Formation behaviors of gas hydrates in water-in-oil emulsions with the coexistence of asphaltenes and resins

Abstract

Hydrate formation is one of the major flow assurance issues for the subsea multiphase pipelines. The effects of the interaction between heavy fractions of crude oil components on hydrate behaviors are still not well understood. In this study, the effects of resins on hydrate formation behaviors in asphaltene-containing emulsions were investigated using a high-pressure reactor apparatus. The results indicated that both resins and asphaltenes inhibited hydrate nucleation and increased the induction time. Furthermore, considerable synergistic effects of asphaltenes and resins on the hydrate formation behaviors were discovered in the water-in-oil emulsions, depending on the aggregation state of asphaltenes. The addition of resins was observed to disperse the asphaltene aggregates significantly and enhance the inhibitory effect of asphaltenes on hydrate nucleation. Additionally, the calculated results of gas consumption showed that the presence of resins can decrease the growth rate of hydrates in the asphaltene-containing emulsions. A potential mechanism was presented to illustrate how resins affect hydrate formation in an emulsion with varying asphaltene aggregation states. These findings offer a better knowledge of the synergistic effects between the heavy components of resins and asphaltenes and have potential application in the hydrate management of crude oil pipelines.