How to Minimize the Environmental Contamination Caused by Hydrocarbon Releases by Onshore Pipelines: The Key Role of a Three-Dimensional Three-Phase Fluid Flow Numerical Model

Abstract

The contamination impact and the migration of the contaminant into the surrounding environment due to the presence of a spilled oil pipeline will cause significant damage to the natural ecosystem. For this reason, developing a rapid response strategy that might include accurate predictions of oil migration trajectories from numerical simulation modeling is decisive. This paper uses a three-dimensional model based on a high-resolution shock-capturing conservative method to resolve the nonlinear governing partial differential equations of the migration of a spilled light nonaqueous liquid oil contaminant in a variably saturated zone employed to investigate the migration of the oil pipeline leakage with great accuracy. The effects of the oil type density, gasoline, and diesel oil, the unsaturated zone depth, its saturation, the hydraulic gradient, and the pressure oil pipeline are investigated through the temporal evolution of the contaminant migration following the saturation profiles of the three-phase fluid flow in the variably saturated zone. The calculation results indicate that the leaking oil’s pressure is the parameter that significantly affects the contaminants’ arrival time at the groundwater table. Additionally, the water saturation of the unsaturated zone influences the arrival time, as the water saturation increases at a fixed depth. The unsaturated zone depth significantly influences the contaminant migration in the unsaturated zone. At the same time, the oil density and the hydraulic gradient have limited effects on the contaminant migration in the variably saturated zone.