This paper investigates the kinetics of structure H (sH) formation kinetics above and below the structure I (sI) formation equilibrium curve at temperatures of between 2Â°C and 6Â°C. Methane was used as a help gas and methylcyclohexane (MCH) was used as sH former. It was concluded that in the points above the sI formation equilibrium curve, at the first, the sI forms, and then converts to sH because of the low solubility of MCH in water. In the points under the sI equilibrium curve, at the first sH forms after a long induction time. The study also show the effect of the addition of hydroxymethylcellulose (in three concentrations of 0.05, 0.1 and 0.15 Wt%) on sH hydrate formation kinetics. With this additive, it was observed that the rate of sH formation increases.