A critical review of the CO_2 huff 'n' puff process for enhanced heavy oil recovery

摘要

Heavy oil resources have become increasingly important in recent years due to a reduction in light oil production and an increase in energy consumption. A large number of heavy oil reserves are found all over the world, and traditional production methods, such as solution gas drive, water flooding, etc., cannot gain a high heavy oil recovery factor, because of the high viscosity of the heavy oil. Although the thermal method has proven efficient and economical to produce heavy oil, it cannot be applied in deep reservoirs or reservoirs with thin pay zones due to the huge heat loss in these reservoirs. Thus, in order to enhance heavy oil production, several CO2 injection processes are applied in heavy oil reservoirs. Among them, the CO2 huff 'n' puff method has proven the most applicable.