## Shuqi Jia , Xiaolei Wang and Zhe Kan## |

Number of experiments | Conductivity tester data (%) | Mixed-phase signal FFT amplitude | Mixed-phase signal Vpp (V) |
---|---|---|---|

1 | 95.8 | 1.56 | 3.10 |

2 | 60.5 | 0.91 | 1.98 |

3 | 40.3 | 0.58 | 1.29 |

4 | 30.7 | 0.50 | 1.10 |

5 | 10.9 | 0.13 | 0.36 |

This study compared three methods for measuring the error in crude oil water content: the capacitive sensor detection method, the infrared spectroscopy detection method, and the embedded FFT-based crude oil water content measurement method. After conducting multiple experiments, the measurement errors of the three methods were analyzed, as depicted in Fig. 8. The curves represent the true values of the measured data, as well as the measurement errors for the proposed embedded FFT method, the capacitive sensor method, and the infrared spectroscopy method. The capacitive sensor detection method exhibits an error range of ±20% relative to the true values, the infrared spectroscopy detection method exhibits an error range of ±15%, while the embedded FFT-based crude oil water content measurement method demonstrates an error range of ±2% with respect to the true values. Therefore, the proposed embedded FFT measurement method demonstrates smaller errors and superior linearity.

As revealed by the comparative experiments using the three crude oil water content measurement methods and indicated by the measurement errors depicted in Fig. 8, the embedded FFT-based crude oil water content measurement method surpasses the capacitive sensor detection method and the infrared spectroscopy detection method in terms of accuracy and linearity. The influence on the capacitive sensor method can be primarily attributed to temperature variations, while errors in the infrared spectroscopy detection method are attributable to interferences caused by impurities or other compounds affecting the spectroscopic signals. By contrast, the proposed embedded FFT-based method effectively mitigates these interferences and achieves superior measurement accuracy. The performance of the embedded FFT-based crude oil water content measurement method is exceptional because it employs Fourier transform techniques to analyze the frequency components of crude oil. Through this method, the water content signal can be effectively separated from the crude oil signal, leading to more accurate measurements. The enhanced linearity further enhances the method's reliability by ensuring a consistent relationship between the measured values and the actual water content.

This paper introduces a method for measuring the moisture content and correlation flow rate of crude oil based on embedded FFT. In the study, a front-end circuit and a software program were developed. As revealed by various experiments, the proposed method has excellent linearity and high measurement accuracy and is, thus, a promising signal processing approach for two-phase flow measurement technology.

She earned her B.S. and M.S. degrees from the School of Information and Control Engineering at Liaoning University of Technology in 2003 and 2006, respectively. From 2006 to 2012, she served as a faculty member at Heilongjiang University of Science and Technology. Since 2012, she has been teaching at the School of Information and Control Engineering at Liaoning Shihua University.

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