Heavy Oil Wellbore Frequency Heating Power

There mainly needs two conditions to pump the viscous oil. One is to make the viscous oil flow on the reservoir by using injecting steam, mixing into hot water or hot oil, decrease oil viscosity with chemical accelerator, etc. The other is to make the viscous oil flow in the shaft by using mixing into hot water or hot oil, decrease oil viscosity with chemical accelerator and power heating etc. The hollow pumping rod power heating which is used widely in viscous oil shaft has many good characters, such as heating uniformity, cheaper investment, etc., but it also has the disadvantage of lots of power loss, low heating efficiency, poor power factor, unsafely and the temperature can't be controlled precisely. In order to solve the problem in current equipment, the paper does some relative research.Firstly, the paper analyzes the theory of power heating viscous oil shaft with hollow pumping rod and sets up the equivalent circuit model of load including the line and hollow pumping rod. Comparing to another distribution equivalent circuit model, the simulation result shows the correction of this model. The paper draws out the high efficiency range of working frequency and finds the optimal working frequency during this range by using of golden sections method.Secondly, the paper designs and realizes the two level variable frequency heating power supply with line of 380V. The main circuit output ac square wave by adopting the technology of ac-dc-ac variable frequency and phase shift PWM. In order to improve the efficiency and safety of the equipment, the paper uses the current optimal control and wireless transfer technology.Thirdly, the paper realizes three level variable frequency heating power supply with line of 1140V on base of two level one. For improving the efficiency and simplifying the control strategy, the paper uses the method of two level output in three level topology. The paper analyzes the character of load short circuit of three level topology, and then gives the related protection schedule.To reduce the volume of medium frequency transformer, the paper proposes two topologies of DC-HFAC (high frequency alternating current) -DC-MFAC (medium frequency alternating current) high frequency link and cycloconverter high frequency link. The simulation shows that the method is correct.At the end of the paper, the directions and measures to be improved and studied further are pointed out.