Reliable wired-pipe data transmission system
A high-frequency data and/or power transmission system suitable for downhole use including signal/power couplers, transmission line segments and signal repeaters. Signals and power are/is transmitted between couplers and/or between couplers and repeaters by means of electromagnetic resonance coupling. In at least a portion of the system, the transmission line segments form parallel data paths and the repeaters provide crossover capability between the data/power paths, thereby significantly improving reliability. The invention also includes methods of transmitting data and/or distributing high-frequency power through a downhole transmission system including multiple data/power paths and multiple crossovers wherein a fault location in one data/power path is bypassed by routing data and/or power to a parallel data/power path by means of electromagnetic resonance coupling.
1. A downhole signal transmission system for communicating along a string of interconnected downhole components, comprising:
at least one communications line that carries radiofrequency signals along the string of downhole components:
at least one communications sub; and
a plurality of signal repeaters spaced along said string of downhole components, the plurality of signal repeaters including a first electromagnetic coupler mounted on a first end of each of the plurality of signal repeaters and adapted to provide resonant coupling and a second electromagnetic coupler mounted on a second end of each of the plurality of signal repeaters and adapted to provide resonant coupling, said signal repeaters being receptive to radiofrequency signals, the radiofrequency signals occurring between 30 megahertz (MHz) and 3 gigahertz (GHz),
wherein said at least one communications sub communicates over said at least one communication line by modulating data onto said radiofrequency signals, and
wherein said radiofrequency signals bypass at least one signal repeater when said at least one signal repeater fails.
2. A downhole transmission system as in claim 1 , wherein said string of downhole components comprises a drill string, a completion string, or a casing string.
3. A downhole transmission system as in claim 1 ,
wherein high-frequency power is carried by at least one of said at least one communication line, and
wherein said high-frequency power is used to power repeaters and/or sensor electronics, and/or for recharging rechargeable batteries.
4. A downhole signal transmission system as in claim 1 , wherein said signal repeater comprises at least one bypass signal path.
5. A downhole signal transmission system as in claim 1 ,
wherein said at least one communications line includes a plurality of transmission segments connected in parallel so as to form parallel data paths along the downhole string, and
wherein at least one of said signal repeaters comprises a crossover path between said parallel data paths.
6. A downhole signal transmission system as in claim 1 , wherein said data is organized in message packets.
7. A downhole signal transmission system as in claim 1 , wherein said communications sub modulates said data onto said radiofrequency signals using burst modulation.
8. A downhole signal transmission system as in claim 1 ,
wherein at least one of said signal repeaters has an ID;
wherein said at least one signal repeater transmits information regarding said ID; and
wherein said information is used to detect and/or locate failed repeaters.
9. A downhole signal transmission system as in claim 1 ,
wherein at least one of said signal repeaters measures received signal strength;
wherein said at least one signal repeater transmits information regarding said received signal strength; and
wherein said information is used to detect and/or locate faults.
10. A downhole transmission system as in claim 1 ,
wherein at least one of said signal repeaters comprises a sensor circuit, and
wherein said at least one signal repeater transmits information regarding sensor data.
11. A downhole signal transmission system as in claim 10 , wherein said transmitted sensor data information is used to adjust the rate of rotation, the drilling speed, and/or the weight-on-bit drilling parameters.
12. A downhole signal transmission system as in claim 10 , wherein said signal repeater transmits said sensor data information upon interrogation by said communications sub.
13. A downhole signal transmission system as in claim 10 , wherein said signal repeater transmits said sensor data information automatically without interrogation by said communications sub.
14. A method of providing communications along a string of interconnected downhole components, comprising:
providing radiofrequency signals having data modulated thereon along the string of downhole components through at least one communications line, wherein the radiofrequency signals are between 30 megahertz (MHz) and 3 gigahertz (GHz);
amplifying the radiofrequency signals using a plurality of signal repeaters spaced along said string of downhole components, the plurality of signal repeaters including a first electromagnetic coupler mounted on a first end of each of the plurality of signal repeaters and adapted to provide resonant coupling and a second electromagnetic coupler mounted on a second end of each of the plurality of signal repeaters and adapted to provide resonant coupling; and
said radiofrequency signals bypassing at least one signal repeater when said at least one signal repeater fails.
15. A method as in claim 14 , further comprising providing high-frequency power over said at least one communications line and using said high-frequency power to power repeaters, sensor electronics, and/or for recharging rechargeable batteries.
16. A method as in claim 14 , further comprising forming in said at least one communications line a plurality of transmission segments connected in parallel so as to form parallel data paths along the downhole string, and providing a crossover path between said parallel data paths in at least one signal repeater.
17. A method as in claim 14 , further comprising organizing said data into message packets.
18. A method as in claim 14 , wherein said data is modulated onto said radiofrequency signals using burst modulation.
19. A method as in claim 14 , further comprising providing at least one signal repeater with an ID, said at least one signal repeater transmitting information regarding said ID, and said information being used to detect and/or locate failed repeaters.
20. A method as in claim 14 , further comprising at least one signal repeater measuring received signal strength and transmitting information regarding said received signal strength, and said information being used to detect and/or locate faults.
21. A method as in claim 14 , wherein at least one signal repeater comprises a sensor circuit, further comprising said at least one signal repeater transmitting information regarding sensor data from said sensor circuit.
22. A method as in claim 21 , wherein said transmitted sensor data information is used to adjust the rate of rotation, the drilling speed, and/or the weight-on-bit drilling parameters.
23. A method as in claim 21 , wherein said signal repeater transmits said sensor data information upon interrogation by a communications sub.
24. A method as in claim 21 , wherein said signal repeater transmits said sensor data information automatically without interrogation by a communications sub.