Artificially synthesizing oil is ridiculously energy expensive if you are doing it de novo.
Most, if not all, modern oil refining if it is not crude is putting materials through extraction processes and conversion processes to convert similar analogous molecules to the desired form.
Part of the interest in biofuels is in using algae or bacteria to synthesize very heavy fats, as converting from a fat to a hydrocarbon chain is quite doable.
However, the chief hurdle in biofuels is not fat production, but figuring out how to efficiently harvest said fats.
Most, if not all, modern oil refining if it is not crude is putting materials through extraction processes and conversion processes to convert similar analogous molecules to the desired form.
Part of the interest in biofuels is in using algae or bacteria to synthesize very heavy fats, as converting from a fat to a hydrocarbon chain is quite doable.
However, the chief hurdle in biofuels is not fat production, but figuring out how to efficiently harvest said fats.
Slave to the Patriarchy no more