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Comment by umvi | Hacker News Reader

> it always surprises me that modern oil wells aren't actually _all_ that shallower

There is a theory that oil is actually generated as a by product of the mantle itself, not by buried prehistoric plants.

If that's the case, oil could truly be a limitless resource, which is bad news for the climate.

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> There is a theory that oil is actually generated as a by product of the mantle itself, not by buried prehistoric plants.

Sounds like more like alchemy than actual science. What magical process transmutes rock into long chain hydrocarbons?

I'm not saying I believe it, but the mantle does contain natural hydrocarbons and it's not just "rock" - it's a very slow moving liquid under immense temperatures and pressures. Who knows what kinds of reactions might happen on mantle-crust (or other) boundaries.

And it helps to remember that hydrogen is the most common element in the solar system. Its not common on the surface, but huge amounts of it are trapped in the earth's interior.

It's not hydrogen that's the limiting factor, it's the carbon. Carbon, like silicon (in rock), tends to bind to oxygen whenever possible. So long-chain hydrocarbons would have to in highly anoxic regions. And there's also the issue of reacting with all that abundant hydrogen to form methane, although I'm not sure offhand which direction the binding energy difference favors on that one.

It is primordial methane that is transformed into long chain hydrocarbons by pressure and heat, according to “The Deep, Hot Biosphere” by Thomas Gold.

Normally this happens in the opposite direction. Complex hydrocarbons are broken down by heat and time into lighter and gassier hydrocarbons.

Well, there's a theory the earth is hollow and inhabited by dinosaurs and aliens, too. ;)

I think the best argument against abiogenic petroleum in the mantle is that if the theory had any merit Exxon would have figured out a way to bore into the mantle decades ago.

Even more directly, geophysicists operating under this model consistently fail to find oil.

Except if it is constantly being produced they have no need to.

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