Research and Application of Nitrogen Foam Slug Flooding in Bohai Oilfield

Based on the production conditions and operation requirements of Bohai Oilfield, nitrogen foam slug flooding was proposed for water control in high water cut oilfield. The experiment results indicated that, if total injection volume is the same, the oil recovery in the foam injection process or following water flooding showed an increasing trend with the decrease of foam slug and increase of injection rounds. The oil recovery of foam continuous injection, 2 foam slugs injection, and 3 foam slugs injection was increased by 19.7%, 23.5% and 31.7% respectively than that of water flooding. From the application in Bohai Oilfield, the nitrogen foam slug flooding showed obvious water shut-off and oil increment effects, and 12 wells of the 13 production wells in the experimental well group showed positive effects. The total daily oil increment was about 50 m³ and the cumulative oil increment was about 14 703 m³.