Mechanism and application of flue gas-assisted steam injection for heavy oil recovery
Flue gas,used as an additive,can enhance the efficiency of steam flooding for heavy oil.To investigate the enhanced oil re-covery mechanism of flue gas in collaboration with different phases of steam,and promote the large-scale application of flue gas in oil fields,the influence of flue gas on steam/hot water oil displacement characteristics was systematically studied by regulating 1D ex-perimental parameters.Later,2D visualization experiments were conducted to explore the impact of flue gas on the expansion law of steam chamber and oil displacement and production performance,the effect of which was verified by the field experiment of flue gas-assisted steam huff and puff.The results show that flue gas can significantly improve the efficiency of steam flooding.When the steam is in a liquid state,the liquid phase of flue gas is transformed into gas and liquid phases,improving the microscopic sweep effi-ciency;as the temperature rises,the synergistic effect of flue gas becomes stronger.When the steam is in a vapor state,flue gas can improve the dryness of steam,and significantly increase the contact degree between steam and heavy oil,as well as the thermal utili-zation efficiency.However,as the temperature rises,the oil displacement effect achieved by flue gas diminishes.The advantageous region where flue gas plays a dominant role is at the vapor-liquid phase boundary,and the oil displacement efficiency can increase up to 24.2％.Flue gas promotes the development of the middle and lower parts of the steam chamber during steam flooding,resulting in a 17.4％increase in the sweep coefficient of steam chamber and a 25.4％increase in oil recovery.In field applications for over 25 well times,the average oil production is increased by 120 t per cycle,and the oil-to-steam ratio is increased by 0.1.In typical wells,the oil production is increased by 775 t per cycle,and the oil-to-steam ratio is increased from 0.3 to 0.9.
heavy oilflue gassteam phase stateenhanced oil recoveryfield application
NETL
NSTL
万方数据
