Load-resistant coaxial transmission line

• US 6,982,384 B2
• Filed: 09/25/2003
• Issued: 01/03/2006
• Est. Priority Date: 09/25/2003
• Status: Expired due to Term

• Current Assignee: IntelliServ, LLC (NOV, Inc.)
• Original Assignee: Intelliserv, Inc. (NOV, Inc.)
• Inventors: Hall, David R., Fox, Joe
• Primary Examiner(s): Mayo, III, William H.
• Application Number:
  US10/605,373
• Publication Number:
  US 20050067159A1
• Time in Patent Office: 831 Days
• Field of Search: 174/15.1, 174/15.4, 174/15.5, 174/21.R, 174/25.R, 174/25.G, 174/28, 174/36, 174/102.R, 174/74.R, 174/78, 385/854.9
• US Class Current: 174/102.00R
• CPC Class Codes: E21B 17/003 with electrically conducting or insulating means E21B17/028 and E21B17/023 take precedence
• CPC Class Codes: E21B 17/0285 characterised by electrically insulating elements
• CPC Class Codes: H01B 11/1865 having the shape of a bead
• CPC Class Codes: H01B 13/0006 for reducing the size of conductors or cables
• CPC Class Codes: H01B 7/046 attached to objects sunk in bore holes, e.g. well drilling means, well pumps

Abstract

A transmission line for downhole tools that make up all or part of a tool string for drilling and production of oil, gas, and geothermal wells that can withstand the dynamic gravitational forces and other accelerations associated with downhole excavations. The transmission line has a metal tube, or outer conductor, that houses a coaxial wire inner conductor. A non-metallic dielectric material is interposed between the inner and outer conductors. The outer and inner conductors and the dielectric are sufficiently compressed together so that independent motion between them is abated. Compression of the components of the transmission line may be achieved by drawing the transmission through one or more dies in order to draw down the outer conductor onto the dielectric, or by expanding the inner conductor against the dielectric using a mandrel or hydraulic pressure. Non-metallic bead segments may be used in aid of the compression necessary to resist the dynamic forces and accelerations of drilling.

Claims

1. A transmission line for a downhole tool, the transmission line comprising a generally tubular outer conductor with a high strength material adjacent a highly conductive material;

an inner conductor generally co-axially disposed within the outer conductor, and a dielectric material disposed intermediate the inner and outer conductors, the dielectric material intially loosely fitted relative to at least one of the outer and the inner conductors;

wherein at least one of the outer and the inner conductors is further deformed to provide an interference fit with the dielectric material, such that independent motion between the outer conductor, inner conductor, and the dielectric material is substantially abated during deployment of the downhole tool.

2. The transmission line of claim 1 wherein the downhole tool is selected from the group consisting of well casings, drill pipes, heavy weight drill pipes, drill collars, tool joints, jars, motors, turbines, batteries, shock absorbers, reamers, drill bits, pumps, hydraulic hammers, pneumatic hammers, electronic subs, logging subs, sensor subs, directional drilling subs, repeaters, swivels, nodes, repeaters, and downhole assemblies.

3. The transmission line of claim 1 , wherein the inner and the outer conductors comprise materials having electrical conductivity at least about 60% of the International Annealed Copper Standard (IACS).

4. The transmission line of claim 1, wherein an inside surface of the outer conductor is in contact with a material having electrical conductivity at least 60% of the IACS.

5. The transmission line of claim 1, wherein the inner conductor comprises a wire, a stranded wire, a braided wire, or a combination thereof.

6. The transmission line of claim 1, wherein the dielectric material is a substantially non-porous material.

7. The transmission line of claim 1, wherein the dielectric material is a substantially porous material.

8. The transmission line of claim 1, wherein the dielectric material comprises a gas.

9. The transmission line of claim 1, wherein the dielectric material comprises porous and/or non-porous, segmented beads.

10. The transmission line of claim 1, wherein the dielectric material comprises a gaseous material associated with a porous material.

11. The transmission line of claim 1, wherein the outer conductor has an outer surface, a portion of which exhibits a rough texture.

12. The transmission line of claim 1, wherein the outer conductor is attached to the downhole tool.

13. The transmission line of claim 12, wherein the outer conductor is attached to the downhole tool by a clamp connection or a plug connector.

14. The transmission line of claim 12, wherein the outer conductor is attached to the downhole tool by a threaded connector.

15. The transmission line of claim 12, wherein the outer conductor is attached to the downhole tool by a liner disposed within said downhole tool.

16. The transmission line of claim 1, wherein the interference between the outer conductor, the dielectric, and the inner conductor is a diametric interference of between about 0.001 and about 0.005 inches.

17. The tranamission line of claim 1, wherein to outer conductor, to dielectric, and the inner conductor are in sufficient contact to withstand gravitational loads of between 100 and 500 g'"'"'s.

18. The transmission line of claim 1, wherein the inner conductor, the dielectric, an the outer conductor are capable of elastic strain of at least about 0.3%.

19. A transmission line for a downhole tool, the transmission line comprising a generally tubular outer conductor attached to the downhole tool;

an inner conductor generally co-axially disposed within the outer conductor, and a dielectric material disposed intermediate the inner and outer conductors, the dielectric material initially loosely fitted relative to at least one of the outer and the inner conductors;

wherein at least one of the outer and the inner conductors is further deformed to provide an interference fit with the dielectric material, and compressing the dielectric material such that independent motion between the outer conductor, inner conductor, and the dielectric material is substantially abated during deployment of the downhole tool.

20. The transmission line of claim 19, wherein the compression of the dielectric material is due to further deformation between the outer conductor and the inner conductor of between about 0.001 inches and about 0.005 inches.

21. The transmission line of claim 19, wherein the outer conductor is attached to the downhole tool by a clamp connection or a plug connector.

22. The transmission line of claim 19, wherein the outer conductor is attached to the downhole tool by a liner disposed within said downhole tool.