MUD PULSE TELEMETRY

• US 20130080063A1
• Filed: 06/21/2010
• Published: 03/28/2013
• Est. Priority Date: 06/21/2010
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Pillai, Bipin K., Marsh, Laban M., Dudley, James H., Spross, Ronald L.
• Granted Patent: US 8,880,349 B2
• Time in Patent Office: Days
• US Class Current: 702/9
• CPC Class Codes: E21B 21/08 Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure valve arrangements therefor E21B21/10
• CPC Class Codes: E21B 47/18 through the well fluid , e.g. mud pressure pulse telemetry
• CPC Class Codes: E21B 49/003 by analysing drilling variables or conditions E21B49/005 takes precedence; systems specially adapted for monitoring a plurality of drilling variables or conditions E21B44/00
• CPC Class Codes: G01V 1/50 Analysing data
• CPC Class Codes: G01V 11/002 Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant means for transmitting well survey signals E21B47/12; signal transmission systems in general G08C; transmission in general H04B
• CPC Class Codes: G01V 9/00 Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions

Abstract

Mud pulse telemetry. The various embodiments are directed to methods and systems of encoding data in a mud pulse telemetry system, where at least a portion of the data is encoded the time between pressure transitions. Moreover, the various embodiments are directed to detection methods and systems that detect the pressure transitions at the surface.

Claims

1. A computer-readable storage medium storing a program that, when executed by a processor, causes the processor to:

read values indicative of pressure within a pipe that has drilling fluid flowing therein, the drilling fluid carries pressure pulses that encode data;

detect, in the values indicative of pressure, pressure transitions associated with the pressure pulses by causing the processor to;

calculate a running average time series with each datum in the running average time series being an average of the values indicative of pressure within a predetermined window of values;

create a filtered pressure time series from the values indicative of pressure;

detect negative pressure transitions in the filtered pressure time series that correspond in time to the running average time series reaching a first predetermined value and the running average time series having a first slope; and

detect positive pressure transitions in the filtered pressure time series that correspond in time to the running average time series reaching a second predetermined value and the running average time series having a second slope; and

determine from an amount of time between pressure transitions at least a portion of the data encoded in the pressure pulses.

2. The computer-readable medium of claim 1 further comprising:

wherein when the processor detects, the program further causes the processor to detect negative pressure transitions in the filtered pressure time series that correspond in time to the running average time series reaching the first predetermined value and first slope being a negative slope; and

detect positive pressure transitions in the filtered pressure time series that correspond in time to the running average time series reaching a second predetermined value and second slope being a positive slope.

3. The computer-readable medium of claim 1 further comprising:

wherein when the processor detects, the program further causes the processor to detect negative pressure transitions in the filtered pressure time series that correspond in time to the running average time series reaching the first predetermined value and first slope being a positive slope; and

detect positive pressure transitions in the filtered pressure time series that correspond in time to the running average time series reaching a second predetermined value and second slope being a negative slope.

4. The computer-readable medium of claim 1 wherein when the processor reads, the program causes the processor to read values indicative of pressure within the pipe that carries pressure pulses created by a down hole device.

5. The computer-readable medium of claim 1 wherein when the processor creates the filtered pressure time series, the program causes the processor to high-pass filter the values indicative of pressure.

6. The computer-readable medium of claim 1 wherein the program further causes the processor to ignore detection of negative pressure transitions when the running average time series has a positive slope.

7. A telemetry detection method comprising:

reading, by a computer system coupled to a pressure transducer, values indicative of pressure within a pipe that has drilling fluid flowing therein, the drilling fluid carries pressure pulses that encode data as the time between pressure transitions;

detecting pressure transitions associated with the pressure pulses by;

calculating a running average of the pressure within the pipe;

calculating a filtered pressure representation of the values indicative of pressure within the pipe;

detecting negative pressure transitions in the filtered pressure representation that correspond in time to the running average reaching a first predetermined value and the running average having a first slope; and

detecting positive pressure transitions in the filtered pressure representation within that correspond in time to the running average reaching a second predetermined value and the running average having a second slope; and

determining from an amount of time between pressure transitions at least a portion of the data encoded in the pressure pulses.

8. The telemetry detection method of claim 7 further comprising:

wherein detecting negative pressure transitions further comprises detecting negative pressure transitions in the filtered pressure representation that correspond in time to the running average reaching the first predetermined value and the first slope being a negative slope; and

wherein detecting positive pressure transitions in the filtered pressure representation further comprises detecting positive pressure transitions in the filtered pressure representation that correspond in time to the running average reaching the second predetermined value and the second slope being a positive slope.

9. The telemetry detection method of claim 7 further comprising:

wherein detecting negative pressure transitions further comprises detecting negative pressure transitions in the filtered pressure representation that correspond in time to the running average reaching the first predetermined value and the first slope being a positive slope; and

wherein detecting positive pressure transitions in the filtered pressure representation further comprises detecting positive pressure transitions in the filtered pressure representation that correspond in time to the running average reaching the second predetermined value and the second slope being a negative slope.

10. The telemetry detection method of claim 7 wherein calculating the running average further comprises calculating each datum of the running average as the average of values indicative of pressure within a predetermined window.

11. The telemetry detection method of claim 7 wherein reading further comprises reading values indicative of pressure within the pipe that carries pressure pulses created by a down hole device in a drilling operation.

12. The telemetry detection method of claim 7 wherein calculating the filtered pressure representation further comprises calculating high-pass filtering the values indicative of pressure.

13. A computer-readable storage medium storing a program that, when executed by a processor, causes the processor to:

read values indicative of pressure within a pipe that has drilling fluid flowing therein, the drilling fluid carries pressure pulses that encode data;

detect, in the values indicative of pressure, pressure transitions associated with the pressure pulses by causing the processor to;

create a filtered pressure time series from the values indicative of pressure;

take the absolute value of the filtered pressure time series; and

detect pressure transitions as pressure spikes in the absolute value of the filtered pressure time series;

decode from an amount of time between pressure transitions at least a portion of the data encoded in the drilling fluid.

14. The computer-readable medium of claim 13 wherein when the processor reads, the program causes the processor to read values indicative of pressure within the pipe that carries pressure pulses created by a down hole device.

15. The computer-readable medium of claim 13 wherein when the processor creates the filtered pressure time series, the program causes the processor to high-pass filter the values indicative of pressure.

16. The computer-readable storage medium of claim 13 wherein when the processor reads values, the program further causes the processor to at least one selected from the group consisting of:

read values indicative of pressure from a pressure transducer;

reading values indicative of changes in pressure from a transducer.

17. A telemetry detection method comprising:

reading, by a computer system coupled to a pressure transducer, values indicative of pressure within a pipe that has drilling fluid flowing therein, the drilling fluid carries pressure pulses that encode data as the time between pressure transitions;

detecting pressure transitions associated with the pressure pulses by;

calculating a filtered pressure representation of the values indicative of pressure within the pipe;

taking an absolute value of the filtered pressure representation; and

detecting pressure transitions as pressure spikes in the absolute value of the filtered pressure representation; and

determining from an amount of time between pressure transitions at least a portion of the data encoded in the pressure pulses.

18. The telemetry detection method of claim 17 wherein reading further comprises reading values indicative of pressure within the pipe that carries pressure pulses created by a down hole device in a drilling operation.

19. The telemetry detection method of claim 17 wherein calculating the filtered pressure representation further comprises calculating high-pass filtering the values indicative of pressure.

20. A method comprising:

obtaining, by a device within a drill string, a first datum indicative of a state or condition downhole;

inducing pressure pulses in drilling fluid within the drill string, the pressure pulses propagate to the surface, comprising;

encoding a first portion of the first datum as an amount of time between coherent features of a first pressure pulse and an immediately subsequent second pressure pulse; and

encoding a second portion of the first datum as an amount of time between a first pressure transition and an immediately subsequent second pressure transition of at least one selected from the group consisting of;

the first pressure pulse; and

the second pressure pulse.

21. The method of claim 20 wherein encoding the first portion further comprises encoding a first number of bits in the range of 3 to 6 bits.

22. The method of claim 21 wherein encoding the second portion further comprises encoding a second number of bits in the range of 1 to 3 bits.

23. The method of claim 20 further comprising wherein inducing pressure pulses further comprises inducing positive pressure pulses.

24. The method of claim 20 further comprising wherein inducing pressure pulses further comprises inducing negative pressure pulses.

25. A computer-readable storage medium storing a program that, when executed by a processor, causes the processor to:

read values indicative of pressure within a pipe that has drilling fluid flowing therein, the drilling fluid carries pressure pulses that encode data;

detect, in the values indicative of pressure, an amount of time between coherent features of a first pressure pulse and an immediately subsequent second pressure pulse;

detect, in the values indicative of pressure, an amount of time between a first pressure transition and an immediately subsequent second pressure transition;

decode from the amount of time between the first and second pressure pulses a first portion of the value sent from the downhole device; and

decode from the amount of time between the first and second pressure transitions a second portion of the value sent from the downhole device.

26. The computer-readable medium of claim 25 wherein when the processor decodes the first portion, the program causes the processor to decode a first number of bits in the range of 3 to 6 bits.

27. The computer-readable medium of claim 25 wherein when the processor decodes the second portion, the program causes the processor to decode a second number of bits in the range of 1 to 3 bits.

28. The computer-readable storage medium of claim 25 wherein the first and second pressure transitions are pressure transitions being part of at least one from the group consisting of:

the first pressure pulse; and

the second pressure pulse,

29. The computer-readable medium of claim 25 wherein when the processor reads values, the program causes the processor to read values indicative of pressure within the pipe that carries pressure pulses created by a down hole device.

30. The computer-readable storage medium of claim 25 wherein when the processor reads values, the program further causes the processor to at least one selected from the group consisting of:

read values indicative of pressure from a pressure transducer;

reading values indicative of changes in pressure from a transducer.

31. A telemetry method comprising:

inducing a pressure pulse in drilling fluid within a drill string, the pressure pulse has a pulse time duration from a predefined set of possible pulse time durations;

reading, at a first location displaced from a reflective device, pressure variations caused by passage of the pressure pulse, the reading creates a first pressure signal;

reading, at a second location displaced from the reflective device, pressure variations caused by passage of the pressure pulse, the reading at the second location creates a second pressure signal;

determining the pulse duration of the pressure pulse by;

correlating the first pressure signal to a first test pressure signal, the first test pressure signal represents an expected waveform for a first pulse duration of the predefined set of possible pulse time durations;

correlating the second pressure signal to a second test pressure signal, the second test pressure signal represents an expected waveform for a second pulse duration of the predefined set of possible pulse time durations; and

establishing the pulse time duration of the pressure pulse based on the correlating.

32. The telemetry method of claim 31 wherein establishing the pulse duration further comprises establishing the pulse duration as the pulse duration with the highest correlation.

33. The telemetry method of claim 31 further comprising:

wherein inducing further comprises inducing by a device down hole; and

wherein reading at the first and second locations further comprises reading at the first and second locations at the surface.

34. The telemetry method of claim 33 further comprising, prior to inducing, sending an indication of the predefined set of possible pulse time durations, the indication based on available location for pressure transducers at the surface.

35. The telemetry method of claim 31 further comprising:

wherein the predefined set comprises a first pulse time duration that corresponds to a first pulse length and a second pulse time duration that corresponds to a second pulse length;

wherein reading at the first location further comprises reading at a location that is substantially half the first pulse length from the reflective device; and

wherein reading at the second location further comprises reading at a location that is substantially half the second pulse length from the reflective device.

36. A telemetry system comprising:

a down hole device that creates a pressure pulse in drilling fluid within a drill string, the pressure pulse has a pulse length selected from a predefined set of pulse lengths that comprises a first pulse length and a second pulse length longer than the first pulse length, and the pulse length selected based on the data encoded in the pressure pulse;

a first transducer that reads pressure variations in the drilling fluid and thereby creates a first pressure signal, the first transducer at a first location that is substantially half the first pulse length from a reflective device;

a second transducer that reads pressure variations in the drilling fluid to create a second pressure signal, the second transducer at a second location that is substantially half the second pulse length from a reflective device;

a computer system coupled to the first and second transducers, the computer system has a processor and a memory device coupled to the processor, and the memory device stores a program that, when executed by the processor, causes the processor to;

read the first and second pressure signals;

correlate the first pressure signal to a first test pressure signal, the first test pressure signal represents an expected waveform at the first location if the pressure pulse has the first pulse length;

correlate the second pressure signal to a second test pressure signal, the second test pressure signal represents an expected waveform at the second location if the pressure pulse has the second pulse length; and

determine the pulse length based on the correlating of the first and second pressure signals to the respective first and second test pressure signals.

37. The telemetry system of claim 36 wherein determining the pulse length further comprises determining the pulse length of the pressure pulse as a pulse length associated with the first or second set of test pressure signals with the highest correlation.

38. The telemetry system of claim 36 further comprising:

wherein the predefined set of pulse length further comprises a third pulse length longer than the second pulse length;

a third transducer that reads pressure variations in the drilling fluid to create a third pressure signal, the third transducer at a third location that is substantially half the third pulse length from a reflective device; and

said memory comprises the program that, when executed by the processor, further causes the processor to;

correlate the third pressure signal to a third test pressure signal, the third test pressure signal represents an expected waveform at the third location if the pressure pulse has the third pulse length; and

determine the pulse length based on the correlating of the first, second and third pressure signals to the respective first, second and third test pressure signals.

39. A telemetry method comprising:

inducing a pressure pulse in drilling fluid within a drill string, the pressure pulse has a leading pressure transition and a trailing pressure transition;

reading, at least three separate locations displaced from a reflective device, pressure variations caused by passage of the pressure pulse, the reading creates at least three pressure signals;

determining a time between the leading pressure transition and the trailing pressure transition by;

algorithmically shifting at least two of the pressure signals based on an expected speed of sound in the drilling fluid such that corresponding features of the at least three pressure signals are substantially aligned in time; and

then

correlating the at least three pressure signals; and

determining an amount of time between the leading pressure transition and the trailing pressure transition of the pressure pulse.

40. The telemetry method of claim 39 further comprising:

wherein correlating further comprises summing corresponding points in time of the at least three pressure signals and thereby creating a summed signal; and

wherein determining further comprises identifying pressure spikes in the summed signal as pressure transitions of the pressure pulse.

41. The telemetry method of claim 39 further comprising:

wherein inducing further comprises inducing by a device down hole; and

wherein reading at the at least three locations further comprises reading at the surface.

42. The telemetry method of claim 39 wherein algorithmically shifting further comprises algorithmically shifting at least two of the pressure signals back in time such that leading pressure transitions among the at least three pressure signals are substantially aligned in time.

43. The telemetry method of claim 39 wherein algorithmically shifting further comprises algorithmically shifting at least two of the pressure signals forward in time such that trailing pressure transitions among the at least three pressure signals are substantially aligned in time.

44. A computer-readable storage medium storing a program that, when executed a processor, causes the processor to:

read, by way of at least three transducers, values indicative of pressure within a pipe that has drilling fluid flowing therein, the drilling fluid carries a pressure pulse that has a leading pressure transition and a trailing pressure transition;

create at least three pressure time series corresponding to the at least three transducers;

shift at least two of the pressure time series based on an expected speed of sound in the drilling fluid such that corresponding features of the at three time series are substantially aligned in time; and

then

correlate the at least time series; and

determine an amount of time between the leading pressure transition and the trailing pressure transition of the pressure pulse.

45. The computer-readable storage medium of claim 44 further comprising:

when the processor correlates, the program causes the processor to sum corresponding points in time of the at least three pressure time series and thereby create a summed time series; and

when the processor determines, the program further causes the processor to identify pressure spikes in the summed time series as pressure transitions of the pressure pulse.

46. The computer-readable storage medium of claim 44 wherein when the processor shifts, the program causes the processor to shift at least two of the pressure time series back in time such that leading pressure transitions among the at least three pressure time series are substantially aligned in time.

47. The computer-readable storage medium of claim 44 wherein when the processor shifts, the program causes the processor to shift at least two of the pressure signals forward in time such that trailing pressure transitions among the at least three pressure signals are substantially aligned in time.