| Submersible Progressing Cavity Pump (SPCP) technology has gradually been used in petroleum exploit. It especially adapts to the oil exploitation task that is dense oil well, highly contained sand oil well, highness hydrocarbon chain oil well; Due to successive operation, lowest power cost, impropriated plantation smallness, ESPCP especially adapts to the petroleum exploitation task that is flat roof on the sea or swampland. To protect the key components effectively and achieve the longest economical run-life of the pumping system is an important task in the future application. Electromechanical controlling system for the rotational speed of ESPCP system is consisted of computer, variable frequency converter, PLC, sensor, reducer, motor, and Progressing Cavity Pump (PCP) etc. Research and design of the control system of rotational speed of ESPCP system was realized by the combination of software and hardware.In this paper, the correspondent factors affecting the rotational speed of pump and the relationship are analyzed in detail. The rule for reasonable selection of speed is discussed. The optimal compatible model between speed and the main factors, such as oil permeability, oil viscosity, differential pressure, volumetric efficiency and machinery efficiency, is established, The factor and the model chain related ESPCP rotate speed is analyzed and constructed; liquid height model and transducer control model, volumetric efficiency model and speed of rotor of PCP are constructed according to the rotational speed relation of frequency converter, motor, reducer, PCP. The priority class control model is applied in control system, which is consisted of soft startup, liquid height model and volumetric efficiency model. The signal is acquired by sounding lead and flowmeter and is transferred to programmable logic control. Frequency of the transducer is changed by PLC according to the control model, consequently, speed of electromotor and rotor of PCP is changed. In order to supervise the work statue real time of the system of SPCP, RS-485 general communication method is applied, as a result, the relation between datacollection system, variable frequency conversion control system, computer control system and programmable logic control is realized.After the research work in this paper, the monitoring functions of the system will be improved, the speed of the rotor will be controlled with priority, and the life of the PCP is prolonged effectually, and the cost of the system will be reduced. The application of esPCP technology will surely get profit from such research work. |
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