Oh, yeah. I remember that. I don't think 2 billion years is enough time to make that much goo in that manner. That is just me. Having hydrocarbons synthesized somewhere between the surface and the magma makes more sense. The magma is just full chemical goodies waiting to be put to use.
Yeah, we can only partially simulate the kinds of temperature and pressure conditions down there, and we were already able to turn simpler hydrocarbons like methane into ones closer to the stuff in crude oil. So I think it’s a good bet that no biological material is required to produce it.
However, we can also use similar processes to turn simple organisms like algae into more complex hydrocarbons. So I think the real truth will turn out that there is both a biotic and an abiotic origin to this stuff. I think the planet can produce it without biological material, but when there is biological material buried deep, it probably accelerates the process and results in bigger deposits.