Journal of Hydrology

Oil invasion, Flow pathway, Residual ganglia, Energy conversion

Understanding the migration behaviors of spilled oil in soil is fundamentally important for taking appropriate remediation measures after a leakage accident. Yet, most previous studies, which have been performed on a field-scale, are unable to reveal the flow behaviors of spilled oil within the soil pores and thus the accurate transport mechanism underlying the oil invasion process. Focusing on the interfaces between the invading oil, resident water, and the solid boundaries within a heterogeneous porous media, this study systematically investigates the evolving dynamics and the dependence on capillary number (Ca), viscosity ratio (M) and wettability using a phase-field method. The results show that the residual water saturation is reversely correlated with each of the three factors. The morphology of residual water ganglia is more subjected to Ca than to M. As Ca decreases, the main form of water ganglia turns from isolated drops and columns to be clusters with larger areas. The dependency of the ganglia characteristics (i.e., number, mean area) on the Ca remains constant under different wettabilities. During the oil invasion, the external work is transformed into surface, dissipated and kinetic energy. The ultimate oil saturation is in line with the dissipated energy ratio in response to Ca changes. This study provides pore-scale insights into the migration behaviors of spilled oil as well as the governing mechanism, which helps to fill the gap left by the field-scale studies and to develop better remediation measures.

Yinglong Zhang,Pei Zhao,Zeyad Almutairi,Xiaodai Xue,Yan Zhou,Gongming Xin

Zhennan He

Journal paper

Ning Qin

134050

662

134050

no

SCI