不同含水期轻质油藏空气泡沫驱试验

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

采用室内物理模拟的方法进行轻质水驱油藏转空气泡沫驱试验,研究油藏含水饱和度对空气与不同性质轻质原油的氧化反应速率及原油耗氧程度的影响。在此基础上,进行长细管耗氧检测试验及水驱后的双管提高采收率试验。结果表明:耗氧量与原油黏度没有绝对的关系,存在一个含水饱和度拐点,当油藏含水饱和度低于此饱和度时,氧化反应速率较大,空气中的氧气基本可以完全消耗;空气泡沫注入油藏之后,氧气被大量消耗,气体突破时的氧气体积分数接近于零,待高温氧化带到达出口端,氧气体积分数突然升高,耗氧效果变差;空气泡沫的注入可以有效封堵高渗管启动低渗管,提高采收率约10.9%。

The experiments of air foam flooding in water flooding light-oil reservoirs were carried out by the method of physi- cal 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%.