Millions of years in the making.....stored decomposed once living material with huge pressure and heat over eons.
Most fields are divided into three main parts....water....oil...and gas......
The decomposition over time, along with the pressure and heat generated allows the material to break into its parts as with most living things today...
The deserts of Saudis Arabia and the likes were once gigantic forests millions of years ago. But today they are just deserts.
But it is all about timing as usual.......In Ireland we have the biggest turf bog land in all of western Europe.....in a few more millions of years it would remain half decomposed but not enough pressure to turn it into coal....so it stays as peat...still a fuel.
But the right ingredients haven't been met yet....