Analysis on the Formation of Water/Oil Emulsion System of High Water-cut Crude Oil and Its Profile and Flooding Effect

In view of the limitations of modulated flooding technology in low permeability high temperature reservoirs, the water/oil emulsion with the effect of expanding sweep volume and its influence on the effect of modulated flooding were studied. Under the condition of high water content (80% water content), the dispersion system formed by emulsifier 55# and crude oil is mainly water/oil emulsion. At the same time, the influence of surfactant type, water content, temperature and other factors on the formation of water/oil emulsion system was investigated, and the influence of emulsion properties on the effect of displacement was analyzed. The low permeability core experiment shows that the emulsifier with the effect of expanding sweep volume can improve the oil recovery by 17.93% on the basis of water flooding, which is obviously higher than that of polymer flooding. At the same time, emulsifier has good temperature resistance, which is of great significance for enhancing oil recovery in high temperature and low permeability water drive reservoirs.