Numerical Model to Evaluate the Consequences of a Gas Release from a Buried Pipeline: Model Construction, Validation and Preliminary Results

Depending on the flow and soil characteristics, the underground gas releases from buried pipelines result in different regimes. The regimes range from migration through the soil, to a visible uplift on the ground, to a crater formation. The proper identification of the regime is key to an accurate quantification of the consequences; thus, a successful risk assessment. There is available work that discussed each regime separately; however, there is not a continuous model that identifies all kinds of regimes simultaneously and the transition between them. In this study, we present a universal computational model, with simplified resources, that covers the whole range of regimes. We developed the model based on the Eulerian approach for fluid flow and the kinetic theory of granular flow for soil as a granular phase. Moreover, we established quantitative guidelines serving as a mechanistic approach to identify the regime. Using the model, we performed a sensitivity analysis to test the effect of some parameters on the regime. This analysis revealed that a higher pressure, a lower pipeline burial depth, and an upper release orientation trigger more damaging consequences. Furthermore, the results from this analysis were presented on a nomograph that allows the determination of the regime for a given release scenario of pipeline pressure and burial depth.