Research On Fault Diagnosis Of Electric Submersible Pumps Based On Vibration Detection

Electric submersible pump (ESP) unit is the main device to extract oil in the world .Its reliability and capability is important to assure the high yield of the oil field. The structure of ESP is relatively complex, and many faults of ESP will lead to vibration. Through analysis of the vibration signals of ESP, preliminary judgement of some faults can be concluded .By acquiring and analyzing wellhead vibration signals of ESP test wells, the fault feature of ESP's vibration can be extracted,and some faults of ESP can be found out. The discussion covers:1. To detect the vibration of ESPs, a vibration signal acquisition system based on DSP (digital signal processor) and MEMS (Micro-electro-mechanical systems) acceleration sensor is designed to collect the ESP's well-head vibration acceleration signals. The data acquisition system is developed to have the function of USB-Host, with which the vibration data can be written to files in mobile USB (universal serial bus) mass storage, thus achieving the portable and mass storage acquisition of ESP's vibration signals.2. The conventional technology of vibration signals is discussed in rotating machinery fault diagnosis, such as time-domain analysis, amplitude analysis, frequency-domain analysis. The base principle, advantage and disadvantage of these methods are expatiated.3. Research on the wavelet analysis theory and wavelet transform in the vibration signal processing applications. Wavelet analysis is a kind of time-frequency analysis. Wavelet transform has the characteristic of multiresolution analysis and overcomes the limitations of Fourier transform. Wavelet analysis was applied to vibration signals of ESP in order to extract fault feature of ESP. A lot of methods, such as time-domain waveform, power spectrum, wavelet decomposition and wavelet packet decomposition and so on, were applied to analyze vibration data of ESP gathered in the experiment. After comparing, contrasting and summarizing, the extraction methods of shaft ran excessive and wear fault feature are obtained, and these faults are diagnosed.In conclusion, it is feasible and effective to extract fault feature of ESP, by analyzing vibration acceleration signals of ESP's wellhead. And the works of the paper provide useful ideas for fault diagnosis technology of ESP.