Oil is one of the biggest businesses any nation can involve themselves in and if you find out that your country has significant amount of oil and the tools to get it, process it and sell it to the world, then it's a matter of time and a lot of foreign cash will be flowing but of course that never guarantees whether you th citizen will be prosperous or not.
Let's take a look at a lot of countries with the most oil reserves.
Screenshot from X attributed to Visual Capitalist
There are 300 Billion barrels of oil in the ground in Venezuela, the 300 billion figure has been mentioned a lot, but the reality is that Venezuela is not able to extract that oil anymore. The Western oil companies, who are coming back to work with Venezuela, were not invited back to do so, they were allowed back because of changes to the sanctions on Venezuela and also the fact that the government has now declared that the same reserves that have been known about for many years now are open to be exploited.
Saudi Arabia has approximately 267 billion barrels of recoverable oil in the ground, with the difference being that the oil in Saudi Arabia is much easier to extract and is made up of a light crude that is more preferred by refineries. Aramco's ability to manipulate the market by simply suggesting, through public comments that they may cut production is well known, other OPEC+ countries will follow suit or maybe pretend to follow suit.
Canada is one of the top six countries with the most recoverable oil resources, assessed at over 170 billion barrels, but the country's oil is located in the tar sands and take an extremely high cost to process. Iraq and Iran have large amounts of crude oil as well, although geopolitics has historically affected their ability to continually sell that crude oil.
The amounts of oil still available for the world to use are reflected in consumption versus availability. The math done suggests if consumption stays at 100 million barrels a day, it will be roughly 47 to 53 years before oil is no longer available. But reality is consumption will not stay at that number, it may go down depending on the extent of the growth of electric vehicles or it may increase if India and Africa develop more rapidly than Europe decarbonizes. The estimates are all guesses based on some form of modelling to support them.
It is also possible that peak consumption can happen before peak production occurs. Or if they're lucky, fracking 3.0 will result in the discovery of a previously unrecognised barrel of crude oil, but no one knows at this time.