Investigation of gas hydrate formation and inhibition in oil-water system containing model asphaltene

Gas hydrate and asphaltene are two major flow assurance issues that will cause severe plugging in the subsea transportation pipelines, but the detailed understanding of their interactions remains insufficient. Systematic experiments were performed in the present study to investigate the influence of light oil components and asphaltene on gas hydrate formation, and to evaluate the performance of commercial kinetic hydrate inhibitors (KHIs) in different oil-water systems. Results demonstrated the promotion effect of light oil on initial hydrate growth, and the inhibition effect of asphaltene particularly with the light oil solvent of toluene. The influence mechanisms of asphaltene were based on the weakening mass transfer of methane at the gas-liquid interface, and the adsorption of free methane in the bulk liquid phase, while the degree of inhibition on hydrate formation was not positively related to the total concentration of asphaltene. Results also indicated that light oil components can weaken the performance of KHIs, but the role of asphaltene was closed related to the type of KHIs and light oil solvent. The overall experimental results of gas hydrate formation in the asphaltene system are consistent with our previous molecular dynamics simulations researches. Meanwhile, it provides an implication that asphaltene may have a potential ability to help some KHIs recover their inhibition performance, and emphasizes the necessity in systematically considering the oil composition when attempting to develop and utilize KHIs in oil-water system.

Automated summary

This study systematically investigated the influence of light oil components and asphaltene on gas hydrate formation through experiments, as well as evaluated the performance of commercial kinetic hydrate inhibitors (KHIs) in different oil-water systems. The results showed that light oil can promote initial hydrate growth, while asphaltene, especially with light oil solvent, has an inhibition effect on gas hydrate formation.