I think high sulfur oil is called “sour crude”. Yup, it has a low value and will only be pumped when there is a shortage. We live on a formation full of it. Had the Bakken not been discovered, we’d be rich, filthy stinken rich.
https://www.strategypage.com/qnd/colombi/articles/20171213.aspx
The production decline is continuing not so much because the government refuses to clean up the mess in the national oil company and the oil production facilities, but because it cannot figure out how to do it. To make matters worse the Venezuelan oil is exceptionally expensive to get process for local or export use because it is “sour” and tar-like. That makes it more expensive to refine and Venezuela must blend its sour crude with imported “light” crude or other diluent (like naphtha) to make their crude oil suitable for foreign refineries. Venezuela is so short of cash that it is not paying for these diluent imports and suppliers are refusing to ship anymore unless they get paid. Same with many other essential services for the oil industry.
This has become critical in 2017 because the Venezuelan refineries, also state owned, have suffered more accidents and received less adequate maintenance over the last decade. As a result domestic refining capability is now about a quarter of normal and getting worse. Shipping sub-standard crude is a violation of the sale agreement and customers are running out of patience. At the moment the largest source of cash sales for Venezuelan crude are Americans. Those buyers have invested heavily in U.S. based refineries modified to handle Venezuelan crude. If the U.S. customers give up on Venezuela they will reconfigure their equipment, at great expense, to handle crude from other sources and Venezuela will have to find new buyers and that will mean selling their sour crude at an even larger discount to more distant and less reliable customers. Currently most of the oil exports go to barter customers (like China) that made large loans that are repaid with oil. These customers are also not getting their oil on time or to the specified quality. No foreign investors are willing to commit the billions need to update and revive the Venezuelan oil operations, mainly because of the massive corruption and the sense that the government is not rational nor dependable. The collapse of the Venezuelan oil industry is doing long-term damage to the ability of Venezuela to process and sell its sour crude.