I once thought I was wrong, but I wasn't. That is why in my 12 October post I used the more technical term alkanes. I think MolaKule and I both forgot the definition of hydrocarbons. They are purely compounds of carbon and hydrogen with no oxygen, nitrogen, etc. They do include the aromatics, benzine and other compounds with its ring structure. As such they are still hydrocarbons, but will swell/destroy a wider range of elastomers. Unkind people will say they stink.
I have no idea of their lubricating properties. Were they much good I doubt the oil companies would go to all the work of breaking down the naphthenic crudes and reassembling them into either straight chain alkanes or branched ones.
Alkanes include straight chain, branched, and cyclic hydrocarbons as long as they are saturated. Olefins are unsaturated, but once polymerized, become saturated, PAO.