From sands. Like river alluvial fans, for instance where lots of organic material is laid down.
Is that why there are tar seeps at the very deepest depths of the oceans?
“Is that why there are tar seeps at the very deepest depths of the oceans?”
I don’t know what you are getting at.
I know what they teach in conventional petroleum curriculum.
I can flip your elevation model, and take you to fossils seashells at 10,000 elevation. The sea floor and seashore aren’t like they always have been.
Plus decades of empirical production results, validate with decline curves, consistent with finite amounts of oil in the bearing strata.