非离子表面活性剂对两相系统毛细压力和饱和度关系的影响

Influence of a nonionic surfactant on the relationships between capillary pressure and saturation in two-phase system

表面活性剂至水相的引入将对原先包含纯水两相系统的毛细压力和饱和度关系存在影响。对含有非离子表面活性剂Triton X-100的水-气和水-油两相系统中的毛细压力-饱和度关系曲线进行了试验测定。试验结果表明,同不含表面活性剂的纯水系列相比,在同一饱和度情况下,含有表面活性剂的Triton X-100(0.1%)系列对应的毛细压力水头值都有不同程度的减小,说明在Triton X-100存在的情况下,驱替出同样数量的湿润相体积所需的毛细压力值较小。以van Genuchten关系式为基础的拟合结果表明,在已知纯水系列毛细压力饱和度关系的情况下,对于Triton X-100-气系统的毛细压力饱和度关系,考虑界面张力降低作用引入折算系数得到的拟合值更接近于真实值;而对于Triton X-100-油系统拟合值接近真实值的程度则随多孔介质的不同而有所不同。

The objective of this study is to investigate the effect of a nonionic surfactant, Triton X-100（0. 1% ）, on the capillary pressure-saturation relationships in two-phase system. This paper sets out the relationships between the capillary pressure and the saturation of water-air and water-oil system with surfactant Triton X-100. Experimental results show that, compared with the system without surfactant, the values of capillary pressure of the system with surfactant are lower under the same saturation, which indicates that lower capillary pressure is enough to drive the same volume of wetting-phase liquid. The data fitting based on the van Genuchten model shows that, when the relationship between capillary pressure and saturation without surfactant is known, ter-air system the fitting values with a scaling factor involving interracial tension accord with the measured values for wasurfactant ; however, for the water-oil system with surfactant, the scaling approach making fitting values accord with the measured values dependeds on the porous media.