A nickel-silica core@shell catalyst was applied for a methane tri-reforming process in a fixed-bed reactor. To determine the optimal condition of the tri-reforming process for production of syngas appropriate for methanol synthesis the effect of reaction temperature (550-750 C), CH4:H2O molar ratio (1:0-3.0) and CH4:O-2 molar ratio (1:0-0.5) in the feedstock was investigated. CH4 conversion rate and H-2/CO ratio in the produced syngas were influenced by the feedstock composition. Increasing the amount of steam above the proportion of CH4:H2O 1:0.5 reduced the H2:CO molar ratio in produced syngas to -1.5. Increasing oxygen partial pressure improved methane conversion to 90% at 750 degrees C. At low -550 degrees C reaction temperature the tri-reforming process was not effective with low hydrogen production (H2 yield -20%) and very low <5% CO2 conversion. Increasing reaction temperature increased hydrogen yield to -85% at 750 C. From all the tested reaction conditions the optimal for tri-reforming over the 11%Ni SiO2 catalyst was: feed composition with molar ratio CH4:CO2:H2O:O-2:He 1:0.5:0.5:0.1:0.4 at T = 750 degrees C. The results were explained in the context of characterisation of the catalysts used. The obtained results showed that the tri-reforming process can be applied for production of syngas with composition suitable for methanol synthesis. Copyright (C) 2014, The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications, LLC.