DOWNHOLE ASSEMBLY

• US 20110120772A1
• Filed: 09/04/2008
• Published: 05/26/2011
• Est. Priority Date: 09/04/2007
• Status: Active Grant

• Current Assignee: George Swietlik, Stephen John Mcloughlin
• Original Assignee: George Swietlik, Stephen John Mcloughlin
• Inventors: McLoughlin, Stephen John, Swietlik, George
• Granted Patent: US 8,622,153 B2
• Time in Patent Office: Days
• US Class Current: 175/56
• CPC Class Codes: E21B 17/05 Swivel joints
• CPC Class Codes: E21B 17/07 Telescoping joints for varying drill string lengths; Shock absorbers
• CPC Class Codes: E21B 17/073 with axial rotation
• CPC Class Codes: E21B 17/10 Wear protectors; Centralising devices , e.g. stabilisers
• CPC Class Codes: E21B 17/1014 Flexible or expansible centering means, e.g. with pistons pressing against the wall of the well E21B17/1042 takes precedence
• CPC Class Codes: E21B 17/1078 Stabilisers or centralisers for casing, tubing or drill pipes devices for off-center positioning E21B17/10; E21B17/1007 - E21B17/1064 take precedence
• CPC Class Codes: E21B 41/0085 Adaptations of electric power generating means for use in boreholes

Abstract

A downhole assembly for insertion into a borehole comprising an articulated mandrel, a passive and an active damping mechanism operating on said mandrel for exercising control over torsional stick-slip and further proposing an improvement over the prior art which diminishes lateral shock.

Claims

1. A downhole assembly for insertion into a borehole comprising an articulated mandrel, a passive and an active damping mechanism operating on said mandrel.

2. A downhole assembly according to claim 1, wherein said active damping mechanism acts in a direction with a component substantially perpendicular to the axis of the borehole.

3. An assembly according to claim 1, wherein said active damping mechanism comprises a hydraulic damping mechanism.

4. An assembly according to claim 1, wherein said active damping mechanism comprises resilient material.

5. An assembly according to claim 3, wherein said hydraulic damping mechanism comprises a plurality of piston assemblies acting on said mandrel, wherein each piston assembly comprises a plurality of pistons in fluid communication with one another.

6. An assembly according to claim 5, wherein hydraulic fluid is transferred between pistons in the same piston assembly in a closed loop.

7. An assembly according to claim 6, wherein each assembly comprises at least two pistons at differing positions along the axis of the borehole.

8. An assembly according to claim 1 wherein said damping mechanisms comprise electro-mechanical or electro-hydraulic valve means.

9. An assembly according to claim 8, wherein said electro-mechanical or electro-hydraulic valve means are configured to control the flow of fluid between said pistons.

10. An assembly according to claim 1, wherein the active damping mechanism comprises rheological materials.

11. An assembly according to claim 10, further comprising magnets configurable to influence the properties of said rheological materials.

12. An assembly according to claim 1, wherein said active and passive damping means are configured to provide lateral, axial and torsional damping.

13. An assembly according to claim 1, further comprising a stabilizer member configured to center said assembly in a borehole, said stabilizer comprising a plurality of blades and configured to provide energy dissipation to said borehole wall.

14. An assembly according to claim 13, wherein said active damping mechanism is at least partially housed in at least one of said blades.

15. An assembly according to claim 1, wherein said articulated mandrel comprises a first part and a second part further configured to provide a torque transfer mechanism between said first mandrel part and said second mandrel part and wherein said mandrel parts are connected in an articulated manner thereby allowing relative motion between said mandrel parts.

16. An assembly according to claim 15, wherein the relative motion has a component lateral to the axis of the bore hole.

17. An assembly according claim 1, further comprising piezo electric members configured to convert vibrations in said assembly into an electrical output.

18. An assembly according to claim 17, wherein said electrical output provides power for said active damping mechanism proportional to any one of input vibration amplitude or frequency.

19. An assembly according to claim 17, adapted to use the output from the piezo electric members for measurement, as a means of quantifying forces to be applied or as an actuation motive means within the device.

20. An assembly according claim 1, further comprising a torque transfer mechanism and a resilient fluid passageway adapted to provide intra-structural support thereby serving to isolate said torque transfer mechanism and said active vibration damping mechanism from drilling fluids.

21. An assembly according claim 1, further comprising receiving means configured to receive information from sensors located within the drilling assembly

22. An assembly according claim 1, wherein said receiving means is configured to receive information from a plurality of locations within the environ of the borehole or on the drilling apparatus.

23. A downhole assembly comprising piezo electric members configured to output an electrical signal in response to vibration of the assembly and controlling means for controlling an aspect of said downhole assembly, wherein the assembly is configured to provide a proportional control voltage for the controlling means from the magnitude of the electric signal outputted from the piezo electric members.

24. A downhole assembly according to claim 23, wherein the control voltage is provided by the electric signal outputted from the piezo electric members.

25. A downhole assembly according to claim 23, wherein said control means comprises means to damp vibrations in the downhole assembly.

26. A method of controlling vibration in a downhole assembly said method comprising;

providing an articulated mandrel in a borehole; and

both passively and actively damping said mandrel.

27. A method according to claim 26, wherein the damping capability is modifiable and variable in both frequency and amplitude, responsive to harmonic vibration encountered in the environs of a drill bit in communication with the articulated mandrel.

28. A method according to claim 26, wherein said damping is hydraulic and hydraulic actuation is proportional, continuous, discontinuous, intermittent or sporadic in response to particular harmonic vibration encountered by said articulated mandrel located in the environs of a drill bit.