Study On The Effect Of Inhibitor On The Rheology Of Complex System Containing Hydrate And Waxy Oil And Water

The high-pressure and low-temperature environment of submarine pipelines is prone to lead to the precipitation of heavy components and the generation of hydrates in the oil-water system,reducing the flow area of pipelines,increasing the risk of pipeline blockage,and posing a great threat to the flow safety of submarine pipelines.The components in the oil-water system are complex,including wax,various surfactants,and various chemical inhibitors.There is still a lack of research on the coupling effect of various chemical inhibitors on hydrate formation.Therefore,mastering the influence of chemical inhibitors on the formation of hydrates in oil-water systems and conducting in-depth research on their underlying mechanisms is of guiding significance for the safe transportation of offshore oil and gas pipelines.This article explores the influence of inhibitors on the formation of hydrates in oil-water systems and the rheological properties of hydrate slurries.The main content is as follows:The effect of EVA pour point depressant on the formation time and rheological properties of cyclopentane hydrate were studied for waxy oil-water emulsion system.EVA pour point depressant prolonged the hydrate induction period by affecting the wax crystal structure at the oil-water interface,but its effect on improving the rheological properties of waxy hydrate slurry was not significant.A study was conducted on the effects of wax crystals and hydrate kinetic inhibitors(KHIs)on the structure of hydrates at the oil-water interface.The synergistic adsorption of wax crystals and Span80 at the oil-water interface hindered the formation of hydrate structures at the interface.KHI could weaken the strength of the interface hydrate structure by affecting the growth of hydrates at the oil-water interface.The effect of KHI on the induction period of hydrate formation in oil-water systems containing Span80 surfactant was analyzed.Low concentration(0-0.1 wt%)of KHI had the effect of prolonging the induction period of hydrate formation and improving the rheological properties of the slurry;The effect of high concentration(0.5wt%)of KHI on prolonging the induction period of hydrate was weakened,and the improvement effect on the rheological properties of hydrate slurry was poor.As the concentration of KHI increased,the decrease in interfacial tension between oil and water became more apparent.KHI molecules occupied the adsorption site of Span80 at the oil-water interface,making the contact between water molecules and hydrate guest molecules more sufficient,which was not conducive to inhibiting the formation of hydrates.The effects of thermodynamic inhibitors on hydrate formation and slurry rheological properties in oil-water systems were studied.When ethanol and KHI were mixed at a lower ratio,the hydrate formation time was significantly prolonged,and the viscosity of the hydrate slurry also demonstrated a decreasing trend.TI2 and KHI could reduce the viscosity of hydrate slurry at lower compounding ratios.