This paper presents a simulation study on the operational parameters of the ES-SAGD process based on an ES-SAGD lab experiment. A numerical model that incorporated the measured data on key physical properties was validated by detailed history matching of the ES-SAGD lab experiment with n-hexane as the solvent. This numerical model was used to evaluate the performance of ES-SAGD with different operating strategies. The simulation results indicate that oil rate lifting from hexane injection is significant in the early stage of the ES-SAGD process but becomes less effective in the later stage of the process. Improved solvent efficiency can be achieved by adjusting operating parameters such as the start time for steam-solvent co-injection, the duration of the steam-solvent co-injection period and the solvent concentration in the steam-solvent injectant. Results from this study could provide a guideline for the design of a solvent injection strategy for field application of ES-SAGD process.