Reaming tool

1. A reaming tool for use in reaming a bore, the tool comprising:

a body adapted for location in a bore, the body defining at least one of a rotor and a stator of a rotary drive arrangement;

a shaft adapted for location in the body, the shaft defining the other of a stator and a rotor of the rotary drive arrangement;

a seal element adapted for location between the shaft and the body, the seal element adapted to define a sealing surface for permitting sealed relative rotation of the rotary drive arrangement, wherein the seal element defines a plain bearing

a fluid conduit formed inside the body and in the shaft configured to direct substantially all fluid flow through the reaming tool to the rotary drive arrangement to cause rotation thereof; and

a reaming member, wherein relative rotation between the body and the shaft facilitates reaming of the bore by the reaming member.

2. The reaming tool of claim 1 , wherein the seal element comprises a substrate having a coating of hard material.

3. The reaming tool of claim 2 , wherein at least one of:

the substrate comprises at least one of: aluminium; aluminium alloy; phosphor bronze; and ceramic material;

the coating comprises at least one of: tungsten; carbide; and cobalt; and

the coating is adapted to be applied by a high velocity oxygen fuel process.

4. The reaming tool of claim 1 , wherein the rotary drive arrangement comprises at least one of: a fluid turbine; an axial vane hydraulic motor; a positive displacement motor; an electric motor.

5. The reaming tool of claim 1 , wherein at least one of:

the shaft is adapted to be held stationary and the body is adapted for rotation relative to the shaft; and

the body and the shaft are adapted for relative rotation.

6. The reaming tool of claim 1 , wherein the body and the shaft are adapted for relative rotation, the shaft being adapted for rotation in an opposing direction to rotation of the body.

7. The reaming tool of claim 1 , wherein the tool further comprises a nose forming a leading end of the tool.

8. The reaming tool of claim 7 , wherein at least one of:

the reaming member is provided on the nose;

the nose is coupled to the body and is adapted for rotation with the body; and

the nose is coupled to the shaft and is adapted for at least one of rotation and reciprocation with the shaft.

9. The reaming tool of claim 7 , wherein the nose further comprises at least one fluid port for permitting fluid to be directed to the exterior of the tool.

10. The reaming tool of claim 9 , wherein at least one of:

at least one of the ports defines a nozzle;

at least one of the ports is integrally formed with the nose; and

at least one of the ports comprises a separate component coupled to the nose.

11. The reaming tool of claim 1 , wherein the tool comprises at least one reaming member, and wherein the at least one reaming member comprises at least one of: a rib; a blade; a projection; a cutting element; a grinding element; a polycrystalline diamond compact cutter; and a carbide particle.

12. The reaming tool of claim 11 , wherein the reaming member extends axially relative to the body.

13. The reaming tool of claim 11 , wherein the reaming member extends around at least a portion of the circumference of the body.

14. The reaming tool of claim 11 , wherein the reaming member extends in at least one of: a spiral configuration; a helical configuration; a serpentine configuration.

15. The reaming tool of claim 1 , wherein the reaming tool is constructed from at least one of: a metallic material; a metal alloy; a ceramic material; a polymeric material; a glass material; a laminate material; and a carbon fibre material.

16. The reaming tool of claim 1 , wherein at least part of the reaming tool is adapted to facilitate drilling through the tool, and wherein at least one of the body, the shaft, a nose, a reaming element, a bearing, a seal element and a fluid port are constructed from a drillable material.

17. The reaming tool of claim 1 , further comprising a tubular string assembly coupled thereto.