Economic Operation Optimization Control And Digital Evaluation Of Sucker-Rod Pumping Wells

With the rapid development of industry, energy problem has attracted worldwide attention. Meantime the energy crisis has become the major crisis of mankind. The study of how to improve the oil extraction efficiency, when oil is one of our main energy, has important research significance. Recently, the development of many oilfields in China have entered mid-to-late period, which leads to the low infiltration efficiency of oil wells with infiltration capacity oil well growing weak, pump efficiency reducing, and cost of oil extraction increasing. So it really makes a difference to keep oilfields running effectively and get stable productions by studying into adaptive control methods of oil wells’economical running according to their working condition.Firstly, the dynamic liquid level and indicator diagram are introduced and analyzed, which reflect well working condition. According to the distribution principle of fluid in well-shaft and mass conservation law, the liquid level change model of oil well is established, and the trend of changing is analyzed. Surface dynamometer cards are collected by load sensors, and converting them into pump diagram by smoothing filtering. Then calculating effective stroke with Graham algorithm, and a new rationality of production calculation is realized based on improved effective stroke method. The calculation method of working liquid level using indicator diagram indirectly are presented. All of those lay a foundation for economic operation optimization control and digital evaluation of oil well.Secondly, economic operation control methods are researched. This paper analyzes the impact of motor frequency on the indicator diagram, and develops a new intelligent frequency conversion controlling method based on indicator diagram for ordinary well. A reasonable decision making strategy of intermittent extraction for stripper well is formulated according to the dynamic liquid level changing model. The optimum starting and stopping position was proved to exist by taking maximizing economic benefits over time as the target over all. Then a new intermittent-extraction controlling method is released based on improved hill-climbing algorithm. From what has been discussed above, the target of stable and efficient producing is achieved and the control of oil well economical running is optimized.Lastly, three evaluation indexes are put forward, including economic benefit, the balance degree of oil pumping machine and the efficiency of the pump. And the evaluation criterions are established. Then it makes digital evaluation for special wells and gives corresponding improvement. All of these provide necessary condition for improving operation efficiency of oil pumping system.The practicability of the controlling method is certified by simulating the mechanism we’ve discussed. The research results in this paper may have some reference value for improving economic benefit and realizing digital management.