The Study On Theory And Technique Of Heavy Oil Exploitation By Electrical Heating

Aim at the problem of the absence of energy and the difficulty of heavy oil pump, the theory and technique of heavy oil exploitation by electrical heating is analyzed. The hollow sucker rod electrical heating system is studied based on so called skin effect theory.Hollow sucker rod electrical heating system is one of new methods to enhance the production of heavy oil with high freezing point. It is widely used in many oil fields in china because of its many good characters, such as simple structure, heating uniformity, cheaper primary investment, no polluting and continuous operation, etc. But limited by the study of theory, this system has some shortcomings like high cost, etc. In this paper, the skin effect theory is presented, the numerical form of skin effect is studied based on the parse theory, the matrix of current density is obtained.Covered with the electromagnetism and heat exchange, the theory and calculation of skin effect are difficult. The temperature of hollow sucker rod and the heating time are estimated by indoor test during the exploitation. The control of temperature is based on the experiences of worker and spot test. This paper advances that using the finite element simulation method, couple of electromagnetic field and temperature field of heating process are simulated and analyzed during the heavy oil exploitation. First, the skin effect in the lead is studied, the current density in the lead is described, and the relationship between the frequency and skin depth is presented. Then the electromagnetic field and temperature field in the hollow sucker rod are simulated and analyzed, the distribution of current density and temperature in the hollow sucker rod are obtained. The relationship among the frequency, the temperature of the hollow sucker rod and the time is obtamed. Meanwhile, the relationship among the frequency, temperature of heavy oil and the heating time is also obtained. By virtue of the critical temperature of heavy oil and the frequency, the heating time is estimated. An example is given to validate the reliability of the finite element simulation method comparing with the practice.