Visual study of methane hydrate kinetics in a microfluidic chip: Effect of the resins extracted from the crude oil

Hydrate plugging in oil and gas transport pipelines is a crucial challenge to the safety of flow and maintenance of pipelines. Specifically, the resins, the strongest polar component in crude oil would significantly affect hydrate kinetics but the mechanism of the interaction remains unclear. Here, a microfluidic chip was used to monitor the hydrate formation under gas flow in-situ, with and without resins extracted from the crude oil. FTIR-ATR and NMR results indicate the presence of a large number of polar components in the resins. High-resolution mass spectrometry showed that two resins contain a variety of heteroatom compounds and sulfur-containing heteroatom. The results indicated that these resins played a surprisingly inhibitory role in the hydrate formation kinetics; this was ascribed to the presence of the polar functional groups. The results also showed that the hydrate grew along the direction of gas flow. Notably, the presence of resins could prolong the induction time and lower the growth rate; this effect could be enhanced with the addition of resins containing more heteroatoms. This study filled the gap in the effect of natural resins on the hydrate formation kinetics and provided guidance on preventing hydrate plugging in oil and gas transport pipelines.