The invention relates to the development of an analytical model to predict the velocity of the continuously expanding front of the steam chamber in a steam assisted gravity drainage (SAGD) hydrocarbon production system. The developed analytical model has advantages over reservoir simulation tool in that it is very fast and can be easily calibrated with field observation well data before making good prediction. One field study shows that the developed model can achieve excellent prediction for a field SAGD performance. A better understanding of the size of the steam chamber and the velocity of the front should provide better time, cost and energy efficiency for the production of high viscosity hydrocarbons.