System and Method for Pump Noise Cancellation in Mud Pulse Telemetry
AssigneeBaker Hughes Incorporated
InventorsJiang Li, Hanno Reckmann
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Abstract
Pump noise in a mud-pulse telemetry system is reduced based on analysis of the frequency characteristics of the noise generated by one or more pumps. Least mean-squares filtering may be done. Alternatively, the frequency domain analysis of the pump frequencies is fine-tuned in the time domain and a synthetic timing signal is used for the filtering.
Claims28
A method of communicating from a downhole location to a surface location, the method comprising:
- (a) producing a pulsed variation in a borehole fluid at the downhole location;
- (b) measuring a signal at the surface location responsive to the pulsed variation;
- (c) determining from the signal a frequency corresponding to at least one pump coupled to the borehole fluid;
- (d) representing a noise associated with the at least one pump by a harmonic series;
- and
- (e) adaptively filtering the signal using the harmonic series and providing an estimate of the pulsed variation.
An apparatus for communicating a signal from a downhole location to a surface location, the apparatus comprising:
- (a) a signal source configured to produce a pulsed variation in a borehole fluid at the downhole location;
- (b) a sensor configured to produce a signal at the surface location responsive to the pulsed variation;
- and
- (c) a processor configured to:
- (A) determine from the signal a frequency corresponding to at least one pump coupled to the borehole fluid,
- (B) represent a noise associated with the at least one pump by a harmonic series, and
- (C) adaptively filter the signal using the harmonic series and provide an estimate of the pulsed variation.
A computer-readable medium for use with an apparatus for communicating a signal from a downhole location to a surface location, the apparatus comprising:
- (a) a signal source configured to produce a pulsed variation in a borehole fluid at the downhole location;
- and
- (b) a sensor configured to produce a signal at the surface location responsive to the pulsed variation;
- the medium comprising instructions which enable a processor to:
- (c) determine from the signal a frequency corresponding to at least one pump coupled to the borehole fluid;
- (d) represent a noise associated with the at least one pump by a harmonic series;
- and
- (e) adaptively filter the signal using the harmonic series and provide an estimate of the pulsed variation.
A method of communicating between a downhole location and a surface location, the method comprising:
- (a) producing a pulsed variation in a borehole fluid at the downhole location;
- (b) measuring a signal at the surface location responsive to the pulsed variation;
- (c) determining, in a frequency domain, a frequency corresponding to at least one pump coupled to the borehole fluid;
- (d) obtaining an improved estimate of the frequency corresponding to the at least one pump using a time domain method;
- and
- (e) filtering the pressure signals using the improved estimate of frequency corresponding to the at least one pump and an output of a timing signal generator coupled to the at least one pump.
An apparatus for communicating between a downhole location and a surface location, the apparatus comprising:
- (a) a signal source configured to produce a pulsed variation in a borehole fluid at the downhole location;
- (b) a sensor configured to measure a signal at the surface location responsive to the pulsed variation;
- and
- (c) a processor configured to:
- (A) determine, in a frequency domain, a frequency corresponding to at least one pump coupled to the borehole fluid,
- (B) obtain an improved estimate of the frequency corresponding to the at least one pump using a time domain method, and
- (C) filter the signal using the improved estimate of frequency corresponding to the at least one pump and an output of a timing signal generator operatively coupled to the at least one pump.
A computer readable medium for use with an apparatus for communicating between a downhole location and a surface location, the apparatus comprising:
- (a) a signal source configured to produce a pulsed variation in a borehole fluid at the downhole location;
- and
- (b) a sensor configured to measure a signal at the surface location responsive to the pulsed variation;
- the medium comprising instructions which enable a processor to:
- (c) determine, in a frequency domain, a frequency corresponding to at least one pump coupled to the borehole fluid,
- (d) obtain an improved estimate of the frequency corresponding to the at least one pump using a time domain method, and
- (e) filter the signal using the improved estimate of frequency corresponding to the at least one pump and an output of a timing signal generator operatively coupled to the at least one pump.
Dependencies are inferred from the claim text.