Surfactants have been reported to promote the gas hydrate formation by changing the hydrate formation pattern. In this work, methane hydrate formation was carried out in glass tubes to study the effects of the existence of surfactant micelles on methane hydrate growth pattern. For comparison, surfactants could and could not form micelles at hydrate formation temperature were used, which were sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS), respectively. SDS led to obvious upward hydrate growth on the reactor sidewall (cover factors 2.8-3.7), while SDBS resulted in obviously less extent of upward hydrate growth (cover factors 1.8-2.6) due to the micelle effect. When SDS-coated polystyrene nanospheres were used, SDS existed in the reaction solution in the form of mimic micelles and consequently much less extent of upward hydrate growth was achieved (cover factors 1.8-2.3). When SDBS was used together with SDS at non-micelle forming condition, prominent upward hydrate growth was obtained (cover factors 2.7-3.3). (C) 2016 Elsevier Ltd. All rights reserved.