Research on optical fiber flow test method with non-intrusion

Abstract

In the field of oil well logging, real-time monitoring of the fluid flow parameter provides a scientific basis for oil and gas optimization exploration and increase in reservoir recovery, so a non-intrusive flow test method based on turbulent vibration was proposed. The specific length of the sensor fiber wound tightly around the outer wall of the pipe was connected with the optical fiber gratings at both ends, and the sensor fiber and the optical fiber gratings composed the flow sensing unit. The dynamic pressure was generated by the turbulence when fluid flows through the pipe, and the dynamic pressure resulted in the light phase shift of the sensor fiber. The phase information was demodulated by the fiber optic interferometer technology, time division multiplexing technology, and phase generated carrier modulation and demodulation techniques. The quadratic curve relationship between the phase change and flow rate was found by experimental data analysis, and the experiment confirmed the feasibility of the optical fiber flow test method with non-intrusion and achieved the real-time monitoring of the fluid flow.

Non-Intrusive Pipeline Flow Detection Based on Distributed Fiber Turbulent Vibration Sensing

“…Therefore, the study of a non-intrusive optical fiber sensing method is of great significance for pipeline flow monitoring, and the use of a turbulent vibration of fluid in the pipeline for flow detection has become a research hotspot in recent years [8][9][10][11]. Shang et al used the FBGs combined with the interference demodulation method to achieve a non-intrusive flow measurement, which had a measurement range of 5.7-46.5 m 3 /h [12]. Ni et al designed a new type of optical fiber flowmeter based on the distributed feedback fiber laser (DFB-FL), which is placed on the outer wall of the pipe, to measure the accurate small flow from 0.71 m 3 /h to 2.35 m 3 /h [13].…”