Method and Apparatus for Optical Sensing

    公开(公告)号:US20210278255A1

    公开(公告)日:2021-09-09

    申请号:US17328014

    申请日:2021-05-24

    Abstract: Embodiments of the invention provide an improved optical fiber distributed acoustic sensor system that makes use of an optical fiber having reflector portions distributed along its length in at least a first portion. In particular, in order to increase the spatial resolution of the sensor system to the maximum, 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. As such, no oversampling of the reflections of the optical pulses from the reflector portions is undertaken, which means that it is important that 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. In order to ensure such alignment, adaptive delay componentry may be used to adaptively align the reflected optical signals (or their electrical analogues) with the sampling points. Alternatively, control over the sampling points can also be undertaken to re-synchronise the sampling points with the returning reflections. In addition, in order to allow higher speed sampling to be undertaken, reflection equalisation componentry may also be used to reduce the dynamic range of the returning reflections.

    METHOD AND APPARATUS FOR OPTICAL SENSING
    32.
    发明申请

    公开(公告)号:US20190323863A1

    公开(公告)日:2019-10-24

    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.

    Submersible pump monitoring
    33.
    发明授权

    公开(公告)号:US10415373B2

    公开(公告)日:2019-09-17

    申请号:US15122038

    申请日:2015-03-02

    Applicant: Silixa Ltd.

    Abstract: In order to address the above noted problems, embodiments of the present invention use distributed acoustic sensing to monitor the fluid level in an ESP activated well so as to monitor the condition and performance of the ESP. Embodiments of the invention use the ESP as an acoustic source in order to monitor the annulus fluid level within the well and to monitor the frequency of the ESP. Additionally, embodiments of the present invention may use distributed acoustic sensing to monitor the flow rates of the production fluid above and below the ESP to determine the pump's efficiency. In particular, some embodiments utilize one or more optical fibers to measure the acoustic waves generated by the ESP, wherein the fiber cabling has already been deployed along the length of the well. As such, the present invention is a non-invasive, in-situ method for monitoring the condition and performance of an ESP.

    Method and apparatus for optical sensing

    公开(公告)号:US10393573B2

    公开(公告)日:2019-08-27

    申请号:US15368954

    申请日:2016-12-05

    Applicant: Silixa Ltd.

    Abstract: The present invention provides novel apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fiber. The present invention can be used for point sensors as well as distributed sensors or the combination of both. In particular this technique can be applied to distributed sensors while extending dramatically the speed and sensitivity to allow the detection of acoustic perturbations anywhere along a length of an optical fiber while achieving fine spatial resolution. The present invention offers unique advantages in a broad range of acoustic sensing and imaging applications. Typical uses are for monitoring oil and gas wells such as for distributed flow metering and/or imaging, seismic imaging, monitoring long cables and pipelines, imaging within large vessel as well as for security applications.

    ENHANCED SEISMIC SURVEYING
    35.
    发明申请

    公开(公告)号:US20180224572A1

    公开(公告)日:2018-08-09

    申请号:US15943197

    申请日:2018-04-02

    Abstract: Embodiments of the present invention help in the processing and interpretation of seismic survey data, by correlating or otherwise comparing or associating seismic data obtained from a seismic survey with flow information obtained from a well or borehole in the surveyed area. In particular, embodiments of the present invention allow for flow data representing a flow profile along a well that is being monitored by a distributed acoustic sensor to be determined, such that regions of higher flow in the well can be determined. For example, in the production zone the well will be perforated to allow oil to enter the well, but it has not previously been possible to determine accurately where in the production zone the oil is entering the well. However, by determining a flow rate profile along the well using the DAS then this provides information as to where in the perforated production zone oil is entering the well, and hence the location of oil bearing sands. This location can then be combined or otherwise correlated, used, or associated with petroleum reservoir location information obtained from the seismic survey, to improve the confidence and/or accuracy in the determined petroleum reservoir location.

    METHOD AND SYSTEM FOR DOWNHOLE OBJECT LOCATION AND ORIENTATION DETERMINATION

    公开(公告)号:US20170082766A1

    公开(公告)日:2017-03-23

    申请号:US15311425

    申请日:2015-05-15

    Applicant: Silixa Ltd.

    Abstract: A downhole device is provided that is intended to be co-located with an optical fiber cable to be found, for example by being fixed together in the same clamp. The device has an accelerometer or other suitable orientation determining means that is able to determine its positional orientation, with respect to gravity. A vibrator or other sounder is provided, that outputs the positional orientation information as a suitable encoded and modulated acoustic signal. A fiber optic distributed acoustic sensor deployed in the vicinity of the downhole device detects the acoustic signal and transmits it back to the surface, where it is demodulated and decoded to obtain the positional orientation information. Given that the device is co-located with the optical fiber the position of the fiber can then be inferred. As explained above, detecting the fiber position is important during perforation operations, so that the fiber is not inadvertently damaged.

    Method and apparatus for optical sensing

    公开(公告)号:US12287235B2

    公开(公告)日:2025-04-29

    申请号:US18370963

    申请日:2023-09-21

    Applicant: Silixa Ltd.

    Abstract: The present invention provides novel apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fibre. The present invention can be used for point sensors as well as distributed sensors or the combination of both. In particular this technique can be applied to distributed sensors while extending dramatically the speed and sensitivity to allow the detection of acoustic perturbations anywhere along a length of an optical fibre while achieving fine spatial resolution. The present invention offers unique advantages in a broad range of acoustic sensing and imaging applications. Typical uses are for monitoring oil and gas wells such as for distributed flow metering and/or imaging, seismic imaging, monitoring long cables and pipelines, imaging within large vessel as well as for security applications.

    Method and Apparatus for Optical Sensing
    39.
    发明公开

    公开(公告)号:US20240011823A1

    公开(公告)日:2024-01-11

    申请号:US18370963

    申请日:2023-09-21

    Applicant: Silixa Ltd.

    Abstract: The present invention provides novel apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fibre. The present invention can be used for point sensors as well as distributed sensors or the combination of both. In particular this technique can be applied to distributed sensors while extending dramatically the speed and sensitivity to allow the detection of acoustic perturbations anywhere along a length of an optical fibre while achieving fine spatial resolution. The present invention offers unique advantages in a broad range of acoustic sensing and imaging applications. Typical uses are for monitoring oil and gas wells such as for distributed flow metering and/or imaging, seismic imaging, monitoring long cables and pipelines, imaging within large vessel as well as for security applications.

    LONG RANGE OPTICAL FIBER SENSING SYSTEMS
    40.
    发明公开

    公开(公告)号:US20230221151A1

    公开(公告)日:2023-07-13

    申请号:US17904599

    申请日:2021-02-19

    Applicant: Silixa Ltd.

    CPC classification number: G01D5/35364

    Abstract: A long range optical fiber sensor such as a distributed acoustic sensor has a sensing fiber located remotely from the interrogator, with a length of transport fiber path connecting the two. Because no sensing is performed on the transport fiber then the pulse repetition rate from the interrogator can be high enough such that the pulse repetition rate and pulse power are optimised according to the sensing fiber length and hence sensing frequency response and sensitivity are also optimised according to the sensing fiber length.

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