Distributed sensing systems and methods with efficient energy spectrum analysis
First Claim
1. A system, comprising:
- an optical fiber positioned in a downhole environment;
an interrogator to provide source light to the optical fiber; and
a receiver coupled to the optical fiber, wherein the receiver comprises;
at least one fiber optic coupler that receives backscattered light and that produces one or more optical interferometry signals from the backscattered light;
photo-detectors that produce an electrical signal for each of the one or more optical interferometry signals;
at least one digitizer that digitizes each electrical signal;
at least one processing unit that processes each digitized electrical signal to obtain a distributed sensing signal and related energy spectrum information, wherein the distributed sensing signal is an unwrapped phase of the digitized electrical signal;
wherein the energy spectrum information corresponds to energy calculated for each of a limited number of frequency subbands of the unwrapped phase as a function of position along a length of the optical fiber, the energy calculated by segmenting the unwrapped phase into blocks having a predetermined block length and by applying a filter having a filter length that is smaller than the predetermined block length.
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Accused Products
Abstract
A system includes an optical fiber and an interrogator to provide source light to the optical fiber. The system also includes a receiver coupled to the optical fiber. The receiver includes at least one fiber optic coupler that receives backscattered light and that produces one or more optical interferometry signals from the backscattered light. The receiver also includes photo-detectors that produce an electrical signal for each of the one or more optical interferometry signals. The system also includes at least one digitizer that digitizes each electrical signal. The system also includes at least one processing unit that processes each digitized electrical signal to obtain a distributed sensing signal and related energy spectrum information. The energy spectrum information corresponds to energy calculated for each of a limited number of frequency subbands by segmenting the distributed sensing signal into blocks having a predetermined block length and by applying a filter having a filter length that is smaller than the predetermined block length.
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Citations
25 Claims
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1. A system, comprising:
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an optical fiber positioned in a downhole environment; an interrogator to provide source light to the optical fiber; and a receiver coupled to the optical fiber, wherein the receiver comprises; at least one fiber optic coupler that receives backscattered light and that produces one or more optical interferometry signals from the backscattered light; photo-detectors that produce an electrical signal for each of the one or more optical interferometry signals; at least one digitizer that digitizes each electrical signal; at least one processing unit that processes each digitized electrical signal to obtain a distributed sensing signal and related energy spectrum information, wherein the distributed sensing signal is an unwrapped phase of the digitized electrical signal; wherein the energy spectrum information corresponds to energy calculated for each of a limited number of frequency subbands of the unwrapped phase as a function of position along a length of the optical fiber, the energy calculated by segmenting the unwrapped phase into blocks having a predetermined block length and by applying a filter having a filter length that is smaller than the predetermined block length. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method, comprising:
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providing source light to an optical fiber deployed in a downhole environment; receiving backscattered light from the optical fiber and producing one or more optical interferometry signals from the backscattered light; converting each of the one or more optical interferometry signals to an electrical signal and digitizing each electrical signal; determining a distributed sensing signal from each digitized electrical signal, wherein the distributed sensing signal is an unwrapped phase of the digitized electrical signal; and obtaining energy spectrum information corresponding to energy calculated for each of a limited number of frequency subbands of the unwrapped phase as a function of position along a length of the optical fiber, the energy calculated by segmenting the unwrapped phase into blocks having a predetermined block length and by applying to each block a filter having a filter length that is smaller than the predetermined block length. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification