HOW is there so much crude oil left?

Question

In grade school I remember learning that the creation of crude oil in the Earth’s crust was a rare event. How was so much created?

In: 19

Answer 1

Oil forms in deposits of ocean sediment where the remains of millions of years of dead plankton have been buried. The Earth’s surface is mostly covered in ocean, and it is billions of years old, so there are a lot of places that have ancient ocean sediment deposits.