method to produce heavy oil sources economically. In this study, the entire process of steam injection was divided into two parts: Steam injection into injection well and injected into the reservoir. A numerical non-isothermal two-phase wellbore model was developed to simulate downward flow of steam and water mixture in the wellbore during steam injection. This model entails simultaneous solution of coupled mass and momentum conservation equations inside the wellbore with an energy conservation equation for the fluids within the wellbore and surrounding medium. A drift-flux model was employed to represent slip between fluid phases. The model predictions were validated against real field data and other available models. So, by using data of steam injection wells for two oil fields of Martha Bigpond and Sallie Lee in a computer program, variations of steam pressure, temperature, and quality were predicted along the well depth. Then, these results were compared with the results of some available models. Finally, after certainty of the model's accuracy, variations of steam pressure, temperature, and quality at one of Iranian heavy oil reservoirs were predicted along the well depth. The model is useful for designing well completion and accurately computing pressure drop and steam quality along the wellbore, which is very important for estimating oil recovery by steam injection method. Also a three dimensional model for steam injection into the reservoir was provided. Formulation details, numerical solution procedures, and computational results were presented. The model described the simultaneous flow of three phases — oil, water and gas — in three dimensions. It included the effects of three-phase relative permeabilities, capillary pressure, and temperature and pressure-dependent fluid properties. Interphase mass transfer of water-steam was allowed, but the oil was assumed nonvolatile and the hydrocarbon gas insoluble in the liquid phases. The three-phase mass balances and energy balance were solved simultaneously using finite difference equations. Laboratory data were reported for steamfloods, were used for checking accuracy and assumptions in this numerical model. Comprehensive and comparative studies together with extensive sensitivity analysis among various important parameters were conducted in order to understand injection operation properties on the oil recovery performance. This work showed that steam injection could improve oil recovery from almost zero up to nearly 60% during fixed period of time. In addition, it illustrated that only 30% of OOIP could be recovered by hot water injection method. The results showed that there is an optimum time for oil production shall be determined according to the flow of oil production and steam-oil ratio (SOR).
