Interesting.
There is a fundamental understanding, or presumption, about the nature of the hydrocarbons.
When a diagram of the Earth sphere is drawn or visualized, how much volume exists in which there can be oil is the entire sphere, but only down 5-10 miles. No more than that.
The reason is temperature. The geology that makes oil disappear are a combination of earthquakes and temperature.
Earthquakes releasing the most energy are only about 25-40 miles deep. Why quakes matter is they occur at plate intersections and they have been going on at that locale for millions of years. If oil collected in some geology porosity in that locale, shallow, it won’t last millions of years. The rocks will crack, new permeability forms, and simply put, oil flows away and dissociates.
So . . . that’s depth. The deeper you go, the hotter it is, and oil cannot survive hot. It becomes nat gas. CH4 vs long chain CH bonds. They just can’t stay together, they dissociate. Oil ceases to exist. It becomes methane.
There is no proposed mechanism underground for hot methane becoming oil. It has to migrate upwards to cool temps and once there, there’s no reason for it to be anything but CH4.
Anyway, this is part of the “running out of the right geology” problem. It is rock of certain types and structures, anywhere around the world, but only down to a depth where the temp didn’t work on it millions of years to eliminate the hydrocarbons from oil form.
The age of the hydrocarbons is presumed to be the Carboniferous Era. Coal formed in the same period, entirely from plant matter buried in a swamp so there was no oxygen for bacteria to rot it. After millions of years of descent into the ground, pressures worked on it and created coal (note only down about 3 miles, somewhat max). Oil, it is presumed, had the same creation method, but not plant matter. Diatoms. Gazillions of them, buried so no oxygen and millions of years to process into oil.
In summary, you don’t find oil in earthquake zones. This caused Pearl Harbor. The Japanese had/have no oil because they have quakes and they were going to have to get it from Indonesia. The Navy had to be stopped from interception.
Alaska’s plate interfaces are nowhere near Prudhoe. It’s also why Europe has none to speak of south of the North Sea. Italy and Greece have quakes often.