Control Mechanism

The present invention relates to the control of certain downhole activities.

In the field of deep hole drilling and in particular extended reach horizontal wells there is frequently a need for a variety of downhole tools to (for example); · Drill formations

• Provide vibration to help eliminate friction

• Free stuck drill pipe etc

• "Fish" for stuck product

Tools for such activities vary but each relies on a rotational input downhole. In order for such to operate to their full potential ideally these devices would have as many of the following characteristics as possible [and at the very minimum at least one of them] :

• Reliable activation

• On / off demand activation

· On demand speed control

• Fit anywhere in the drill string

• There could be multiple units in the drill string - each able to be activated as

required

• It would be energised by any suitable means (hydraulic, electric, mechanical etc) · It can be controlled at surface and/or by a downhole feedback mechanism

Of particular interest are fluid actuated rotary devices (eg. PDMs, turbines) able to outfeed downhole both a rotational output and the fluid itself to a vibrational apparatus reliant on oscillating movement eg interacting magnetic arrays to mechanically induce oscillation. See for example WO2006/065155, WO2099/028964 (which are herein incorporated by reference); our US provisional application No. 61/489409 (which is herein incorporated by reference) filed simultaneously on 24 May 2011 with this application; and PCT/NZ/2011/ 000123 filed 29 June 2011 (which is herein incorporated by reference).

The present invention describes a mechanism to achieve the above objectives. In an aspect the invention is the use in a drillstring of a PDM with both an output upwardly and an output downwardly to devices spaced at least by the PDM. In another aspect the invention is a dual output PDM, the outputs being uphole and downhole of the PDM itself.

In another aspect the invention is a downhole drivetrain of at least one device above a dual output PDM and/or at least one device below that PDM, wherein a mud or other fluid flow through the higher device(s) is diverted more outward of the drive train axis for its passage through the PDM and from thence to the lower device(s).

Preferably the uphole output is for coupling to a device and/or the downhole output is for coupling to a device.

Preferably the devices are a vibratory device and/or rotary device. Preferably the vibratory device is one or more of: any oscillator, hammer, or other vibration outputting device requiring a rotational input for any suitable purpose downhole including those discussed elsewhere.

Preferably, the vibratory device is one requiring a rotational input to generate magnetic array interactions. Preferably the rotary device is one or more of: a bit, a core bit, a reamer, a hammer/impacting bit assembly, a power generator, a vibratory or hammer device/tool requiring relative rotation, etc.

It is a further or alternative object of the invention to provide a dual output from a single PDM or from back to back PDMs to enable devices upwardly of and downwardly of the respective outputs to operate responsive to a mud flow fed downhole.

In an aspect the invention is a method of control of outputs reliant on a downfeed of a pressured drilling fluid, said method comprising or including, feeding at least some of that fluid, when downhole, to a device to provide a rotary input ("rotary input device") to at least one downhole device; wherein the downhole device, or one of the downhole devices, is responsive to output from the rotary input device to cause relative rotation and, in turn, at least in part axial relative reciprocation between assemblies, each with a magnet array to interact with the other; and wherein the rotary input device, whether with or without its own fluid bypass and whether receiving, or to receive, all or only part of the fluid flow downfeed, provides a rotation causing output to the, or the one, downhole device with the magnet arrays only when exposed to fluid pressure/flow within "on demand" parameters. Preferably there is a threshold required to initiate the "on demand" rotation causing output.

The invention also consists in any one or more, or hybridisation of, any one of the layout options herein described with reference to the drawings.

In another aspect the invention is apparatus having a control mechanism

[preferably that works in conjunction with downhole tool(s)] to control rotary output(s), if any, from a rotary output(s) generator as a result of a pressurised drilling fluid input, the control mechanism allowing pressurised fluid to bypass or not, whether wholly or in part, and whether through or about, the rotary output(s) generator so that it can be treated as turned off or on. Preferably such off/on output(s) is (are) able to rotationally activate a downhole axially oscillating device, such a device including a magnetic component that rotates responsive to any rotational output of the rotary output(s) generator and a second magnetic component that is rotationally constrained and is forced to oscillate.

Optionally the control function can be activated (or not) by drilling fluid, electrical signals, mechanical actuation or any other suitable means.

Preferably the control mechanism can fit anywhere in the drill string.

Preferably the apparatus can have multiple rotary output generators within the drill string.

Such multiple units can be pointing in opposite directions (eg. one uphole and one downhole).

Preferably each control mechanism can be controlled individually / independently of other such devices.

A preferred option includes as the rotary output generator a fluid driven rotational device source (PDM/ turbine etc) which has a rotary output shaft at each end. In another aspect the invention is a method of downhole control of a vibrational generating tool as part of a drill string, the method comprising or including

attenuating downhole, by any suitable means, the volume and/or pressure of a pressurised fluid supplied from uphole to a PDM, turbine or other like fluid rotatable rotational output device thereby to effect any one or more of onset of rotational output, halting of rotational output and variation of speed of rotational output, and

using that rotational output, if any, as the rotational input to vibrational apparatus that uses relative rotation of interacting magnetic assemblies to generate vibration by relatively of axial positioning of those assemblies.

The invention also is a control mechanism that works in conjunction with downhole tools which generate rotary output(s) as a result of a pressurised drilling fluid input whereby; the control mechanism allows pressurised fluid to bypass (or not) through the rotary generation tool so that the tool is able to be turned off or on, such a device is then able to rotationally activate a downhole axially oscillating device, such a device including a cam / wobble plate or other, a compliant member that transmits rotational torque and controls an axially oscillating mass in both compression and tension.

In another aspect the invention is a device whereby the multiple units can be pointing in opposite directions (e.g one uphole and one downhole). The apparatus of the present invention can be used in the following non exhaustive downhole activities:

• drilling

• milling

• reaming

· core drilling

• scale removal

• sand control /screen setting

• cementing In a further aspect a downhole assembly having a fluid actuable rotating device, or fluid actuable rotating devices, when rotated by the fluid, to provide a rotational drive both above and below the device(s).

Preferably the device is a PDM with an output at top and bottom. Preferably the devices are two PDMs, one with its output at its top and one with its output at its bottom.

Preferably the two PDMs are in close proximity or contiguous bottom to top.

Preferably the fluid is drilling mud. Preferably a downhole valve is able to attenuate the fluid flow to the device(s).

Preferably one said rotational drive is to a vibrational device.

Preferably the vibrational device relies upon interacting magnets to generate vibration.

Preferably the vibrational device does not rely upon interacting magnets to generate vibration.

The above mentioned tools generally have some commonality of design (although their functions are significantly different) these being;

• They require a suitable rotary drive mechanism, preferably a Positive

Displacement Motor (PDM) but could be a fluid turbine, electric motor, mechanical drive etc.

• The rotary drive is preferably speed controllable.

• The rotary drive is able to pass / work with commonly used downhole drilling

fluids.

• The rotary drive is generally responsive to a combination of hydraulic flow and pressure.

• Optionally the rotary drive would work in conjunction with a flow control valve.

• The rotary drive may (may not) have a double (top and bottom) output shaft.

• The rotary drive may be activated from surface or by a downhole feedback loop responsive to a variety of downhole conditions (e.g weight on bit, drill rod PM, rate of penetration, vibration, drilling mud flow pressure, formation hardness etc).

As used herein the term "and/or" means "and" or "or", or both.

As used herein the term "(s)" following a noun includes, as might be appropriate, the singular or plural forms of that noun.

As used herein the term "device(s)" is to be construed broadly to relate to any device/tool able to benefit from PDM output. For example it may be a device having a vibrational, hammer, power generation, bit, impact bit assembly, reamer or other functionality. In some aspects there might only be a device reliant on interacting magnetic arrays to generate a vibrational or impact output responsive to relative rotation being caused by the output of the or a PDM, or such a device coupled to other functional device, whilst the output in the other direction can be used with another device.

As used here in dual output PDM preferably refers to a unitary assembly but in less preferred forms can refer to PDMs, each with a single, output acting back to back such that the outputs are respectively directed uphole and downhole.

A preferred form of the present invention will now be described with reference to the accompany drawings in which

Figure 1 shows, as option 1, a rotary input device (eg. PDM, turbine, electric motor) above a vibrational apparatus above a downhole tool (eg. bit, BHA, etc),

Figure 2 shows, as option 2, the rotary input device (eg. PDM, turbine, electric motor) with a top and bottom output shaft, the vibrational apparatus (eg. magnetic oscillator) being above the rotary input device,

Figure 3 shows, as option 3, a flow diverter valve above a hollow shaft PDM in turn above a vibrational apparatus (magnetic oscillator),

Figure 4 shows, as option 4, the arrangement of option 3 but where the vibrational apparatus (magnetic oscillator) is above the flow diverter valve, Figures 5A and 5B shows an example of a fluid (eg. drilling mud) control valve, and

Figure 6 shows in solid outline within a "stator" "S" surround of a PDM, the "rotor" "R" having both a top and bottom take off ("T" and "B" respectively) for a drive connection (e.g. ball drive coupling or other. Figure 7 shows a dual output PDM coupled to an oscillating apparatus uphole and a rotary tool downhole.

In the options of Figures 1 to 4 the zones shown in the layouts indicate according to the following key:

1. Drill pipe/wireline etc 2. PDM/turbine/electric motor/etc

3. Oscillator (magnetic, mechanical and/or other] 4. Downhole tool/bit/BHA/etc

5. Double output shaft from PDM/etc

6. Flow diverter valve

7. Hollow shaft PDM The oscillator (vibratory device) could be for example one of the devices described in our US provisional application 61/489409.

Option 1.

Referring to Figure 1, the uphole portion of the tool (1) would typically be a drill pipe / coil tube etc - (but could equally be a wire line - providing electricity to an electric drive) to provide a means of placing the tool(s) downhole and providing a conduit for drilling fluid and the like. The rotary power source (2) is usually a Positive Displacement Motor (PDM) or turbine - and generates rotational power by converting pressured drilling fluid pumped from surface into pressure - thus forcing the internal rotor(s) on the PDM turbine etc to rotate the internals of the vibratory / impact tool (3) (generally speaking this is a magnetic type device). However, it may be a mechanical device as described in our US provisional application No. 61/489409 entitled "Downhole Sinusoidal Vibrational Apparatus" that is being filed simultaneously with this application and is incorporated entirely by reference. Generally, such a mechanical device is under a rotatable input and by the use of a wobble plate, cams or the like, causes an axial movement of a mass relative to the outer body to thereby cause vibration.

Below the vibratory / impact tool there may be any number of tools such as drill bits, reamers, drill pipe, or any other downhole tool(s).

In some instances the vibratory tool is not required to run - in this instance you can either; · Turn off the fluid pumps at surface or more preferably;

• Limit the flow through the PDM / turbine etc so that some flow is available

downhole through leakage - without building enough pressure to cause the PDM / turbine etc to rotate. Conversely by increasing the flow of mud from the surface pressure will build through the PDM /Turbine etc causing the PDM /Turbines internal rotors to turn -therefore powering the vibratory /impact device.

Option 2. Referring to Figure 2 - this is a similar to that shown in option 1 however a dual output PDM is provided. In this configuration the vibratory tool (3) sits above the rotary drive (e.g. PDM) (2) - the rotary drive has a double output shaft (5) - both uphole (coupled to the vibratory tool) and downhole. The downhole drive can be used to power some other vibratory and/or rotary downhole tool (4), such as but not limited to, a rotary tool such as a drill bit etc. Figures 6 and 7 show other possible embodiments in more detail.

Figure 7 shows diversion of fluid flow via a cross over sub from the uphole vibratory device (tool) (3) through the PDM (2), again through a cross over sub and back though a tool; for example a drill bit (4), if a drill bit is used. Alternatively, the mud flows to the downhole rotary device (tool) eg drill bit, reaming tool, etc.

As an alternative this can be accomplished by using two PDM's /Turbines back to back with a connection between them.

Option 3

Referring to Figure 3, this configuration shows a drill pipe (or other) at (1) connected to a flow diverter valve (6) such a valve can be mechanical /electrical /hydraulic or any other type which until activated allows the drilling fluid to pass through a hollow shafted PDM / Turbine etc (7) this flow continues through the vibratory /impact tool (which is not being activated) and out through some other downhole tool (4).

Conversely, when the vibratory /impact tool is required to be energised -the flow diverter valve (6) is activated (either from surface - or by a closed loop feedback system) diverting the drilling fluid between the rotor and stator on the PDM /Turbine etc. causing the rotor to turn and thereby energising the vibratory / impact tool.

Option 4

Now referring to Figure 4. This option is similar to option 3 - however in this

configuration the PDM /Turbine etc (7) has a double output shaft (similar to option 2) whereby the vibratory / impact tool (3) is positioned uphole of the diverter valve and PDM / Turbine (6&7) and can be energised as can a downhole tool (e.g. a drill bit) (4) when the flow diverter valve (6) diverts the drilling fluid from the hollow centre of the PDM /Turbine and forces the flow of drilling mud between the Rotor /Stator of the PDM/Turbine.

As an alternative this can be accomplished by using two PDM's /Turbines back to back with a connection between them. Figures 5A and 5B show a pressure susceptible valve assembly able to redirect a fluid flow downhole. In either of the conditions shown, the drilling mud (if the fluid) can still get further downhole. It does show however that any such flow diverter valve, in a layout of Figure 3 or 4, can activate, or not, the further downhole PDM (eg. either pass the fluid about a tube in the PDM (to activate the PDM) or into a tube of the PDM (not to activate the PDM) yet still provide the drilling mud to the downhole tool, bit, BHA, etc.