Optical fiber cable
    2.
    发明授权

    公开(公告)号:US10451462B2

    公开(公告)日:2019-10-22

    申请号:US15962196

    申请日:2018-04-25

    Abstract: Embodiments of the present invention provide a cable for optical fiber sensing applications formed from fiber wound around a cable core. A protective layer is then preferably placed over the top of the wound fiber, to protect the fiber, and to help keep it in place on the cable core. The cable core is preferably of a diameter to allow bend-insensitive fiber to be wound thereon with low bending losses. The effect of winding the fiber onto the cable core means that the longitudinal sensing resolution of the resulting cable is higher than simple straight fiber, when the cable is used with an optical fiber sensing system such as a DAS or DTS system. The achieved resolution for the resulting cable is a function of the fiber winding diameter and pitch, with a larger diameter and reduced winding pitch giving a higher longitudinal sensing resolution.

    STRUCTURE MONITORING
    3.
    发明申请

    公开(公告)号:US20140025319A1

    公开(公告)日:2014-01-23

    申请号:US13944407

    申请日:2013-07-17

    Abstract: A method and apparatus for monitoring a structure using an optical fiber based distributed acoustic sensor (DAS) extending along the length of the structure. The DAS is able to resolve a separate acoustic signal with a spatial resolution of 1 m along the length of the fibre, and hence is able to operate with an acoustic positioning system to determine the position of the riser with the same spatial resolution. In addition, the fiber can at the same time also detect much lower frequency mechanical vibrations in the riser, for example such as resonant mode vibrations induced by movement in the surrounding medium. By using vibration detection in combination with acoustic positioning then overall structure shape monitoring can be undertaken, which is useful for vortex induced vibration (VIV) visualisation, fatigue analysis, and a variety of other advanced purposes. The structure may be a sub-sea riser.

    STRUCTURE MONITORING
    4.
    发明申请
    STRUCTURE MONITORING 审中-公开
    结构监测

    公开(公告)号:US20140022530A1

    公开(公告)日:2014-01-23

    申请号:US13944469

    申请日:2013-07-17

    Abstract: A method and apparatus for monitoring a structure using an optical fiber based distributed acoustic sensor (DAS) extending along the length of the structure. The DAS is able to resolve a separate acoustic signal with a spatial resolution of 1 m along the length of the fibre, and hence is able to operate with an acoustic positioning system to determine the position of the riser with the same spatial resolution. In addition, the fiber can at the same time also detect much lower frequency mechanical vibrations in the riser, for example such as resonant mode vibrations induced by movement in the surrounding medium. By using vibration detection in combination with acoustic positioning then overall structure shape monitoring can be undertaken, which is useful for vortex induced vibration (VIV) visualisation, fatigue analysis, and a variety of other advanced purposes. The structure may be a sub-sea riser.

    Abstract translation: 一种用于使用沿着结构的长度延伸的基于光纤的分布式声学传感器(DAS)来监视结构的方法和装置。 DAS能够沿着光纤的长度解析出具有1m空间分辨率的单独的声信号,因此能够利用声学定位系统来操作,以确定具有相同空间分辨率的提升器的位置。 此外,光纤同时也可以检测提升管中的低频机械振动,例如诸如周围介质中的运动引起的共振模式振动。 通过使用振动检测与声学定位结合,可以进行整体结构形状监测,这对于涡流诱发振动(VIV)可视化,疲劳分析和各种其他先进目的是有用的。 该结构可以是海底立管。

    Structure monitoring
    5.
    发明授权

    公开(公告)号:US10145821B2

    公开(公告)日:2018-12-04

    申请号:US13944469

    申请日:2013-07-17

    Abstract: A method and apparatus for monitoring a structure using an optical fiber based distributed acoustic sensor (DAS) extending along the length of the structure. The DAS is able to resolve a separate acoustic signal with a spatial resolution of 1 m along the length of the fibre, and hence is able to operate with an acoustic positioning system to determine the position of the riser with the same spatial resolution. In addition, the fiber can at the same time also detect much lower frequency mechanical vibrations in the riser, for example such as resonant mode vibrations induced by movement in the surrounding medium. By using vibration detection in combination with acoustic positioning then overall structure shape monitoring can be undertaken, which is useful for vortex induced vibration (VIV) visualisation, fatigue analysis, and a variety of other advanced purposes. The structure may be a sub-sea riser.

    OPTICAL FIBER CABLE
    6.
    发明申请
    OPTICAL FIBER CABLE 审中-公开

    公开(公告)号:US20180245957A1

    公开(公告)日:2018-08-30

    申请号:US15962196

    申请日:2018-04-25

    Abstract: Embodiments of the present invention provide a cable for optical fiber sensing applications formed from fiber wound around a cable core. A protective layer is then preferably placed over the top of the wound fiber, to protect the fiber, and to help keep it in place on the cable core. The cable core is preferably of a diameter to allow bend-insensitive fiber to be wound thereon with low bending losses. The effect of winding the fiber onto the cable core means that the longitudinal sensing resolution of the resulting cable is higher than simple straight fiber, when the cable is used with an optical fiber sensing system such as a DAS or DTS system. The achieved resolution for the resulting cable is a function of the fiber winding diameter and pitch, with a larger diameter and reduced winding pitch giving a higher longitudinal sensing resolution.

    Method and apparatus for optical sensing

    公开(公告)号:US11022467B2

    公开(公告)日:2021-06-01

    申请号:US16474747

    申请日:2018-01-05

    Abstract: An improved optical fiber distributed acoustic sensor system uses an optical fiber having reflector portions distributed along its length in at least a first portion. The reflector portions are positioned along the fiber separated by a distance that is equivalent to twice the distance an optical pulse travels along the fiber in a single sampling period of the data acquisition opto-electronics within the sensor system. No oversampling of the reflections of the optical pulses from the reflector portions is undertaken. The sampling points for data acquisition in the sensor system are aligned with the reflections that arrive at the sensor system from along the sensing fiber. Adaptive delay componentry adaptively aligns the reflected optical signals (or their electrical analogues) with the sampling points. Control over the sampling points can re-synchronise the sampling points with the returning reflections. Reflection equalisation componentry may reduce the dynamic range of the returning reflections.

    Non-isotropic acoustic cable
    10.
    发明授权

    公开(公告)号:US10345139B2

    公开(公告)日:2019-07-09

    申请号:US15804657

    申请日:2017-11-06

    Applicant: Silixa Ltd.

    Abstract: Embodiments of the present invention address aliasing problems by providing a plurality of discrete acoustic sensors along a cable whereby acoustic signals may be measured in situations where the fiber optic cable has not been secured to a structure or area by a series of clamps. Acoustic sampling points are achieved by selectively enhancing the acoustic coupling between the outer layer and the at least one optical fiber arrangement, such that acoustic energy may be transmitted selectively from the outer layer to the at least one optical fiber arrangement. The resulting regions of acoustic coupling along the cable allow the optical fiber to detect acoustic signals. Regions between the outer layer and the at least one optical fiber arrangement that contain material which is acoustically insulating further this enhancement since acoustic waves are unable to travel through such mediums, or at least travel through such mediums at a reduced rate.

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