## Summary

Presented here is a steam–assisted–gravity–drainage (SAGD) forecasting technique for oil and water production and steam injection based on linear steam–chamber geometry and an empirical form for the progression of the steam/oil interface with time. The oil forecast model generates full–cycle SAGD production profiles using three empirical inputs (the initial plateau oil rate $qo,si$, an exponent n, and the rising–phase–chamber angle θ) and volumetric parameters (well length, pay thickness, porosity, half–well spacing, and initial and residual oil saturation). Steam and produced–water forecasts are derived analytically using the resulting steam–chamber geometry and the heat required for the fluids, rock, and overburden.

Peak rate is a direct input in this methodology, and as a result only volumetric and some thermodynamic parameters are required, but not fluid or transmissibility inputs, such as viscosity and permeability. This allows for direct use of commercial SAGD production data in the forecasting process. The model predictions are validated at a high level with field data from Devon Canada Corporation's Jackfish SAGD project and numerical simulation.