It makes sense that much of the hydrocarbon material formed before there was life. Experiments by Miller and others during the 1950's to generate the precursors of life using simple molecules and electricity, not only made amino acids but also lipids which are long chain hydrocarbons. Other studies made resinous solids. Although the inference of hydrocarbons before life should have been common sense, I often wondered why a bias form against the obvious in favor of just life. I would guess there were politics involved and the use of mercenary science to stack the deck.