Study on Temperature Field of Deep-Water Heavy Oil Wellbore by Electric Heating

Heavy oils are characterized by high viscosity, high flow friction, and temperature sensitivity. For offshore heavy oil development, thermal recovery processes are now commonly used. Electric heating is one of the main methods of thermal recovery of offshore heavy oil. In this paper, a steady-state mathematical model of the temperature field of an electrically heated offshore heavy oil wellbore is developed based on the theory of heat transfer, and considering the coupling effect of temperature and viscosity. Using two heavy oil wells in the field as examples, the temperature fields of shallow and deep water wellbores were calculated for different heating powers and heating depths. A comparison of the temperature field of shallow water wellbore with that of deep water was used to obtain the wellbore temperature field pattern for electrically heated extraction of deep-water heavy oil. The results of the calculations show that the higher the power of the heating rod, the higher the extraction temperature of the heavy oil, whether in deep or shallow water. Increasing the heating depth increases the temperature of the heavy oil, but when the heating depth exceeds a certain value the increase in wellhead temperature is not significant. Deep-water wells require more heating power or a deeper depth than shallow water wells to reach their inflection point temperature. The results of the study can provide theoretical guidance and reference for the selection of process sensitivity parameters for the extraction of deep-water heavy oil by electric heating.