Hydrate formation and wax precipitation can occur simultaneously due to the high pressure and low temperature conditions in subsea pipelines, leading to complicated flow assurance issues. In this study, we provided direct measurements of hydrate induction time with different wax contents by using a high pressure autoclave equipped with an online viscometer. It was found that the presence of wax can significantly increase the hydrate induction time for the diesel oil systems. The petroleum samples from an operational well and real wax deposits from the pigging process were also mixed and used to represent in the field and real hydrate formation conditions. The hydrate induction time of field fluids showed that the presence of wax deposition could weaken the inhibiting effect of wax on hydrate nucleation by causing a reduction in the amount of wax adsorbed at the water/oil interface.
Keywords hydrate nucleation, interfacial adsorption, wax deposition, mass transfer resistance