Laboratory experiment optimization of foam system for separated layer water injection in offshore oilfields

Several foam agents were prepared for separated layer water injection in offshore oilfields with high porosity and permeability. The performance of nitrogen foam was investigated through FOAMSCAN observzation, resistance factor tests and other physical simulation experiments. The Ⅱ foam system with the foam agent concentration of 0.5% and the gas-liquid ratio from 1:1 to 3:1 was proved to have excellent foamability, stability and flushing resistance ability, which can form effective plugging in the high permeability zone with the permeability of 20 μm².