A process and apparatus for preparing a synthesis gas suitable for feeding to a suitable hydrocarbon production reactor, such as a Fischer Tropsch reactor is described. According to one aspect, the process and apparatus utilize heat exchangers that thermally integrate the reaction steps such that heat generated by exothermic reactions, e.g., combustion, are arranged closely to the heat sinks, e.g., cool methane, water and air, to minimize heat loss and maximize heat recovery. Effectively, this thermal integration eliminates excess piping throughout, reduces initial capital and operating costs, provides built-in passive temperature control, and improves synthesis gas production efficiencies.