Flowloop investigation into hydrate formation and slurry flow in the presence of micron-sized sand particles

Hydrate flow assurance is critical to the exploitation of natural gas hydrate reservoirs. So far, hydrate formation and slurry flow behaviors in the presence of micron-sized sand particles are still unclear. Therefore, experiments of hydrate formation and slurry flow in the presence of micron-sized sand particles were performed in a high-pressure flow loop. The induction time and formation subcooling during hydrate formation process with micron-sized sand particles were studied, and cumulative formation probability under different formation sub-cooling with micron-sized sand particles was explored. Coupled with a semi-empirical hydrate formation kinetics model, hydrate formation kinetics parameters with micron-sized sand particles were calculated. The influence mechanism of micron-sized sand particles on hydrate formation was revealed. The calculation method for hy-drate slurry viscosity under conditions of constant volume fraction and variable shear rate was derived. Com-bined with viscosity of hydrate slurry with micron-sized sand particles, the importance of the fractal dimension to the accuracy of slurry viscosity prediction was emphasized. Considering hydraulic factors, collision between hydrates or micron-sized sand particles and pipe wall, and friction between hydrates or micron-sized sand particles and pipe wall, the calculation method of flow resistance coefficient of hydrate slurry with micron-sized sand particles was established.