Optical fiber based distributed temperature systems deployment for measurement of boreholes temperature profiles in the rock massif

Šiška, Petr; Látal, Jan; Bujok, Petr; Vanderka, Aleš; Клемпа, Мартин; Koudelka, Petr; Vašinek, Vladimír; Pospíšil, Pavel

doi:10.1007/s11082-016-0379-3

Cited by 15 publications

(6 citation statements)

References 29 publications

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“…Combining the conventional TRT apparatus with distributed temperature-sensing technology using fiber optic cables to measure temperature (Siska et al 2016) at depth was initially achieved by Fujii et al (2006), followed by other researchers (Fujii et al 2009;Acuña et al 2011;Acuña and Palm 2013;Holmberg et al 2016). The fiber optic cable is installed in the GHE inside or outside the pipe.…”

Section: Downhole Temperature Measurementsmentioning

confidence: 99%

Colloquium 2016: Assessment of subsurface thermal conductivity for geothermal applications

Raymond

2018

Can. Geotech. J.

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The construction of green buildings using geothermal energy requires knowledge of the ground thermal conductivity, assessed when designing the heating and cooling system of commercial buildings with ground-coupled heat pumps. The most commonly used method for active field assessment is the thermal response test (TRT), which consists of circulating heated water in a pilot ground heat exchanger (GHE) where temperature and flow rate are monitored. The transient thermal perturbation is analyzed to evaluate the subsurface thermal conductivity. Heat injection can also be performed with a heating cable in the GHE to conduct a TRT without water circulation, which can be affected by surface temperature variations. Mots-clés : géothermie, géothermique, géophysique thermique, pompe à chaleur, conductivité thermique, test de réponse thermique, échangeur de chaleur au sol.

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Section: Downhole Temperature Measurementsmentioning

confidence: 99%

Colloquium 2016: Assessment of subsurface thermal conductivity for geothermal applications

Raymond

2018

Can. Geotech. J.

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“…Fibers with such design are mechanically robust and successfully used at ambient conditions in telecommunication and some other applications. Within the past few decades, optical fibers are being more and more used in harsh environments, like oil wells, as distributed temperature or acoustic sensors . In parallel, optical fibers are being used for strain sensing .…”

Section: Introductionmentioning

confidence: 99%

Sensing carbon allotropes in protective coatings on optical fibers with far‐ and near‐field Raman spectroscopy and microscopy

Kharintsev

Saparina

Stolov

et al. 2017

J Raman Spectroscopy

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Hermetic carbon coatings of different thicknesses ranging from 1 to 100 nm on a series of optical fibers are characterized with confocal Raman spectroscopy and atomic force microscopy. Standard far‐field Raman spectra in the region of 1,000–2,000 cm−1 were fitted and well reproduced using 5 individual components assigned to different species of graphite‐like and disordered phases. Based on the fitting, a new spectroscopic indicator was proposed: G*D*true/Δ, where G* and D* and Δ are intensities at the maxima of the graphite‐like G peak and the disorder‐induced D peak and the dip between them, respectively. This indicator provides a measure of soot fraction in carbonaceous materials. A tip‐enhanced Raman scattering (TERS) technique confirmed the complex structure of the first‐order Raman D band assigned to disordered graphitic lattice vibrations. In addition, the TERS method provided convincing evidence for the formation of carbon allotropes, such as carbon nanotubes in the coatings. Possible effects of allotropes on hydrogen and water permeation through carbon coating are discussed in the view of the obtained results.

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“…Regarding the use of DTS in geothermal wells, laboratory and field tests were carried out in the late 1980s to prove the ability of FO-techniques for temperature and pressure measurements (Angel et al 1986). After that, DTS has been installed in geothermal wells for various applications, such as for testing DTS systems or assessing lithology in boreholes (Hurtig et al 1994(Hurtig et al , 1996Reinsch and Henninges 2012;Reinsch et al 2013;Förster et al 1997;Wisian et al 1998;Henninges et al 2005;Freifeld 2008;Siska et al 2016). Further, a few studies have shown that DTS-measurements in geothermal wells can identify hydraulically active zones and fracture characteristics and measure pressure profiles (Sharma et al 1990;Sakaguchi and Matsushima 2000;Smithpeter et al 1999).…”

Section: Dtsmentioning

confidence: 99%

Monitoring cold water injections for reservoir characterization using a permanent fiber optic installation in a geothermal production well in the Southern German Molasse Basin

et al. 2021

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Fiber optic sensing has gained importance for wellbore monitoring and reservoir characterization in geothermal fields as it allows continuous, spatially highly resolved measurements. Distributed acoustic sensing (DAS) and distributed temperature sensing (DTS) technologies, among others, enable monitoring of flow regimes and heat transport inside the wellbore to describe the dynamical behavior of the reservoir. The technically challenging installation of a permanent fiber optic monitoring system in a geothermal production well over the entire wellbore length was conducted for the first time at the geothermal site Schäftlarnstraße in Munich, Germany. One cable with two DAS fibers, two DTS fibers, and one fiber for a downhole fiber optic pressure/temperature gauge were clamped to ¾-in. sucker rods and installed to 3.7 km measured depth to collect data from the wellbore after drilling, during testing, and during operations. We present DTS profiles during 3 months of well shut-in and show the results of two cold water injection tests conducted to localize inflow zones in the reservoir and to test the performance of the fiber optic setup. A vertical displacement in temperature peaks of approximately 1.5 m was observed during the injection tests, presumably resulting from thermal contraction of the sucker rod–cable setup. This was verified by analyzing the strain information from the DAS records over 1 h of warm-back after cold water injection with the calculated theoretical thermal contraction of DTS of the same period. We further verified the flowmeter measurements with a gradient velocity analysis of DTS profiles during injection. Intake to the major inflow zone was estimated to 93.5% for the first injection test, respective 94.0% for the second, intake of flowmeter was calculated to 92.0% for the same zone. Those values are confirmed by analyzing DTS profiles during the warm-back period after the well was shut.

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Optical fiber based distributed temperature systems deployment for measurement of boreholes temperature profiles in the rock massif

Cited by 15 publications

References 29 publications

Colloquium 2016: Assessment of subsurface thermal conductivity for geothermal applications

Colloquium 2016: Assessment of subsurface thermal conductivity for geothermal applications

Sensing carbon allotropes in protective coatings on optical fibers with far‐ and near‐field Raman spectroscopy and microscopy

Monitoring cold water injections for reservoir characterization using a permanent fiber optic installation in a geothermal production well in the Southern German Molasse Basin

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