[crusty old prospector]

There has never been nor will there ever be any oil created in a subduction zone. That would be a place where oil fields go to die. The heat would break the oil first into lighter components that we call natural gas. Eventually, the heat and pressure would turn it into elemental carbon. Oil is thermally stable down to around 11,000’ in most basins. Below that, it becomes natural gas. Subduction zones take the rocks several tens of miles below the surface. Go put some Quaker State in a pot and turn on a Bunsen burner beneath it and watch what happens. Eventually, all of the lighter components would cook out and evaporate and you would be left with a pile of crap, figuratively speaking.

[GonzoGOP]

Eventually, all of the lighter components would cook out and evaporate and you would be left with a pile of crap,

Thanks for the correction. Aren't Java and Borneo over a subduction zone? Or was all the oil there shallow. I'm not familiar with the fields, just know from WWII history that there were big fields in the region.

[cookcounty]

Then again, perhaps there could be some sort of natural “reversal” that happens (just wildly speculating here), since in the lab, it is possible to make liquid petroleum products out of natural gas.