Serious answer: the last refined oil will probably be left in storage until it goes bad, because it's ultimately not valuable enough to keep extracting once the reserves run low enough that alternatives become cheaper, and they have clear enough data on their reserves that they'll know when that point is going to be. Oil is used because it's cheap, readily available, and there have yet to be any consequences for the people profiting off of it for the harm it has caused, is causing, and will continue to cause, not because there are no alternatives when push comes to shove. Between electric vehicles, synthetic solutions, and shit like GMO algae modified to create large hydrocarbons they can replace oil as a fuel source once oil stops being profitable enough to bother extracting.

The obvious problem there is that continuing to use oil at even current levels until it hits that point will be catastrophic, just as having used oil as it has been used is and will be catastrophic. This is one of the many reasons liberalism and its market solutions fundamentally cannot solve climate change: the oligarchs will not allow themselves to be held accountable for the consequences of their actions, nor will they allow themselves to pre-emptively bear the costs they will cause; they scream bloody murder and fight tooth and nail against even the most tepid and ineffectual measures aimed at politely discouraging their destructive behavior, they certainly wouldn't tolerate the price of oil being increased by an order of magnitude through taxes or the common use of oil being banned outright, nor even tolerate aggressive subsidies for carbon-neutral alternatives to oil to make those the cheaper and more profitable option for everyone else.