Influence of Asphaltene Polarity on Hydrate Behaviors in Water-in-Oil Emulsions

In order to evaluate the influence of asphaltene polarity on the behaviors of hydrates, four subfractions with different polarities fractionated from asphaltenes are used for hydrate nucleation, growth, and dissociation experiments. It is found that the subfraction with higher polarity shows a higher self-aggregate tendency in emulsions and tends to adsorb less at the oil-water interface, which is mainly caused by its larger C/H ratio and higher aromaticity. The addition of asphaltenes increases the induction time of hydrates, and this effect is strengthened in the emulsion with the less polar subfraction. The calculation results of total gas consumption indicate that the amount of formed hydrate decreases with the increase of asphaltenes, especially in the emulsion with the higher polarity subfraction. Moreover, asphaltene subfractions are observed to accelerate the dissociation process of hydrates.