A process for the preparation of a synthetic predominantly single carbon number hydrocarbon fluid comprises the steps of: contacting an alpha olefin having a carbon number of 4 to 30 with a single site catalyst under conditions effective to produce reactive hydrocarbon oligomers that contain reactive double bonds and comprising predominantly dimers, trimers, and tetramers wherein at least 10 weight percent of such reactive hydrocarbon oligomers at least one of trimers and tetramers; separating at least one of said trimers and tetramers in said reactive hydrocarbon oligomers; dimerizing said separated one of said trimers tetramers by contacting said separated one of said trimers or tetramers with a dimerization catalyst thereby producing an unsaturated synthetic hydrocarbon fluid; and contacting said unsaturated synthetic hydrocarbon fluid with hydrogen in the presence of a hydrogenation catalyst thereby producing a synthetic hydrocarbon fluid having predominantly single carbon number.