Downhole tool

Abstract

A hydraulic lock for locking the position of an actuation member of a downhole tool relative to the body of the downhole tool is described. The hydraulic lock comprises first and second fluid chambers fluid communication between which is provided by a first fluid conduit. Located with the first fluid conduit is a first logic controlled valve that is moveable between an open configuration and a closed configuration to selectively permit fluid communication between the first and second chambers. The hydraulic lock further comprises a secondary control mechanism that provides a second means to selectively permit fluid communication between the first and second chambers. Incorporating the secondary control mechanism within the hydraulic lock provides a means for increasing the reliability and working lifetime of the hydraulic lock. It also provides a means for reducing the risk of unintentional or false activation of the hydraulic lock.

1 . A hydraulic lock for locking the position of an actuation member of a downhole tool relative to the body of the downhole tool, the hydraulic lock comprising:
 a first fluid chamber;   a second fluid chamber;   a first fluid conduit that provides a means for fluid communication between the first and second chambers;   a first logic controlled valve located within the first fluid conduit and moveable between an open configuration and a closed configuration to selectively permit fluid communication between the first and second chambers;   wherein the hydraulic lock further comprises a secondary control mechanism that provides a second means to selectively permit fluid communication between the first and second chambers.   
     
     
         2 . A hydraulic lock as claimed in  claim 1  wherein the first logic controlled valve comprises a first valve controlled by a first valve control system. 
     
     
         3 . A hydraulic lock as claimed in  claim 2  wherein the valve comprises a solenoid valve, an electro-mechanical valve or a hydraulic valve. 
     
     
         4 . A hydraulic lock as claimed in  claim 2  wherein the first valve control system comprises a first valve controller that provides a means for opening and closing the first valve. 
     
     
         5 . A hydraulic lock as claimed in  claim 4  wherein the first valve control system further comprises one or more sensors configured to detect an activation event. 
     
     
         6 . A hydraulic lock as claimed in  claim 5  wherein the first valve control system further comprises a first logic module that communicates with the one or more sensors and the first valve controller. 
     
     
         7 . A hydraulic lock as claimed in  claim 5  wherein the first valve control system further comprises a battery pack to supply power to one or more of the one or more sensors, the first logic module and the first valve controller. 
     
     
         8 . A hydraulic lock as claimed in  claim 5  wherein the one or more sensors comprise a first pressure sensor arranged to measure a pressure within the downhole tool and a second pressure sensor arranged to measure a pressure outside of the downhole tool. 
     
     
         9 . A hydraulic lock as claimed in  claim 5  wherein the one or more sensors comprise a motion sensor arranged to detect a motion within the downhole tool. 
     
     
         10 . A hydraulic lock as claimed in  claim 1  wherein the secondary control mechanism comprises a second fluid conduit that provides a second means for fluid communication between the first and second chambers. 
     
     
         11 . A hydraulic lock as claimed in  claim 10  wherein the secondary control mechanism comprises a second logic controlled valve located within the second fluid conduit and moveable between an open configuration and a closed configuration to selectively permit fluid communication between the first and second chambers. 
     
     
         12 . A hydraulic lock as claimed in  claim 11  wherein the second logic controlled valve comprises a second valve controlled by a second valve control system. 
     
     
         13 . A hydraulic lock as claimed in  claim 12  wherein the second valve control system comprises a second valve controller that provides a means for opening and closing the second valve. 
     
     
         14 . A hydraulic lock as claimed in  claim 12  wherein the second valve control system further comprises one or more sensors configured to detect an activation event. 
     
     
         15 . A hydraulic lock as claimed in  claim 14  wherein the second valve control system further comprises a second logic module that communicates with the one or more sensors and the second valve controller. 
     
     
         16 . A hydraulic lock as claimed in  claim 14  wherein the second valve control system further comprises a battery pack to supply power to one or more of the one or more sensors, the second logic module and the second valve controller. 
     
     
         17 . A hydraulic lock as claimed in  claim 14  wherein the one or more sensors comprise a first pressure sensor arranged to measure a pressure within the downhole tool and a second pressure sensor arranged to measure a pressure in the outside of the downhole tool. 
     
     
         18 . A hydraulic lock as claimed in  claim 14  wherein the one or more sensors comprise a motion sensor arranged to detect a motion within the downhole tool. 
     
     
         19 . A hydraulic lock as claimed in  claims 14  wherein the one or more sensors of the second valve control system are of a different type to the one or more sensors of the first valve control system. 
     
     
         20 . A hydraulic lock as claimed in  claim 10  wherein the secondary control mechanism comprise one or more pressure relief devices located within the second fluid conduit. 
     
     
         21 . (canceled) 
     
     
         22 . A hydraulic lock as claimed in  claim 1  wherein the secondary control mechanism comprises a third logic controlled valve located within the first fluid conduit. 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . (canceled) 
     
     
         31 . A hydraulic lock as claimed in  claim 1  wherein the secondary control mechanism comprises a timer unit connected to the first logic controlled valve the timer unit providing a means for automatically unlocking the hydraulic lock. 
     
     
         32 . A hydraulic lock as claimed in  claim 31  wherein the timer unit automatically unlocks the hydraulic lock at predetermined periodic intervals. 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . (canceled) 
     
     
         36 . A downhole tool comprising:
 a body;   an actuation member moveable relative to the body;   an actuation arrangement configured to move the actuation member relative to the body;   and a hydraulic lock as claimed in  claim 1 ,   wherein the hydraulic lock is configured in a first configuration to permit movement of the actuation member by the actuation arrangement and configured in a second configuration to provide a fluid lock across the actuation member which prevents movement of the actuation member by the actuation arrangement.   
     
     
         37 . A method for increasing the reliability of a hydraulic lock comprising:
 a first fluid chamber; a second fluid chamber; a first fluid conduit that provides a means for fluid communication between the first and second chambers and a first logic controlled valve located within the first fluid conduit and moveable between an open configuration and a closed configuration to selectively permit fluid communication between the first and second chambers,   the method comprising providing the hydraulic lock with a secondary control mechanism that provides a second means to selectively permit fluid communication between the first and second chambers.   
     
     
         38 . A method for increasing the reliability of a hydraulic lock as claimed in  claim 37  wherein providing the hydraulic lock with a secondary control mechanism comprises providing a second means for fluid communication between the first and second chambers. 
     
     
         39 . A method for increasing the reliability of a hydraulic lock as claimed in  claims 38  wherein providing the hydraulic lock with a secondary control mechanism further comprises providing a second logic controlled valve moveable between an open configuration and a closed configuration within the second fluid conduit. 
     
     
         40 . A method for increasing the reliability of a hydraulic lock as claimed in  claim 38  wherein providing the hydraulic lock with a secondary control mechanism further comprises providing one or more pressure relief devices within the second fluid conduit. 
     
     
         41 . A method for increasing the reliability of a hydraulic lock as claimed in  claim 37  wherein providing the hydraulic lock with a secondary control mechanism further comprises providing a third logic controlled valve moveable between an open configuration and a closed configuration within the first fluid conduit. 
     
     
         42 . A method for increasing the reliability of a hydraulic lock as claimed  claim 37  wherein providing the hydraulic lock with a secondary control mechanism further comprises providing a means to automatically unlock the hydraulic lock. 
     
     
         43 . A method for increasing the reliability of a hydraulic lock as claimed in  claim 42  wherein the hydraulic lock is automatically unlocked at predetermined periodic intervals. 
     
     
         44 . (canceled) 
     
     
         45 . (canceled) 
     
     
         46 . (canceled) 
     
     
         47 . (canceled) 
     
     
         48 . (canceled) 
     
     
         49 . (canceled) 
     
     
         50 . (canceled)