| There are many electronic control equipment in the field of oil production.The fine layered water injection technology is a highly automated water injection and oil displacement technology used in oilfields downhole combined with electronic control technology.This technology assembles the water distributor in the well and adjusts the opening of the water valve through the electronic control device.Degree to achieve the purpose of fine water injection.From the perspective of power supply,the existing water distribution and injection technology includes two forms,one is a cable type,where the underground equipment is powered by a cable;the other is a cableless type,where the underground water distribution device is preset with a battery.As an emerging power transmission method,non-contact power transmission technology has the advantages of frictionless and good sealing conditions.It can supply power to downhole devices in oil fields.Compared with other wireless power transmission technologies,electromagnetic induction coupling technology is used in the near field.Coupled,the transmission power is large,and it is more suitable for the downhole environment of the oil field.First,This article studies the structure of the water distributor and the downhole working environment of the oil field,compares several different styles of electromagnetic couplers,and selects the coaxial solenoid type coupling coil.For the coaxial solenoid type inductive coupling coil,the calculation formula of the coil parameters is derived,the mathematical relationship model between the coupling coefficient and the structural parameters is established,and the finite element software is used to simulate the magnetic circuit of the coil to verify and correct the coil parameters.According to the coil parameters,the mutual inductance coupling model of the circuit is established,and the compensation technology of induction transmission is studied.The output power and transmission efficiency can be optimized as the goal,and the string compensation structure is selected.Secondly,under the condition of constant coupling,analyze the characteristics of the system output power from the perspective of the circuit resonant frequency.The structure of the oilfield water distributor determines the coil coupling coefficient.When the coupling coefficient is fixed,the output power characteristic is analyzed from the circuit resonance condition for the string compensation model,the critical condition of the system resonance state power output is calculated by the circuit phasor theory,and the critical splitting is calculated by the coupled mode theory condition.In the case of frequency splitting,using resonance theory,the natural frequency of the induction transmission system is proposed,the resonance frequency of the circuit is connected,and the extreme point of the system splitting frequency is calculated.Then,analyze the characteristics of the transmission efficiency of the system with respect to the circuit resonance frequency and the operating frequency,combined with the output power characteristics,take the circuit resonance frequency and the operating frequency as the optimized parameters,and in the case of a certain output power,take the highest transmission efficiency as the target value for nonlinearity Optimize the calculation to obtain the most efficient frequency optimization parameters,and then obtain the capacitance compensation parameters according to the optimized circuit resonance frequency,and determine the system inverter frequency according to the optimized operating frequency.Then,analyze the variation characteristics of the system transmission efficiency with respect to the circuit resonant frequency and operating frequency,combined with the output power characteristics,take the circuit resonant frequency and operating frequency as the optimized parameters,and under the condition of a certain output power,take the highest transmission efficiency as the target value for non-compliance.Linear optimization calculation is used to obtain the most efficient frequency optimization parameters,and then the capacitor compensation parameters are obtained according to the optimized circuit resonance frequency,and the system inverter frequency is determined according to the optimized operating frequency.Finally,the circuit was designed according to the coil design parameters and circuit compensation parameters,and the simulation model and experimental platform were built to verify: the output power and transmission efficiency of the non-contact power transmission system with respect to the change characteristics of the circuit resonance frequency and operating frequency;the feasibility of optimizing the frequency selection scheme. |
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