Real-time calibration for downhole spectrometer
First Claim
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1. A downhole apparatus for performing real-time analysis of a subterranean formation fluid, comprising:
- a light source configured to transmit at least a sample signal through a sample of the subterranean formation fluid and a reference signal;
a modulator for modulating the sample and reference signals,a signal separation assembly for separating the modulated sample signal from the modulated reference signal, wherein the signal separation assembly comprises a spectrometer,at least one photodetector configured to continuously detect the sample and reference signals;
an electronics assembly configured to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal.
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Abstract
An apparatus for performing real-time analysis of a subterranean formation fluid includes a light source configured to transmit at least a sample signal through a sample of the subterranean formation fluid and a reference signal, at least one photodetector configured to continuously detect the sample and reference signals, and an electronics assembly configured to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal.
38 Citations
27 Claims
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1. A downhole apparatus for performing real-time analysis of a subterranean formation fluid, comprising:
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a light source configured to transmit at least a sample signal through a sample of the subterranean formation fluid and a reference signal; a modulator for modulating the sample and reference signals, a signal separation assembly for separating the modulated sample signal from the modulated reference signal, wherein the signal separation assembly comprises a spectrometer, at least one photodetector configured to continuously detect the sample and reference signals; an electronics assembly configured to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 11, 12)
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9. A downhole apparatus for performing real-time analysis of a subterranean formation fluid, comprising:
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a light source configured to transmit at least a sample signal through a sample of the subterranean formation fluid and a reference signal; a modulator for modulating the sample and reference signals, wherein the modulator generates a phase shift between the sample signal and the reference signal; wherein the modulator comprises a single optical chopper; wherein the single optical chopper comprises a single aperture for modulating the sample and reference signals; the sample signal is positioned to contact the single optical chopper at a first position; the reference signal is positioned to contact the single optical chopper at a second position; the second position is separated from the first position by a desired phase shift angle; at least one photodetector configured to continuously detect the sample and reference signals; an electronics assembly configured to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal. - View Dependent Claims (10)
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13. A downhole apparatus for performing real-time analysis of a subterranean formation fluid, comprising:
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a light source configured to transmit at least a sample signal through a sample of the subterranean formation fluid and a reference signal; a modulator for modulating the sample and reference signals, wherein the modulator comprises a digital modulator; at least one photodetector configured to continuously detect the sample and reference signals; an electronics assembly configured to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal.
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14. A method for analyzing a subterranean formation fluid downhole, comprising:
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extracting the subterranean formation fluid in downhole; transmitting a sample signal through a sample of the extracted subterranean formation fluid; continuously transmitting a reference signal; modulating the sample and reference signals; separating the modulated sample signal from the modulated reference signal by using a signal separation assembly with a spectrometer; continuously detecting the sample and reference signals using at least one photodetector; correcting drift in the detected sample signal in real-time based on the value of the detected reference signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method for analyzing a downhole fluid, comprising:
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transmitting a sample signal through a sample of the downhole fluid using a light source; transmitting a reference signal using the light source; modulating the sample and reference signals; separating the modulated sample signal from the modulated reference signal by using a signal separation assembly with a spectrometer; continuously measuring the sample signal and reference signal to compensate for drift in the sample signal in real-time, wherein the analyzing is performed downhole. - View Dependent Claims (25)
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26. A downhole apparatus for performing real-time analysis of a subterranean formation fluid, comprising:
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a downhole sampling assembly for sampling the subterranean formation fluid; a light source; a reference signal continuously transmitted by the light source; a sample signal transmitted by the light source through a sample of the subterranean formation fluid extracted by the downhole sampling assembly; a modulator for modulating the sample and reference signals at different frequencies; a signal separation assembly for separating the modulated sample signal from the modulated reference signal, wherein the signal separation assembly comprises a spectrometer; at least one photodetector configured to continuously detect the sample and reference signals; an electronics assembly configured to demodulate the sample signal and the reference and to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal.
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27. An apparatus for performing real-time analysis of a subterranean formation fluid, comprising:
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a downhole tool, The downhole tool comprising a fluid analysis module, the fluid analysis module comprising; a light source configured to transmit at least a sample signal through a sample of the subterranean formation fluid and a reference signal; a modulator for modulating the sample and reference signals; a signal separation assembly for separating the modulated sample signal from the modulated reference signal. wherein the signal separation assembly comprises a spectrometer; at least one photodetector configured to continuously detect the sample and reference signals; an electronics assembty configured to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal.
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Specification