| Thermal recovery is widely used in heavy oil production,its effect is directly affected the final oil production.And the loss of the heat in the formation is very important for thermal recovery.Therefore it is necessary to study the heat efficiency for further improvement of the thermal recovery system.Firstly,on the basis of existed models,the vertical wellbore injection process is analyzed,then based on mass,momentum and energy balance principles,the author studied the calculation method for the wellbore heat transfer and mass transfer when inject mutli-medium.At the same time,the seawater flow was taken into consideration,and outstand the method of this process.Secondly,summarized the solving method for thermal physical properties of formation fluid and reservoir.considering the actual temperature distribution and proposed a way to calculate the heating radius when exist the steam overlap phenomenon.Then divided the heat efficiency in injection process into two part: the wellbore heat efficiency and the formation heat efficiency,and established an evaluation method.Finally,based on measured field data,The evaluation method of heat efficiency in the injection process is applied and analyzed.Then calculated the wellbore heat efficiency and analyzed the effect of injection factors.Also verified the new model by compared with the existed model.starting from the geological factors and injection factors,the effects of different factors on formation heat efficiency are analyzed.The thesis research of heat efficiency of overlap phenomenon has certain significance and it is hoped to provides guidance for its practical application on heavy oil recovery. |
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