Modeling of a Gas Release from Underground Pipeline

Abstract

The underground gas releases from buried pipelines can cause serious damage to the environment, properties, and population. This work aims at modelling the underground gas releases using a computational fluid dynamics numerical tool to allow the user to obtain a desired property (velocity, release rate, etc.) and visualize the behavior of a release. This was done through performing a sensitivity analysis on five crucial parameters that affect the results significantly, namely, the meshing size, soil particle diameter, turbulence model and the granular viscosity characterizing the soil. The resulting model was validated and used to delineate the boundaries between the different regimes corresponding to various release forces. The regimes are the resulting outcomes of the methane’s flow which vary according to its release force ranging from migration through the soil, to uplift visible on the ground, till a crater formation. The pipeline burial depth was changed to investigate the effect of the change of burial height on the regime. The result was presented on a nomograph that allows to identify the regime corresponding to a given inlet force and pipeline burial depth, for an upward release orientation. The effect of the release orientation on the outcome was investigated for given pressures.