Downhole telemetry using adaptive feedback
First Claim
1. A feedback telemetry system, comprising:
- at least one downhole tool comprising a source assembly, the source assembly further comprising;
a source device that transmits a light signal having a first phase,wherein the source assembly utilizes dual-polarization redundancy in transmitting the light signal;
at least one telemetry unit coupled with the at least one downhole tool and operable to implement an adaptive feedback system; and
a receiving assembly communicatively coupled with the source assembly, the receiving assembly comprising;
an oscillator that transmits an oscillator signal having a second phase;
a coupler that mixes the light signal with the oscillator signal to produce a first interference signal and a second interference signal;
a detector that produces an output indicative of the first interference signal and the second interference signal;
a difference amplifier that receives the output from the detector and determines a difference between the first interference signal and the second interference signal;
a processor that receives the difference between the first interference signal and the second interference signal and estimates the first phase of the light signal based on the difference; and
an encoder that receives the estimate of the first phase of the light signal and adjusts the second phase of the oscillator signal,wherein the difference between the first interference signal and the second interference signal is proportional to cos(Φ
(t)−
Θ
),wherein Φ
(t) is the light signal transmitted from the source device and Θ
is the second phase of the oscillator signal.
1 Assignment
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Accused Products
Abstract
Systems, methods, and computer-readable media for providing adaptive feedback in downhole telemetry in a wellbore. A feedback system includes a source assembly, which can be located on the surface or downhole, and a receiving assembly, which can likewise be located on the surface or downhole. The source assembly includes a source device that transmits a light signal having a first phase, and an encoder coupled to the source device. The receiving assembly comprising an oscillator that transmits an oscillator having a second phase, a coupler that couples the light signal with the oscillator signal, a detector and difference amplifier that detect and determine the difference between the first phase and second phase and a processor that receives the difference between the phases and provides the difference to an encoder so that the encoder can adjust the oscillator phase.
10 Citations
18 Claims
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1. A feedback telemetry system, comprising:
-
at least one downhole tool comprising a source assembly, the source assembly further comprising; a source device that transmits a light signal having a first phase, wherein the source assembly utilizes dual-polarization redundancy in transmitting the light signal; at least one telemetry unit coupled with the at least one downhole tool and operable to implement an adaptive feedback system; and a receiving assembly communicatively coupled with the source assembly, the receiving assembly comprising; an oscillator that transmits an oscillator signal having a second phase; a coupler that mixes the light signal with the oscillator signal to produce a first interference signal and a second interference signal; a detector that produces an output indicative of the first interference signal and the second interference signal; a difference amplifier that receives the output from the detector and determines a difference between the first interference signal and the second interference signal; a processor that receives the difference between the first interference signal and the second interference signal and estimates the first phase of the light signal based on the difference; and an encoder that receives the estimate of the first phase of the light signal and adjusts the second phase of the oscillator signal, wherein the difference between the first interference signal and the second interference signal is proportional to cos(Φ
(t)−
Θ
),wherein Φ
(t) is the light signal transmitted from the source device and Θ
is the second phase of the oscillator signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of using adaptive feedback in downhole telemetry, the method comprising:
-
providing at least one downhole tool unit comprising a source assembly and coupled with a telemetry unit, the source assembly communicatively coupled with a receiving assembly; mixing a source signal having an unknown phase with an oscillator signal having a known phase, the source signal transmitted from a light source of the source assembly, the oscillator signal coupled with the source signal at the receiving assembly at a surface outside a wellbore, the source signal and the oscillator signal having a same frequency; and detecting a phase difference between the unknown phase of the source signal and the known phase of the oscillator signal, wherein the phase difference between the unknown phase of the source signal and the known phase of the oscillator signal is proportional to cos(Φ
(t)−
Θ
),wherein Φ
(t) is the light signal transmitted from the source device and Θ
is the second phase of the oscillator signal, andwherein the light source utilizes dual-polarization redundancy in transmitting the source signal. - View Dependent Claims (12, 13, 14)
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15. A method of using adaptive feedback in downhole telemetry, the method comprising:
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providing at least one downhole instrument comprising a source assembly and coupled with a telemetry unit, wherein the source assembly is further communicatively coupled with a receiving assembly; utilizing dual-polarization redundancy to transmit a light signal from a light source at the source assembly; receiving, at a detector of the receiver assembly, a first interference signal and a second interference signal from a mixing of an oscillator signal residing at the receiver assembly and the light signal; providing the first interference signal and second interference signal to a differential amplifier to determine a difference between the first interference signal and second interference signal; and estimating, by a processor, a phase difference between a first phase of the light signal and a second phase of the oscillator signal based on the difference between the first interference signal and the second interference signal, wherein the difference between the first interference signal and the second interference signal is proportional to cos(Φ
(t)−
Θ
),wherein Φ
(t) is the light signal transmitted from the source device and Θ
is the second phase of the oscillator signal. - View Dependent Claims (16, 17, 18)
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Specification