Considering oil forms under compression of trees and the like, doesn’t that mean there must have been a lot of life and vegetation there a long time ago? Why did all of that dissappear and only leave mostly barren wasteland?
In: 4590
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.
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.
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.
Almost all Oil and gas is formed from organic sediments deposited on seabed over million of years. This means that the areas that have oil was in all likelyhood at some point under water. Most of the oil fields on Arabic peninsula and Iran are very close to the sea [http://oges-files.s3.amazonaws.com/p/assets/2615cba7-d8fa-478d-b243-1be0f5d22620.jpg](http://oges-files.s3.amazonaws.com/p/assets/2615cba7-d8fa-478d-b243-1be0f5d22620.jpg)
To add, yes there is a LOT of oil in the Middle East, it is exponentially easier to get to. With drilling like places in the GoM, you have to also deal with all the water above the rock. Safety is probably the biggest factor. A blowout on land? I mean yeah it’s dangerous but just drive away. Can’t really swim away from an offshore one.
As someone else pointed out, crude oil comes from marine plants and animals. So where we have oil is based on the shifts of tectonic plates and movements of the continents. Where the Middle East sits today would have been water. The world used to be one giant supercontinent and when they split into Laurasia and Gondwanaland they began to cover up spaces that were once purely oceans.
The Middle East is a barren desert because of the human influence, deforestation. The Middle East is widely accepted as the birth place of civilization (but China and India are about as equally old). Because of this most of the trees were culled to make homes, firewood, goods… and most importantly… weapons.
Most of the Middle East was deforested about 2000 years ago. In 63 BCE Rome conquered most of the Middle East and began exporting remaining lumbers to Rome. By the 19th century the last forest of the Middle East was in modern day Israel/Lebanon which vanished by the beginning of the 20th century.
Without trees there was no ground stability and slowly all of the life in the soil died creating a desert. One of the misconceptions about desert is that it’s pure sand. It’s not. Sandy desert is an incredibly small stretch of it that gets re-used at different angles for movies.
Fun fact, the organic material that makes up ~~oil~~ coal is from before bacteria that was able to degrade biological material had evolved.
Edit: Coal
Edit 2: this is just the leading theory, another theory of abiogenic oil formation also exists.
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
So most of your points have been addressed, the big one that I think is being missed is your emphasis on the middle east. Oil is in a lot of places, why the middle east seems to rule the market is that the sandstone the oil is locked is very porous. Places like the US have lots of oil, but the oil can’t seep into vacancies as well because the rock is just not friendly. That means if you find an oil deposit in middle east you can plop a pump down and sip off it for years with high efficiency. Meanwhile in the US that same pump will lose most of its efficiency in the same year, then you need to go put more pumps down to hot different areas of the same reservoir.
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 these 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.
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