Design Of Energy-saving Device For Pumping Unit Based On Indicator Diagram Method

The beam pumping unit is a widely used production equipment in oil fields at home and abroad,and is also the main energy-consuming equipment in oil fields.Due to the complicated working conditions of the oil field,the beam pumping unit generally has the problems of high energy consumption and low efficiency,and it is of great significance to realize energy saving and consumption reduction of the beam pumping unit.The various existing improvement methods can not effectively improve and solve the phenomenon,so this paper has carried out a study of energy-saving methods from the following aspects.Firstly,the structure,working principle and energy consumption of the beam pumping unit are analyzed in depth,and the direct cause of the large energy consumption of the pumping unit system is found.The operating characteristics of the pumping unit motor do not match the oil production capacity of the oil well.By comparing the existing energy-saving methods of pumping units,the strategies on frequency and speed control of the pumping unit based on dynamometer diagram method are put forward.Secondly,the function of frequency and speed control and the dynamometer diagram are studied while the calculation method of dynamometer area is proposed.According to the analysis including characteristics and changing laws of the dangling point dynamometer diagram,amount of indicator diagram area changes to reflect the well feeding ability to change,the relationship between the area change of the dynamometer diagram and the liquid supply capacity of the well and the mathematical relationship between the area change of the dynamometer diagram and the pumping stroke,and the paper proposes certain strategies to control the speed rate of the pumping unit by using the area change of the dynamometer diagram and then to adjust the pumping stroke.In order to verify the energy-saving effect of the system,this paper designed the experimental device with PLC S7-200 as the controller,including the inverter,displacement sensor and load sensor.The system control core was designed with the programming language of ladder diagram.The system was debugged in the laboratory.By comparing the relevant data after using the energy-saving control system,it was found that the pumping unit pump fullness and operating efficiency were improved,and the effect of increasing production and saving energy was realized.