Abstract:Canadian oil sands are mainly developed by horizontal SAGD well pairs, in which mode reserves above the interlayers (upper oil) are hard to be developed. The lithology, thickness and permeability of interlayers in different regions are different in meandering river deposition, which makes the barrier standards vary greatly in oil sands companies. Therefore, it is always hard for companies to reach an agreement of the SAGD exploitable reserves. The phenomenon of potential gradient threshold (PHT) in bitumen flow process was confirmed by 30 sets of indoor physical simulation experiments under different permeability and different temperature (or, crude oil viscosity). The PHT is an exponential function of apparent mobility, with a negative exponential index. The relationship chart of upper oil reserve recovery factor, the interlayer permeability, and, thickness was drawn based on 42 sets of numerical simulation, which both took or not the PHT into consideration. Simulation results showed that the upper oil can be completely sealed by the continuous interlayer with the vertical permeability less than 25mD, partially sealed by the continuous interlayer with the vertical permeability 25mD~500mD, and, hardly sealed by the continuous interlayer with the vertical permeability higher than 500mD. The influence of thickness is very obvious in the partially sealed mode. The optimized upper oil development methods for different kind of interlayers are as below, to sidetrack the lower steam injector into an upper single producer for completely sealed barrier, and, to sidetrack the lower steam injector into an upper single injector for partially sealed one. The preliminary economic calculation showed that both recommendations had good economic benefits.