Patent
Optical time-domain reflectometry
Arthur H. Hartog,P.C. Wait +1 more
- 30 Jan 2003
187
TL;DR: In this paper, an optical time domain reflectometry method of sensing a parameter to be measured in a region of interest comprises launching optical radiation (4) at a probe wavelength into an-optical fiber (5, 6) and producing electrical output signals in response to optical radiation backscattered from the optical fibre (5 and 6).
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Abstract: An optical time domain reflectometry method of sensing a parameter to be measured in a region of interest comprises launching optical radiation (4) at a probe wavelength into an-optical fibre (5, 6) and producing electrical output signals in response to optical radiation backscattered from the optical fibre (5, 6). In one aspect of the invention the optical fibre comprises first and second sections (5, 6), the second section (6) having a lower intensity threshold for the onset of non-linear effects than the first section (5) and being deployed in the region of interest. Optical radiation (4) at the probe wavelength is launched into the said first section (5) at an intensity lower than the non-linear effects intensity threshold of the first section (5) but higher than the non-linear effects intensity threshold of the second section (6), the attenuation characteristics of the said first section (5) being chosen so that the intensity of the optical radiation (4) at the probe wavelength reaching the second section (6) is below that of the non-linear effects intensity threshold of the said second section (6). In another aspect of the invention the optical fibre comprises first and second sections connected together by a remote amplifier, the gain of the amplifier being selected so as to compensate for attenuation losses in the probe wavelength in the first section.
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Citations
Recent progress in distributed fiber optic sensors.
Xiaoyi Bao,Liang Chen +1 more
TL;DR: A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices.
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Joseph A. Ayoub,Stuart Inglis Jardine,Peter Fitzgerald +2 more
- 17 Apr 2003
TL;DR: In this paper, the authors proposed methods of fracturing a subterranean formation including the step of pumping at least one device actively transmitting data that provides information on the device position, and further comprising the steps of assessing the fracture geometry based on the positions of said at least device or pumping metallic elements, preferably as proppant agents, and locating the position of said metallic elements with a tool selected from the group consisting of magnetometers, resistivity tools, electromagnetic devices and ultra-long arrays of electrodes.
184
Raman-based fibre sensors: Trends and applications
TL;DR: The physical principles behind Raman-based distributed temperature sensors are set out and the many approaches to their design, the relevant parameters, and the significant features of employed schemes such as optical time- or frequency-domain reflectometry are summarized.
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Distributed Optical Fibre Sensor
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- 06 Dec 2011
TL;DR: In this article, a distributed optical fiber sensor for detecting one or more physical parameters indicative of an environmental influence on a sensor optical fibre, as a function of position along the sensor fibre, is described.
138
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Use of fiber optics in deviated flows
Glynn R Williams,Kevin J Forbes,Arthur H. Hartog,Christian Koeniger,George Albert Brown +4 more
- 17 Dec 2002
TL;DR: In this article, the authors proposed a system to determine the mixture of fluids in the deviated section of a wellbore comprising at least one distributed temperature sensor adapted to measure the temperature profile along at least two levels of a vertical axis.
97
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Distributed temperature sensing in solid-core fibres
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Patent
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