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.
Hydrate nucleation events are stochastic within the stable phase equilibrium zone, which means that nucleation is a distributed property with some probability associated with different thermodynamic properties. Hence, high fidelity datasets are required to construct nucleation distributions. Within the research group, High Pressure Stirred Automated Lag Time Apparatus (HPS-ALTA) was recently developed to quantify (1) subcooling (how far deep in the hydrate equilibrium region can the system operate?) (2) growth rate (how fast will hydrate grow?) and (3) induction time (how long can we wait until we see hydrates? – equivalent to no touch time). Within reasonable timeframes, this novel apparatus can measure thousands of nucleation events in an automated fashion. The data obtained enable us to generate statistical significant probability distributions, which allow us to have more confident whilst assessing the risks of hydrate formation in subsea pipelines.