Laboratory Investigation of Enhanced Light-Oil Recovery By CO_2/Flue Gas Huff-n-Puff Process

摘要

This paper focuses on phase behaviour measurements with reservoir oil-CO_2 mixtures and on coreflooding tests in the huff-n-puff mode to characterize the system, determine the influential mechanisms, and supply data for simulation of the field implementation. The results indicate that significant amounts of CO_2 could dissolve in the oil, which caused oil swelling and viscosity reduction. During the puff cycle, the oil retained CO_2 preferentially to methane; thus, the beneficial swelling and viscosity effects were maintained over an extended portion of this cycle. Corefloods were performed to investigate the effect of water-flood residual oil saturation and injection gas composition (CO_2 and enriched flue gas) on oil recovery. Incremental oil recovery was observed to be sensitive to waterflood residual oil saturation and to the process application scheme. Coreflooding results suggest that the huff-n-puff process may be more suitable to oil-wet than water-wet reservoirs.