Earth hydrocarbons are different? Seriously?
What makes Earth based Methane, butane, Ethane and octane different, do they have a velicoraptor molecule attached to them?
Where's the non-earthly butane, ethane and octane? Have little green men been drilling for it?
Um, see the blue lakes on Titan I keep referring to?
They're not methane.
Blue?!?! That alone should tell you that it's not the same as hydrocarbons found on earth. Crude oil on earth is BLACK!!!