The Study of the Oil Unit Connectivity for Microscopic Displacement Efficiency by CT scan

In this paper, the main factors that affect the displacement efficiency were experimental studied by means of the physical cylinder model filled with sand, based on the high efficiency of oil displacing water in the process of hydrocarbon accumulation. After eliminating of some factors that affect displacement efficiency, such as viscosity ratio, wettability and reservoir heterogeneity and so on, the research founds that the crude oil unit connectivity, that is continuity of displaced phase, has a significant impact on the displacement efficiency. The experimental results show that the crude oil unit connectivity is more than wettability, and not less than viscosity, as the factors of the impact of displacement efficiency. If the crude oil unit connectivity is serious damaged, even if the wettability of reservoir rocks was changed by improving the viscosity of injected water, its effect of enhanced oil recovery should not be obvious. In fact, this is main reason that the effect of current the EOR method such as polymer flooding, surfactant flooding and stuff was not obvious. It is expected that the research results will be useful in the displacement efficiency of waterflooding that is controlled by the crude oil unit connectivity.