Borehole communication and measurement system

• US 20060131014A1
• Filed: 03/11/2005
• Published: 06/22/2006
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Huang, Songming, Sheffield, Randolph J., Tennent, Robert W., Monmont, Franck Bruno Jean
• Granted Patent: US 7,348,893 B2
• Time in Patent Office: Days
• US Class Current: 166/250.70
• CPC Class Codes: E21B 47/138 Devices entrained in the flow of well-bore fluid for transmitting data, control or actuation signals
• CPC Class Codes: E21B 47/18 through the well fluid , e.g. mud pressure pulse telemetry

Abstract

A technique that is usable with a well includes using at least one downhole sensor to establish telemetry within the well. The sensor(s) are used as a permanent sensing device.

Claims

1. A method usable with a well, comprising:

using at least one downhole sensor to establish telemetry within the well; and

using said at least one sensor as a permanent sensing device.

2. The method of claim 1, wherein said at least one sensor comprises a flow meter.

3. The method of claim 2, wherein the flow meter decodes a command communicated from the service of the well and monitors a production flow downhole.

4. The method of claim 1, further comprising:

communicating with said at least one sensor from the surface of the well to communicate a command downhole for a downhole tool; and

in response to the tool acting upon the command, creating a fluid column in the well for communication of a stimuli uphole indicative of a measurement taken by said at least one sensor.

5. The method of claim 4, wherein said at least one sensor comprises a flow meter.

6. A system usable with a subterranean well, comprising:

at least one sensor;

a downlink circuit coupled to said at least one sensor to use said at least one sensor to receive a command communicated from a surface of the well; and

an uplink circuit coupled to said at least one sensor to communicate a well condition sensed by the sensor uphole.

7. The system of claim 6, wherein said at least one sensor comprises a flow meter.

8. The system of claim 7, wherein the flow meter decodes a command communicated from the service of the well and monitors a production flow downhole.

9. The system of claim 7, wherein the flow meter comprises at least one of an orifice restriction through which a downhole fluid flows, a Venturi restriction through which the downhole fluid flows and a device to communicate a Doppler wave through the downhole fluid.

10. The method of claim 7, wherein the flow meter comprises at least one pressure sensor.

11. A method usable with a well, comprising:

encoding a first code sequence with a synchronization code to produce a second code sequence; and

generating a stimulus in fluid of the well to communicate the second code sequence downhole.

12. The method of claim 11, wherein the first code sequence indicates a command for a downhole tool.

13. The method of claim 11, further comprising:

encoding the first code sequence with an error correction code.

14. The method of claim 11, wherein the act of generating the stimulus comprises adjusting a pressure magnitude of the fluid to indicate each bit of the second code sequence.

15. The method of claim 11, wherein the act of generating comprises changing a gradient of pressure of the fluid to indicate each bit of the second code sequence.

16. The method of claim 11, wherein the act of generating the stimulus comprises:

adjusting a pressure of the fluid at the surface of the well;

measuring the pressure; and

repeating the acts of adjusting and measuring in a feedback loop to establish predetermined pressure profiles for logical bit states.

17. A method usable with a well, comprising:

receiving a code sequence indicative of information to be communicated downhole;

modulating the code sequence to remove a portion of spectral energy of the code sequence located near zero frequency to create a signal; and

generating a stimulus in fluid of the well to communicate the signal downhole.

18. The method of claim 17, wherein the information comprises a command for a downhole tool.

19. The method of claim 17, further comprising:

adding an error correction code to the received code sequence prior to the modulation.

20. The method of claim 17, wherein the act of generating the stimulus comprises for each bit of the signal, controlling a pressure magnitude of the fluid to indicate a logical state of the bit.

21. The method of claim 17, wherein the signal comprises bits and the act of generating the stimulus comprises for each bit of the signal, adjusting a pressure gradient of the fluid to indicate a logical state of the bit.

22. The method of claim 17, wherein the signal comprises bits and the act of generating the stimulus comprises:

measuring a pressure of the fluid at the surface of the well;

applying pressure to the fluid at the surface of the well; and

repeating the acts of adjusting and measuring in a feedback loop to establish predetermined pressure profiles for logical bit states.

23. A method usable with a well, comprising:

decoding a flow signal downhole to generate a first code sequence;

decoding a pressure signal downhole to generate a second code sequence; and

selectively combining the first code sequence and the second code sequence to generate a third code sequence indicative of information communicated downhole.

24. The method of claim 23, wherein the information comprises a command for a downhole tool.

25. The method of claim 23, wherein the act of selectively combining comprises selectively combining bits from the first code sequence and the second code sequence on a bit-by-bit basis.

26. The method of claim 23, wherein the act of selectively combining comprises selecting, for each bit of the third code sequence, either a bit from the first code sequence or a bit from the second code sequence.

27. The method of claim 23, wherein the act of selectively combining comprises averaging the first code sequence and the second code sequence.

28. The method of claim 23, wherein the act of decoding the flow signal comprises measuring pressures associated with a Venturi flow downhole.

29. The method of claim 23, wherein the act of decoding the flow signal downhole comprises at least one of communicating an ultrasonic wave through a downhole fluid, flowing the downhole fluid through a Venturi restriction and flowing the downhole fluid.

30. A system usable with a well, comprising:

an uplink modulator located downhole in the well to modulate a carrier stimulus to generate a second stimulus transmitted uphole indicative of a downhole measurement; and

a downlink module adapted to decode a flow signal communicated from the surface of the well and a pressure signal communicated from the surface of the well and selectively combine the decoded flow and pressure signals to provide a command for a downhole tool.

31. The system of claim 30, wherein the downlink module comprises a Venturi flow device comprising sensors to detect flow of fluid downhole to decode the flow signal.

32. The system of claim 30, wherein the downlink module comprises an ultrasonic transmitter to transmit an ultrasonic wave into downhole fluid and at least one sensor to use the ultrasonic wave to detect the flow signal.

33. The system of claim 30, further comprising:

a downhole tool actuated by the command provided by the downlink module.

34. The system of claim 30, further comprising:

a pressure generator to adjust the pressure of fluid at the surface of the well to communicate a command downhole;

a sensor to measure the pressure; and

a controller to repeat the measurement and the adjustment of the pressure in a feedback loop to establish predetermined pressure profiles for logical bit states.

35. A system usable with a well, comprising:

an encoder to encode a first code sequence with a synchronization code to generate an encoded code sequence; and

a stimulus generator to generate a stimulus in fluid of the well to communicate the encoded code sequence downhole.

36. The system of claim 35, wherein the first code sequence indicates a command for a downhole tool.

37. The system of claim 35, wherein the encoder is further adapted to encode the first code sequence with an error correction code.

38. The system of claim 35, wherein the encoded command sequence comprises bits and the stimulus generator is adapted to, for each bit of the encoded command sequence, adjust a pressure magnitude of the fluid to indicate a logical level of the bit.

39. The system of claim 35, wherein the encoded command sequence comprises bits and the stimulus generator is adapted to, for each bit of the encoded command sequence, cause a pressure gradient of the fluid to indicate a logical level of the bit.

40. The system of claim 35, further comprising:

a sensor located at the surface of the well to measure a pressure of the fluid, wherein

the stimulus generator uses the measurement in a feedback loop to regulate the pressure.

41. A system usable with a well, comprising:

a modulator to receive a code sequence indicative of information to be communicated downhole and modulate the code sequence to remove a portion of spectral energy of the code sequence located near zero frequency to create a signal; and

stimulus generator to generate a stimulus in fluid of the well to communicate the modulated code sequence downhole.

42. The system of claim 41, wherein the code sequence comprises error correction code.

43. The system of claim 41, wherein the information comprises a command.

44. The system of claim 41, wherein the encoded command sequence comprises bits and the stimulus generator is adapted to, for each bit of the modulated code sequence, adjust a pressure magnitude of the fluid to indicate a logical level of the bit.

45. The system of claim 41, wherein the encoded command sequence comprises bits and the stimulus generator is adapted to, for each bit of the modulated encoded signal, generate a pressure gradient in the fluid to indicate a logical state of the bit.

46. The system of claim 41, further comprising:

a sensor adapted to measure a pressure of the fluid, wherein

the stimulus generator is adapted to use the measurement to generate the stimulus in a feedback loop to establish predetermined pressure profiles for logical bit states.

47. The system of claim 41, wherein the code sequence comprises synchronization code.

48. A downhole receiver usable with a well, comprising:

a flow signal detector adapted to decode a flow signal downhole to generate a first code sequence;

a pressure signal detector adapted to decode a pressure signal downhole to generate a second code sequence; and

a combiner to selectively combine the first code sequence and the second code sequence to generate a third code sequence indicative of information communicated from a surface of the well.

49. The downhole receiver of claim 48, wherein the information comprises a command.

50. The downhole receiver of claim 48, wherein each of the first, second and third code sequences comprises bits, and the combiner, for each bit of the third code sequence, chooses between a bit of the first code sequence and a bit of the second code sequence.

51. The downhole receiver of claim 48, wherein each of the first, second and third code sequences comprises bits, and the combiner, for each bit of the third code sequence, selects between a bit of the first code sequence and a bit of the second code sequence.

52. The downhole receiver of claim 48, wherein the combiner is adapted to average the first code sequence and the second code sequence to generate the third code sequence.