Experiments on air foam flooding in light-oil reservoirs at different water cut stage

Key words:  reservoir  air foam  low temperature oxidation  oxygen consumption  plugging effect

Abstract:

The experiments of air foam flooding in water flooding light-oil reservoirs were carried out by the method of physical simulation. The influence of water saturation on oxidation rate and oxygen consumption rate were discussed through the static experiments. In order to verify the oxygen consumption capacity of oil, the slim tube displacement experiment and EOR experiment of air foam flooding in double tubes were performed. The results show that there is no obvious correlation between oil viscosity and oxygen consumption. There is a water saturation breakpoint. When the water saturation is low, the oxidation rate will be large. After air foam is injected into the reservoir, the oxygen in air can be fully consumed. The volume fraction of oxygen is near zero when the gas breakthrough occurrs. Once the oxidation region reaches the outlet, the volume fraction of oxygen increases suddenly, and the effect of oxygen consumption gets badly. The injection of air foam could effectively plug the high-permeability tube and restart the low one. The final recovery is enhanced by 10.9％.