Research And Implementation Of Electromagnetic Induction Heating Technology For Tubing Elevator

With the rapid development of science and technology in China,on the premise of ensuring high safety of industrial production,the oil field has become more and more demanding for energy saving of production equipment and for reducing the burden on workers.The commonly used tubing elevators in oil fields are closed-loop elevators.According to the principle of the closed-loop elevator and the low temperature in the northeastern region,the locking ring and safety pin of the elevator will freeze in winter,and the tubing elevator will not open and close normally.If the tubing elevator does not work properly,it will directly affect the oilfield production operations.Such as increasing the labor intensity of the workers and increasing the burden on the workers,which will affect the work efficiency.At present,the steam heater is mainly used to deicing the tubing elevator.The purpose is to use high-efficiency and energy-saving electromagnetic induction heating technology to heat and deicing the tubing elevator.It can solve the problems of low heating efficiency,fast heat dissipation and poor flexibility of the steam heating currently used for tubing elevators.The theoretical analysis and experimental research of the electromagnetic induction heating deicing of the tubing elevator is completed by the combination of theoretical simulation and experiment.The main research contents are summarized as follows:Firstly,the principle of induction heating of tubing elevator was analyzed.Based on this,the Maxwell equation was deduced and solved by introducing magnetic vector potential.And then the mathematical model of induction heating electromagnetic field of tubing elevator was analyzed.Based on the boundary conditions of heat conduction and the basic principles of heat conduction,the mathematical model of the induction heating temperature field of the tubing elevator was analyzed by the method of variational principle.The concomitant effects of induction heating are analyzed,including skin effect,ring effect and proximity effect,and then the two stages in the induction heating process of tubing elevator were analyzed.Secondly,because the electromagnetic-thermal coupling process of electromagnetic induction heating is complex and difficult to analyze,based on the theory of electromagnetic field and temperature field mathematical models.Finite element analysis software was used to perform finite element numerical simulation of the electromagnetic field during induction heating of the tubing elevator.Through numerical simulation calculation,the eddy current distribution and eddy loss during the induction heating process of the tubing elevator could be obtained.Then,the numerical results of the electromagnetic field were imported,and the electromagnetic-thermal coupling process of the tubing elevator was subjected to finite element numerical simulation.The numerical distribution of the temperature field was obtained through numerical simulation calculation.Thirdly,in order to realize the drive and prototype of electromagnetic induction heating,the key points of induction heating drive were designed.Several common circuit structures of the inverter circuit were compared.And the half-bridge inverter circuit was selected as the main circuit to meet the actual requirements.Calculated the parameters of the IGBT in the circuit,and used the optocoupler isolation to drive the IGBT.The heating inductance of the coil was easy to change,so a phase-locked frequency tracking circuit was designed.Finally,according to the special environment of the oil field,a 3.5k W electromagnetic induction heating prototype that meets the requirements of the oil field operation site was designed.The induction heating prototype was tested under laboratory conditions,and the experimental results verified the accuracy of the numerical simulation results of induction heating.Combined with the numerical simulation calculation results,the influence of different parameters on the induction heating process of the tubing elevator was analyzed,reasonable heating parameters were selected.Then the induction heating prototype was tested under field conditions in the oil field.The experimental results show that the electromagnetic induction heating technology can be effectively applied to the heating and deicing of the tubing elevator.The comparison between electromagnetic induction heating and steam heating proves that the induction heating method is superior to the traditional steam heating method.