Systems and methods for distributed interferometric acoustic monitoring
First Claim
1. A method for using a fibre optic cable for acoustic monitoring, comprising:
- transmitting a monitoring signal through the fiber optic cable, wherein the monitoring signal comprises at least one pulse of a coherent beam of electromagnetic radiation and a coherence time of the coherent beam of electromagnetic radiation is equal to or longer than a duration of the at least one pulse;
detecting coherent Rayleigh noise generated by the transmission of the coherent beam of radiation through the fiber optic cable; and
measuring a phase of the coherent Rayleigh noise; and
processing the measured phase of the coherent Rayleigh noise to identify an acoustic occurrence along the fibre optic cable.
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Abstract
Acoustic monitoring is carried out using a fiber optic cable. Coherent Rayleigh noise generated by the transmission of a coherent beam of radiation through the fiber optic cable is detected, a phase of the coherent Rayleigh noise is measured and the measured phase is processed to identify an acoustic occurrence along the fiber optic cable. In certain aspects an optical fiber serves as a distributed interferometer that may be used to monitor a conduit, wellbore or reservoir. The distributed interferometric monitoring provides for accurate detection of acoustic occurrences along the fiber optic cable and these acoustic occurrences may include fluid flow in a pipeline or wellbore, processes taking place in a wellbore or pipeline, fracturing, gravel packing, or production logging.
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Citations
14 Claims
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1. A method for using a fibre optic cable for acoustic monitoring, comprising:
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transmitting a monitoring signal through the fiber optic cable, wherein the monitoring signal comprises at least one pulse of a coherent beam of electromagnetic radiation and a coherence time of the coherent beam of electromagnetic radiation is equal to or longer than a duration of the at least one pulse; detecting coherent Rayleigh noise generated by the transmission of the coherent beam of radiation through the fiber optic cable; and measuring a phase of the coherent Rayleigh noise; and processing the measured phase of the coherent Rayleigh noise to identify an acoustic occurrence along the fibre optic cable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification