scholarly journals Distributed Fiber Optic Sensors for the Monitoring of a Tunnel Crossing a Landslide

2018 ◽  
Vol 10 (8) ◽  
pp. 1291 ◽  
Author(s):  
Aldo Minardo ◽  
Ester Catalano ◽  
Agnese Coscetta ◽  
Giovanni Zeni ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Strain Distribution ◽  
Fiber Optic ◽  
Temporal Evolution ◽  
Strain Sensor ◽  
Fiber Optic Sensors ◽  
Railway Tunnel ◽  
Long Term Monitoring ◽  
Term Monitoring

This work reports on the application of a distributed fiber-optic strain sensor for long-term monitoring of a railway tunnel affected by an active earthflow. The sensor has been applied to detect the strain distribution along an optical fiber attached along the two walls of the tunnel. The experimental results, relative to a two-year monitoring campaign, demonstrate that the sensor is able to detect localized strains, identify their location along the tunnel walls, and follow their temporal evolution.

scholarly journals ANALYSIS OF THE ACCURACY OF FIBRE-OPTIC STRAIN GAUGES

2013 ◽  
Vol 53 (6) ◽  
pp. 872-877
Author(s):  
Dita Jiroutová ◽  
Miroslav Vokáč
Keyword(s):  
Fiber Optic ◽  
Strain Gauges ◽  
Relative Deformation ◽  
Fibre Optic ◽  
Reinforced Concrete Structure ◽  
Structure Monitoring ◽  
Fiber Optic Technology ◽  
Long Term Monitoring ◽  
Term Monitoring

In recent years, the field of structure monitoring has been making increasing use of systems based on fiber-optic technologies. Fiber-optic technology offers many advantages, including higher quality measurements, greater reliability, easier installation and maintenance, insensitivity to the environment (mainly to the electromagnetic field), corrosion resistance, safety in explosive and flammable environments, the possibility of long-term monitoring and lower cost per lifetime. We have used SOFO fibre-optic strain gauges to perform measurements to check the overall relative deformation of a real reinforced concrete structure. Long-term monitoring of the structure revealed that the measurement readings obtained from these fibre-optic strain gauges differed from each other. Greater attention was therefore paid to the calibration of the fibre-optic strain gauges, and to determining their measurement accuracy. The experimental results show that it is necessary to calibrate SOFO strain gauges before they are used, and to determine their calibration constant.

scholarly journals Horizontal wellbore production profile evaluation by distributed fiber-optic temperature surveillance

2021 ◽  
Vol 6 (4) ◽  
pp. 81-91
Author(s):  
Andrey I. Ipatov ◽  
Mikhail I. Kremenetsky ◽  
Ilja S. Kaeshkov ◽  
Mikhail V. Kolesnikov ◽  
Alexander  A. Rydel ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Phase Segregation ◽  
Gas Production ◽  
Fiber Optic Sensor ◽  
Well Testing ◽  
Reservoir Properties ◽  
Horizontal Wellbore ◽  
Long Term Monitoring ◽  
Term Monitoring

The main goal of the paper is demonstration of permanent downhole long-term monitoring capabilities for oil and gas production profile along horizontal wellbore in case of natural flow. The informational basis of the results obtained is the data of long-term temperature and acoustic monitoring in the borehole using a distributed fiber-optic sensor (DTS + DAS). Materials and methods. At the same time, flowing bottom-hole pressure and surface rates were monitored at the well for rate transient analysis, as well as acoustic cross-well interference testing [1], based on the results of which “well-reservoir” system properties were evaluated, the cross-well reservoir properties of the were estimated, and the possibility of cross-well testing using downhole DTS-DAS equipment was justified. The research results made it possible to assess reliability of DTS-DAS long-term monitoring analysis results in case of multiphase inflow and multiphase wellbore content. In particular, DTS-DAS results was strongly affected by the phase segregation in the near-wellbore zone of the formation. Conclusions. In the process of study, the tasks of inflow profile for each fluid phase evaluation, as well as its changes during the well production, were solved. The reservoir intervals with dominantly gas production have been reliably revealed, and the distribution of production along the wellbore has been quantified for time periods at the start of production and after production stabilization.

THE APPLICATION OF THE COVARIANCE METHOD ANALYSING THE DIGITAL IMAGES OF LAND SURFACE / ŽEMĖS DANGOS POKYČIŲ NUSTATYMAS ATLIEKANT FOTOGRAFINIŲ VAIZDŲ PALYGINIMĄ KOVARIACIJOS METODU / ИЗМЕНЕНИЯ ПОЧВЕННО-РАСТИТЕЛЬНОГО ПОКРОВА, ВЫЯВЛЕННЫЕ ПРИ СРАВНЕНИИ ЦИФРО ВЫХ ИЗОБРАЖЕНИЙ КОВАРИАЦИОННЫМ МЕТОДОМ

2011 ◽  
Vol 37 (3) ◽  
pp. 105-110 ◽  
Author(s):  
Jurgita Milieškaitė
Keyword(s):  
Correlation Coefficient ◽  
Land Surface ◽  
Temporal Evolution ◽  
Digital Images ◽  
Remote Access ◽  
Access Methods ◽  
Absolute Value ◽  
Long Term Monitoring ◽  
Term Monitoring

Accuracy issues of identification possibilities and analyzing digital images of land surface are examined using a covariance method. Digital images received using remote access methods are treated by the computer programes developed in the Matlab 7 software package environment. The paper investigates the opportunity to automatically compare two digital images of fragments and determines the interdependence of comparable images. The interdependence of two images is verified according to the calculated values of the correlation coefficient. Considering a more absolute value of the correlation coefficient between compared digital images, dependency is higher and vice versa. Such method could be applied to long-term monitoring in order to control the temporal evolution of selected images. Santrauka Aprašomas metodas, kuris galėtų būti taikomas atliekant ilgalaikę stebėseną – stebint pasirinktų objektų kitimą laikui bėgant. Nagrinėjama galimybė automatizuotai palyginti du skaitmeninių vaizdų fragmentus ir nustatyti šių lyginamų vaizdų tarpusavio priklausomybę. Skaitmeniniai vaizdai, gauti nuotoliniais metodais, apdorojami pagal sudarytą kompiuterinę programą Matlab 7 programinio paketo operatorių aplinkoje. Šia programa tarpusavyje lyginami du skaitmeniniai vaizdai. Jų tarpusavio priklausomybė įvertinama šia programa apskaičiuotomis koreliacijos koeficientų reikšmėmis. Kai koreliacijos koeficiento absoliučioji reikšmė didesnė, priklausomybė didesnė, ir atvirkščiai. Pagal tai galima įvertinti dviejų skaitmeninių vaizdų arba vieno vaizdo dviejų dalių (fragmentų) tarpusavio priklausomybę (panašumą). Резюме Описывается метод, который может быть применен для долгосрочного мониторинга – наблюдения за изменениями выбранных объектов во времени. Изучается возможность автоматически сравнивать между собой два фрагмента цифровых изображений и определять взаимозависимость этих сравниваемых изображений. Цифровые изображения, полученные дистанционными методами, обрабатываются по созданной компьютерной программе Matlab 7 в среде операторов программного пакета. По этой программе сопоставляются два цифровых изображения, взаимозависимость которых оценивается по рассчитанным программой значениям коэффициентов корреляции. При более высоких абсолютных значениях коэффициента корреляции взаимозависимость более высокая и наоборот. По этим значениям можно оценить взаимозависимость (сходство) двух цифровых изображений или двух частей (фрагментов) одного изображения.

scholarly journals Long-term monitoring of reinforced earth structures using distributed fiber optic sensing

2016 ◽  
Vol 6 (3) ◽  
pp. 321-327 ◽  
Author(s):  
Florian Moser ◽  
Werner Lienhart ◽  
Helmut Woschitz ◽  
Hartmut Schuller
Keyword(s):  
Fiber Optic ◽  
Reinforced Earth ◽  
Earth Structures ◽  
Long Term Monitoring ◽  
Fiber Optic Sensing ◽  
Term Monitoring
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