Investigation on Hydrate Growth at the Oil–Water Interface: In the Presence of Wax and Kinetic Hydrate Inhibitor

In
oil industry, the coexistence of hydrate and wax can result
in a severe challenge to subsea flow assurance. In order to study
the effects of wax on hydrate growth at the oil–water interface,
a series of microexperiments were conducted in a self-made reactor,
where hydrates gradually nucleated and grew on the surface of a water
droplet immersed in wax-containing oil. According to the micro-observations,
hydrate shells formed at the oil–water interface in the absence
of kinetic hydrate inhibitor (KHI). The roughness and growth rate
of hydrate shells were analyzed, and the effects of wax were investigated.
In addition, vertical growth of the hydrate shell was observed in
the presence of wax, and a mechanism was proposed for illustration.
In the presence of KHI, small hydrate crystals formed separately at
the oil–water interface instead of hydrate shells. The presence
of KHI reduced the growth rate of hydrates and changed the wettability
of hydrates. Moreover, the presence of wax showed no obvious effect
on the effectiveness of KHI under experimental conditions.