GB2462306A

GB2462306A - Reamer attached to a stator or rotor shaft

Info

Publication number: GB2462306A
Application number: GB0814103A
Authority: GB
Inventors: Edward Docherty Scott
Original assignee: Futuretec Ltd
Current assignee: Deep Casing Tools Ltd
Priority date: 2008-08-01
Filing date: 2008-08-01
Publication date: 2010-02-03
Anticipated expiration: 2028-08-01
Also published as: GB2462306B; GB0814103D0

Abstract

A reaming tool 10 comprises a body 12 coupled to either the stator 16 or rotor shaft 18 of downhole motor. The tool 10 is adapted for location in a bore, such as a wellbore. The tool 10 may coupled to the stator 16 by a clutch 56 such as a dog clutch to permit selective holding or restraining of the body 12 relative to the stator 16. A shear pin 34 may be provided to secure the body to the rotor and a spring mounted pin 64 may be provided to selectively lock the body to the rotor after engagement of the clutch.

Description

REAMING TOOL

FIELD OF THE INVENTION

This invention relates to reaming tool and, in particular, but not exclusively, to a selectively engageable reaming tool.

BACKGROUND TO THE INVENTION

In order to access hydrocarbon-bearing or geothermal formations, one or more bores may be drilled from surface, the bores typically being lined with sections of metal tubes, known as casings or liners. A number of tubes may be coupled together as a tubular string, the string being run into the bore substantially without rotation. The annulus between the string and the bore is subsequently filled and sealed with cement to secure the string in place.

When running the string into the bore, it is common that the string will encounter obstructions which prevent or limit further completion or operation of the bore. These may include, for example, ledges extending into the bore, partially collapsed regions of the formation, or drill cuttings lying on the lower side of an inclined bore.

*:*::* A reaming tool may be attached to a eading end of the string and run into the bore. The Casing string is reciprocated and/or rotated from surface to facilitate removal of the obstructions. However, typical casings and casing couplings are generally not suited to transferring torque and rotation of the casing string may be limited. Furthermore, rotating the casing string greatly complicates the drive and coupling arrangements required at surface.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a reaming tool adapted for location in a bore, the tool comprising: a body comprising at least one reaming member, the body adapted to be selectively operatively coupled to one of a rotor and a stator of a downhole rotary drive arrangement to permit control of the movement of the body by the rotary drive arrangement.

For example, in a first configuration, the body is adapted to be selectively operatively coupled to the rotor of the rotary drive arrangement to permit reaming of the bore. Where the body is operatively coupled to the rotor, the tool may be adapted for rotation at a relatively high speed relative to the tubular component. For example, the tool may be run into the bore substantially without rotation, or with a limited degree of rotation, and the body may be adapted for high speed rotation independently of the tubular component and at a speed that may otherwise result in damage to the tubular component or connections.

In a second configuration, the body is adapted to be selectively operatively coupled to the stator of the rotary drive arrangement to facilitate holding or restraining of the body relative to the rotary drive arrangement. The body may be held or restrained to facilitate drilling through the rotary drive arrangement and the tool.

Alternatively, or in addition, the body may be held or restrained to facilitate a cementing operation in the bore.

The rotary drive arrangement may be of any suitable form. For example, the

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20 rotary drive arrangement may comprise at least one of: a mud-powered motor; fluid s.. turbine; axial vane hydraulic motor; a positive displacement motor; an electric motor **5* 5: or any other suitable rotary drive arrangement. In particular embodiments, the rotary drive arrangement may be fluid driven, at least one of the rotor and the tool defining a fluid conduit for directing fluid through the tool.

The tool may comprise a clutch for permitting selective engagement between the body and the stator of the rotary drive arrangement. The clutch may be of any suitable form. For example, the clutch may comprise a first clutch member formed on, or coupled to, the stator. The clutch may further comprise a second clutch member formed on, or coupled to, the body and the first clutch member may be adapted to engage the second clutch member to operatively couple the body to the stator.

The clutch may be adapted to substantially prevent fluid leakage through the clutch on engagement of the clutch. For example, the clutch may define or provide mounting for a seal member.

In particular embodiments, the clutch may comprise corresponding profiles and, in particular embodiments, the clutch may define a dog clutch or the like. The provision of a dog clutch provides a substantially non-slip connection between the body and the rotary drive arrangement. Alternatively, the clutch may comprise a slip clutch or other suitable clutch.

The clutch may be manufactured by any suitable process. In particular embodiments, the clutch profiles may be manufactured by a wire erosion process, thereby facilitating a matched fit on connection of the clutch profiles which substantially prevents fluid leakage through the clutch. Alternatively, the clutch profiles may be manufactured by laser cutting, precision machining, computer numeric control (CNC) machining or other suitable process. The clutch may be subject to a strengthening process, for example, a drop forging process, whereby the clutch profiles may be plastically deformed. Beneficially, the use of drop forging ** 20 process or other suitable process may assist in improving the circumferential shear strength of the clutch. *...

The body may be coupled to the rotor of the rotary drive arrangement, for example, by a spline connection, or other suitable connection for transmitting torque.

The body may be coupled to the rotor such that the body is adapted for relative axial movement relative to the rotor.

The tool may further comprise a retention member coupled between the body and the rotor. The retention member may be adapted to restrain relative movement of the body and the rotor. The retention member may be adapted to yield, that is plastically deform, in response to a force exceeding a selected threshold, thereby permitting relative movement of the body and the rotor. Alternatively, or in addition, the retention member may be adapted to break or otherwise fail to permit relative movement between the body and the rotor. Thus, on shearing or breaking of the retention member, the body may be adapted for axial movement relative to the rotor to engage the clutch.

The tool may comprise a single retention member. Alternatively, the tool may comprise a plurality of retention members and, in particular embodiments, a number of retention members may be provided around the circumference of the tool.

Alternatively, or in addition, a number of retention members may be provided at axially spaced location along the tool. The retention member may be of any suitable form and, in particular embodiments, the retention member may comprise a shear pin or the like.

The tool may further comprise a nose portion defining a leading end of the tool. The nose portion may comprise a separate component of the tool. The nose portion may be coupled to the body, for example, by a spline connection, thread connection, by adhesive bonding or by another suitable connection. Alternatively, the nose portion may be formed on or with the body. The nose portion may be *:*::* adapted to move with the body. For example, part of the nose portion may be * **.

adapted to engage the leading end of the rotor to block fluid flow exiting the rotor. In particular embodiments, the nose portion may define, or provide mounting for, a plug *.se adapted to engage the rotor to substantially prevent fluid flow through the rotor. In particular embodiments, the plug may comprise a separate component bonded or otherwise secured to at least one of the nose and the body.

The nose portion may define, or provide mounting for, a seal member. The seal member may be of any suitable form. The seal member may comprise a mechanical contact seal, for example. The seal member may comprise an elastomeric seal and, in particular embodiments, the seal member may be constructed from hydrogenated nitrite butadiene rubber (HNBR) or carboxylated nitrile butadiene rubber (XNBR). This provides a relatively high strength seal member capable of maintaining an effective seal on exposure to the temperatures and chemicals that may be experienced in the bore. Alternatively, the seal member may comprise a polymeric seal, metallic seal or other suitable sealing member. For example, the seat member may be constructed from a metallic material such as brass.

The nose portion may further comprise at least one fluid port for permitting fluid to be directed to the exterior of the tool. The provision of a port permits fluid, such as drilling fluid, mud or the like, to be directed through the tool to assist in the removal and/or displacement of obstructions from the bore. At least one of the ports may be integrally formed in the nose portion. Alternatively, or in addition, at least one of the ports may comprise a separate component coupled to the nose. The fluid port may be constructed from any suitable material, including for example a ferrous metal, non-ferrous metal or a material such as ceramic or machinable glass.

In particular embodiments, at least one of the ports may define, or provide mounting for, a nozzle. For example, the nozzle may be adapted to direct fluid from the fluid conduit out from the toot to facilitate removal of obstructions by jetting.

*:*::* The body may define, or provide mounting for, the reaming member.

*::::* 20 Alternatively, or in addition, the nose portion may define, or provide mounting for, the reaming member. The reaming member may be of any suitable form. For example, *.... the reaming member may comprise at least one of: a rib; a blade; a projection; and r the like. The reaming member may be arranged to extend radially to engage the bore to facilitate reaming of the bore. The reaming member, or members, may extend around at least a portion of the circumference of the body and may extend in a spiral, helical, serpentine, or other configuration. In an alternative arrangement, the reaming member may extend substantially axially.

The tool may further comprise an element defining a cutting or grinding surface, for example, polycrystalline diamond compact (PDC) cutters, thermally stable polycrystalline cutters, carbide particles or any other arrangement suitable for assisting in performing the reaming operation. At least one of the body, reaming member and nose portion may provide mounting for the elements.

The tool may further comprise a locking member adapted to axially lock the body to the rotor of rotary drive arrangement. The locking member may be adapted to move from a retracted position to an extended position to selectively lock the body to the rotor of the rotary drive arrangement after engagement of the clutch. The locking member may be of any suitable form and, in particular embodiments, the locking member may comprise a spring mounted pin or the like.

The tool may further comprise a drive cone arrangement comprising a female tapered portion and a male tapered portion. The female tapered portion may be formed on, or coupled to, the body. The male tapered portion may be formed on, or coupled to, the rotor. Where the male tapered portion comprises a separate component, the tool may further comprise a fastener adapted to couple the male tapered portion to the rotor. For example, the fastener may comprise a locking nut adapted to facilitate lock up of the drive cone arrangement.

The tool may further comprise a further retention member, for example a *::::* 20 shear ring, adapted for coupling between the fastener and the male tapered portion.

The drive cone arrangement may assist in alignment of the tool, for example, assisting in centralising and stabilising the body and the rotor during operation and/or assembly.

The tool may be constructed from any suitable material or combination or

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materials, including for example a metallic material or alloy, a ceramic material, a polymeric material, a glass material, a laminate material such as carbon fibre, glass fibre or the like. In particular embodiments, the tool may be constructed from aluminium. At least part of the tool may be adapted to facilitate drilling through the tool. For example, at least part of the tool may be constructed from a readily drillable material which may be frangible or otherwise adapted to break, thereby permitting the tool to be drilled through. In particular embodiments, at least one of the body, nose portion, reaming member, seal member, seal element and fluid port may be frangible or otherwise adapted to break to permit drilling through the tool.

According to another aspect of the present invention there is provided a reaming tool assembly for use in a bore, the assembly comprising: a reaming tool comprising a body having at least one reaming member; and a downhole rotary drive arrangement coupled to the reaming tool, the reaming tool adapted to be selectively operatively coupled to one of a rotor and a stator of a downhole rotary drive arrangement to permit control of the movement of the tool by the rotary drive arrangement.

The assembly may further comprise a tubular component, for example, a casing string, liner string, drill string, connector sub or other tubular component. The rotary drive arrangement may be coupled to the tubular component. The rotary drive arrangement and reaming tool may, for example, be adapted for location in a bore, such as a wellbore or the like, on the tubular component.

In a first configuration, the body is adapted to be selectively operatively * ** coupled to the rotor of the rotary drive arrangement to permit reaming of the bore. * S S

Where the body is operatively coupled to the rotor, the tool may be adapted for S...

rotation at a relatively high speed relative to the tubular component. For example, I...

the tool may be run into the bore substantially without rotation, or with a limited * S.... * I

degree of rotation, and the body may be adapted for high speed rotation independently of the tubular component and at a speed that may otherwise result in 1s1*11 * *25 damage to the tubular component or connections.

The assembly may comprise at least one fluid port for diverting fluid away from the rotary drive arrangement. For example, the fluid port may be adapted to permit fluid communication with an annulus defined between the assembly and the bore. The fluid port may be provided in the tubular component and the fluid port may be adapted to provide fluid communication through the tubular component.

The fluid port may be selectively openable and any suitable arrangement for selectively opening the fluid port may be used. For example, the port may be adapted to open in response to a fluid pressure differential. In particular embodiments, a rupture element may be provided, the rupture element adapted to break or blow out in response to the pressure differential. Alternatively, or in addition, the assembly may comprise a closure member adapted to close the fluid port. Any suitable closure member may be used. For example, the closure member may comprise a sacrificial plug adapted to sit across the fluid port to effect closure of the port. In particular embodiments, the sacrificial plug may comprise a deformable ball or the like. The fluid port may be adapted to be opened and/or re-opened by removal of the closure member. For example, the closure member may be adapted to be pushed through the fluid port by the pressure differential or other selected fluid pressure. In an alternative embodiment, the port may define or provide mounting for S...

a valve, the valve comprising a valve member adapted to permit selective access through the fluid port.

The provision of sacrificial plugs permits the tool to be cycled between configurations where fluid flow is directed through the rotary drive arrangement, for example to permit reaming of the bore, and configurations where fluid flow is diverted away from the rotary drive arrangement, for example to permit cementing operations to be carried out. The tool may be cycled as many times as required, as the sacrificial plugs may be retrieved and reinserted and/or new plugs located over the ports to seal oft the ports.

It should be understood that the features defined above in accordance with any aspect of the present invention may be utilised, either alone or in combination with any other defined feature, in any other aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described by way of example, with reference to the accompanying figures, in which: Figure 1 is a partial longitudinal sectional view of a reaming tool according to an embodiment of the present invention; Figure 2 is a partial longitudinal sectional view of a first portion of the reaming tool of Figure 1; Figure 3 is a partial longitudinal sectional view of a second portion of the reaming tool of Figures 1 and 2; Figure 4 is an enlarged diagrammatic view of a clutch of the reaming tool of Figures 1, 2 and 3; Figure 5A is an enlarged cross sectional view of a portion of the reaming tool of Figures 1, 2 and 3 showing a lock pin in a first position; Figure 5B is an enlarged cross sectional view of a portion of the reaming tool of Figures 1, 2 and 3 showing the lock pin in a second position; "S.

Figure 6A is a diagrammatic view of a reaming tool assembly according to an embodiment of the present invention, the assembly shown in a first configuration; Figure 6B is a diagrammatic view of the assembly of Figure 6A in a second S.....

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configuration; Figure 6C is an enlarged view of a portion of the assembly of Figure 6B; Figure 6D is a diagrammatic view of the assembly of Figures 6A and 6B in a third configuration; and Figure 6E is an enlarged view of a portion of the assembly of Figure 60.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to Figures 1, 2 and 3 of the drawings, there is shown partial longitudinal sectional views of a reaming tool 10 in accordance with an embodiment of the present invention. The tool 10 comprises a reamer body 12 coupled to a motor 14 and, in use, the body 12 and the motor 14 are run into a bore (not shown) on the leading end of a tubular string, such as a casing string (not Shown), and operated to ream the bore wall and/or remove obstructions which may otherwise obstruct or limit further operations in the bore.

In the embodiment shown, the motor 14 comprises a mud-powered motor having a stator 16 and a rotor shaft 18, the stator 16 coupled to the casing string and the rotor shaft 18 rotatably coupled to the stator 16 by bearings 20. In use, fluid flow through the motor 14 causes rotation of the rotor shaft 18 relative to the stator 16 and thus the casing string.

As shown in Figures 1 and 2, the reamer body 12 is coupled to a leading end portion of the rotor shaft 18 by splines 22 with an internal portion 24 of the body 12 engaging an external portion 26 of the rotor shaft 18. A seal element in the form of an 0-ring 28 is provided in a recess or groove 30 in the rotor shaft 18, the seal element 28 adapted to substantially prevent fluid leakage through the portions 24,26.

I... In addition, a bore 32 extends through the reamer body 12 and into the rotor S...

shaft 18, a shear pin 34 secured in the bore 32 by a collar 36. In use, the shear pin 34 is arranged to restrain relative axial movement between the reamer body 12 and the rotor shaft 18.

S.....

S -

As shown most clearly in Figure 3, part of the reamer body 12 defines a radially extending blade portion 38 adapted to engage the bore to facilitate reaming of the bore wall. Elements 40, such as carbide particles, ceramic cutters or other cutting or grinding elements are provided on an outer surface of the blade portion 38 to assist in the grinding and/or cutting away of the bore wall or obstructions.

In addition, a nose portion 42 is coupled to the reamer body 12 by a spline connection 44 or other threaded connection, the nose portion 42 forming a ading end of the tool 10. A seal element in the form of an 0-ring 46 is also provided in a recess or groove 48 defined between the reamer body 12 and the nose portion 42 to substantially prevent fluid leakage between the body 12 and the nose portion 42.

Elements 50, such as carbide particles, ceramic cutters or other cutting or grinding elements are provided on an outer surface of the nose portion 42 to assist in the grinding and/or cutting away of the bore or obstructions.

Furthermore, a fluid conduit 52 is provided in the rotor shaft 18 for directing fluid flow through the nose portion 42, the nose portion 42 further comprising one or more nozzle 54 (one nozzle 54 is shown in Figures 1 and 3) for directing fluid out from the nose portion 42 to assist in the removal or displacement of bore obstructions.

The tool 10 thus defines a first configuration (as shown in Figures 1 to 3) in which the reamer body 12 is adapted to rotate with the rotor shaft 18. Fluid, such as drilling mud, is passed through the motor 14 to rotate the rotor shaft 18 relative to the stator 16. As the body 12 and the shaft 18 are coupled together, the reamer body 12 .... 20 rotates with the shaft 18 to facilitate reaming of the bore. Where required, the body 12 and the nose portion 42 can be reciprocated with the motor 14 to permit reciprocal reaming of the bore or stabbing through bore obstructions, On passing through the nose portion 42, the fluid exits via the nozzles 54 and is then re-circulated to surface (not shown).

The tool 10 alternatively defines a second configuration in which the reamer body 12 is coupled to the stator 16 and thus the casing string so that movement of the reamer body 12 can be controlled by controlling movement of the casing string.

The reamer body 12 is selectively coupled to the stator 16 by a clutch 56 and, in the embodiment shown, the clutch 56 consists of a dog clutch having a drive dog profile 58 coupled to the motor stator 16 and a corresponding driven dog profile 60 coupled to the reamer body 12. Figure 4 shows an enlarged view of the clutch 56, the clutch profiles 58,60 having axially aligned engaging faces 62, though it will be recognised that other arrangements may be used. The profiles 58,60 are formed by a mechanical process, such as a wire erosion process, though other suitable process may be used where appropriate. The manufacturing process is selected to provide high tolerances in the dimensions of the profiles 58,60 such that a substantially sealed connection is provided between the drive dog profile 58 and the driven dog profile 60 on engagement of the clutch 56. The profiles 58,60 are also subject to a drop forging process whereby the profiles are plastically deformed, this assisting in improving the circumferential shear strength of the clutch.

In use, engagement of the clutch 56 is achieved by applying weight from surface, the weight applied being selected to piasticaily deform the shear pin 34.

Beneficially, the shear pin 34 will yield without breaking to assist in holding the tool together while permitting relative movement between the reamer body 12 and rotor shaft 18. Thus, the reamer body 12 moves axially relative to the rotor shaft 18 until the clutch profiles 58,60 engage, engagement of the clutch 56 permitting control over the axial and rotational movement of the tool 10 by the stator 16 and casing I.., .... 20 string and/or holding of the reamer body 12 to permit drilling through operations or to facilitate cementing operations in the bore. S...

In reference now in particular to Figure 3 and also to Figures 5A and 5B of the drawings, a spring-mounted lock pin 64 is coupled to the rotor shaft 18, the lock pin 64 located in a bore 66 in the rotor shaft 18. The lock pin 64 is biased radially outwards by a spring 68 and, in use, the lock pin 64 is adapted to move from a retracted position when the tool 10 is in the first, clutch disengaged, configuration (Figure 4A) to an extended position (Figure 4B) when the tool 10 is in the second, clutch-engaged configuration. In this second configuration, the pin 64 engages a recess or slot 70 in the reamer body 12 to axially lock the body 12 and the shaft 18 on engagement of the clutch 56.

The tool 10 further comprises a drive cone arrangement 72 having a female tapered portion 74 formed on the reamer body 12 and a male tapered portion 76 coupled to the rotor shaft 18. The male portion 76 is coupled to the rotor shaft 18 by an axial tension nut 78 and a shear ring 80 is provided therebetween.

During assembly of the tool 10, an axial tensile force is generated by the interaction between the female tapered portion 74, the male tapered portion 76, the shear ring 80 and the axial tension nut 78. On assembly, torque is applied to the nut 78, which generates a force urging the shaft 18 to move towards the leading end of the tool 10. The torque is selected to maximise system tension and compression without plastically deforming the shear pin 34.

In use, the motor 14 can be disconnected from the reamer body 14 by applying an upwards axial force to the casing string, that is a force in the opposing direction to the normal direction of travel of the tool 10. This force shears through both the shear pin 34 and the shear ring 80, thereby permitting separation of the motor 14 and body 12. The motor 14 may be withdrawn from the bore and the body 12 can be retrieved from the bore by a fishing tool or the like (not shown) or drilled *:*::* through.

*** 20 As shown most clearly in Figure 1, the nose portion 42 further comprises a plug 82 formed by a male portion 84, the male portion 84 adapted to engage a female distal end 86 of the rotor shaft conduit 52. The male portion 84 provides mounting for an elastomeric mechanical contact seal element 88, whereby the seal element 88 is adapted to engage the female portion 86 on engagement of the clutch 56 to substantially seal and/or prevent flow of fluid through the nose portion 42.

Sealing off fluid flow through the nose portion 42 permits fluid pressure to be built up above the tool 10, this permitting fluid flow to be diverted away from the tool 10 as will described in more detail below.

Referring now to Figures 6A to 6E, there is shown a reaming toot assembly according to an embodiment of the present invention. As shown in Figure 6A, the assembly 110 comprises a motor 114 and a reamer body 112 having reaming blades 138. The motor 114 and the body 112 are similar to the motor 14 and the reaming tool 10 described in relation to Figures 1 to 5B and like components are represented hereinbelow by like numerals incremented by 100. The motor 114 and body 112 are coupled to the leading end of a tubular component or string or tubular components such as a casing string 101. The assembly 110 is adapted for location in a wellbore 102 and an annulus 103 is defined between the assembly 110 and the bore 102. In a first configuration, the reamer body 112 is coupled to a rotor shaft (not shown) of the motor 114 to permit rotation of the body 112 relative to the string 101, thereby permitting reaming of the bore 102. In a second configuration, the reamer body 112 is locked to a stator (not shown) of the motor 114 to permit controlled movement of the body 112 with the string 101.

In addition, fluid ports 104 are provided in the string 101 to permit fluid access between an internal bore 105 of the string 101 and the annulus 103. As shown in Figure 6A, the fluid ports 104 are initially closed by rupture discs 106 such that fluid flow through the string 101 is directed through the motor 114 to drive rotation of the body 112 to ream the bore 102. The fluid is directed through nozzles 154 of nose * .* S portion 142 to assist in reaming the bore 102 by jetting.

Accordingly, the assembly 110 is operated to permit reaming of the bore 102, S...

for example to remove obstructions in the bore 102, including for example, ledges *: extending into the bore 102, drill cuttings or the like.

Referring now in particular to Figures 6A, 6B and 6C, on encountering the total depth (TO) of the wellbore 102 or an impassable obstruction 107, weight is applied from surface (not shown) to engage the clutch (represented schematically by numeral 156 in Figures 6A and 6B) and seat the fluid conduit 152 through the nose portion 142. Fluid pressure breaches the rupture discs 106 and diverts fluid to the annulus 103. The fluid is then re-circulated to surface (not shown). The assembly is locked in position relative to the string 101, for example to facilitate drilling through the assembly 110 or to permit a cementing operation to be carried out.

Referring now to Figures 60 and 6E, where it is desirable to re-establish flow through the motor 114 and the body 112, sacrificial plugs 108 are dropped or otherwise located in the internal bore 105 of the string 101, the plugs 108 blocking flow through the fluid ports 104. In the embodiment shown, the sacrificial plugs 108 comprise deformable balls of larger diameter than the ports 104, the balls 108 travelling with the fluid flow and becoming fixed into the ports 104. Fluid is thus re-directed through the motor 114 and the body 112 to permit further reaming of the wellbore 102. In addition, the assembly 110 may be lifted off TD or away from the* obstruction 107 to permit fluid flow through the nozzles 154 of the nose portion 142 and to permit re-circulation of the fluid to surface via the annulus 103.

Locking of the assembly 110 may again be achieved by applying weight to the assembly 110 to seal off fluid flow through the conduit 152. Pressure increases, the pressure acting to force the balls 108 through the ports 104, which are then returned to surface with the return flow.

It should be understood that the embodiments described are merely *:*::* exemplary of the present invention and that various modifications may be made S...

without departing from the scope of the invention.

*::::* For example, although one shear pin is shown in Figure 1, a plurality of shear pins may be provided and the shear pins may be spaced around the circumference :* of the tool. Although the embodiment describes the use of an integral collar to secure the shear pin in place, any suitable arrangement, such as a circlip, may be used where appropriate.

In addition, the engaging face of the clutch may be arranged at an angle to a longitudinal axis of the tool.

Claims

CLAIMS1. A reaming tool adapted for location in a bore, the tool comprising: a body comprising at least one reaming member, the body adapted to be selectively operatively coupled to one of a rotor and a stator of a downhole rotary drive arrangement to permit control of the movement of the body by the rotary drive arrangement.
2. The reaming tool of claim 1, wherein the rotary drive arrangement comprises at least one of: mud-powered motor; fluid turbine; axial vane hydraulic motor; a positive displacement motor; an electric motor; an impellor; a pelton wheel, a radial reaction turbine; and Francis turbine; and cross flow turbine.
3. The reaming tool of claim 1 or 2, wherein the rotor and the tool define a fluid conduit for directing fluid through the tool.
4. The reaming tool of claim 1, 2 or 3, further comprising a clutch for permitting selective engagement between the body and the stator of the rotary drive arrangement.* ** * * S Se..
5. The reaming tool of claim 4, wherein the clutch comprises a clutch drive member formed on or coupled to the stator. S. *S * S S * S
6. The reaming tool of claim 4 or 5, wherein the clutch comprises a clutch driven member formed on or coupled to the body.
7. The reaming tool of claim 4, 5 or 6, wherein the clutch comprises corresponding profiles manufactured by a wire erosion process.
8. The reaming tool of claim 4, 5 or 6, wherein the clutch comprises corresponding profiles manufactured by at least one of: laser cutting; precision machining; and computer numeric control machining; and a drop forging process.
9. The reaming tool of claim any one of claims 4 to 8, wherein the clutch defines a dog clutch.
10. The reaming tool of any one of claims 4 to 8, wherein the clutch comprises a slip clutch.
11. The reaming tool of any preceding claim, further comprising a retention member coupled between the body and the rotor.
12. The reaming tool of claim 11, wherein the retention member is adapted to yield to permit relative movement of the body and the stator.
13. The reaming tool of claim 11 or 12, wherein the retention member is adapted to break to permit relative movement between the body and the rotary drive . 20 arrangement. S... S... * S S...
14. The reaming tool of any preceding claim, wherein the body is adapted for axial movement relative to the rotor. S. ** * S * * .S

*..*.* *
15. The reaming tool of any one of claims 11 to 14, wherein the retention member comprises a shear pin.
16. The reaming tool of any preceding claim, further comprising a nose portion defining a leading end of the tool.
17. The reaming tool of claim 16, wherein the nose portion comprises a separate component of the tool.
18. The reaming tool of claim 16 or 17, wherein the nose portion is adapted to engage the rotor on axial movement of the body relative to the rotor.
19. The reaming tool of any preceding claim, further comprising a plug adapted to engage the rotor to substantially prevent fluid flow through the tool.
20. The reaming tool of claim 19, wherein the plug is coupled to the nose.
21. The reaming tool of claim 19, wherein the plug is coupled to the body.
22. The reaming tool of any one of claim 16 to 21, wherein the nose portion comprises a seal member. * ** * * * * *s

* .* *
23. The reaming tool of claim 22, wherein the seal member comprises a mechanical contact seal. * S**** * *

*:*
24. The reaming tool of claim 22 or 23, wherein the seal member comprises an elastomeric seal member.
25. The reaming tool of claim 22 or 23, wherein the seal member comprises a polymeric seal member.
26. The reaming tool of claim 22 or 23, wherein the seal member comprises a metallic seal member.
27. The reaming tool of any one of claims 16 to 26, wherein the nose portion further comprises at least one fluid port for permitting fluid to be directed to the exterior of the tool.
28. The reaming tool of claim 27, wherein at least one of the fluid ports comprises a nozzle.
29. The reaming tool of any preceding claim, wherein the body defines or provides mounting for the reaming member.
30. The reaming tool of any one of claims 16 to 28, wherein the nose portion defines or provides mounting for the reaming member.
31. The reaming tool of any preceding claim, wherein the reaming member comprises at least one of: a rib; a blade; and a projection. * ** * S * * SS S.S. 20
32. The reaming tool of any preceding claim, further comprising an element ** defining a cutting or grinding surface. *.S

S.....

*:.
33. The reaming tool of claim 32, wherein the element comprises at least one of: polycrystallirie diamond compact (POC) cutters; thermally stable polycrystalline cutters (TSP) and carbide particles.
34. The reaming tool of any preceding claim, further comprising a locking member adapted to selectively lock the body to the rotor of rotary drive arrangement.
35. The reaming tool of claim 34, wherein the locking member is adapted to selectively lock the body to the rotor of the rotary drive arrangement after engagement of the clutch.
36. The reaming tool of claim 34 or 35, wherein the locking member comprises a spring mounted pin.
37. The reaming tool of any preceding claim, further comprising a drive cone arrangement comprising a female tapered portion and a male tapered portion.
38. The reaming tool of claim 37, wherein the female tapered portion is coupled to or formed on the body.
39. The reaming tool of claim 37 or 38, wherein the male tapered portion is coupled to or formed on the rotor.
40. The reaming tool of claim 37, 38 or 39, further comprising a fastener adapted * .S to couple the male tapered portion to the rotor. S... * . *S.*
41. The reaming tool of claim 40, wherein the fastener comprises a locking nut S...adapted to facilitate lock up of the drive cone arrangement. S. *. * . . * .
42. The reaming tool of any preceding claim, further comprising a retention member adapted for coupling between the fastener and the male tapered portion.
43. The reaming tool of claim 42, wherein the retention member comprises a shear ring.
44. The reaming tool of any preceding claim, wherein the tool is constructed from at least one of: a metallic material; metallic alloy; a ceramic material; a polymeric material; a glass material; a laminate material; a carbon fibre material; and a glass fibre material.
45. The reaming tool of any preceding claim, wherein the tool is constructed from aluminium.
46. The reaming tool of any preceding claim, wherein at least part of the tool is adapted to facilitate drilling through the tool.
47. The reaming tool of any preceding claim, wherein at least part of the tool is frangible or otherwise adapted to break to permit drilling through the tool.
48. A reaming tool assembly for use in a bore, the assembly comprising: a reaming tool comprising a body having at least one reaming member; and a downhole rotary drive arrangement coupled to the reaming tool, the reaming tool adapted to be selectively operatively coupled to one of a rotor and a ** . stator of a downhole rotary drive arrangement to permit control of the movement of the tool by the rotary drive arrangement. * *
49. The assembly of claim 48, further comprising a tubular component.

*S.*.* * S
50. The assembly of claim 49, wherein the tubular component comprises at least one of a casing string, liner string, drill string, and connector sub.
51. The assembly of claim 49 or 50, wherein the rotary drive arrangement is coupled to the tubular component.
52. The assembly of claim 49, 50 or 51, wherein the rotary drive arrangement and reaming tool are adapted for location in the bore on the tubular component.
53. The assembly of any one of claims 48 to 52, further comprising at least one fluid port for diverting fluid away from the rotary drive arrangement.
54. The assembly of claim 53, when dependent on claim 49, wherein the fluid port is provided in the tubular component and the fluid port is adapted to provide fluid communication through the tubular component.
55. The assembly of claim 53 or 54, wherein the fluid port is selectively openable.
56. The assembly of claim 53, 54 or 55, wherein the port is adapted to open in response to a fluid pressure differential.
57. The assembly of any one of claims 48 to 56, further comprising a rupture .... 20 element adapted to break in response to the pressure differential. a... * S a...

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58. The assembly of any one of claims 53 to 57, further comprising a closure member adapted to close the fluid port. S *
59. The assembly of claim 58, wherein the closure member comprises a sacrificial plug adapted to sit across the fluid port to effect closure of the port.
60. The assembly of claim 59, wherein the sacrificial plug comprises a deformable ball.
61. The assembly of claims 58 to 60, wherein the fluid port is adapted to be opened by removal of the closure member.
62. The assembly of any one of claims 58 to 61, wherein the closure member is adapted to be pushed through the fluid port by fluid pressure.
63. The assembly of any one of claims 48 to 62, further comprising a valve adapted to permit selective access through the fluid port.
64. A reaming tool substantially as described herein and as shown in the accompanying drawings.
65. A reaming tool assembly substantially as described herein and as shown in the accompanying drawings. * ** * * S * ** S... * . *5IS * S S...SI..... * S *. .* * S * * *S*SSSSS S *