油藏岩石润湿性对气驱剩余油微观分布的影响机制

Effect of reservoir rock wettability on microcosmic distribution of residual oil after gas displacement

注气驱是目前油田进一步提高原油采收率的重要措施之一,油藏岩石润湿性对注气的效果有重要影响。基于三维孔隙级网络模型,运用孔隙级流动模拟方法,系统研究了6种不同润湿性油藏注气过程的油气水孔隙级分布和气驱效果。结果表明,水湿和MWS混合润湿(小孔隙为油湿)体系中的注气效果相对于另外4种润湿体系较差;这4种效果较好的润湿体系分别是油湿、中性润湿、MWL混合润湿(大孔隙为油湿)和部分润湿(其中30%孔隙水湿)体系。

Gas injection is one of the most important methods to enhance oil recovery.The rock wettability of reservoir has a great effect on gas displacement efficiency.Based on a three-dimensional pore-scale network model,the distribution and displacement efficiencies of gas injection in six reservoirs with different wettability were investigated using the pore-scale flow modeling method.The results show that gas injection efficiency in water-wet and mixed-wet small（small pores are oil-wet） reservoirs is poorer than that in oil-wet,intermediate-wet,mixed-wet large（large pores are oil-wet） and fractionally-wet（30% of pores is water-wet） systems.