Abstract:There are some difficulties in the development of deep heavy oil reservoirs, including high oil viscosity, high percolation resistance, poor performance of conventional water flooding, high injection pressure and low injectivity. Based on the evaluation of surfactant adaptability, the influences of interfacial tension, permeability, injection rate and injection speed of surfactant slug flooding to improve water flooding performance for Dongxin oil field are investigated. The experimental results show that, the surfactants used have good compatibility with injection fluid, showing a better ability to reduce the oil-water interfacial tension. Under 70 ℃,the mass fraction of 0.01% surfactant solution and oil is lowered to 10-2 mN/m. After the injection of surfactant slug, the subsequent water flooding pressure is reduced evidently, the recovery efficiency is improved. Lower interfacial tension between oil and water, higher injection rate and lower injection speed can achieve higher injection pressure reduction and enhance the recovery factor by subsequent water flooding. The reduction of injection pressure can be up to 18%, and the recovery rate can be increased by 15.7%. In the same experiment conditions, for lower permeable cores, percolation requirements become tougher and the performance of surfactant slug flooding is poor.For the injection of 0.7 pore volume, the permeability falls from 256.65×10-3 μm2 to 36.16×10-3 μm2, and the subsequent injection pressure of water flooding falls from 17.1% to 10.0%, and recovery efficiency reduces from 15.7% to 11.7%.