Why is there so much Oil in the Middle East?

You’re not thinking back nearly far enough in time.

The modern desert covering the Arabian peninsula is like the past 2 minutes of your life vs what happened years ago when you were 3 years old. The organic material that formed the oil deposits are hundreds of millions years old. They were ancient when dinosaurs were still walking around the earth.

FYI the Middle East doesn’t have the most oil of any place on earth. They just have the most “easy to get to, high grade” oil.

There are tons of other options but cost more to drill. Venezuela has more than Saudi but theirs is low grade. Texas and North Dakota have a lot of high grade but expensive to extract oil. And there are vast areas of the earth that haven’t been explored for potential oil yet.

About 400 million years ago, the Persian Gulf area was under a large shallow-ish tropical sea. Oil is created not from trees (that’s coal) but from organic sediment washed down from rivers, and marine microorganisms like plankton and algae that love these warm climates (think about how coral reefs today are teeming with life).

Then huge amounts of limestone was also deposited on top of these organic rich sediments. Limestone also tends to form in tropical conditions, and limestone can create good reservoirs for the oil.

As the sea closed up because of plate tectonics, the layers of rocks were fractured, wrinkled and folded up. This created “compartments” in the rocks where oil & gas can get trapped. An oilfield needs 3 things: a source rock in thic case was mudstones and shales rich in organic matter, a reservoir rock where the oil sits which is the limestone here, and a cap rock that stops the oil escaping which is more shale and salts here. When the rocks get folded into an arch shape due to tectonics the oil from the source can float up and accumulate at the peak of the arch.

These arch shaped compartments in the middle east just so happen to be relatively shallow underground, massive in size, and made of relatively good rock with a lot of spaces to trap the oil like a sponge. This makes it cost effective to extract because you don’t need to drill using too much complicated equipment, and because of the type of rock the oil can flow relatively well so you don’t need too many wells to extract all of it. Something to bear in mind is that all petroleum, not just shale gas, is trapped inside rocks. Some rocks like sandstone and limestone just have more connected pores than others like shale, which makes it easier to extract from.

Just a small correction- oil and gas were created by marine plants and animals, not land based ones. Coal it’s what was formed by dead land-based vegetation.

Most oil is from algae not trees. It basically says that that area was underwater at some point and most deserts were. There is a spot in New Mexico where this mountain at the very top has all these fish fossils. It’s kinda wild. https://en.wikipedia.org/wiki/Tucumcari_Formation

I can answer part of this. The Middle East is not barren. There is in fact quite a bit of lush forestry and not just sandy desert as many people believe. However, this oil was formed millions of years ago when the landscape was significantly different. Plates shift over millions of years, land is frozen and unfrozen, and new biomes emerge.