多孔介质中轻非水相液体污染物多相流体系的电阻率特性试验研究

目前,对于多孔介质中轻非水相液体(LNAPL)污染物的电阻率特性存在2种截然相反的观点,影响了LNAPL污染场地电阻率资料的解释结果。为此,通过自行设计的装置进行试验,重点探讨电阻率与砂样颗粒粒径、含水量和LNAPL饱和度等参数之间的变化关系。结果发现,在砂样被LNAPL饱和过程中,砂样的颗粒粒径和含水量对其电阻率相对值的变化有重大影响,含水量低的砂样电阻率相对值变化幅度很小,而含水量高的砂样电阻率相对值变化幅度很大,粗粒径的砂样电阻率相对值的变化明显高于细颗粒砂样。对于"水-油-气"三相体系和"水-油"二相体系,电阻率和含水量的关系曲线均可用Archie公式很好拟合。该试验结果对于提高LNAPL污染场地电阻率资料的解释结果的准确度具有重要的意义,在确定相关的参数如渗透系数、LNAPL饱和度等方面具有重要的实际应用价值。

Experimental investigation on the electrical resistivity properties of multi-phase porous media containning LNAPL

The batch experiments are carried out in self made experimental setup to explore the relation between electrical resistivity and media parameters espacially grain size, water content and LNAPL saturation. The result shows, water content and grain size of media have great effect on variation of electrical resistivity while saturating with LNAPL. During the process of saturated by LNAPL, electrical resistivity of media with low water content chan-ges little, while electrical resistivity of media with high water content changes much. The variation of electrical resis-tivity in coarse-grained media was higher than that in fine-grained media. To three phase system of "water-oil-gas" and two phase system of "water-oil", the relationship between electrical resistivity and water content both can be fit-ted, well by Archie formula. The result of experiment has great significance to raise the accuracy explanation of field e-lectrical resistivity data; it also has important practical value in establishing relative parameter such as permeability coefficient, saturation.