We know know that algae can form methane hydrates in the sea floor. The idea that these need to be cooked for millions of years is baseless. The sea floor is on a conveyor belt being subducted beneath huge volcanic island arcs and other zones where the oceanic crust sinks to the bottom of the earth's crust because it is denser than continental crust. Those methane hydrates are buried in the sediment at the bottom of the ocean and are put under intense pressure and temperature and it is thought that is how we get oil.
This is based on the fact that oil is percolating up from beneath the sedimentary layers that we previously thought were where oil formed.
This is based on the fact that oil is percolating up from beneath the sedimentary layers that we previously thought were where oil formed.
It's about the pressure of the earth above forcing it downwards over a long time