Transient convective heat transfer in a steam-assisted gravity drainage (SAGD) process

• Published in: Fuel (Guildford) 2019-07, Vol.247, p.315-323
• Main Authors: Jia, Xinfeng, Qu, Tailai, Chen, Haidong, Chen, Zhangxin
• Format: Article
• Language: English
• Subjects: Compressibility; Conduction; Conduction and convection; Conduction heating; Convection; Convection velocity; Convective heat transfer; Drainage; Gravitation; Heat transfer; Heat transport; Initial pressure; Mathematical models; Pressure; Pressure diffusion; Reservoirs; SAGD; Sensitivity analysis; Steam; Transient heat transfer; Transport; Velocity; Viscosity
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2019.03.022

Viscosity reduction through heat transport from steam to bitumen is one of the most important recovery mechanisms of a steam-assisted gravity drainage (SAGD) process. Both heat convection and conduction contribute to the heat transport. Although conduction is considered as dominant through most of a SAGD process, an understanding of heat convection, especially accurate modeling of a condensate convection velocity, is still limited in the literature. This paper develops a mathematical model for the transient heat transfer beyond a steam chamber boundary in SAGD. A convection velocity is clearly formulated, which requires the coupling of heat transport and pressure diffusion. Calculation results show that in SAGD, convection plays a minor role than conduction. In addition, the relative contribution of convection can be influenced by reservoir formation compressibility, steam chamber boundary advancing velocity, and particularly by a difference between steam injection pressure and reservoir initial pressure. Correlations are regressed to estimate the relative contribution of heat convection (ratio) in the overall heat transfer process during a stabilized production period of SAGD.