Expandable downhole tool

Abstract

The present invention provides a down-hole tool ( 7 ) with at least one radially outwardly deployable tool element ( 33 ) for use in a bottom hole assembly ( 1 ) provided with a pressurised down-hole motor drive fluid supply ( 50 ). The tool ( 7 ) comprises a body ( 9 ) having at least one tool element ( 33 ) having a mounting, proximal, end portion ( 32 ) pivotally mounted ( 31 ) on said body, and a working, distal, end portion ( 34 ) displaceable between a stowed, radially inward, position and a deployed, radially outward, position. The proximal end portion ( 32 ) is provided with an engagement portion ( 29, 30 ) formed and arranged for driven engagement with a drive member ( 23 ) axially displaceable by a piston and cylinder device ( 19, 20 ). In use of the tool ( 7 ), axial displacement of the drive member ( 23 ) causes said proximal end portion ( 32 ) to rotate and displace said tool element working end portion ( 34 ) between said stowed and deployed positions thereof.

1 . A down-hole tool with at least one radially outwardly deployable tool element for use in a bottom hole assembly provided with a pressurised down-hole motor drive fluid supply, which tool comprises a body having at least one tool element having a mounting, proximal, end portion pivotally mounted on said body, and a working, distal, end portion displaceable to and operable in a position anywhere between a stowed, radially inward, position and a fully deployed, radially outward, position, said proximal end portion being provided with an engagement portion in the form of a pinion gear sector portion and formed and arranged for driven engagement with a drive member having a rack or worm gear portion and axially displaceable by a piston and cylinder device operable, in use of the tool, by means of said pressurised drive fluid supply, so as to rotate said proximal end portion about said pivotal mounting and displace said tool element working end portion between said stowed and deployed positions thereof.  
     
     
         2 . A tool as claimed in  claim 1  wherein the drive member has a worm gear portion and is provided with a guide device mounted for action between the drive member and an opposed body part so as to impart an angular rotational displacement to the drive member when it is axially displaced by said piston and cylinder device.  
     
     
         3 . A tool as claimed in  claim 2  wherein said guide device comprises a guide channel or slot and a guide pin received in said channel or slot for running therealong.  
     
     
         4 . A tool as claimed in  claim 3  wherein said guide channel or slot extends helically around a generally cylindrical part of the drive member.  
     
     
         5 . A tool as claimed in  claim 3  wherein said guide channel or slot has a ‘J’ shaped form.  
     
     
         6 . A tool as claimed in  claim 1  wherein the drive member has a rack gear portion and is formed and arranged so as to have only an axial component of motion.  
     
     
         7 . A tool as claimed in any one of  claims 1  to  6  wherein the piston and cylinder device is provided with a resilient biasing means formed and arranged for urging said drive member towards a stowage position in which said at least one tool element is stowed, said piston and cylinder device being formed and arranged for displacement of said drive member against the biasing force of said resilient biasing means when an increased fluid pressure differential is applied to said piston and cylinder device.  
     
     
         8 . A tool as claimed in any one of  claims 1  to  7  wherein said at least one tool element is articulated and provided with a guide device formed and arranged so that said working end portion of said at least one tool element is constrained to follow a substantially non-arcuate directly radially outwards path, at least at a radially outer, material cutting, portion of said path.  
     
     
         9 . A down-hole tool with at least one radially outwardly deployable tool element for use in a bottom hole assembly provided with a pressurised down-hole motor drive fluid supply, which tool comprises a body having at least one tool element having a mounting, proximal, end portion pivotally mounted on said body, and a working, distal, end portion displaceable to and operable in a position anywhere between a stowed, radially inward, position and a fully deployed, radially outward, position, said proximal end portion being provided with an engagement portion formed and arranged for driven engagement with a drive member axially displaceable by a piston and cylinder device operable, in use of the tool, by means of said pressurised drive fluid supply, so as to rotate said proximal end portion about said pivotal mounting and displace said tool element working end portion between said stowed and deployed positions thereof, with said working end portion displaceable directly radially outwardly at a position towards the deployed position of the tool element, characterised in that said at least one tool element is articulated and provided with a guide device formed and arranged so that said working end portion of said at least one tool element is constrained to follow a substantially non-arcuate directly radially outwards path, at least at a radially outer, material cutting, portion of said path.  
     
     
         10 . A tool as claimed in  claim 8  or  claim 9  wherein the tool element comprises a drive link having pivotally connected thereto a tool member, which tool member has a guide device formed and arranged for acting between said tool member and an opposed part of the body, said guide device being formed and arranged so that as said pivotally connected part of the tool member is displaced outwardly, said tool member is angularly displaced by said guide device, so that a working portion of said tool member follows a substantially directly radially outward path, at least along a radially outer, material cutting, portion thereof.  
     
     
         11 . A tool as claimed in  claim 10  wherein the guide device is in the form of a channel or slot provided in one of said opposed body part and tool member, the other one thereof having a guide pin engaged in said channel or slot.  
     
     
         12 . A tool as claimed in any one of  claims 1  to  11  wherein is provided a plurality of, angularly distributed, radially outwardly deployable tool elements.  
     
     
         13 . A tool as claimed in  claim 12  wherein is provided from 2 to 4 of said tool elements.  
     
     
         14 . A tool as claimed in any one of the preceding claims wherein said tool element is selected from a mechanical cutting tool and a jetting tool.  
     
     
         15 . A tool as claimed in  claim 14 , wherein is provided a said tool element suitable for use for pipe cutting applications where it is desired to cut off a length of pipe.  
     
     
         16 . A tool as claimed in  claim 14 , wherein is provided a said tool element suitable for use for under reaming where the cutting tool element is used to remove scale from the interior wall of a pipe.  
     
     
         17 . A tool as claimed, in any one of  claims 1  to  16  wherein the piston and cylinder device is provided with a pressurised fluid supply connection formed and arranged so that a drive fluid pressure drop across a flow restriction, which pressure drop varies with the drive fluid flow rate, is utilised to provide a driving force to actuate the piston and cylinder device.  
     
     
         18 . A tool as claimed in  claim 17  wherein one side of the piston and cylinder device is connected to the low pressure side of the drive fluid flow restriction and the other side is connected to the high pressure side of the flow restriction so that as the pressure differential therebetween is increased, the piston and cylinder exerts an increased force on the drive member tending to displace the tool element(s) from its (their) stowed position to its (their) deployed position.