An Analytical Model for Heat Transfer Process in Steam Assisted Gravity Drainage

Abstract

A new analytical model is developed and solved to reveal heat transfer mechanism during steam assisted gravity drainage (SAGD). The new model is transformed to a boundary value problem (BVP) for second order ordinary differential equations (ODEs) to be solved. Moreover, a new relationship between oil saturation and dimensionless reservoir temperature is established and utilized to solve the model. The results reveal three main conclusions. Firstly, although the specific proportion of convection to conduction during heat transfer process is influenced by properties of rock and fluids in the reservoir, convective heat flux is more important than conductive heat flux near steam chamber edge (around 0–2 m). Secondly, convective heat flux decreases rapidly away from the chamber edge and quickly becomes negligible compared to conductive heat flux. As a result, the influence of convection on reservoir temperature is marginal during the whole heat transfer process. Thirdly, classic relationship between reservoir temperature and distance measured from the steam-chamber edge, which is developed under conductive heat transfer assumption, is still applicable when considering both conductive and convective heat transfer.