Saudis officially unofficially running out of oil

OIL

Sadly there's still plenty in the ground and in reserves to last for at least one more generation.

You'll know it's beginning to dry up when places like Saudi Arabia get serious about building desalination plants and developing large scale hydroponic farms.

Until then, you'll notice they're content to let other people grow food and pipe in water into their countries - consequently they are very comfortable with their dependence on imports.

It'll start off slow - a couple more desalination plants and some massive experimental greenhouses wth solar power panels and possibly some sand resistant wind turbines ... once it looks like they're trying to get themselves self sufficient - then you'll know the black gold is getting harder and harder to pull out.

Meanwhile certain countries are happy to keep buying it and leaving their supply relatively intact, any home drilling they do is primarily to keep work crews trained and develop better skills and refinery techniques.