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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.

No MeSH data available.


(a) Scheme diagram of π-FBG sensor structure; (b) π-FBG probe’s responses versus ultrasonic directions (this figure is concluded by recording the peak power of ultrasonic signals in the different detection directions).
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sensors-17-00429-f014: (a) Scheme diagram of π-FBG sensor structure; (b) π-FBG probe’s responses versus ultrasonic directions (this figure is concluded by recording the peak power of ultrasonic signals in the different detection directions).

Mentions: In general, there are two methods for realizing the coupling of UW-to-fiber. One is that UW is coupled to fiber through the fiber end-face, so that the efficiency is determined by the materials and size of the fiber end-face. The other is that the UW is applied laterally to the fiber. For the longitudinal wave, the latter method is more effective. In our group’s work, a π-FBG is mounted across the middle of tilted end face of a plastic tube, where the both ends of π-FBG are attached on the side of the tube, as shown in Figure 14a. The UW impinges directly on theπ-FBG (it is not transmitted along the fiber to avoid transmission loss). Because of the asymmetrical structure, the probe presents different sensitivities to the ultrasonic wave impinging from different directions, as shown in Figure 14b. The orientation-dependence can help tolocate the UW source.


Fiber Bragg Grating Sensors for the Oil Industry
(a) Scheme diagram of π-FBG sensor structure; (b) π-FBG probe’s responses versus ultrasonic directions (this figure is concluded by recording the peak power of ultrasonic signals in the different detection directions).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

sensors-17-00429-f014: (a) Scheme diagram of π-FBG sensor structure; (b) π-FBG probe’s responses versus ultrasonic directions (this figure is concluded by recording the peak power of ultrasonic signals in the different detection directions).
Mentions: In general, there are two methods for realizing the coupling of UW-to-fiber. One is that UW is coupled to fiber through the fiber end-face, so that the efficiency is determined by the materials and size of the fiber end-face. The other is that the UW is applied laterally to the fiber. For the longitudinal wave, the latter method is more effective. In our group’s work, a π-FBG is mounted across the middle of tilted end face of a plastic tube, where the both ends of π-FBG are attached on the side of the tube, as shown in Figure 14a. The UW impinges directly on theπ-FBG (it is not transmitted along the fiber to avoid transmission loss). Because of the asymmetrical structure, the probe presents different sensitivities to the ultrasonic wave impinging from different directions, as shown in Figure 14b. The orientation-dependence can help tolocate the UW source.

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.