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: 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: Apparatus and methods for acquiring strain profiles of an optical conductor of a wireline cable in a wellbore, either while the cable is lowered and/or at intervals during the lowering when the cable is briefly stationary. Changes in the acquired strain profiles are utilized to infer or otherwise determine changes in the disposition of the cable.

Abstract: Apparatus and methods for acquiring strain profiles of an optical conductor of a wireline cable in a wellbore, either while the cable is lowered and/or at intervals during the lowering when the cable is briefly stationary. Changes in the acquired strain profiles are utilized to infer or otherwise determine changes in the disposition of the cable.

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.