Investigation Of Wellbore Temperature Distribution Of The Mechanical Pumping Wells In Heavy Oil Reservoir

There are several hundreds million tons of high wax content and high pourpoint heavy oil in proven oil reserves in China. Because of low fluidity of this kind of oil, the production and pumping efficiency are affected seriously; the key to developing heavy oil reservoirs is solving the low fluidity. High consistence and high pourpoint are the main causes of low fluidity. Both heating and improving the temperature can amend the fluidity. Therefore, studying the wellbore temperature distribution of heavy oil reservoir to improve the fluid temperature and the fluidity by taking some assistant technology is more significant in developing the inspissated pool.The operation principle, the adaptability and the application of the lifting technology and assistant technology in heavy oil reservoir are analyzed in this paper. On the basis of the preceding analysis, the suitable conditions of various lifting technologies and assistant technologies are concluded. At the same time, based on the basic theories of heat transfer, considering heat transfer of the wellbore and the formation around the wellbore, applying the theories of mass conservation, momentum conservation, energy conservation, the mathematical models for predicting wellbore temperature distributions of conventional wells, electric heating wells and blending light oil wells (including blending from casing and oil tube) are established, and the analytical solutions are solved. According to the actual production data of Tahe Oilfield, the curves of wellbore temperature distribution are drawn and the temperature was calculated. The average coincidence rate of the well head temperature from calculated and measured is above 90 percent. At the same time, the influential factors of wellbore temperature distribution of various condiation are analyzed. The analysis shows that the water cut obviously affects the wellbore temperature distribution. The higher water cut is, the higher temperature is. From the heating point to the wellbore head, for electric heating wells, the temperature of the wellbore declines as the increasing in heating depth; the greater the heating power is, the higher the temperature of the wellbore is. For the blending light oil wells, the temperature of the blending point changes obviously. With the increasing of the amount of light oil and the depth of the blending point, the temperature of the wellbore from the blending point to well head ascend gradually.