There are 1.65 trillion barrels of proven oil reserves in the world as of 2016.
The world has proven reserves equivalent to 46.6 times its annual consumption levels. This means it has about 47 years of oil left (at current consumption levels and excluding unproven reserves).
This means that the oil is going to run out in our lifetime
Source/more reading: https://www.worldometers.info/oil/
Update: It is infact not true (or just partially true), because it only considers already known oil reserves that can be pumped out with current technology.
There is more oil that can potentially be used as technology and infrastructure advances, so the estimate of 50 years is wrong.
For the correction thanks to Cephalotrocity@biglemmowski.win (their original comment)
Consider especially huge infrastructure like refineries, pipelines, shipping terminals, that take many years to break a profit. Why would anyone build those anymore?
At this point, new exploration and drilling too. I don’t know how long it takes for those to be profitable, but if countries follow through with EV and other targets for renewable energy, we should expect a huge surplus and price drops in less than a decade