| In the later stage of gas well exploitation,the energy at the bottom of the well weakens,leading to the accumulation of liquid in the wellbore,seriously affecting the efficiency of natural gas exploitation.Plunger gas lift is an artificial lifting method that uses the gas stored in the oil and casing space of the gas well to push the plunger lift liquid up to the wellhead to complete drainage and gas recovery.Conventional plungers are unable to monitor the operation of the plunger and changes in parameters such as temperature and pressure in the wellbore,and cannot adaptively adjust the drainage,gas production,and liquid lifting height based on changes in well conditions.Therefore,it is difficult to meet the demand for further efficiency improvement in gas wells.In response to the above shortcomings,a design of an intelligent plunger automatic control system based on existing intelligent plunger gas lift devices is proposed,which enables the plunger gas lift system to achieve intelligence,automation,low cost,and high efficiency.The main research content of this article is as follows:(1)Based on the working principle of intelligent plunger drainage and gas extraction,determine the overall functional requirements,design criteria,and technical indicators of the intelligent plunger control system,and complete the overall design plan of the control system.The open loop automatic control scheme is adopted for the regulation of the intelligent plunger outlet,enabling it to achieve automatic hovering function and adaptively adjust the lifting height according to the well conditions.(2)Selecting magnetic coupling resonance as the radio energy transmission method,based on the basic principle of magnetic coupling resonance electric energy transmission,establish an equivalent circuit for system radio energy transmission.Analyze the coil coupling characteristics,electrical characteristics,and mutual inductance characteristics of the coaxial spiral coil structure used in the intelligent plunger radio energy transmission system.Based on the structure and size of the coil winding framework of the intelligent plunger,the coupling mechanism parameters of the spiral coil are determined.Simulation analysis is conducted on the magnetic field distribution in the coil,and it is concluded that the actual coil can achieve strong coupling.Finally,it is determined that the wireless energy transmission efficiency of the intelligent plunger is the highest when the working voltage is 24 V,the excitation current is 2A,and the working frequency is 50 kHz.(3)Based on the environmental characteristics and automatic control system requirements in natural gas wells,select the main hardware equipment and design the circuit.The system adopts a low power consumption,high temperature resistance,and high performance C8051F500 microcontroller as the main control chip.The hardware circuit design includes the peripheral circuit of the main control chip,sensor data acquisition circuit,motor drive and protection circuit,external storage circuit,wireless data transmission circuit,wireless energy transmission circuit,and power circuit.(4)According to the workflow of the intelligent plunger automatic control system,combined with the principles and ideas of hardware circuit design and software program design,using Keil u Vision5 to develop software modular programming,the main module functions and software programs in the intelligent plunger automatic control system are analyzed and designed to achieve the control system.Considering the limitations of gas well power supply,the entire system is designed with low power consumption in both software and hardware.The system has functions such as data acquisition,data storage,wireless data transmission,motor drive,and wireless charging control based on battery SOC estimation. |
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