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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.


Schematic diagram of FBG sensor for simultaneous temperature and pressure measurements simultaneously.
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sensors-17-00429-f010: Schematic diagram of FBG sensor for simultaneous temperature and pressure measurements simultaneously.

Mentions: Pressure is measured in the transmission or reflection spectrum of the FBG by detecting shifts in the peak of the Bragg resonance. However temperature cross-talk can degrade the accuracy of the pressure measurements. One solution is to use a cascaded dual-FBG structure to measure the temperature and pressure simultaneously [165]. An example is shown in Figure 10. The device comprises two cascaded FBGs and three interconnected chambers. A FBG, sealed in the left metal chamber, only measures temperature. The second concatenated FBG is positioned in the open middle chamber, which is open to the surrounding medium. The third chamber is sealed by a membrane, which acts like a piston. The second of the two gratings which is attached to the diaphragm, measures both pressure (as the diaphragm responds to the oil or gas pressure) and to temperature. Under the assumption that the structure does not undergo plastic deformation, these measurements can be linearly related to the parameters applied on each FBG, so that the temperature and pressure can be derived by the vector functions of the wavelengths versus the parameters.


Fiber Bragg Grating Sensors for the Oil Industry
Schematic diagram of FBG sensor for simultaneous temperature and pressure measurements simultaneously.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

sensors-17-00429-f010: Schematic diagram of FBG sensor for simultaneous temperature and pressure measurements simultaneously.
Mentions: Pressure is measured in the transmission or reflection spectrum of the FBG by detecting shifts in the peak of the Bragg resonance. However temperature cross-talk can degrade the accuracy of the pressure measurements. One solution is to use a cascaded dual-FBG structure to measure the temperature and pressure simultaneously [165]. An example is shown in Figure 10. The device comprises two cascaded FBGs and three interconnected chambers. A FBG, sealed in the left metal chamber, only measures temperature. The second concatenated FBG is positioned in the open middle chamber, which is open to the surrounding medium. The third chamber is sealed by a membrane, which acts like a piston. The second of the two gratings which is attached to the diaphragm, measures both pressure (as the diaphragm responds to the oil or gas pressure) and to temperature. Under the assumption that the structure does not undergo plastic deformation, these measurements can be linearly related to the parameters applied on each FBG, so that the temperature and pressure can be derived by the vector functions of the wavelengths versus the parameters.

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.