Use of bragg gratings with coherent otdr
AssigneeBaker Hughes Incorporated
InventorsBrooks A. Childers, Roger Glen Duncan
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Abstract
An interferometer and a method of monitoring a downhole environment are described. The interferometer includes a coherent light source to emit pulses of light on a fiber, and a plurality of reflectors arranged on the fiber to reflect light from the coherent light source, each of the plurality of reflectors comprising broad band fiber Bragg gratings (FBGs), the fiber being rigidly disposed within a cable that is rigidly attached in the downhole environment. The interferometer also includes a processor to process a reflection signal resulting from the light reflected by two or more of the plurality of reflectors.
Claims16
An interferometer, the interferometer comprising:
- a coherent light source configured to emit pulses of light in a fiber;
- a plurality of reflectors arranged in the fiber and configured to reflect light from the coherent light source, each of the plurality of reflectors comprising broad band fiber Bragg gratings (FBGs), the fiber being rigidly disposed within a cable that is rigidly attached in a downhole environment;
- and
- a processor configured to process a reflection signal resulting from the light reflected by two or more of the plurality of reflectors.
A method of monitoring a downhole environment, the method comprising:
- disposing a fiber in the downhole environment, the fiber comprising a plurality of reflectors, each of the plurality of reflectors including broad band fiber Bragg gratings (FBGs) and the fiber being rigidly disposed in a cable that is ridigly attached in the downhole environment;
- emitting pulses of light from a coherent light source to illuminate the fiber;
- receiving a reflection signal based on the pulses of light from at least two of the plurality of reflectors;
- and
- processing the reflection signal using a processor to monitor the downhole environment.
Dependencies are inferred from the claim text.