Modeling and simulation of multiphase high-pressure natural gas release from subsea pipelines due to possible breakage

The dynamics of the release of natural gas from subsea high-pressure pipelines is analyzed and discussed to evaluate the consequences of it on the sea surface in terms of plume shape and hazard degree due to explosion, determining quantitatively the extension of the danger zone, which is crucial to prevent accidents for vessels, ships, and offshore structures. The influence of several parameters is discussed: (i) release water depth, (ii) flow rate of release, (iii) velocity of sea current, (iv) velocity of wind, and (v) breakage size. In particular, safety maps can be developed based on different hazard scenarios. Specifically, in the presence of a fire scenario, the dangerous area is delimited according to the inflammable limits of natural gas in the air. Overall, simulation studies can accurately describe the real plume behavior on the sea surface, allowing us to develop safety maps. This is crucial to predict the consequences of risk scenarios and to implement the necessary countermeasures to protect workers and installations.