Solvent-Steam Assisted Gravity Drainage (S-SAGD) processes for bitumen extraction are proposed to reduce the environmental impact of steam injection. However, due to the unknowns of solvent-bitumen interaction and high cost of solvents, S-SAGD processes require more research to optimize the process performances by reducing cost and environmental impact.<br/>This study investigates propane-SAGD (P-SAGD) and propane-steam flooding (P-SF) performance for the recovery of a Canadian bitumen from Alberta with 9.6 API gravity, 290,000 cP viscosity (at 25 °C), and 21.7 wt% asphaltenes (n-pentane insoluble) content. Three two-dimensional SAGD experiments (one SAGD and two P-SAGD at two different propane doses) and three one-dimensional flooding experiments (propane, steam, and propane-steam) were conducted. By comparing 2D experiments with 1D, we were able to discuss the effect of continuous steam flow and steam chamber development on process performance in microscopic scale. Produced and residual oil samples were analysed for their water and asphaltenes content.<br/>It has been observed that the steam chamber development with propane coinjection enhances the oil production, however, displaced oil samples favour more water-in-oil formation than solvent-steam flooding cases. Thus, we also tested first steam injection till maintaining the communication between the injector and producer in SAGD configuration and then, switching steam-propane coinjection. After allowing the steambitumen interaction first, propane injection did not resulted in severe water-in-oil emulsion formation. Lesser permeability reduction due to asphaltenes deposition is observed.<br/>Moreover, application of propane-SAGD as follow up to SAGD, optimize the solvent amount to maximize oil production and quality by minimizing the amount of steam and solvent injected.

Propane-Steam Assisted Gravity Drainage (propane-SAGD) as a follow-up process to SAGD

253rd National Meeting (2017)

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