特低渗油藏水驱剩余可动油分布特征实验研究

Experimental research of remaining movable oil in ultra-low permeability reservoir after water flooding

为了深入研究特低渗油藏水驱剩余可动油特征,结合核磁共振、常规压汞、油驱水和水驱油等实验技术对特低渗储层岩心进行了剩余可动油实验。结果表明,其T2截止值平均为34 ms,剩余油饱和度平均61.0%,可动油饱和度平均为61.72%,驱油效率平均为38.82%,剩余可动油平均为22.9%,剩余可动油较多。结合压汞实验结果,利用多元回归的方法建立了核磁共振T2谱与压汞孔隙分布的转换关系,分析了剩余可动油的微观分布特征。分析结果表明,剩余可动油主要分布在2.2~10.0μm的大孔隙中,剩余油中还有37.54%可以采出,特低渗透油藏水驱后还有较大的挖掘潜力。

In order to further study on the characteristics of remaining movable oil in ultra-low permeability reservoirs after water flooding,the remaining movable oil in ultra-low permeability cores is studied by NMR,conventional mercury injection,oil driving water and water driving oil. The results show that the average T2cut-off of the cores is 34 ms,the average remaining oil saturation and the average movable oil saturation are 61. 0% and 61. 72% separately,the average oil displacement efficiency is 38. 82%. The percentage of remaining movable oil is 22. 9%,and it is relatively high. The relationship between T2 spectrum and mercury injection pore distribution is established by multiple regression,and the micro-distribution characteristics of remaining movable oil are analyzed. It is shown that the remaining movable oil distributes mainly in the large pores of 2. 2 ~ 10. 0 μm,and 37. 54% of the remaining oil can also be produced. So after water flooding,the super-low permeability reservoirs still have certain development potential.