Study On Dynamics Of The Underground Unit Of The Electric Submersible Pump

The electric submersible pump (ESP) is a large liquid discharge of oil pumping rodless lifting equipment, applied to injection wells flooding, high water cut wells and a low gas-oil ratio oil wells, one of the most common ways of rodless pump oil-production method used in oil field, and occupies a very important position. However, as a result of the complex structure and badly working environment of the ESP, it has a a higher failure rate during the course of production, and there will be serious the whole pan into the fire a major incident unit, resulting in heavy economic losses. Monitoring equipment on-site data collection and pump the actual situation of statistical analysis show that the excessive vibration is often caused electric submersible pump unit, one of the root causes of failure. This paper study on the vibration characteristic of the system of the ESP, establish the mechanical model of the torsional vibration and the bendint vibration of the ESP, and research the problem of the natural frequency, startup procedure and critical speed. This paper mainly includes the following content:(1)This paper establishes the mechanical model of the torsional vibration of the ESP system, infer the transition matrix equation, and analysis the natural frequency of the torsional vibration of the ESP system.(2)Based on the mechnical model of the torsional vibration of the ESP system, this paper establish the startup procedure dynamic model of ESP system, and complete the simulation analysis of the startup procedure of the ESP system.(3)This paper the mechnical model of the bearing and the bending vibration of the ESP sytem, infer the transiton matrix equation, analysis the critical speed of the bending vibration, and discuss the influence of the oil film stiffness, the bearing seat and the foundation equivalent mass and the equivalent static stiffness to the critical speed of the ESP system.