SYSTEM AND METHOD FOR BOREHOLE COMMUNICATION

• US 20130021166A1
• Filed: 07/20/2011
• Published: 01/24/2013
• Est. Priority Date: 07/20/2011
• Status: Abandoned Application

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Kusuma, Julius, Shah, Jagdish
• Application Number:
  US13/186,886
• Publication Number:
  US 20130021166A1
• Time in Patent Office: Days
• US Class Current: 340/853.1
• CPC Class Codes: E21B 47/20 by modulation of mud waves, e.g. by continuous modulation
• CPC Class Codes: H04B 2203/5475 adapted for drill or well combined with data transmission

Abstract

To produce a desired telemetry signal, the desired telemetry signal is first determined and then decomposed into two or more component signals. For each component signal, commands are sent to an individual modulator. The individual modulators each produce individual signals according to their received commands. The individual signals from each individual modulator are combined to produce the desired telemetry signal, or the individual signals from each individual modulator are allowed to combine to produce the desired telemetry signal. A telemetry system that produces such desired telemetry signals includes an uplink transmitter/receiver pair, a downlink transmitter/receiver pair, or both pairs, wherein each uplink transmitter and each downlink receiver is disposed in a wellbore. Two or more modulators are provided, as is a telemetry signal generator having a processor capable of decomposing a desired telemetry signal into two or more component signals and issuing commands to control the two or more modulators.

Claims

1. A method, comprising:

determining a desired telemetry signal;

decomposing the desired telemetry signal into two or more component signals;

sending, for each of the two or more component signals, commands to an individual modulator;

producing an individual signal from each individual modulator according to the received commands; and

combining the individual signals from each individual modulator to produce the desired telemetry signal or allowing the individual signals from each individual modulator to combine to produce the desired telemetry signal.

2. The method of claim 1, wherein an individual signal conveys integral information whereby the signal can be decoded individually.

3. The method of claim 1, further comprising decoding the desired telemetry signal.

4. The method of claim 1, wherein the desired telemetry signal is an uplink or a downlink.

5. The method of claim 1, wherein the decomposing is based on polyphase decomposition, wavelet decomposition, or Fourier decomposition.

6. The method of claim 1, wherein each modulator comprises a rotary valve, an oscillating valve, or a poppet valve.

7. The method of claim 1, wherein all modulators are within one tool and controlled by one controller.

8. The method of claim 1, wherein each modulator is controlled by an individual controller, and all controllers are driven by a single clock.

9. The method of claim 1, wherein each modulator is controlled by an individual controller, and each controller is driven by a separate clock.

10. The method of claim 9, wherein all clocks are synchronized.

11. The method of claim 1, wherein the desired telemetry signal has a wider bandwidth than any of the individual signals.

12. The method of claim 1, wherein the desired telemetry signal has less noise than a comparable signal produced by a single modulator.

13. The method of claim 1, wherein the desired telemetry signal has less propagation distortion than a comparable signal produced by a single modulator.

14. The method of claim 1, wherein the power to produce the desired telemetry signal is less than the power required to produce a comparable signal using a single modulator.

15. The method of claim 1, wherein the modulators use an effective flow area to produce the individual signals.

16. The method of claim 1, wherein a first individual modulator controls the effective flow area between itself and a rotor, and a second individual modulator generates a carrier modulation or a baseband modulation.

17. The method of claim 16, wherein the first modulator is an oscillating valve or a poppet valve, and the second modulator is a rotary valve.

18. A telemetry system, comprising:

an uplink transmitter/receiver pair, a downlink transmitter/receiver pair, or both pairs, wherein each uplink transmitter and each downlink receiver is disposed in a wellbore;

two or more modulators; and

a telemetry signal generator having a processor capable of;

decomposing a desired telemetry signal into two or more component signals; and

issuing commands to control the two or more modulators based on the two or more component signals.

19. The telemetry system of claim 18 wherein each uplink receiver and each downlink transmitter is located on or near the earth'"'"'s surface.

20. The telemetry system of claim 18, wherein each modulator comprises a rotary valve, an oscillating valve, or a poppet valve.