Much of Venezuela’s oil is highly sulfurous and needs a lot of extra processing and controls before it is refined into various products.
In other words, they may have lots of oil (not nearly as much as Hugo’s bald face lie), but it is crap.
Citco - Cheap Insolvents Take Ghetto Oil
Ah, so that's it.
I recall hearing that the Saudi petroleum was a better grade of crude. We lived in the KSA for five years and I learned a lot about the "awl bidness" but that was decades ago.