Assessment of the infiltration of water-in-oil emulsion into soil after spill incidents

The issue of inland oil spills exerts an adverse impact on environmental and ecological health. Many cases are concerned with water-in-oil emulsions, especially in the oil production and transport system. To understand the contamination and take an efficient response work after spill, this study investigated the infiltration behavior of water-in-oil emulsions and the influencing factors by measuring the characteristics of different emulsions. The results showed that an increase of water and fine particle content and decrease in temperature would improve the viscosity of emulsions and reduce the infiltration rate, whereas salinity levels had a negligible impact on infiltration if the pour point of emulsion systems was far higher than the freezing point of water droplets. It is worth mentioning that excessive water content at a high temperature may cause demulsification during the infiltration process. The oil concentration in different soil layers was related to the viscosity of emulsion and infiltration depth, and the adopted Green-Ampt model simulated well under low temperature. This study reveals the new features of emulsion infiltration behavior and distribution patterns under different conditions and is helpful for the response work after spill accidents.