Comparative Experimental Study of a High-Temperature Raman-Based Distributed Optical Fiber Sensor with Different Special Fibers

In order to improve the performance of fiber sensors and fully tap the potential of optical fiber sensors, various optical materials have been selectively coated on optical fiber sensors under the background of the rapid development of various optical materials. On the basis of retaining the original characteristics of the optical fiber sensors, the coated sensors are endowed with new characteristics, such as high sensitivity, strong structure, and specific recognition. Many materials with a large thermal optical coefficient and thermal expansion coefficients are applied to optical fibers, and the temperature sensitivities are improved several times after coating. At the same time, fiber sensors have more intelligent sensing capabilities when coated with specific recognition materials. The same/different kinds of materials combined with the same/different fiber structures can produce different measurements, which is interesting. This paper summarizes and compares the fiber sensors treated by different coating materials.

Section: Sensors Coated With Polyimide Acrylate and Materials Fomentioning

confidence: 99%

Section: Sensors Coated With Polyimide Acrylate and Materials Fomentioning

confidence: 99%

A Review of Coating Materials Used to Improve the Performance of Optical Fiber Sensors

Yang

Wang

et al. 2020

“…The light's backscattered spectrum consists of a Rayleigh band, Brillouin band, and Raman band, as shown in Figure 1b [14]. The main fiber optic measurements widely used today are the Distributed Temperature Sensing (DTS), Distributed Acoustic Sensing (DAS) and Distributed Strain Sensing (DSS) [16]. Where, DAS is measured from Raleigh scattering, DTS from Raman scattering, and DSS from Brillouin scattering.…”

Section: Overview Of Distributed Fiber Optic Sensing Technologymentioning

confidence: 99%

Distributed Fiber Optic Sensing for Real-Time Monitoring of Gas in Riser during Offshore Drilling

Feo

Sharma

Kortukov

et al. 2020

Effective well control depends on the drilling teams’ knowledge of wellbore flow dynamics and their ability to predict and control influx. Unfortunately, detection of a gas influx in an offshore environment is particularly challenging, and there are no existing datasets that have been verified and validated for gas kick migration at full-scale annular conditions. This study bridges this gap and presents pioneering research in the application of fiber optic sensing for monitoring gas in riser. The proposed sensing paradigm was validated through well-scale experiments conducted at Petroleum Engineering Research & Technology Transfer lab (PERTT) facility at Louisiana State University (LSU), simulating an offshore marine riser environment with its larger than average annular space and mud circulation capability. The experimental setup instrumented with distributed fiber optic sensors and pressure/temperature gauges provides a physical model to study the dynamic gas migration in full-scale annular conditions. Current kick detection methods primarily utilize surface measurements and do not always reliably detect a gas influx. The proposed application of distributed fiber optic sensing overcomes this key limitation of conventional kick detection methods, by providing real-time distributed downhole data for accurate and reliable monitoring. The two-phase flow experiments conducted in this research provide critical insights for understanding the flow dynamics in offshore drilling riser conditions, and the results provide an indication of how quickly gas can migrate in a marine riser scenario, warranting further investigation for the sake of effective well control.

“…Equation (3) can be simplified as follows:T=γC+LΔα−lnR where C=ln[GasGsKasKs(vasvs)4] indicates the difference between the Stokes and anti-Stokes photoelectric conversion channels; Δα = −(αas−αs) is the difference between the attenuation of the Stokes and anti-Stokes scattering light propagating in the optical fiber; and γ=hΔfk indicates the energy drift of the incident pulse light and the scattered light. These parameters are suitable for the whole optical fiber [19].…”

Section: Principle Of the Raman Distributed Temperature Sensing Mementioning

confidence: 99%

Monitoring a Heatsink Temperature Field Using Raman-Based Distributed Temperature Sensor in a Vacuum and −173 °C Environment

Zhang

Peng

Liu

2019

A heatsink is a large experimental device which is used to simulate the outer space environment. In this paper, a Raman-based distributed temperature sensor was used for real-time and continuous heatsink temperature monitoring, and a special Raman-based distributed temperature sensing method and system have been proposed. This method takes advantage of three calibration parameters (Δα, γ,C) to calculate the temperature. These three parameters are related to the attenuation of the optical fiber, the Raman translation, and the difference of optoelectronic conversion, respectively. Optical time domain reflectometry was used to calculate the location. A series of heatsink temperature measurement experiments were performed in a vacuum and −173 °C environment. When the temperature dropped to −100 °C, the parameter Δα was found to vary. A method was proposed to recalculate Δα and modify the traditional Raman fiber temperature equation. The results of the experiments confirmed the validity of this modified Raman fiber temperature equation. Based on this modified equation, the temperature field in the heatsink was calculated. The Raman-based distributed temperature sensor has potential applications in temperature measurement and judging the occurrence of faults in space exploration.