Abstract:
A setting tool ( 10 ) for use in a downhole wellbore is described as having a hydraulic fluid pumping mechanism ( 78 ) for providing pressurised hydraulic fluid. A piston mechanism ( 116 ) is moveable by said pressurised hydraulic fluid acting upon a portion of the piston mechanism ( 116 ). A resetting mechanism ( 84 ) is provided which when operated releases the pressurised hydraulic fluid from acting upon said portion of the piston ( 116 ) and which results in the resetting of the setting tool ( 10 ). In addition, a method for resetting a setting tool ( 10 ) is described including the steps of:
       (i) running the setting tool ( 10 ) downhole;   (ii) actuating the setting tool ( 10 ) and thereby deploying an apparatus ( 203 ) downhole;   (iii) retrieving the setting tool ( 10 ) to surface; and   (iv) bleeding off pressure to reset the setting tool ( 10 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a downhole apparatus for setting a tool. More particularly, but not exclusively, the present invention relates to a setting tool and a method for repeated use and maintenance of same. 
       BACKGROUND 
       [0002]    Apparatus such as plugs, packers and hangars are commonly deployed in downhole oil and gas wellbores. The apparatus is typically run downhole and a setting force is applied to expand the outer diameter of the apparatus such that the apparatus contacts the interior of the wellbore. Setting force can be applied using a setting tool that is run downhole connected to the tool to be set in the wellbore. Electronics embedded within the setting tool typically activate the setting tool to set the apparatus after a certain predetermined period of time. The time period is predetermined to account for the time taken to run the apparatus to the required downhole depth with some additional redundancy in case of unforeseen delays. Once the predetermined time period has elapsed the electronics triggers actuation of a setting mechanism to deploy the apparatus and expand the outer diameter. 
         [0003]    Following the setting of the apparatus downhole, the setting tool is released from the apparatus and retrieved to surface. At surface the tool is typically stripped down by a skilled operator. The electronics embedded within the setting tool can then be accessed and reprogrammed for use with another apparatus. Rewiring, soldering and/or replacement of failed electronic components is undertaken by a skilled technician as required. The tool is stripped down so that seals, batteries and other consumable components can be replaced before the next use of the tool. Thus, typical setting tools suffer from the disadvantage that the presence of a skilled technician is a prerequisite for strip down and reprogramming of the setting tool prior to its redeployment in the wellbore. 
       SUMMARY 
       [0004]    According to one aspect of the invention, there is provided a method for resetting a setting tool including the steps of:
       (i) running the setting tool downhole;   (ii) actuating the setting tool and thereby deploying an apparatus downhole;   (iii) retrieving the setting tool to surface; and   (iv) bleeding off pressure to reset the setting tool.       
 
         [0009]    Preferably, the method further comprises the step of:
       (v) repeating steps (i) to (iv)
 
thereby providing a method for multiple use of the setting tool.
       
 
         [0011]    According to one aspect of the invention, there is provided a method for multiple use of a setting tool including the steps of:
       (i) running the setting tool downhole;   (ii) actuating the setting tool and thereby deploying an apparatus downhole;   (iii) retrieving the setting tool to surface;   (iv) bleeding off pressure to reset the setting tool; and   (v) repeating steps (i) to (iv).       
 
         [0017]    Following step (iii), the method can further include the step of remotely accessing data from the setting tool. 
         [0018]    According to another aspect of the invention there is provided a setting tool for use in a downhole wellbore, the setting tool comprising:
       a hydraulic fluid pumping mechanism for providing pressurised hydraulic fluid;   a piston mechanism moveable by said pressurised hydraulic fluid acting upon a portion of the piston mechanism;   and a resetting mechanism which when operated releases the pressurised hydraulic fluid from acting upon said portion of the piston and which results in the resetting of the setting tool.       
 
         [0022]    Preferably, the setting tool is operable to provide mechanical movement to set a downhole apparatus such as a packer or the like when required. Preferably, movement of the piston mechanism provides the mechanical movement to set the said downhole apparatus when required. 
         [0023]    Typically, the piston mechanism is located within a cylinder arrangement and which is further typically located within a housing of the setting tool. 
         [0024]    Preferably, movement of the piston mechanism in a first direction provides the mechanical movement to set the said downhole apparatus when required. More preferably, movement of the piston mechanism in a second direction results in the resetting of the setting tool when required. 
         [0025]    Preferably, the setting tool further comprises a biasing device adapted to store energy and which more preferably stores energy when said piston mechanism moves in a first direction and which is preferably the same direction as the direction of said mechanical movement and more preferably stores said energy until the resetting mechanism is operated following which the biasing device preferably releases said energy and in so doing preferably moves said piston mechanism in a second direction to preferably return said piston mechanism to a starting position thereby resetting said setting tool. 
         [0026]    Preferably, the piston mechanism is moved in the first direction by hydraulic fluid being pumped from a first chamber in fluid contact with a first side or face of the piston mechanism to a second chamber in fluid contact with a second side or face of the piston mechanism. More preferably, the piston mechanism is moved in the second direction by hydraulic fluid being moved from the second chamber to the first chamber. 
         [0027]    Typically, the hydraulic fluid is moved to the second chamber from the first chamber by the hydraulic fluid pump which results in movement of the piston mechanism in the first direction. Preferably, upon actuation of the resetting mechanism, the biasing device releasing the said stored energy which causes the piston mechanism to move in the second direction and which causes the hydraulic fluid to move from the second chamber to the first chamber. 
         [0028]    Preferably, the resetting mechanism comprises a pressure release mechanism and which permits hydraulic fluid to flow from the second chamber back to the first chamber in order to reset the tool for a future setting operation. Typically, unless and until the resetting mechanism is actuated, pressurised hydraulic fluid is permitted to flow from the first chamber to the second chamber but is prevented from flowing back from the second chamber to the first chamber. Typically, the resetting mechanism comprises an obturation member which may preferably be a moveable plug and which may be moved by an operator between: —
       a first (setting) configuration in which hydraulic fluid is permitted to flow from the first chamber to the second chamber and is prevented from flowing from the second chamber to the first chamber; and   a second (re-set) configuration in which hydraulic fluid is permitted to flow from the second chamber back to the first chamber.       
 
         [0031]    Preferably, the moveable plug is located in an aperture formed in a housing of the setting tool and may be moved: —
       into a sealed relationship with a hydraulic fluid conduit such that no fluid may pass along the said hydraulic fluid conduit when the operator requires the first (setting configuration); and   may be moved out of a sealed relationship with the said hydraulic fluid conduit such that fluid may pass along the said hydraulic fluid conduit when the operator requires the second (re-set) configuration.       
 
         [0034]    Preferably, the moveable plug and the aperture are provided with corresponding and co-operating threads such that the plug may be moved in the aperture by means of rotating it with a suitable tool. 
         [0035]    Preferably, the setting tool comprises a locking mechanism which resists movement of the piston mechanism in at least one of the first and second directions. 
         [0036]    According to a further aspect of the present invention there is provided a locking mechanism for a downhole tool, the locking mechanism being adapted to resist movement of a piston mechanism in at least one of the first and second directions. Preferably, the downhole tool is a downhole setting tool for setting an apparatus downhole and which may be run into a downhole wellbore to set the apparatus downhole and which may then be pulled from the downhole wellbore and re-set for a subsequent operation. 
         [0037]    More preferably, the locking mechanism resists movement of the piston mechanism in the first direction until at least a pre-determined pressure is reached in the pressurised hydraulic fluid in the second chamber. More preferably, the locking mechanism permits movement of the piston mechanism in the first direction once at least a pre-determined pressure is reached in the pressurised hydraulic fluid in the second chamber. The locking mechanism thereby preferably permits testing such as diagnostic testing of the tool to occur up to the pre-determined pressure without causing the piston mechanism to move in the first direction thereby not causing the setting tool to set the downhole apparatus. 
         [0038]    Typically, the locking mechanism comprises a locking piston arrangement which is biased in a first direction into a locked configuration by a locking biasing device. Preferably, movement of the locking piston arrangement in the second direction against the biasing device overcomes the biasing action of the biasing device and results in an unlocked configuration of the locking mechanism. 
         [0039]    Preferably, the locking mechanism further comprises a locking member which is selectively engageable with the said piston mechanism and the locking piston arrangement is further adapted such that: —
       when the locking piston arrangement is in the locked configuration, it prevents the locking member from disengaging with the said piston mechanism; and   when the locking piston arrangement is in the unlocked configuration, it permits the locking member to disengage from the said piston mechanism.       
 
         [0042]    Typically, the locking member disengages from the said piston mechanism by relative movement between the two in a radial direction with respect to the longitudinal axis of the setting tool which then permits longitudinal movement of the said piston mechanism with respect to the locking member and/or other parts of the setting tool. Typically the locking member comprises one of more dog members engageable with one or recesses formed on the piston mechanism. 
         [0043]    Preferably, the setting tool comprises a visual indication unit adapted to display variable data and/or other variable information to an operator of the tool. Preferably, the visual indication unit is mounted on an outer part or outer housing of the setting tool. 
         [0044]    According to a further aspect of the present invention there is provided a visual indication unit for a downhole tool, the visual indication unit being adapted to be mounted on an outer part or outer housing of the setting tool and being adapted to display variable data and/or other variable information to an operator of the downhole tool. Preferably, the downhole tool is a downhole setting tool for setting an apparatus downhole and which may be run into a downhole wellbore to set the apparatus downhole and which may then be pulled from the downhole wellbore and re-set for a subsequent operation. 
         [0045]    Preferably, the visual indication unit is preferably outwardly facing such that an operator may view the visual indication unit without having to open the setting tool or otherwise interfere with the setting tool. Preferably, the visual indication unit comprises one or more visual displays preferably located beneath a window, the outer face of which is typically in contact with the outer environment and the inner face of which is preferably sealed from the outer environment such that the visual displays are protected from contacting downhole fluids. Preferably, the visual displays comprise one or more light displays and may be one or more LED&#39;s and may comprise a screen capable of displaying alpha-numeric characters and/or a graphical arrangement of a plurality of pixels and which may be used to display data and/or information to an operator. 
         [0046]    Preferably, the setting tool further comprises a housing and more preferably further comprises a power source for supply of electric power to operate the hydraulic fluid pump. 
         [0047]    Preferably, the setting tool further comprises electronic components connectable to the power source. 
         [0048]    Typically, there is at least one module for accommodating the power source and the electronic components. 
         [0049]    Preferably, the at least one module is connectable with the housing in a first configuration for downhole use and removable from the housing in a second configuration in which the at least one module and the housing are separable. 
         [0050]    According to another aspect of the invention there is provided apparatus for use in a wellbore, the apparatus comprising:
       a housing;   a power source for supply of electric power;   electronic components connectable to the power source;   at least one module for accommodating the power source and the electronic components;   wherein the at least one module is connectable with the housing in a first configuration for downhole use and removable from the housing in a second configuration in which the at least one module and the housing are separable.       
 
         [0056]    According to another aspect of the invention there is provided downhole apparatus, the apparatus comprising:
       a body;   a power source for the supply of electric power;   a module for accommodating the power source; and   an end cap releasably connectable to the module;   wherein the apparatus is movable between   a first configuration for use downhole wherein the module is at least partially housed within the body and secured thereto by the end cap; and   a second configuration in which the end cap and the module are collectively removable from the body.       
 
         [0064]    The body may be releasably connectable with the end cap such that in a connected configuration axial movement of the end cap causes corresponding axial movement of the module and rotational and radial force applied to at least one of the module or the end cap causes release of the end cap and the module. 
         [0065]    According to another aspect of the present invention, there is provided a down-hole tool, said down-hole tool comprising:
       an attachment module for attaching said tool to means for moving the tool within a bore-hole, and   a linear chain of functional modules connected to said attachment module, said linear chain being formed of a plurality of discrete functional modules that are connected together,   the arrangement being such that individual discrete modules of the chain can be removed from the chain for replacement without disassembling the entire chain.       
 
         [0069]    Typically, each said functional module is capable of one or more of fluid, mechanical and electrical interaction with one or more adjacent functional modules in said chain. 
         [0070]    Typically, said chain comprises an operations module that includes a source of electrical power and a controller provided within an outer housing, said operations module including an electrical interface at one end of said operations module for electrically coupling said operations module to a neighbouring functional module of said chain. 
         [0071]    Optionally, said electrical power source and said controller are sealed within said outer housing. 
         [0072]    The said controller is typically configured to control the operation of said tool and is further typically configured to interface with one or more sensors of said tool, and optionally to record data generated by said sensors. 
         [0073]    Preferably, said source of power comprises one or more batteries, for example a plurality of discrete lithium-ion battery packs. 
         [0074]    The said operations module further preferably comprises means for facilitating the proper alignment of said operations module electrical interface with an electrical interface of another module in said chain and said facilitating means preferably comprises a body that projects radially outwardly from a terminal connector portion of said operations module housing. 
         [0075]    Typically, said terminal connector portion of said operations module housing is of a smaller diameter than the remainder of said operations module housing. 
         [0076]    Preferably, said body is configured to locate within a complementary formation provided in a neighbouring module of said chain to thereby align said operations module electrical interface with the electrical interface of said neighbouring module. Typically, said body radially inwardly deforms before locating in the complementary formation provided in said neighbouring module. 
         [0077]    Preferably, the electrical connector of said operations module can be used for interrogating and/or programming said controller. 
         [0078]    Typically, the other end of said operations module is configured for attachment to said attachment module. 
         [0079]    Preferably, said other end of said operations module and one end of said attachment module are each provided with a part of a two-part coupling mechanism, a first part of said mechanism being complementary to a second part of said mechanism. More preferably, said two-part coupling mechanism is configured so that relative rotation of said respective parts of said mechanism will not decouple one said part from the other. 
         [0080]    Typically, said two-part coupling mechanism is configured so that one said part can only be decoupled from the other said part by sliding said attachment module relative to said operations module. 
         [0081]    Typically, a first part of said mechanism comprises: —
       a generally horseshoe-shaped body comprised of a horseshoe-shaped peripheral wall that has a radially inwardly extending flange, said flange and said peripheral wall cooperating to define a recess within said horseshoe-shaped body, and   a second part of said mechanism comprises a projecting generally tongue-shaped body having a radially outwardly flanged outer portion that is configured to side into said recess and a second portion configured to fit within the radially inwardly extending flange of said first part.       
 
         [0084]    Preferably, said two-part coupling mechanism includes a two-part locating mechanism, the respective parts of said locating mechanism being configured to engage when said first part of said coupling mechanism is coupled with said second part of said coupling mechanism, said first and second parts of said locating mechanism acting to resist inadvertent decoupling of said two-part coupling mechanism and said first and second parts of said locating mechanism further preferably acting to aid selective axial and rotational alignment of said two-part coupling mechanism when alignment is required but permit axial alignment but permit relative rotation to occur between said first and second parts of said locating mechanism to occur when a particular stage in the coupling process is reached. 
         [0085]    Typically, said first part of said locating mechanism comprises a projection and said second part of said locating mechanism comprises a socket into which said projection fits when the respective parts of said coupling mechanism are coupled together. 
         [0086]    Typically, the first part of said locating mechanism comprises a domed projection and said second part of said locating mechanism comprises a dished recess. Preferably, one of the first and second parts of said locating mechanism are biased by a biasing device in a direction and more preferably, said direction is in a direction toward the other of said first and second parts when connected. Preferably, the biasing device prevents unwanted rotation occurring between the first and second parts but permits wanted rotation to occur between the first and second parts, wanted rotation typically being rotation above a level of torque required to overcome the biasing device. Accordingly, the locating mechanism provides the advantage that an operator can insert one part of the tool into another part of the tool and the locating mechanism keeps the first and second parts thereof in rotational alignment until a certain stage in the insertion of the said one part of the tool has been reached at which point, an operator may rotate the said one part of said locating mechanism relative to the said second part of the locating mechanism with more torque than the said level of torque and thereby overcome the biasing device. 
         [0087]    The said attachment module and one or more functional modules of said chain may be provided with an externally visible indicator, said attachment module and said one or more functional modules of said chain being at least roughly aligned for connection when one said indicator is aligned with the other. 
         [0088]    Preferably, the tool further comprises a communications module configured for external communication with control and/or sensing components of the tool. 
         [0089]    Preferably, said communications module is configured to interface with the controller of said operations module when the modules of the chain are assembled together. 
         [0090]    Typically, said communications module includes a wireless transceiver and circuitry for establishing a wireless interface for the wireless transmission and reception of signals. 
         [0091]    Typically, said communications module includes an indicator for informing a user when said communications module is capable of wireless communications. 
         [0092]    Preferably, said communications module is responsive to a signal from an external transmitter to enable said wireless interface. 
         [0093]    Typically, said communications module includes an indicator for informing a user of a fault with a said functional module of said chain. 
         [0094]    Typically, said communications module comprises means responsive to an external stimulus to turn on the controller of said operations module when the functional modules of said chain are connected together. 
         [0095]    Typically, said communications module comprises a reed switch that is responsive to an external magnetic stimulus to turn on the controller of said operations module when the functional modules of said chain are connected together. 
         [0096]    Preferably. a functional module at an end of the chain distal from said attachment module comprises a module for deploying apparatus into said bore hole. 
         [0097]    The apparatus to be deployed may comprise a packer or a plug or another downhole tool that requires to be set into the well, typically by being mechanically actuated. 
         [0098]    Preferably, one end of said deployment module is configured for coupling to the apparatus to be deployed and the other end of the deployment module is configured for coupling to another functional module of the chain. 
         [0099]    Typically, said deployment module comprises a mechanical connector configured to be capable of being coupled to apparatus to be deployed. 
         [0100]    Typically, said mechanical connector is provided towards a distal end of a deployment piston that is axially moveable into to a peripheral annular shroud to decouple said mechanical connector from said apparatus to be deployed. 
         [0101]    Typically, said annular shroud is configured to bear on said apparatus to be deployed as said deployment piston is axially withdrawn into the shroud. 
         [0102]    Preferably, a proximal end of said deployment piston is moveable into a cylinder provided within a hydraulic fluid directing part of said deployment module. 
         [0103]    Typically, said cylinder includes a compressible fluid, such as a gas, so that said deployment piston compresses said fluid as the proximal end of said deployment piston moves into the cylinder. 
         [0104]    Typically, said deployment piston is coupled to an actuator piston, fluid pressure acting on said actuator piston causing said deployment piston to move relative to said shroud. 
         [0105]    Typically, said deployment module includes a fluid supply part in fluid communication with said fluid directing part, and a pump for pumping fluid from a reservoir in said first fluid supply part through a supply passageway in said fluid directing part to the actuator piston and thereby drive the actuator piston away from the shroud and the deployment piston into the cylinder in said fluid directing part of said deployment module. 
         [0106]    Typically, said fluid directing part includes a return passageway so that fluid between the actuator piston and said fluid directing part can return to said fluid reservoir for pumping through said supply passageway as said actuator piston moves to drive the deployment piston into the cylinder. 
         [0107]    Preferably, the tool further comprises a reset mechanism operable after deployment of the apparatus to be deployed to couple said fluid supply passageway to said return passageway, the arrangement being such that compressed fluid in said cylinder expands to drive said deployment piston and said actuator piston away from said fluid directing part and towards said shroud, and thereby drive fluid between the actuator piston and the shroud back through the supply passageway to thereby replenish the fluid reservoir in the fluid supply part. 
         [0108]    According to a further aspect of the present invention, there is provided a down-hole tool comprising: an attachment module having a distal end that is coupled to an operations module having the features of any of another aspect of the present invention, a distal end of said operations module being coupled to a communications module according to another aspect of the present invention, and a distal end of said communications module being coupled to a deployment module according to another aspect of the present invention. 
         [0109]    According to a further aspect of the present invention, there is provided an operations module for use in the tool according to another aspect of the present invention. 
         [0110]    According to a further aspect of the present invention, there is provided an communications module for use in the tool according to another aspect of the present invention. 
         [0111]    According to a further aspect of the present invention, there is provided a deployment module for use in the tool according to another aspect of the present invention. 
         [0112]    According to a further aspect of the present invention, there is provided an attachment module for a down-hole tool and an operations module for a down-hole tool, wherein:
       the attachment module has a proximal end that is configured for attachment to means for moving a down-hole tool within a bore-hole, and a distal end that includes a first part of a two-part coupling mechanism, said first part comprising a generally horseshoe-shaped body comprised of a horseshoe-shaped peripheral wall that has a radially inwardly extending flange, said flange and said peripheral wall cooperating to define a recess within said horseshoe-shaped body, and   the operations module comprises a source of electrical power and a controller provided within an outer housing, a proximal end of said housing including a second part of said two-part coupling mechanism, said second part comprising a projecting generally tongue-shaped body having a radially outwardly flanged outer first portion that is configured to slide into said recess and a second portion configured to fit within the radially inwardly extending flange of said first part, a distal end of said housing including an electrical interface for electrically coupling said operations module to a functional module of a down-hole tool.       
 
         [0115]    All aspects of the present invention, and preferred, optional or typical features disclosed herein can be combined with one another and with any other feature in any, or multiple combinations where appropriate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0116]    Embodiments of the invention will now be described with reference to the accompanying drawings in which: 
           [0117]      FIG. 1  is a perspective view of a downhole setting tool according to a first aspect of the invention; 
           [0118]      FIG. 2  is a sectional view of the setting tool of  FIG. 1 ; 
           [0119]      FIGS. 3 to 6  are detailed sectional views of portions of the tool shown in  FIG. 2 ; 
           [0120]      FIG. 7  is a perspective view of a top sub of the tool of  FIG. 1 ; 
           [0121]      FIG. 8  is a partial perspective view of an upper end of an electronics power unit of the tool of  FIG. 1 ; 
           [0122]      FIG. 9  is a partial perspective view of a lower end of the electronics power unit of  FIG. 8 ; 
           [0123]      FIG. 10  is a perspective view of a connector of the tool of  FIG. 1 ; 
           [0124]      FIG. 11  is a sectional view of an electromechanical subassembly of the tool of  FIG. 1 ; 
           [0125]      FIG. 12  is a detailed sectional view of part of a window portion of the tool of  FIG. 1 ; 
           [0126]      FIG. 13  is a top view of a viewing window of the tool of  FIG. 1 ; 
           [0127]      FIG. 14  is a partial perspective view showing the viewing window of  FIG. 13 ; 
           [0128]      FIG. 15  is a detailed sectional view of a mechanical interlock of the tool of  FIG. 1 ; 
           [0129]      FIG. 16  is a sectional view of part of the tool of  FIG. 1  in a run-in configuration; 
           [0130]      FIG. 17  is a sectional view of part of the tool of  FIG. 16  in a partially set configuration; 
           [0131]      FIG. 18  is a sectional view of part of the tool of  FIG. 16  in a set configuration; 
           [0132]      FIG. 19  is a perspective view of an electronics power unit subassembly of the tool of  FIG. 1 ; 
           [0133]      FIG. 20  is a sectional view of the electronics power unit subassembly of  FIG. 19 ; 
           [0134]      FIG. 21  is a perspective view of an anti-rotation ring of the tool of  FIG. 1 ; 
           [0135]      FIG. 22  is a perspective view of a pressure release plug of the tool of  FIG. 1 ; 
           [0136]      FIG. 23  is a schematic view of a lower part of the tool of  FIG. 1  engaged with a plug to be set; 
           [0137]      FIG. 24  is a flow diagram of a method of initiating the setting tool of  FIG. 1 ; and 
           [0138]      FIG. 25  is a schematic view of a magnetic initiation key and a tablet communicating with the setting tool of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0139]    A setting tool according to one embodiment of the invention is shown generally at  10  in  FIG. 1 . The setting tool  10  has an upper end  11 , which remains closest to the surface when the tool  10  is deployed downhole in use and a lower end  19  which is located proximate the apparatus to be set when the tool is in use downhole. Accordingly the terms ‘upper’ and ‘lower’ as used herein are intended to refer to parts of a component or subcomponent that are located uphole or downhole, respectively relative to another part of that same component or subcomponent. These terms are used in a relative sense only and are not to be construed as limiting the disclosure in any way. 
         [0140]    The exterior of the tool  10  shown in  FIG. 1  comprises several parts: a top sub  20 ; an anti-rotation ring  121 , an upper housing  12 , a window portion  60  with upper and lower anti-rotation rings  52 ,  53  respectively, a middle housing  13 , an anti-rotation ring  172 , a spring piston housing  14 , an anti-rotation ring  188 , a lower housing  15 , an anti-rotation ring  199  and a connector sub  16 . As shown in  FIG. 2 , an end connector  193  extends on a stroke piston  92  from the interior of the tool  10  at its lower end  19 . 
         [0141]    A detailed view of the top sub  20  is shown in  FIGS. 3 and 7 . The top sub  20  is a solid steel component having an upper end  23  with a reduced diameter and external threads for industry standard threaded connection to slickline (not shown). An alignment notch  125  is provided on an external surface of the top sub  20  for alignment with a viewing window  61  located in the window portion  60  of the tool  10  in use. An annular downwardly facing shoulder  120  defines a step along which three radially equispaced anti-rotation slots  128  are located. A middle portion  29  of the top sub  20  has external threads machined on an outer surface to create a threaded pin connector  28 . Towards a lower end  24 , the top sub  20  is provided with two parallel annular grooves  21 , each of which houses an o-ring seal  22  ( FIG. 3 ). The lower end  24  of the top sub  20  has a horseshoe connector  25  comprising a c-shaped radially inward projection or lip  26  defining a c-shaped groove  27  therebeneath. A lower end face  127  of the top sub has a detent hole  124  centrally positioned between the ends of the c-shaped lip  26 . 
         [0142]    The anti-rotation ring  121  is located between the top sub  20  and the upper housing  12  ( FIG. 3 ). As shown in  FIG. 21 , the anti-rotation ring is a flat annular ring having twelve radially equispaced tabs  122  defined by a series of radial slots  128  cut into the ring  121 . During assembly and before use of the tool  10 , the anti-rotation ring  121  is slipped over the lower end of the top sub  20  and positioned adjacent the downwardly facing annular shoulder  120 . Once the upper housing  12  is secured in position adjacent the antirotation ring  121 , the tabs  122  are deformed into the three slots  128  of the top sub  20 . 
         [0143]    Four tabs  122  of the anti-rotation ring  121  are deformed in the opposing direction for accommodation in similar anti-rotation slots (not shown) in the upper housing  12 . Thus, the anti-rotation ring  121  resists relative rotational movement of the top sub  20  and the upper housing  12  in use. 
         [0144]    The upper housing  12  is a hollow cylindrical steel tubular with an upper box threaded connector  17  and a lower box threaded connector  18 . A bore of the upper housing  12  is dimensioned to accommodate an electronics power unit  31 . 
         [0145]    The electronics power unit (EPU)  31  (shown in  FIGS. 19 and 20 ) is a removable and replaceable subassembly. In use, the EPU  31  functions to power and control actuation of the tool  10 . Outer components of the EPU  31  include an upper end cap  37 , a cylindrical hollow anodised aluminium tubular housing  131  and a lower end cap  34 , which are interconnected to form a closed cylindrical casing that houses batteries  30  and an electronics pack  32 . 
         [0146]    A detailed view of the upper end cap  37  in shown in  FIG. 8 . The upper end cap  37  has an end connector  137  comprising an annular projection  39  defining an annular slot  38  therebeneath. The annular projection  39  of the end connector  137  is sized to interlock with the c-shaped groove  27  of the top sub  20  horseshoe connector  25 . The end connector  137  is provided with a detent mechanism  138  embedded therein. The detent mechanism (not shown) includes a ball that is spring biased to form a partially spherical protrusion extending from an end face of the end connector  137  and, in use, the said ball (not shown) will be biased into the detent hole  124  of the top sub  20  to ensure correct rotational alignment therebetween. An annular groove  134  (shown in  FIG. 20 ) provided on a lower external surface of the end cap  37  accepts a plurality of balls  135  to axially lock the end cap  37  to the EPU  31  housing  131 . 
         [0147]    The batteries  30  comprise a series of interconnected primary lithium cells  130  or other suitable batteries. Lower wires  132  ( FIG. 20 ) connect the lower terminals of the cells  130  with the electronics pack  32 . Similarly upper wires  133  extend from an upper end of the batteries  30  and run parallel with and along the length of the batteries within the housing  131  to connect the upper terminals of the cells  130  with the electronics pack  32 . The batteries  30  can be provided with temperature sensitive labels (not shown) to indicate maximum temperatures reached during downhole use. 
         [0148]    The electronics pack  32  is located within a metal bulkhead  136 . The bulkhead  136  is a cylindrical housing with a closed end  237  and an open end  238  into which the electronics pack  32  is inserted. The bulkhead  136  serves to protect the electronics pack  32  against shock loads that the tool  10  may experience downhole in use. An external surface of the bulkhead  136  has two parallel axial slots (not shown) for accommodating the upper and lower wires  133 ,  132  that connect the batteries  30  and the electronics pack  32 . The external surface of the bulkhead  136  also has an annular recessed portion  232 . The recessed portion  232  allows fixing means such as tape to secure the upper and lower wires  133 ,  132  in their respective axial slots. The bulkhead  136  is bolted to the end cap  34  by means of a bolt  236 . 
         [0149]    The electronics pack  32  includes a series of stacked interconnected printed circuit boards (PCBs)  139 . A pocket (not shown) is milled within the bulkhead  136  adjacent one of the PCBs  139  to accommodate a temperature sensor (not shown). The temperature sensor is wired into one of the PCBs  139  within the electronics pack  32 . In addition, components such as accelerometers, vibration sensors, motion sensors (none shown) and other electronic equipment for logging downhole parameters are electronically coupled to the PCBs  139 . A timer (not shown) is provided on one the PCBs  139 . The PCBs  139  contain electronic circuitry programmed to log, process and respond to certain data obtained by the electronics pack  32  components and equipment measuring downhole conditions. The end cap  34  secures the electronics pack  32  within the bulkhead  136  by means of the bolt  236 . 
         [0150]    The end cap  34  is a generally cylindrical metal solid cap. An upper external surface of the end cap  34  has an annular groove  234  into which a plurality of balls  235  are inserted to axially lock the end cap  34  to the EPU  31  housing  131 . A lower external surface of the end cap  34  is provided with an axially and radially extending key  33  which projects into and is held rotationally by an axially extending slot  33 S formed in the inner surface of the upper housing  12  to ensure correct alignment of the EPU  31  within the upper housing  12  of the tool  10  ( FIG. 4 ). A lower end face  239  of the end cap  34  has a fifteen pin socket  35  that provides a connection means to the PCBs  139  via wires extending from a lower end of the electronics pack  32 . The lower end face  239  ( FIG. 9 ) is also provided with an orientation washer  36  adjacent the socket  35 . The orientation washer is adapted to receive a mating pin connection  41  ( FIG. 10 ) that ensure correct alignment of the socket  35  and cooperating pins  42 . 
         [0151]    An electromechanical (EM) subassembly  50  is shown in  FIG. 11 . The EM subassembly  50  is located within a portion of the upper housing  12  and the middle housing  13  of the tool  10 . An upper end of the EM subassembly  50  mates with the lower end cap  34  of the electronics power unit  31  ( FIG. 4 ). A lower end of the EM subassembly  50  is connectable with the spring piston housing  14  ( FIG. 5 ). 
         [0152]    The electromechanical subassembly  50  includes a bulkhead  51  at its upper end. The bulkhead  51  has a hollow cylindrical female end  45  arranged to accept the end cap  34  of the EPU  31 . The female end  45  is provided with an axially extending keyway  44  on an inner surface. The keyway  44  is aligned with a central diameter of the viewing window  61  and accepts the key  33  on the EPU  31  end cap  34  to rotationally align the EPU  31  with the electromechanical subassembly  50 . An exterior of the bulkhead  51  is provided with two parallel annular grooves  146  that house o-ring seals  147  ( FIG. 4 ). 
         [0153]    The EM subassembly  50  bulkhead  51  accommodates an electric connector  40  and a wire housing  48  (shown in  FIG. 11 ). A detailed view of the connector is shown in  FIG. 10 . 
         [0154]    The connector  40  has fifteen upper electrical pins  42  and fifteen lower electrical pins  43  although it should be noted that the connector  42  could be modified to have a different number of pins  42 ,  43  as required. 
         [0155]    An upper end of the connector  40  is also provided with the alignment pin  41  for engagement with the orientation washer  36  in the end cap  34 . An external lower surface of the connector  40  has an alignment slot  141  to ensure correct alignment with the wire housing  48 . The wire housing  48  provides a protective casing around wires extending between the lower pins  43  of the connector  40  and the other electronic components within the EM subassembly  50 . A middle region of the bulkhead  51  has a reduced diameter portion  158 . The reduced diameter portion  158  has a slot  143  cutaway allowing access in one radial position to the wire housing  48 . The wire housing  48  also has a slot  144  cutaway in the same region to allow wires (not shown) extending from the lower pins  43  to be connected with wires extending from a pressure transducer  75  and other electronic components within the EM subassembly  50 . The bulkhead  51  is bolted by means of bolts  49  to the window portion  60  of the tool  10 . The window portion  60  of the tool  10  accommodates visible indictors and supporting electronics regarding the state of the tool  10 . The window portion  60  is a substantially cylindrical steel component having a hollow bore  54  that houses electrical and mechanical components. 
         [0156]    The window portion  60  has an upper annular groove  59  for housing an o-ring seal  56  ( FIG. 4 ). The window portion  60  has upper and lower threaded pin connectors  57 ,  58  respectively. The upper pin connector  57  is arranged to engage the lower threaded box connector  18  of the housing  12 . A central area  68  of the window portion  60  has an increased outer diameter, such that the outer diameter of the central area  68  window portion  60  in this region is equal to the outer diameter of the tool  10  housing portions  12 ,  13 ,  15 . Thus, the central area  68  of the window portion  60  forms an outer surface of the tool  10 . Upper and lower anti-rotation rings  52 ,  53  (identical to the anti-rotation ring of  FIG. 21 ) are positioned immediately adjacent the central area  68  increased diameter portion. 
         [0157]    An axially extending wire housing  67  within the window portion  60  provides a continuation of the protective casing provided by the wire housing  48 . Wires (not shown) extend within the wire housing  67  to electrically connect wires extending from the lower pins  43  to other electronic components within the tool  10 . A hollow cylindrical wire housing  167  extends in a radial direction perpendicular from the wire housing  67 . The wire housing  167  is provided for carrying wires (not shown) from the wire housing  67  to a visible printed circuit board (PCB)  64  ( FIG. 11 ). 
         [0158]    A cylindrical hollow  166  ( FIG. 11 ) extending radially from the hollow bore  54  is machined in the window portion  60 . The cylindrical hollow  166  houses a viewing assembly module  168  ( FIG. 12 ). The viewing assembly module  168  includes the printed circuit board  64  mounted on a metal base stand  165  ( FIG. 12 ). The area surrounding the stand  165  and PCB  64  is encased in resin  163 . The PCB  64  carries a suitable visual indication means such as a red light emitting diode (LED)  62  and a blue LED  63  mounted thereon. The PCB  64  also carries a suitable wireless data transceiver means such as a Bluetooth™. transmitter (not shown) and a magnetic sensor  164  as shown in  FIGS. 13 and 14 . A sapphire glass viewing window  61  is located above the resin  163  encased PCB  64 . A circular groove  160  is cut in the window portion  60  surrounding the cylindrical hollow  166 . An o-ring seal  161  is located in the groove  160  to fluidly isolate the PCB  64  and internal electronics. The glass viewing window  61  is retained in place by an annular rim  162  held in position by a brass circlip (not shown). The PCB  64  and LEDs  62 ,  63  are visible to an operator through the viewing window  61  to provide a visual indication of the state of the tool  10 . 
         [0159]    A lower end portion  152  of the EM subassembly  50  has an increased bore  54  diameter that houses a motor  76 , a gearbox  77 , a pump  78  and the pressure transducer  75 . The motor  76 , gearbox  77  and pump  78  are all electrically actuated components that provide the necessary drive and output to cause setting and actuation of the apparatus attached to the lower end  19  of the setting tool  10 . The motor  76  is any suitable motor such as a brushless sensorless direct current motor. The gearbox  77  is any suitable gearbox compatible with the motor  76 . The pump  78  is any suitable standard downhole pump having an inlet  80  and an outlet  81  having a non return valve (not shown). A protective housing  69  ( FIG. 4 ) is provided within a sidewall of the lower end portion  152 . The protective housing  69  extends axially to carry wires (not shown) between the wire housing  67  and the pump  78 , gearbox  77  and pressure transducer  75 . 
         [0160]    An upper threaded box connector  79  of the middle housing  13  enables connection of the window portion  60  and the middle housing  13  via the lower threaded pin connector  58  of the window portion  60 . An annular balance piston  70  ( FIG. 5 ) is slidably coupled to the exterior of the lower end portion  152 . The balance piston  70  has an external annular groove  170  for housing an annular seal  171  ( FIG. 4 ) to provide a sliding seal between the piston  70  and an interior of the middle housing  13 . Optionally, a spring (not shown) can be provided between an end shoulder  169  ( FIG. 11 ) of the window portion  60  and an upper face  173 U of the balance piston  70  to bias the piston  70  downwardly, away from the end shoulder  169  and toward the pump  78  such that the piston  70  compresses hydraulic fluid located in a second chamber  73  to provide some positive hydraulic pressure to prime the pump  78  via the inlet  80 . 
         [0161]    The middle housing  13  has two radially spaced ports  71  extending through the sidewall of the housing  13  proximate the end shoulder  169  of the window portion  60 . The ports  71  allow fluid communication between the ambient external environment and the upper face  173 U of the piston  70  exposing the upper face  173 U of the piston  70  to well fluids in use. Ambient fluid is admitted via the ports  71  into a first annular chamber  72  defined by an interior of the middle housing  13 , the upper face  173 U of the piston  70  and the end shoulder  169  of the window portion  60 . On the lower side of the balance piston  70  a second annular chamber  73  contains clean hydraulic fluid. The second chamber  73  is defined by an interior of the middle housing  13 , a lower end face  173 L of the piston  70  and the interior of a portion of the spring piston housing  14 . Both the first and second annular chambers  72 ,  73  are of variable axial length according to the ambient conditions and the state of the setting tool  10 , although the tool  10  is designed such that minimal axial travel of the balance piston  70  should be required. 
         [0162]    A threaded box end connector  149  at a lower end of the middle housing  13  engages a threaded pin connector  154  on the spring piston housing  14  to secure the middle housing  13  to the piston housing  14 . An anti-rotation ring  172  is located therebetween and is identical to the anti-rotation ring of  FIG. 21 . 
         [0163]    The spring piston housing  14  ( FIG. 5 ) is a cylindrical block of metal having axial and radial chambers machined therein to accommodate the gas spring  90  and for the communication of hydraulic fluid. The spring piston housing  14  has an upper pin threaded connector  154  for threaded connection with the box threaded connector  149  of the middle housing  13 . 
         [0164]    The spring piston housing  14  is sealed against the interior of the middle housing by means of an o-ring  157  housed within an annular groove  156 . An anti-rotation ring  172  is provided between the middle housing  13  and the spring piston housing  14 . 
         [0165]    A bore  74  for carrying hydraulic fluid extends axially through a sidewall of the piston spring housing  14  fluidly connecting the second chamber  73  with a third annular chamber  194  ( FIG. 6 ). The third annular chamber  194  is defined by an inner surface of the lower housing  15 , an external surface of the stroke piston  92 , part of the spring piston housing  14  and an upper end face  183  of an actuator piston  99 . Thus the second fluid chamber  73  is in fluid communication with the third fluid chamber  194 . Both the second and third fluid chambers  73 ,  194  contain clean hydraulic fluid. 
         [0166]    The pump outlet  81  ( FIG. 5 ) is connected to an axially extending bore  82  for carrying hydraulic fluid. The bore  82  extends centrally within the spring piston housing  14 . Towards the end of the bore  82 , a radially extending bore  83  carrying hydraulic fluid is fluidly connected and extends perpendicular therefrom. One end of the bore  83  has an increased diameter  151 , which intersects the longitudinal bore  74 . A portion of the bore  83  having increased diameter  151  is provided with threads  159  that mate with threads  186  on a plug  84 . Thus the plug  84  obturates one end of the hydraulic line  83 . The increased diameter portion  151  of the bore  83  opens into a port  182  that provides communication between the bore  83  and the exterior of the tool  10  to allow hydraulic fluid to be inserted into bore  83  and the rest of the hydraulic system and, when the hydraulic system has been filled, a plug  84  is inserted into port  182 . Towards the port  182  in an end region of the increased diameter portion  151 , an annular groove  55  is provided to house an o-ring seal  65 . This seal  65  isolates the port  182  from the intersecting bore  74  when the plug  84  is threaded in place within the bore  83 . 
         [0167]    The plug  84  has a hexagonal end socket  184  such that the plug  84  can be rotated within the threaded  159  bore  83  using a conventional allen key (not shown). The plug  84  is shown in greater detail in  FIG. 22 . The plug  84  has a frustoconical end  185  having a variable outer diameter a middle part of which engages the end of the increased diameter portion  151  to thereby plug the bore  83 . A longitudinal bypass slot  187  extends from the frustoconical end  185  across the threads  186  of the plug  84 . The bypass slot  187  provides a route for fluid communication around the threads  186  of the plug  84  once the frustoconical end  185  is displaced from the bore  83 . However, the plug  84  is shaped such that it permits hydraulic fluid to flow along bore  74  past the plug  84  at all times. 
         [0168]    An opposite end of the radially extending bore  83  from the increased diameter portion  151 , is fluidly connected to a perpendicular and longitudinally extending bore  174  ( FIG. 5 ) that extends axially to an end of the piston spring housing  14 . The end of the bore  174  is stopped and sealed by a plug  66 . A radially extending bore  89  is fluidly connected perpendicular to the bore  174  towards its plugged end. 
         [0169]    A central bore  129  ( FIG. 5 ) within the spring piston housing  14  accommodates the gas spring  90 . The stroke piston  92  is inserted and sealed within the central bore  129  by means of an annular seal  94  located within an annular groove  93  provided towards an upper end of the stroke piston  92 . An upper face  92 U of the gas spring piston  92  and the central bore  129  define a gas spring chamber  91 . 
         [0170]    The stroke piston  92  is mainly located within the lower housing  15  ( FIG. 6 ). The lower housing  15  is a substantially cylindrical hollow tubular. At an upper end, the lower housing  15  has an upper threaded box connector  112  ( FIG. 5 ) for engagement with a lower threaded pin connector  155  of the piston housing  14 . A lower end of the piston housing  14  is sealed around the stroke piston  92  by means of an o-ring seal  88  ( FIG. 6 ) located within an annular groove  85 . The lower end of the piston housing  14  is sealed against an internal surface of the lower housing  15  by means of an o-ring seal  87  located in an annular groove  86  ( FIG. 6 ). 
         [0171]    The stroke piston  92  has an internal bore  96  for carrying hydraulic fluid. The bore  96  is sealed and stopped at an upper end with a plug  115 . The stroke piston  92  has a radially extending bore  95  perpendicular and fluidly connected to the central bore  96 . An end of the radial bore  95  is exposed to hydraulic fluid between the piston seal  94  and the inner seal  88  when the stroke piston  92  is in the position shown in  FIG. 6  such that the bore  95  is in fluid communication with the radial bore  89 , which also has an outlet between o-ring seals  94 ,  88 . At an opposing end, the bore  96  within the stroke piston  92  is in fluid communication with a radially extending bore  97 . The radial bore  97  exposes a lower face  175  of the actuator piston  99  to hydraulic fluid. An outer surface of the actuator piston  99  has an annular groove  197  formed therein. The groove  197  accommodates a slidable annular seal  198 . The actuator piston  99  is connected to the stroke piston  92  by bolts  98  to form a piston assembly  116 . The piston assembly  116  is movable within the third annular chamber  194  and the gas spring piston chamber  91 . The actuator piston  99  is axially slidable along the bolts  98  relative to the stroke piston  92 . A spring  140  ( FIG. 15 ) biases the actuator piston  99  to the full extent of travel. Hydraulic pressure applied to the right hand side of the annular seals  198 ,  119  of the actuator piston  99  can act on the end face  175  to overcome the spring  140  force to slide the actuator piston  99  along the bolts  98  (in the direction left to right as shown in  FIG. 15 ) with the pressurised hydraulic fluid creating a chamber  111  (see the chamber  111  increasing in volume from close to zero in  FIG. 15  to that shown in  FIG. 17  to that shown in  FIG. 18 ). 
         [0172]    A lower extremity of the stroke piston  92  is provided with threads  117  ( FIG. 6 ) that engage internal threads  118  of the end connector  193 . The end connector  193  is rotationally locked by pins  179  that fix the end connector  193  to the stroke piston  92 . A lower external surface of the end connector  193  has threads  190  for mating with the threads of apparatus to be deployed and set downhole. 
         [0173]    At a lower end, the lower housing  15  has a lower threaded box connector  189  for engagement with an upper threaded box connector  177  of the connector sub  16 . 
         [0174]    The antirotation ring  176  similar to that shown in  FIG. 21  is located between the lower housing  15  and the connector sub  16 . An annular groove  195  ( FIG. 15 ) is provided on an external surface of the sub  16  and an annular groove  191  is located on an internal surface of the sub  16  towards an upper end. The outer and inner annular grooves  195 ,  191  accommodate outer and inner o-rings  196 ,  192  respectively. The connector sub  16  is a substantially cylindrical steel component with a wide longitudinal bore  178  formed in a lower end of the sub  16 . The connector sub  16  has an annular protrusion that accommodates an interlock mechanism  100 . 
         [0175]    A detailed view of the interlock  100  is shown in  FIG. 15 . The interlock mechanism  100  comprises a set of four circumferentially spaced dogs  102 , each dog  102  having three angled teeth  103  on an inner surface. A matching tooth profile  101  is machined on an outer surface of the stroke piston  92  such that the teeth  103  of each dog  102  are accommodated within the profile  101  formed on the stroke piston  92 . Each dog  102  has a central hole  104  into which a pin  105  is inserted to secure the dogs  102  to the connector sub  106 . The actuator piston  99  has an annular nose  107  that urges the dogs  102  into the matching tooth profile  101 . In this way the dogs  102  lock the connector sub  16  with the stroke piston  92 , until the annular nose  107  of the actuator piston  99  is axially displaced. 
         [0176]    The transmitter (not shown) carried on the PCB  64  of the setting tool  10  is any suitable wireless transmission and receiving means such as a transceiver designed for Bluetooth™ communication and can be used with a portable and/or a handheld device such as a tablet computer  300  ( FIG. 25 ). According to the present embodiment, the tablet computer  300  used for communication with the tool is a Panasonic Android tablet specially designed for extra durability with shock and water resistance. The tablet  300  has a protective casing  301  and a visual display screen  302 . The tablet  300  has a series of applications  308  (or “apps”) preinstalled that appear on the visual display screen  302  when the tablet  300  is turned on. Each application  308  is directed to a specific task. 
         [0177]    Examples of applications include an initiation app  311  (covering the method for priming the tool  10 ), a post-run app  312  (covering retrieval of data from the tool  10 ), change out of electronics power unit app  313  (covering steps for removal and replacement of an EPU  31 ), a reset app  314  (covering the steps for resetting the tool  10  for re-use), a troubleshooting app  315 , a programming app  316  (taking a user through options for programming the tool prior to use) and a test app  317  (indicating a performance of a test that can be run to check the correct functioning of the tool  10  prior to downhole use). 
         [0178]    The applications all include simple animations so that use of the tablet  300  is facilitated and language is not a barrier to use. 
         [0179]    A handheld magnetic key  303  shown in  FIG. 25  is required for initiation of the tool  100 . The magnetic key  303  has a handle  305  that a user can grasp and a circular head  304  which should be placed parallel to and adjacent the viewing window  61  of the tool  10  in use. The circular head  304  contains an electronic circuit, a timer, a switch and a thick walled ring magnet (approximately 1 inch or 2.54 cm in diameter). A button  306  is located proximate the handle  305 . 
         [0180]    Prior to use in a wellbore the setting tool  10  is assembled and supplied as shown in  FIGS. 1 and 2 . The setting tool  10  is supplied with the magnetic key  303  for initiation and the tablet  300  containing all operating instructions. 
         [0181]    The tool  10  is designed for initiation with the key  303  to prevent the Bluetooth™ transmitter on the PCB  64  from constantly monitoring and processing Bluetooth™ signals, which would drain the batteries  30  as the tool  10  is transported to a wellbore of interest on land or offshore. Before use, it is necessary to prime the tool  10  or turn on the tool  10  by activating the magnetic sensor  164  carried on the PCB  64 , which is responsive to synchronised magnetic pulses provided by the magnetic key  303 . The button  306  on the magnetic key  303  is pressed to turn on a switch within the key head  304 . Pressing the button  306  causes intermittent magnetisation of the ring magnet within the key head  304  in a particular pre-programmed sequence. The magnetic sensor  164  and electronics in the PCB  64  are pre-programmed to respond to the unique pre-programmed sequence emitted by the ring magnet within the key  303 . Recognition of this pre-programmed sequence by the electronics in the PCB  64  ‘switches on’ or primes the tool  10 . Use of a specific sequence reduces the likelihood of accidental priming of the tool by spurious magnetisation during transportation or on a wellsite where the tool  10  is likely to be surrounded by large metal tubulars, some of which may have been subject to downhole rotation and are inadvertently magnetised. 
         [0182]    If successful, the priming of the tool  10  electronics is denoted by the blue LED  63 , emitting light that is visible through the viewing window  61 . Thus, blue light emitted by the blue LED  63  signifies that the tool is switched on and the Bluetooth™ is responsive to commands from the tablet  300 . 
         [0183]    If the electronics within the tool recognise a problem, the red LED  62  emits a red light visible through the viewing window  61 . Thus, red light emitted by the red LED  62  indicates a fault and a user may be instructed to contact the supplier of the setting tool  10  in these circumstances. 
         [0184]    An unskilled technician at the wellsite is able to follow simple instructions provided on the display screen  302  of the handheld tablet  300  in order to prime the tool. One possible sequence of instructions and outcomes is shown in  FIG. 24 . Thus the setting tool  10  can be switched on in a simple manner by an unskilled technician. Further the LEDs  62 ,  63  provide immediate visual feedback regarding the state of the setting tool  10 . 
         [0185]    The setting tool  10  is pre-programmed before use downhole according to the specific requirements of an operator. For example, an operator may want to set a timer (which may be the timer in the electronics pack  32 ) to initiate actuation of the motor  76  and thereby travel of the setting tool  10  after a predetermined period of time has elapsed. Additionally/alternatively, the operator may want to alter the time set such that actuation of the motor  76  occurs in indirect response to physical manipulation of the setting tool  10  by jarring slickline (not shown) attached to the top sub  20 . For example, the operator may want to alter the time set in the timer within the tool  10  such that physical manipulation of the string or wireline or slickline (not shown) attached to the top sub  20  alters the timer to either advance the timer, slow down or retard the timer or actuate the timer to start counting down to operation or switch the timer off. 
         [0186]    In any event, such motion can be detected by accelerometers and motion sensors within the electronics pack  32 . The operator may also require the setting force to be limited to avoid damage to the setting tool  10 , the apparatus to be deployed or the wellbore itself. For example, if an operator calculates that the setting pressure required to set the apparatus is in the region of 10000-12000 psi, the operator can limit the motor  76  current to an equivalent pressure of 12500 psi (as measured by the pressure transducer  75 ). This maximum pressure output is large enough to ensure the apparatus is set with sufficient force but minimises the chance of damage to the tool  10 , apparatus or wellbore. The value for this maximum pressure, 12500 psi can be entered into the tablet  300  via a keypad on the visual display screen  302 . The tablet  300  then communicates this information to the transmitter within the tool  10  at surface to pre-program the maximum output force of the motor  76 . One or more alarms can be entered into the tablet  300  so that a timer within the tablet  300  synchronises with the timer in the electronics pack  32 . 
         [0187]    Thus, an alarm can be used to alert the user to imminent actuation of the setting mechanism for example. In this manner the tablet  300  maintains an indirect link with the setting tool  10  even after the setting tool  10  is deployed downhole and the active Bluetooth™ link is no longer available. Other parameters and options can be preprogrammed so that the electronics log or respond to downhole conditions in a manner desirable to the operator. An unskilled user can enter the various commands and parameters for the operation into the tablet  300  via the visual display screen  302  and the setting tool is programmed using short wavelength Bluetooth™ transmissions  310  (illustrated schematically in  FIG. 25 ). 
         [0188]    According to the present embodiment the setting tool  10  is intended to deploy a packer  203  ( FIG. 23 ) downhole in a wellbore. The packer  203  is releasably attached to the end connector  193  of the setting tool  10 . Threads  190  on the end connector  193  mate with threads  202  on an upper end of an engager  201 . A lower end of the engager  201  has a latch  213  that engages a groove  214  on an upper internal end of a body  215  of the packer  203 . A lower  18  end portion  204  of the packer  203  body  215  has an increased diameter portion thereby defining an upwardly facing annular step  205 . A pair of opposing annular ramps  206  having inclined outer surfaces are coupled to an outer surface of the packer  203 . The lower ramp  206  is located adjacent the annular step  205 . Three sets of slips  207  are radially spaced and positioned between the ramps  206  with complementary inclined inner surfaces. The slips  207  have a profiled external surface  209  for gripping the wellbore. A rubber packing element  210  is positioned between an upper end of the upper ramp  206  and a gauge ring  211 . A housing  212  extends from an upper end of the packer  203  and an end face  109  of the connector sub  16  of the setting tool  10  shoulders out on an upper end face of the housing  212 . 
         [0189]    The setting tool  10  is run downhole in a run-in configuration shown in  FIG. 16 . The setting tool is run downhole on slickline connected to threads  23  on the top sub  20  and with the attached packer  203  at the lower end  19 . The pressure transducer  75  registers a gradual rise in pressure as the tool  10  is run downhole. The interlock mechanism  100  prevents the tool  10  from premature setting by locking the stroke piston  92  to the connector sub  16 . The packer  203  and attached setting tool  10  are run downhole to the required depth. Shortly prior to deployment of the packer  203 , the tablet  300  at surface sounds an alarm to alert an operator that actuation of the setting tool  10  and deployment of the packer  203  is imminent. In the event that the operator was not located in the correct position or should any unforeseen delays have been experienced, the operator could override the setting sequence by manipulating the slickline in such a manner that the resulting movement is registered by accelerometers and motion sensors. This physical manipulation of the tool can trigger a pre-programmed event within the electronics pack  32  such as a resetting of the timer. 
         [0190]    According to the present embodiment, the setting tool  10  is actuated by the timer in the electronics pack  32 . Once the tool  10  is actuated, the electronics pack  32  initiates the motor  76  to provide an output force that is stepped up by the gearbox  77  to drive the pump  78 . The pump  78  draws clean hydraulic fluid from the second chamber  73  through the inlet  80 , which fluid is pumped through the outlet  81  and travels via bores  82 ,  83 ,  174 ,  89 ,  95 ,  96 ,  97  to act on the end face  175  of the actuator piston  99  between the seals  119 ,  198 . Since the interlock mechanism  100  locks the connector sub  16  to the stroke piston  92 , the stroke piston  92  is constrained against collective movement with the actuator piston  99  to permit some pressure in the hydraulic fluid to be built up to enable diagnostic checks to be made. Once made, continued application of hydraulic fluid pressure on the end face  175  of the actuator piston  99  overcomes the bias of the spring  140  to compress the spring  140  and to urge the actuator piston  99  axially uphole so that the piston  99  and the bolts  98  slide along the piston  92  (from right to left in  FIG. 6 ). When the annular nose  107  of the actuator piston  99  has travelled a short distance in the uphole axial direction, an inclined surface  108  is adjacent the dogs  102  of the locking mechanism  100 . The dogs  102  are now able to move radially outwardly urged by the geometry of the teeth  103 , and the serrated profile  101 . The 600 inclined profile  101  aids the radial movement of the teeth  103  as the teeth  103  ‘climb out’ and thereby release the interlock mechanism  100 . Thus the interlock mechanism  100  is disengaged and the stroke piston  92  is no longer locked to the connector sub  16 . The actuator piston  99  and the stroke piston  92  are able to move collectively as the piston assembly  116  as shown in  FIG. 17 . 
         [0191]    Hydraulic fluid supplied by the pump  78  continues to act on the lower face  175  of the actuator piston  99 . As a result, the piston assembly  116  moves axially relative to and away from the connector sub  16  in the upwards direction (from right to left in  FIG. 17 ). Axial movement of the piston assembly  116  causes the stroke piston  92  to compress gas within the chamber  91  of the gas spring  90 . The non return valve in the pump  78  ensures that the piston assembly  116  remains locked in its axial position. Current supplied to the motor  76  is monitored. The electronics pack  32  ensures that the motor  76  does not provide an output during the setting process that equates to a setting pressure of more than 12500 psi. 
         [0192]    Axial movement of the piston assembly  116  causes a downhole pushing force on the packer  203  by the end face  109  of the connector sub  16  acting against the housing  212  of the packer  203 . In other words, end face  109  remains stationary and provides an anchor or reaction point against which the force provided by the axial upwards movement of the piston assembly  116  can react against to set the packer  203  or plug (not shown) or any other suitable tool to be set. Axial movement of the piston assembly  116  also provides a pulling force on the packer  203  as the stroke piston  92  moves uphole and this movement is translated to the packer  203  via the connector  201 . As a result the ramps  206  and the rubber packing element  210  are squeezed between the gauge ring  211  and the annular step  205 . As the ramps  206  converge the slips  207  are driven radially outwardly until the teeth  209  engage the wellbore. The rubber packing element  210  is deformable and squeezed to make a contact seal with the wellbore. According to the present embodiment the force required to set the packer  203  is provided by the hydraulic fluid located within chamber  111  reaching 12000 psi. Once this pressure is reached the slips  207  and the rubber packing element  210  are in full contact with the wellbore. A shear ring (for example within the connector  201 ) within the packer  203  apparatus shears to release the setting tool  10  from the packer  203  so that the setting tool  10  can be pulled out of the hole back to surface.  FIG. 18  shows the final position of the setting tool  10  in the set configuration following deployment of the packer  203 . The pressure transducer  75  and electronics pack  32  register that the pressure has reached 12000 psi. In addition, motion sensors within the PCBs log the jolt received by the tool  10  as the packer  203  is deployed and release of the setting tool  10  occurs. The pressure transducer  75  senses the consequent drop in pressure in chamber  111 , which is fed back to the electronics pack  32 . Thus the electronics pack  32  logs the combination of data detected within a short time window and equates this information to the deployment of the packer  203 . This information is then fed back to the operator by Bluetooth™ once the tool  10  is retrieved to surface, providing confirmation of successful deployment of the packer  203 . 
         [0193]    Once the packer  203  has been deployed, and the setting tool  10  is released, it can be pulled out of the hole on the slickline. An operator can then access electronic data logged during the tool  10  run. The tablet  300  is located within communication range of the viewing window  61  and data from the setting tool  10  is downloaded via the Bluetooth™ link with the help of the post-run app  312  (covering retrieval of data from the tool  10 ). 
         [0194]    A run report can be downloaded onto the tablet  300  from the tool  10  giving details such as a force displacement graph. This provides an operator with assurance that the packer  203  has been correctly deployed and also allows an operator to assess correct function of the setting tool  10 . Data such as a temperature profile, displacement measurements, pump efficiency and other stored information can be downloaded from the electronics pack  32  to inform the operator and provide an indication of the success of the run, health of the tool  10  and downhole conditions. 
         [0195]    Should the Bluetooth™ communication link with the tool  10  fail, a redundancy is provided which still allows data to be derived from the electronics pack  32 . A redundancy communications pack (not shown) having identical pins  42  to the connector  40  can be stabbed directly in the socket  35  of the EPU  31 . Thus data from the electronics pack  32  can also be derived via a hard link with the redundancy communications pack. 
         [0196]    As well as downloading data from the electronics pack  32  the redundancy communications pack can override and reprogram the electronics. 
         [0197]    If an operator wants the setting tool  10  to deploy another apparatus downhole, the tool  10  needs to be reset for reuse. After use the tool  10  is in the set configuration shown in  FIG. 18  and needs to return to the run-in configuration shown in  FIG. 16 . The operator would refer to the reset app  314  for animations instructing the steps required for reset. A suitable key such as an allen key is inserted into the hexagonal socket  184  of the plug  84 . The allen key is turned several times to rotate the plug  84  towards the port  182 . The frustoconical surface  185  of the plug moves radially to unplug the radial bore  83 . Thus clean hydraulic fluid travels from the radial bore  83  along the fluid bypass slot  187  of the plug  84  ( FIG. 22 ) and communicates with the return bore  74 . The hydraulic fluid is therefore returned along the fluid path from chamber  111  through radial bore  97 , through central bore  96 , through radially extending bore  95  (and thereby travelling through the stroke piston  92 ) ( FIG. 6 ) and through radial bore  89  and along longitudinally extending bore  174  ( FIG. 5 ) and along radial bore  83  past the plug  84  via the fluid bypass slot  187  and along longitudinal bore  74  and into third fluid chamber  194  (see  FIGS. 6 and 16 ), urged by the gas spring piston  90 . The compressed gas within the chamber  91  is free to expand and push the stroke piston  92  towards a lower end  19  of the tool  10 . Movement of the stroke piston  92  pushes fluid out of the chamber  111  and allows return of this fluid to the third annular chamber  194  which is therefore now also in fluid communication with the second annular chamber  73 . Thus the tool  10  is easily reset without any mechanical manipulation. 
         [0198]    A supplier may recommend that a technician performs a minor servicing of the tool after a certain number of runs, such as ten trips downhole. The tablet  300  provides the operator with an automatic alert when a minor service interval is reached. During the minor service, the batteries  30  and the electronics pack  32  are replaced. The operator refers to the ‘change out of electronics power unit app’  313  for animations giving clear instructions regarding replacement of the EPU  31 . 
         [0199]    The first step is to remove the EPU  31  from the upper housing  12 . The tabs  122  on the anti-rotation ring  121  are deformed such that the top sub  20  is separable from the upper housing  12 . The operator holds the end  23  of the top sub  20  and applies an axial pulling force. Since the top sub  20  is connected to the EPU  31  by the horseshoe connector  25  engaging with the end connector  137 , the EPU  31  also moves axially out of the upper housing  12 . The horseshoe connector  25  and detent mechanism  138  allows a controlled removal of the EPU  31 . The lithium batteries  30  within the EPU  31  are contained within the unit housing  131  and released in a controlled manner, which is an important safety feature for personnel in the region of potentially dangerous lithium batteries  30 . The used EPU  31  can now be disposed of, recycled or returned to the supplier. 
         [0200]    A replacement EPU  31  is now ready to be inserted within the tool  10  upper housing  12 . The replacement EPU  31  is identical to the previous EPU  31 . The top sub  20  is provided with an anti rotation ring  121  ( FIG. 3 ) abutting the annular shoulder  120  ( FIG. 7 ). The end connector  137  ( FIG. 8 ) of the replacement EPU  31  is inserted into the c-shaped groove  27  of the horseshoe connector  25  ( FIG. 7 ) of the top sub  20 . The top sub  20  is then rotated until a technician senses that the spring loaded detent mechanism  138  ( FIG. 8 ) clicks into detent hole  124  ( FIG. 7 ) to releasably connect the end connector  137  and the electronics power unit  31 . The top sub  20  and replacement EPU  31  are then offered up to the uppermost end (i.e. left hand end as viewed in  FIG. 2 ) of the upper housing  12 . The lower end (i.e. the right hand end as viewed in  FIG. 2 ) of the EPU  31  is then inserted into the upper end of the upper housing  12 . The alignment notch  125  ( FIG. 7 ) provided on the top sub  20  is aligned by the operator with the viewing window  61  of the tool  10 . This visual aid allows approximate alignment of the key  33  ( FIG. 4 ) on the end cap  34  of the EPU  31  with the keyway  44  ( FIG. 11 ) in the EM subassembly  50 . The operator applies an axial force to the top sub  20  to urge the EPU  31  into the upper housing  12 . The operator pushes the EPU  31  into the upper housing  12  until the orientation washer  36  aligns with the locator pin  41  guided by the key  33  sliding within the keyway  44  of the EM subassembly  50 . The combined length of the connected top sub  20  and EPU  31  is arranged during the engineering design process with reference to the length of the upper housing  12  such that, at this point in the tool  10  make up sequence, the pin threads  28  of the top sub  20  meet the upper box threaded connector  17  of the upper housing  12  at which point the operator must rotate the top sub  20  (and in doing so overcomes the spring of the spring loaded detent mechanism  138 ) such that the top sub  20  rotates relative to the EPU  31  and by virtue of the cooperation of the threads  28  and  17 , continued rotation of the top sub  20  relative to the housing  12  axially advances both the top sub  20  and the EPU  31  into the housing  12  and further continued axial movement of the top sub  20  and attached EPU  31  connects the socket  35  with the fifteen upper electrical pins  42 . Tabs  122  of the anti-rotation ring  121  are deformed into position to rotationally lock the top sub  20  and the upper housing  12 . The minor service interval is now complete. 
         [0201]    The tool can be reset, reprogrammed and re-run as described multiple times. Thus, the tool is quickly ad simply reset for reuse without the involvement of a skilled technician. 
         [0202]    The supplier of the tool  10  receiving a used EPU  32  can access the electronics pack  32  and download data via the socket  35 . Stored data from the pressure transducer  75 , accelerometer, temperature sensor, vibration sensor and motion sensor allow the supplier to compile a run history of the tool  10 . This field run history can be advantageous to the supplier to derive information relevant to the warranty for the tool  10  or the time intervals between major service intervals for the tool  10 . 
         [0203]    The operator of the tool  10  can be alerted to major service intervals, which may be required after, say fifty runs. Major service intervals can involve replacement of the EM subassembly  50 . The major service interval can also include a change of hydraulic fluid. 
         [0204]    The batteries  30  are consumable and require regular replacement to power the tool  10  downhole. Additionally the stacked PCBs  139  within the electronics pack  32  are subject to excessive shock and vibration in the downhole environment, the damaging effects of which are shown to be cumulative. Electronics components are also prone to failure by fatigue due to thermal cycling. Thus, the electronics on the PCBs  139  have a limited life. Grouping and inclusion of these two consumable components (the batteries  30  and electronics pack  32 ) within the EPU  31  provide a discrete self-contained subassembly suitable for removal and replacement with a new EPU  31  subassembly. The EPU  31  is designed for ease of access, removal and insertion. This has the advantage that there is no requirement for a skilled technician. Any operator following a simple list of instructions provided by the ‘change out of electronics power unit app’  313  on the tablet  300  has the ability to remove and replace the EPU  31 . Additionally the EPU  31  and EM subassembly  50  can be vibration and temperature tested and proven to ensure that the components are robust and able to operate within the rated limits before dispatch to an operator for use. 
         [0205]    The gas spring  90  within the tool  10  has several advantages. The compressed gas within the chamber  91  of the gas spring  90  provides an automatic ‘re-cock’ on release of the plug  84 . No manual intervention is required, other than the act of plug  84  release using several turns of a standard allen key. The automatic ‘re-cock’ allows the tool  10  to be set for reuse without using any power from the batteries  30 , which would cause additional power drain from the tool  10 . There is no requirement for the tool  10  to be stripped down for the ‘re-cock’ and therefore the internal mechanism remains isolated resulting in minimal or no debris ingress into the tool  10  that may impair proper functioning. The presence of the gas spring  90  downhole is also an advantage. Since the gas within the chamber  91  is sealed at ambient surface pressure, a pressure differential exists between the gas within the chamber  91  and the greater ambient pressure downhole at depth in a wellbore. Thus, on release of the interlock mechanism  100 , the compressible gas within the chamber  90  assists with the setting of the tool  10 . 
         [0206]    An operator of the tool  10  can ensure that downhole use of the tool  10  conforms with the tested and verified safe operating limits of the tool  10 . For example, the tool  10  will be rated for use in an environment with a maximum temperature, such as 1500 C. On retrieval of the tool  10 , the operator can verify that the tool  10  has been exposed to temperatures lower than the maximum temperature rating. Temperature data is logged by the temperature sensor (not shown) embedded within and electronically linked with the electronics pack  32 . Temperature data is downloaded from the electronics pack  32  via the Bluetooth™ Link with the handheld tablet. The handheld tablet provides the figures of downhole temperatures on the digital display. Should the electronics pack  32  fail to record temperature values or some problem is encountered downloading temperature data, the temperature sensitive labels (not shown) fixed to the batteries  30  provide a secondary indication of maximum temperature reached downhole. This data provides assurance for the operator that the tool  10  is working within safe rated operating limits. Should the tool  10  have been exposed to higher temperatures than those for which it is rated, the tool  10  can be returned to the manufacturer for safety checks and for the verification and/or replacement of temperature sensitive components within the tool  10 . 
         [0207]    The described setting tool  10  has many advantages. Set-up, use and reset of the tool  10  is simple and quick. These activities can be performed with the aid of the tablet  300  and without the need for a skilled technician. Consumable components within the tool  10  can be easily removed and replaced. The tool  10  is ‘smart’ and versatile since the electronics within the tool  10  allow reprogramming to account for different downhole conditions and apparatus to be deployed. Electronics within the tool  10  provide feedback, such as data on downhole conditions and performance data of the tool  10 . The viewing window  61  provides a visual indicator of the state of the tool  10  and immediately alerts an operator to a potential problem by emitting light from the red LED  62  or no LED  62 ,  63  response when expected. The overall design of the tool  10  allows multiple use of the tool  10  with minimal intervention. 
         [0208]    This description is intended for the purposes of illustration only. Modifications and alterations can be made without departing from the scope of the invention. 
         [0209]    The detailed description of the invention sets forth numerous specific details in order to provide a thorough understanding of the invention. However it will be apparent to a person skilled in the art that the invention may be practised without some or all of these specific details. 
         [0210]    Although the described embodiment deploys the setting tool  10  on slickline, the setting tool  10  could also be run downhole on wireline, braided line or any other type of downhole deployment means with the connector to the deployment means provided at the upper end  23  of the top sub  20  being altered appropriately. 
         [0211]    Any relatively portable tablet, computer, phone or other electronic device that can communicate with the tool electronics can be used in combination with the setting tool. 
         [0212]    Suitable tables or portable devices include, but are not limited to, Apple i-pad., any Android tablet, any Microsoft table, any mobile phone. The described embodiment refers to communication between the portable and/or handheld device and the setting tool  10  using Bluetooth™, although other methods of remote or wireless communication can be utilised such as WiFi or radio frequency identification (RFID). Additionally, different coloured LED&#39;s or other indicators could be used. 
         [0213]    The setting tool  10  can be used to deploy apparatus in any type of wellbore such as in cased hole or open hole.