LNAPL Migration Monitoring in Simulated Sand Aquifer Using Resistivity Method
LNAPL在砂质含水层中动态迁移的电阻率法监测试验研究

Laboratory model tests of diesel spillage were performed on the beach sand samples collected from intertidal zone in Qingdao. The dynamic resistivity changes during the diesel infiltration in sand-water system were monitored by the self-made Resistivity Monitoring System. The impact factors on resistivity were discussed by preparing sand samples with different oil contents. The water content and oil content were measured by sampling after the simulation experiment to verify the monitoring data. The micro-structure of contaminated sand was tested by image technique using microscope. It shows that cementation is evident from the micro-structure of contaminated sand. The resistivity closely relates with the water saturation, and the specific resistivity with oil saturation, both fitted with Archie equation, the n values are 2.36 and 0.15 separately. Through electrical resistivity measurements, the thickness of diesel lens was effectively estimated. The vertical distribution of oil content and water content could be reflected by resistivity changes with depths. It provides an effective way for in-situ monitoring of light non-aqueous phase liquid (LNAPL) contaminating processes and mechanism research in beach sand after underground tank leakage or oil spillage during transport by seas. It can also supply reference to contamination detection or monitoring of typical petroleum contaminated sites using resistivity method.