Effect of Oil–Water Emulsion Components on Hydrate Growth and Aggregation

Hydrate blockage represents a critical challenge to flow assurance in deep-water oil production. This research systematically investigates the effects of hydrocarbon chain length (nC6, nC10, nC14, nC15), water content and surfactant concentration on CH4 hydrate formation and aggregation in oil-dominated emulsions. Experimental results reveal that hydrocarbon chain length not only affects hydrate growth rate and particle aggregation behavior but also influences CH4 occupancy within the cage-like cavities of crystals. Shorter-chain hydrocarbons enhance CH4 consumption rates and total CH4 consumption. CH4 consumption is strongly influenced by water content, and the emulsion containing 30 vol % water exhibits the highest total CH4 consumption. Surfactant addition enhances hydrate growth while partially inhibiting particle aggregation. Notably, the system with 1.0 wt % sodium secondary alkyl sulfonate shows optimal slurry fluidity after 7 h. The inhibition of hydrate growth by n-tetradecane and n-pentadecane is affected by the chain length of liquid hydrocarbons. The presence of n-tetradecane and n-pentadecane reduces CH4 occupancy in large cages, with particularly significant inhibition observed in systems containing n-pentadecane. These findings provide critical insights into hydrate management strategies for multiphase flow systems.