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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 structure of the proposedaccelerometer; (b) Photograph of the accelerometer and testing exciter; (c) Amplitude-frequency response of accelerometer; (d) Transverse direction dependence of resonance wavelength difference of FBGsunder the acceleration excitation of 1.5 G.
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sensors-17-00429-f003: (a) Scheme structure of the proposedaccelerometer; (b) Photograph of the accelerometer and testing exciter; (c) Amplitude-frequency response of accelerometer; (d) Transverse direction dependence of resonance wavelength difference of FBGsunder the acceleration excitation of 1.5 G.

Mentions: The 1D accelerometer is only required to respond to vibration along a single axis. The key to success is to transfer vibratory motion along the desired axis only, to the FBG by appropriate design of the mechanical transducer. At the same time, the mechanical transducer also determines the sensitivity, the mechanical response frequency and bandwidth of the sensor. In previous work, our group proposed a hybrid cantilever beam-based FBG accelerometer [103], as shown in Figure 3. The moving component of the sensor consists of an elastic rectangular cantilever beam and a pair of relatively massive L-shaped aluminum blocks. The cantilever beam, made from spring steel, supports the mass block formed by bolting the aluminum blocks back-to-back. FBG1 and FBG2 are pre-stressed each with one end fixed to the upper and lower surfaces of the mass block, respectively, and to a support pillar at their other ends. When vibration is applied vertically, the mass moves up and down, compressing and stretching FBG1 and FBG2 in opposite senses. In this work, the cross-axis sensitivity is decreased to 3.2% thanks to the dual-beam’s directional vibration responses, as shown in Figure 3d. Furthermore, the temperature is self-compensated based on the same responses to temperature of two reflection wavelengths. Finally, a considerable sensitivity of 215.6 pm/G is achieved stably over the frequency range of 10 Hz to 150 Hz.


Fiber Bragg Grating Sensors for the Oil Industry
(a) Scheme structure of the proposedaccelerometer; (b) Photograph of the accelerometer and testing exciter; (c) Amplitude-frequency response of accelerometer; (d) Transverse direction dependence of resonance wavelength difference of FBGsunder the acceleration excitation of 1.5 G.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

sensors-17-00429-f003: (a) Scheme structure of the proposedaccelerometer; (b) Photograph of the accelerometer and testing exciter; (c) Amplitude-frequency response of accelerometer; (d) Transverse direction dependence of resonance wavelength difference of FBGsunder the acceleration excitation of 1.5 G.
Mentions: The 1D accelerometer is only required to respond to vibration along a single axis. The key to success is to transfer vibratory motion along the desired axis only, to the FBG by appropriate design of the mechanical transducer. At the same time, the mechanical transducer also determines the sensitivity, the mechanical response frequency and bandwidth of the sensor. In previous work, our group proposed a hybrid cantilever beam-based FBG accelerometer [103], as shown in Figure 3. The moving component of the sensor consists of an elastic rectangular cantilever beam and a pair of relatively massive L-shaped aluminum blocks. The cantilever beam, made from spring steel, supports the mass block formed by bolting the aluminum blocks back-to-back. FBG1 and FBG2 are pre-stressed each with one end fixed to the upper and lower surfaces of the mass block, respectively, and to a support pillar at their other ends. When vibration is applied vertically, the mass moves up and down, compressing and stretching FBG1 and FBG2 in opposite senses. In this work, the cross-axis sensitivity is decreased to 3.2% thanks to the dual-beam’s directional vibration responses, as shown in Figure 3d. Furthermore, the temperature is self-compensated based on the same responses to temperature of two reflection wavelengths. Finally, a considerable sensitivity of 215.6 pm/G is achieved stably over the frequency range of 10 Hz to 150 Hz.

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