A semi-analytical model based on unsteady conductive heat transfer in steam-assisted gravity drainage (SAGD).

Steam-assisted gravity drainage (SAGD) is one of the most successful in-situ recovery methods for bitumen reservoirs. Seeking the function of oil production with parameters of steam injection is significant for rapid performance evaluation of the SAGD process in fields. In this study, a new semi-analytical model based on unsteady conductive heat transfer is developed to estimate SAGD performance and describe the evolution of the steam chamber synchronously. These are implemented by interface velocity of steam chamber, as the function of the parameters of steam with the exponent-shape assumption and energy balance to link the oil output and chamber growth. It is worth mentioning that the equation of oil production is obtained based on the assumption of unsteady temperature distribution along with the interface, which is close to the real condition of the reservoir in fields. Then, the model is validated by using the Phase B, UTF project of the Athabasca reservoir. Finally, the impacts of steam injection parameters on SAGD oil production are discussed in this paper. Initial higher rate of heat injection to reach the production peak quickly and the subsequent lower rate for maintaining peak should be adopted to achieve the efficient target of oil production. [ABSTRACT FROM AUTHOR]