Abstract: A distributed measurement system includes a first distributed optical sensing fiber deployed along a first desired measurement path and a second distributed optical sensing fiber deployed along a second desired measurement path. The system further includes an interrogation system coupled to the first distributed optical sensing fiber and to the second distributed optical sensing fiber. The system also includes a first distributed measuring instrument launch a first interrogating probe pulse set comprising a first pulse having a first frequency and a second pulse having a second frequency. The interrogation system is designed to direct the first pulse to the first distributed optical sensing fiber and the second pulse to the second distributed optical sensing fiber.

Abstract: A distributed measurement system includes a first distributed optical sensing fiber deployed along a first desired measurement path and a second distributed optical sensing fiber deployed along a second desired measurement path. The system further includes an interrogation system coupled to the first distributed optical sensing fiber and to the second distributed optical sensing fiber. The system also includes a first distributed measuring instrument launch a first interrogating probe pulse set comprising a first pulse having a first frequency and a second pulse having a second frequency. The interrogation system is designed to direct the first pulse to the first distributed optical sensing fiber and the second pulse to the second distributed optical sensing fiber.

Abstract: Monitoring one or more items of equipment associated with a borehole or other conduit. A sensor system includes a vibration sensor for sensing vibrations at one or more sensor locations associated with one or more items of the equipment and/or the borehole or other conduit. A processing system processes the sensor information to determine a characteristic of the operation of the one or more items of equipment and/or the borehole or other conduit.

Abstract: A technique facilitates the use and application of a distributed vibration sensing system in, for example, a well application. The technique enables selection of a desired gauge length to achieve an optimum trade-off between the spatial resolution of a distributed vibration sensing/distributed acoustic sensing system and signal-to-noise ratio. The optimum gauge length can vary according to specific factors, e.g. depth within a well, and the present technique can be used to account for such factors in selecting an optimal gauge length which facilitates accurate collection of data on dynamic strain.

Abstract: A method for calibrating a distributed vibration sensing system includes applying a localized calibration event, such as a temperature change, to at least one location along an optical fiber cable. Backscattered light generated the optical fiber while the localized calibration event is applied includes phase information having low frequency components. The center of energy of the low frequency components can be identified in order to generate a reference point along the fiber that can be used to generate a channel-depth calibration scale that can be applied to vibration data acquired from the fiber when used in various applications, such as borehole seismic surveying.

Abstract: Techniques are disclosed that facilitate use of a distributed vibration sensing system for collecting data in a well application to provide improved collection of strain related data, such as for a seismic survey. The techniques facilitate selection of a variable optimal gauge length that optimally preserves the signal bandwidth and temporal resolution of the sensing system and that can be tuned using the actual apparent velocity and maximum recoverable frequency of the monitored parameters. Techniques for real-time processing of DVS data using a preliminary variable optimal gauge length are disclosed, as well as techniques for re-processing the DVS data at a later time using an updated variable optimal gauge length that is derived from the preliminary processing of the DVS data.

Abstract: A technique facilitates the use and application of a distributed vibration sensing system in, for example, a well application. The technique enables selection of a desired gauge length to achieve an optimum trade-off between the spatial resolution of a distributed vibration sensing/distributed acoustic sensing system and signal-to-noise ratio. The optimum gauge length can vary according to specific factors, e.g. depth within a well, and the present technique can be used to account for such factors in selecting an optimal gauge length which facilitates accurate collection of data on dynamic strain.

Abstract: Monitoring one or more items of equipment associated with a borehole or other conduit. A sensor system includes a vibration sensor for sensing vibrations at one or more sensor locations associated with one or more items of the equipment and/or the borehole or other conduit. A processing system processes the sensor information to determine a characteristic of the operation of the one or more items of equipment and/or the borehole or other conduit.

Abstract: A method for calibrating a distributed vibration sensing system includes applying a localized calibration event, such as a temperature change, to at least one location along an optical fiber cable. Backscattered light generated the optical fiber while the localized calibration event is applied includes phase information having low frequency components. The center of energy of the low frequency components can be identified in order to generate a reference point along the fiber that can be used to generate a channel-depth calibration scale that can be applied to vibration data acquired from the fiber when used in various applications, such as borehole seismic surveying.