Advanced feed-through systems for in-well optical fibre sensing

Shiach, G; Nolan, Andrew; McAvoy, Scott; McStay, Daniel; Prel, C.; Smith, Michael S. D.

doi:10.1088/1742-6596/76/1/012066

Cited by 8 publications

(2 citation statements)

References 3 publications

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“…A number of optical fibre point sensors have been developed for in-well sensing applications (5-7), examples include Bragg grating based temperature, pressure, strain and flow devices. Such devices may, for example, be used to monitor temperature at discrete locations, the strain on a well casing (8) and endpoint detection of a sliding sleeve valve (9). Other examples of in-well uses of optical fibre sensors include use in the formation for processes such as fracturing and acidizing, acoustic sensors for monitoring well logging equipment and systems for detecting the operation of a downhole tool.…”

Section: In-well Monitoringmentioning

confidence: 99%

Advanced feed-through systems for in-well optical fibre sensing

Shiach¹,

Nolan²,

McAvoy³

et al. 2007

J. Phys.: Conf. Ser.

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A new optical fibre feed-through for use in subsea in-well optical fibre sensing systems is reported. The new feed-through is compatible for use with standard subsea Christmas Tree penetrators and allows multiple re-mating of the feed-through over the lifetime of the device. The system has been extensively tested under in-well conditions and found to conform to the performance requirements. The new feed-through is planned to be used in one of the first subsea optical fibre in-well sensing systems.

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Section: In-well Monitoringmentioning

confidence: 99%

Advanced feed-through systems for in-well optical fibre sensing

Shiach¹,

Nolan²,

McAvoy³

et al. 2007

J. Phys.: Conf. Ser.

Self Cite

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“…These limitations have a major impact when used in subsea wells with long lead-in lengths due to attenuation of optical connections, splices, and downhole fibres (Seabrook et al 2022). In addition, the number of fibre-optic cables is limited at the subsea tree with older versions of optical feedthrough systems being limited to a single fibre (Shiach et al, 2007). In the deployment of subsea wells, it is common for the well to pass through a manifold, making them highly extensive in length.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Temperature Profiles using Low-Frequency Distributed Acoustic Sensing from In-Well Measurements

Bradley,

Haavik,

Landrø

2023

SPE Journal

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Summary Distributed fiber-optic sensing for in-well measurements is primarily used for monitoring purposes. Distributed acoustic sensing (DAS) is used to record acoustic disturbances and is sensitive to changes in strain, pressure, and temperature. Distributed temperature sensing (DTS) is used to measure temperature along the fiber. Here, we compare temperature changes measured by DAS and DTS in wells over different time periods. We affirm the linear dependency between DAS’s phase change and temperature, with the derived strain rate being proportional to the time derivative of the temperature response. Given that low-frequency (LF) DAS is sensitive to strain, pressure, and temperature effects, one must choose quiet periods in the well or condition the data to only analyze the effect of temperature on the fiber. We show that LF-DAS data can be used to track temperature changes over several weeks. We then propose a method, using liquid column movements, to invert LF-DAS data for absolute temperature profiles. The temperature profile in a well can be measured using DTS. However, DTS data are not always available, and conventional Raman scattering DTS is not used in subsea wells with long lead-in lengths. Hence, it would be desirable to acquire the temperature response from LF-DAS data to use as a multipurpose tool for in-well monitoring. Here, we show that when purely investigating the response to an initial displacement of the fluid column (i.e., from rest), LF-DAS can be used along with reference sensors, such as the wellhead and downhole temperature gauge data to estimate the depth variations in temperature in production and injection wells.

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