Abstract: To configure the closed equipment with hot fluid circulation and set its circulation parameters properly,the temperature field model was established for heating and non-heating sections of a closed wellbore with hot fluid circulation on the basis of relevant heat transfer theories.Under the condition of definite solution,the model was used to determine the coupling values of pressure and temperature in wellbore.Moreover,the model was also used to predict the wellhead temperature of fluids produced and returned in four closed wells in which hot fluids were circulated,and the influences of production and circulation parameters on wellbore heating were discussed.The results showed that the average error of predicted wellhead temperature of fluids produced and returned was 3.08% and 1.38% respectively,compared with the measured values,which meet the engineering requirements;the temperature of fluid produced declined by 0.134 5 ℃ if fluid volume increased one ton per day,and declined 0.161 ℃ if water cut increased by 10%;and the temperature of produced fluids rises with the increase of circulation rate and injecting temperature,which is the main factor to affect the heating effects.The method can provide basis for the design of the hot fluid circulation in closed wellbore to lower viscosity of produced fluids by modeling the temperature field.