| Smart layered oil production technology for oil wells is an intelligent technology applied inside oil wells to improve oil production efficiency and resource utilization by blocking high water-bearing layers and opening productive oil layers with packers through real-time monitoring and control of downhole environment and reservoir dynamics.The intelligent valve switch,which controls the work of the packer,works in the well for a long time and is powered by a battery,which has a relatively short working period.Therefore,this paper takes the resonant wireless energy transmission technology as the research object and analyzes the influence of the coil parameters on the transmission performance of the system,and the main research contents are as follows:Firstly,starting from the resonant wireless energy transmission system with two-coil structure,an equivalent coupling model is established.According to the scheme of the downhole wireless energy transmission system,the structure of the coil coupler and the mechanical structure of the whole device are designed.Secondly,the electrical parameters of the coil are analyzed in detail to determine the calculation methods of resistance,inductance and mutual inductance of the coaxial spiral coil,and the theoretical and simulation results are compared.Analyze the reasons that affect the high frequency loss of the coil so as to select the appropriate wire diameter.Then,the derivation of the formula shows that the quality factor and the coupling coefficient are the two main factors affecting the maximum transmission efficiency,and the characteristics of the coupling coefficient with the change of the coil size parameter are studied to deduce the analytical relationship between the coil size parameter and the maximum transmission efficiency,and simulation to compare the variation of magnetic field around the coil with the coil size parameter.The effect of having a ferrite coil inner core on the electrical parameters and coupling coefficient of the coil is discussed.Finally,the inverter and rectifier circuits of the system are analyzed and designed,different topologies and corresponding device types are selected,and the experimental device is built and tested and analyzed to obtain the results that the theoretical,simulated and measured values of the maximum transmission efficiency of the system are basically the same,which verifies the feasibility of optimizing the coil parameters to improve the transmission efficiency. |
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