I thought that much was obvious, but for those who have not been paying attention, we are close to using up our hydrocarbons.
Maybe four centuries for all sources of fossil carbon, hydrogenated or otherwise, depending on usage rate.
Remember that "reserves" means "the stuff we already found while exploring". Nobody with a financial clue spends today's private money exploring for stuff they won't be digging up and selling for decades. So you only have more than about 20 years of "reserves" when there have been giant finds, the known reserves are too expensive to exploit and there might be easier stuff out there, or too much of the known reserves are unexploitable due to things like government intervention. There's no doubt quite a lot more out there, though it's still finite.
Running out is not a disaster. We can easily make all the stuff that's made from oil and there are other energy sources - including more coming down the pipeline. We're only digging/pumping up most of our energy and much of our chemical feedstocks right now because it's CHEAPER than the alternatives.
But it's not cheaper by much. (Photovoltaic is now becoming competitive with grid power in many areas, even without government market distortions, and the tech just keeps improving.)
By the time the fossil fuels run out we'll have lots of alternatives, and they'll run out by gradually getting more expensive, so people will smoothly transition to alternatives (thanks to Adam Smith's "Invisible Hand"). The main problem (if the CO2->global warming conjecture is true and substantial) will be keeping the Earth from crashing into the next orbital-mechanics driven Ice Age (as humans MAY have been doing for about the last 10,000 years or so, as the orbital climate-forcing has been curving down steadily.)