oil gas injection

Gas drive oil refinery technology is mainly miscible and partially miscible flooding. Miscible displacement is an important method of enhanced oil recovery, one of its basic mechanism is flooding agent miscible gas injection and the displacement of formation oil at reservoir conditions to form mixed phase, eliminating the interface, the porous medium capillary force drops to zero, thereby reducing the capillary retention due to the capillary effect produces petroleum traps, in principle, can make microscopic oil displacement efficiency of 100%. In fact, the heterogeneity of the formation permeability stratification, mobility ratio unfavorable, gravity tongue forward, viscous fingering and other factors, oil recovery is less than 100%, but under suitable conditions its recovery generally higher than waterflood recovery factor is high. So far, the oil can be used to gas miscible with hydrocarbon gases and non-hydrocarbon gases. Hydrocarbon gases are dry gas, oil expeller, rich gas and liquefied petroleum gas, non-hydrocarbon gases are carbon dioxide, nitrogen, flue gas. Gas miscible flooding their mixed camera processing can be divided into first contact miscible (direct contact with the mixed phase), multi-level contacts miscible flooding (dynamic mixed phase), near miscible flooding (condensing / vaporizing gas drive), in accordance with the injected gas type classified as follows: LPG slug, carbon dioxide flooding, nitrogen flooding (flue gas drive), dry gas drive, the rich gas drive.