TRANSMISSION SYSTEM FOR COMMUNICATION BETWEEN DOWNHOLE ELEMENTS

• US 20130048269A1
• Filed: 05/12/2011
• Published: 02/28/2013
• Est. Priority Date: 05/12/2010
• Status: Active Grant

• Current Assignee: Roxar Flow Measurement As
• Original Assignee: Andre Johann Blindheim, Oyvind Wetteland
• Inventors: Tarayre, Christophe, Blindheim, Andr Johann, Wetteland, yvind
• Granted Patent: US 9,217,327 B2
• Time in Patent Office: Days
• US Class Current: 166/65.1
• CPC Class Codes: E21B 47/13 by electromagnetic energy, e.g. radio frequency
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/72 for local intradevice communication

Abstract

The invention relates to a transmission system for transmitting signals between an inner and an outer unit separated by an annular pipe section wall, wherein said inner unit is provided with a first antenna and the second unit is provided with a second antenna, the antennas preferably constituted by coils, being adapted to be brought into essentially the same positions along the pipe section, wherein said pipe section is made from a material having low magnetic permeability and wherein at least one of the antennas is provided magnetic shield having high magnetic permeability, the corresponding antenna being positioned between the pipe wall and the magnetic shield and the magnetic shield extending along the length of the antenna.

Claims

1. A transmission system for transmitting signals between an inner and an outer unit separated by an annular pipe section wall providing a pressure barrier between the inside and outside of said pipe and an annular gapadapted to contain a fluid, wherein said inner unit is provided with a first antenna and the outer unit is provided with a second antenna, the antennas being adapted to be brought into essentially the same positions along the pipe section, wherein said pipe section wall is made from a material having low magnetic permeability and wherein at least one of the antennas is provided magnetic shield having high magnetic permeability, the corresponding antenna being positioned between the pipe wall and the magnetic shield and the magnetic shield extending along the axial length of the antenna.

2. The transmission system according to claim 1, wherein the antennas are constituted by conductive coils the axis of which being essentially coaxial with the pipe section.

3. The transmission system according to claim 1, wherein an annular channel is positioned between at least one antenna and the pipe section wall.

4. The transmission system according to claim 1, wherein the magnetic shield is included in a hermetic sealing enclosing the corresponding antenna.

5. The transmission system according to claim 1, wherein both antennas are provided with magnetic shields.

6. The transmission system according to claim 1, wherein the antennas are operated in the frequency range of 1 Hz-5 kHz, preferably less than 1 kHz.

7. The transmission system according to claim 1, wherein a first of said units comprises a coupling to an external power supply and the second unit comprises a sensor coupled thereto, the first antenna being adapted to transmit power to the second antenna.

8. The transmission system according to claim 7, wherein said second unit comprises a sensor being powered through said transmitted power, the sensor and corresponding antenna also being adapted to transmit signals to the antenna in said first unit.

9. The transmission system according to claim 1, wherein a first of said units comprises a coupling to an signal transmission line and the second unit comprises a sensor coupled thereto, the transmission system thus being adapted to transmit signals between said signal transmission line and said sensor through the antennas.

10. A transmission unit for use in a transmission system for transmitting signals between an inner and an outer unit separated by an annular pipe section wall, the transmission unit constituting one of said inner or outer units, wherein an antenna is placed in said unit, the unit being provided with a hermetic shield constituted by a complete metal cover of the windings.

11. An antenna according to claim 10, wherein the hermetic shield is made from a Nickel alloy.

12. An antenna according to claim 10, wherein the hermetic seal is made from a metal foil having a thickness less than 1 mm.

13. An antenna according to claim 10, wherein the hermetic shield comprises a magnetic shield having high magnetic permeability, the corresponding antenna being positioned between the pipe wall and the magnetic shield and the magnetic shield extending along the length of the antenna.

14. An antenna according to claim 10, wherein the antenna is constituted by a coil of magnetic wire.