The low cost of the injected solvent, which can be also recovered and recycled, and the applicability
of VAPEX technique in thin reservoirs are among the main advantages of VAPEX process compared
to thermal heavy oil recovery techniques. In this research, an extensive experimental investigation
is carried out to first evaluate the technical feasibility of utilization of various solvents for VAPEX
process. Then the effect of drainage height on the stabilized drainage rate in VAPEX process was
studied by conducting series of experiments in two large-scale 2D VAPEX models of 24.5 cm and
47.5 cm heights. Both models were packed with low permeability Ottawa sand (#530) and saturated with a heavy oil sample from Saskatchewan heavy oil reservoirs with viscosity of 5650 mPa s.
Propane, butane, methane, carbon dioxide, propane/carbon dioxide (70%/30%) and propane/
methane (70%/30%) were considered as respective solvents for the experiments, and a total of
twelve VAPEX tests were carried out. Moreover, separate experiments were carried out at the end
of each VAPEX experiment to measure the asphaltene precipitation at various locations of the
VAPEX models. It was found that injecting propane would result in the highest drainage rate and oil
recovery factor. Further analysis of results showed stabilized drainage rate significantly increased in
the larger physical model