Process for the preparation of synthesis gas from an essentially dry hydrocarbon feedstock (1) comprising olefins, hydrogen and carbon monoxide, the process comprising the steps: (a) selectively hydrogenating the olefins in the hydrocarbon feedstock at a temperature between 60 to 190° C. (2) to obtain a hydrogenated hydrocarbon feedstock comprising hydrogen, carbon monoxide and saturated hydrocarbons (3; (b) adding steam (4) to the hydrogenated hydrocarbon feedstock; (c) performing a water gas shift reaction in the presence of steam on the hydrogenated hydrocarbon feedstock (6) to obtain a shifted, hydrogenated hydrocarbon mixture; (d) converting the shifted, hydrogenated hydrocarbon mixture (8) to obtain a synthesis gas.