Abstract: To investigate the distribution patterns of wellbore temperature fields during well flushing via hot fluid circulation in electric submersible pump (ESP) wells of the Bohai Oilfield, we constructed a computational model for the temperature fields of wellbores during hot fluid circulation in ESP wells based on the principle of conservation of heat. This model accounts for effects associated with the heating of the ESP, electric cable cooling, volume of hot fluid injection, injection depth, injection temperature, heat transfer in the wax-clogged pipeline segments, and thermal conductivities of seawater and air. Using this model, we analyzed the effects of injection temperature and injection volume on the wellbore temperature distribution of mixed production fluids. The results of this study show that the temperature distributions of mixed production fluids along the wellbore are positively correlated with increases in injection temperature and injection volume. Our model can be used as a guide to dewaxing processes in the field, thus prolonging the dewaxing cycles in wax-prone wells and reducing the rates at which fluid and oil production decrease over time.

Key words: Bohai Oilfield, electric submersible pump wells, wellbore wax deposition, well flushing by hot fluid circulation