     
         17 . The method of  claim 19 , wherein decreasing the pressure of fluid external to the downhole tool includes:
 increasing a pressure differential across a valve to cause the valve to open; and   releasing fluid from a chamber through the valve to an external environment to cause a piston to move such that an expandable member retracts to a radially inward position.   
     
     
         18 . The method of  claim 20 , wherein using the controller includes:
 downlinking a signal to the controller in the downhole tool to cause a valve to open or to change a pressure setpoint of the valve;   releasing fluid from a chamber through the valve; and   causing a piston to move such that an expandable member retracts to a radially inward position.   
     
     
         19 . The method of  claim 14 , wherein transitioning the downhole tool into the active state includes:
 increasing a pressure differential across a first valve; and   pressurizing a chamber with the supply fluid by flowing the supply fluid through the first valve to move a piston, the piston acting to extend an expandable member to a radially outward position.   
     
     
         20 . The method of  claim 14 , wherein transitioning the downhole tool into the active state includes:
 downlinking a signal to a controller in the downhole tool, the downlinking signal being configured to:
 cause the first valve to open; 
 change an opening pressure setpoint of the first valve; or 
 change a closing pressure setpoint of the first valve; and 
   pressurizing a chamber with the supply fluid by flowing the supply fluid through the first valve to move a piston, the piston acting to extend an expandable member to a radially outward position.