Inclusion of polyethylene oxide into a kinetic inhibitor solution was found to enhance the performance of the inhibitor. Polyethylene oxide is a commercially available high molecular weight polymer that is not a kinetic inhibitor by itself. The hydrate formation experiments in the presence of the various inhibitor solutions were conducted in a vessel in a semi-batch manner at constant pressure and using methane and methane-ethane gas mixtures. In some experiments a non-aqueous liquid phase (n-heptane) was also present. The induction time. the gas uptake and the temperature were measured. It was found that the induction time is prolonged in the presence of the additive by an order of magnitude in some cases compared to the inhibitor only. (c) 2005 Elsevier Ltd. All rights reserved.