Probabilistic Hydrate Formation Risk


Gas hydrate management, rather than avoidance, could be a viable strategy if a precise description of when and where the solids are likely to form was available. Conventional approaches for estimating the risk of plug formation are based simplistically on a single sub-cooling threshold of 3.6 K below the hydrate equilibrium boundary. This heuristic is derived from only five experimental tests even though it is a primary variable in determining the amount of hydrate inhibition infrastructure required in each subsea project (up to $400 million per installation). More accurate statistical descriptions of the sub-cooling are needed to determine when and where hydrate particles are likely to nucleate and then form a blockage through aggregation and deposition. The PhD student in this project will use a third-generation Automated Lag Time Apparatus, customised to measure the probability distribution of gas hydrate nucleation as a function of sub-cooling and shear. They will then develop a quantitative probabilistic model that can be coupled to pipeline pressure-temperature data to replace the simple industry heuristic used currently. This data will directly impact oil and gas operators by reducing the significant overdesign margins currently placed on subsea infrastructure, which represent about 30 % of total project investment.

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