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Fiber Bragg Grating Sensors for the Oil Industry

View Article: PubMed Central - PubMed

ABSTRACT

With the oil and gas industry growing rapidly, increasing the yield and profit require advances in technology for cost-effective production in key areas of reservoir exploration and in oil-well production-management. In this paper we review our group’s research into fiber Bragg gratings (FBGs) and their applications in the oil industry, especially in the well-logging field. FBG sensors used for seismic exploration in the oil and gas industry need to be capable of measuring multiple physical parameters such as temperature, pressure, and acoustic waves in a hostile environment. This application requires that the FBG sensors display high sensitivity over the broad vibration frequency range of 5 Hz to 2.5 kHz, which contains the important geological information. We report the incorporation of mechanical transducers in the FBG sensors to enable enhance the sensors’ amplitude and frequency response. Whenever the FBG sensors are working within a well, they must withstand high temperatures and high pressures, up to 175 °C and 40 Mpa or more. We use femtosecond laser side-illumination to ensure that the FBGs themselves have the high temperature resistance up to 1100 °C. Using FBG sensors combined with suitable metal transducers, we have experimentally realized high- temperature and pressure measurements up to 400 °C and 100 Mpa. We introduce a novel technology of ultrasonic imaging of seismic physical models using FBG sensors, which is superior to conventional seismic exploration methods. Compared with piezoelectric transducers, FBG ultrasonic sensors demonstrate superior sensitivity, more compact structure, improved spatial resolution, high stability and immunity to electromagnetic interference (EMI). In the last section, we present a case study of a well-logging field to demonstrate the utility of FBG sensors in the oil and gas industry.

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(a) Scheme diagram of directional FBG-FP sensor structure; (b) Photo image of the sensing probe; (c) FBG-FP spectrum with several interference dips overlapping on the top of the FBG resonance spectrum.
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sensors-17-00429-f015: (a) Scheme diagram of directional FBG-FP sensor structure; (b) Photo image of the sensing probe; (c) FBG-FP spectrum with several interference dips overlapping on the top of the FBG resonance spectrum.

Mentions: In another experiment, we developed a more compact structure employing a 5 mm-long FBG-based Fabry-Perot interferometer (FBG-FP), as shown in Figure 15, to detect the ultrasonic wave instead of the PS-FBG. There are several notches on the top of the reflection spectrum of the FBG-FP, as shown in Figure 15c. High writing laser energy and hydrogen-loading the fiber contributes resulted in large RI modification, contributing to high step-index profiles at the both ends of the inscribed of grating region. The Fabry-Perot interferometer is created by the high average index step at each end of the grating, resulting in Fabry-Perot fringes superimposed on the FBG resonance spectrum. Because their fringe contrasts of interference spectrum are different, it results in a different 3 dB in the bandwidth or the full width half maximum. We selected one FP notch with a 3 dB bandwidth of 8 pm for detecting ultrasonic waves.


Fiber Bragg Grating Sensors for the Oil Industry
(a) Scheme diagram of directional FBG-FP sensor structure; (b) Photo image of the sensing probe; (c) FBG-FP spectrum with several interference dips overlapping on the top of the FBG resonance spectrum.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5375715&req=5

sensors-17-00429-f015: (a) Scheme diagram of directional FBG-FP sensor structure; (b) Photo image of the sensing probe; (c) FBG-FP spectrum with several interference dips overlapping on the top of the FBG resonance spectrum.
Mentions: In another experiment, we developed a more compact structure employing a 5 mm-long FBG-based Fabry-Perot interferometer (FBG-FP), as shown in Figure 15, to detect the ultrasonic wave instead of the PS-FBG. There are several notches on the top of the reflection spectrum of the FBG-FP, as shown in Figure 15c. High writing laser energy and hydrogen-loading the fiber contributes resulted in large RI modification, contributing to high step-index profiles at the both ends of the inscribed of grating region. The Fabry-Perot interferometer is created by the high average index step at each end of the grating, resulting in Fabry-Perot fringes superimposed on the FBG resonance spectrum. Because their fringe contrasts of interference spectrum are different, it results in a different 3 dB in the bandwidth or the full width half maximum. We selected one FP notch with a 3 dB bandwidth of 8 pm for detecting ultrasonic waves.

View Article: PubMed Central - PubMed

ABSTRACT

With the oil and gas industry growing rapidly, increasing the yield and profit require advances in technology for cost-effective production in key areas of reservoir exploration and in oil-well production-management. In this paper we review our group’s research into fiber Bragg gratings (FBGs) and their applications in the oil industry, especially in the well-logging field. FBG sensors used for seismic exploration in the oil and gas industry need to be capable of measuring multiple physical parameters such as temperature, pressure, and acoustic waves in a hostile environment. This application requires that the FBG sensors display high sensitivity over the broad vibration frequency range of 5 Hz to 2.5 kHz, which contains the important geological information. We report the incorporation of mechanical transducers in the FBG sensors to enable enhance the sensors’ amplitude and frequency response. Whenever the FBG sensors are working within a well, they must withstand high temperatures and high pressures, up to 175 °C and 40 Mpa or more. We use femtosecond laser side-illumination to ensure that the FBGs themselves have the high temperature resistance up to 1100 °C. Using FBG sensors combined with suitable metal transducers, we have experimentally realized high- temperature and pressure measurements up to 400 °C and 100 Mpa. We introduce a novel technology of ultrasonic imaging of seismic physical models using FBG sensors, which is superior to conventional seismic exploration methods. Compared with piezoelectric transducers, FBG ultrasonic sensors demonstrate superior sensitivity, more compact structure, improved spatial resolution, high stability and immunity to electromagnetic interference (EMI). In the last section, we present a case study of a well-logging field to demonstrate the utility of FBG sensors in the oil and gas industry.

No MeSH data available.


Related in: MedlinePlus