Simulation of Hydrate Migration and Deposition in Pipe with Diameter Reduction and Direction Variation

Summary Pipes with diameter reduction and direction variation are very common in deepwater extraction. While the high-pressure and low-temperature conditions may trigger severe hydrate problems, current studies on hydrate particle migration and deposition are mainly carried out in pipes with a constant diameter, whereas the law of diameter reduction has been less explored; in particular, the effect of diameter reduction + direction variation in pipe has not been reported. In this study, a model of hydrate particle migration and deposition in special pipelines is established based on the computational fluid dynamics (CFD)-discrete element solver (DEM)-application programming interface (API) method, which can be used to carry out real-time visualization calculations of hydrate particles. Simultaneously, this paper reveals the mechanism of hydrate particle migration and deposition at the diameter reduction and direction variation, which provides a new idea for the design of the pipe. Furthermore, for the pipe with diameter reduction + direction variation, the entire process of deposition blockage is simulated, and dangerous locations of pipe clogging are identified. The simulation results found that there is a maximum hydrate deposition particle diameter (MHDPD) for hydrate deposition in the pipe. The results of this work may provide valuable references for accurate prediction of particle deposition in deepwater development.