First the oil didn’t migrate down it was layed there millions of years ago along with water, one of the biggest problems we face in the oilfields now is what to do with all the salt water that comes up with the oil. Our tank battery’s are designed with seperators and water knockouts and heater treaters just to remove the oil.
Our oceans are a soup of living organisms and as they die the go to the bottom where over millions of years are layed down in deposits, that process is ongoing today and will continue as long as we have water on earth.
Nobody knows for sure how many times the sea has risen and fallen over the life time of the earth but every time it has done this it has left parts the ocean floor exposed. Where I am in West TX we’re 2300 ft above sea level, at one time we were 2000 ft below it. That was a time when 3/4 ths of the US was under water. Now from here I’m going to just use heating and cooling, it’s with these process’s that once the earth started to heat up again that the water would run back into the ocean covering the floor with large deposits of sediment. This process also helps to explain why we find oil at various depths and layer thickness’s. Put here we’re find oil as shallow as 1500 ft all the way down to 9000 ft, in other area’s that varies. In California and a few other area’s you with find oil at the surface, such as the tar pits.
The surface temperatures of Titan are around minus 300 degree’s Fahrenheit cold enough to turn methane back into a liquid, where it rains upon the surface of Titan daily more like a drizzle and collecting on the surface and forming landscapes similar to running and are standing water.
Now where does that methane come from? Some say it comes from within others say it accumaltes in it’s atmosphere and falls to the surface as rain. I’m of the belief that it accumulates as it hits the cold temps of Titan and falls to the surface.
I’m not done here but the wife and I are going fishing on the ranch, I’ll check back in later.
Let me add that should it proven that the methane comes from Titan then it also proves that organic life at one time flourished there.
The coker units in refineries use the release of pressure (and the resulting rapid loss of heat) to crack carbon atoms out of heavy hydrocarbon chains. Would this not also allow coal to be deposited in layers with fossils?
The areas in which sediment deposits migrate down in the crust are necessarily the porous areas of the crust. That explains why more oil and coal are found there if it migrates from the core.