Two sensor impedance estimation for uplink telemetry signals
First Claim
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1. A method of communicating a signal through a fluid in a borehole between a first location and a second location, the method comprising:
- (a) measuring signals in the fluid at at least two spaced apart positions at or near the second location in response to operation of at least one of (A) a noise source, and, (B) a message source;
(b) estimating from the signals at the at least two spaced apart positions a characteristic of a fluid channel between the at least two spaced apart positions;
(c) generating a message signal simultaneously with operation of the noise source;
(d) measuring additional signals at the at least two positions responsive to the message signal and the simultaneous operation of the noise source; and
(e) estimating the message signal from the additional signals and the estimated fluid characteristic.
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Abstract
Measurements made with dual sensors (flow rate or pressure) are used to attenuate pump noise in a mud pulse telemetry system.
27 Citations
25 Claims
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1. A method of communicating a signal through a fluid in a borehole between a first location and a second location, the method comprising:
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(a) measuring signals in the fluid at at least two spaced apart positions at or near the second location in response to operation of at least one of (A) a noise source, and, (B) a message source; (b) estimating from the signals at the at least two spaced apart positions a characteristic of a fluid channel between the at least two spaced apart positions; (c) generating a message signal simultaneously with operation of the noise source; (d) measuring additional signals at the at least two positions responsive to the message signal and the simultaneous operation of the noise source; and (e) estimating the message signal from the additional signals and the estimated fluid characteristic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for communicating a signal through a fluid in a borehole between a bottomhole assembly (BHA) and a surface location, the system comprising:
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(a) a message source on the bottomhole assembly (BHA) configured to generate a message signal; (b) sensors at at least two spaced apart positions configured to measure signals in response to operation of at least one of (A) a noise source, and, (B) the message source; and (c) a processor configured to estimate from the signals a characteristic of a fluid channel between the at least two spaced apart positions; wherein the sensors at the at least two spaced apart positions are further configured to receive additional signals responsive to a message signal at the downhole location generated simultaneously with operation of the noise source; and
wherein the processor is further configured to estimate the message signal from the additional signals and the estimated fluid characteristic. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A machine readable medium for use in conjunction with a bottomhole assembly (BHA), conveyed in a borehole in an earth formation, the medium encoded with instructions which enable:
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(a) estimating from signals in a fluid at at least two spaced apart positions at or near a surface location in response to operation of at least one of (A) a noise source, and, (B) a message source at the downhole location, a characteristic of a fluid channel between the at least two spaced apart positions; (b) estimating a value of a message signal generated at the BHA simultaneously with operation of the noise source from; (A) additional signals measured at the at least two spaced apart positions responsive to operation of the message source and the simultaneous operation of the noise source, and (B) the estimated fluid channel characteristic. - View Dependent Claims (21, 22, 23, 24, 25)
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Specification