Mar 9
Sweat/Sour Crude Oil
In real life, crude Oil has a classification based on the amount of sulfur in the Oil. The idea would be to have Oil wells pump out one of three types; "Sweet Crude Oil", "Crude Oil" or "Sour Crude Oil" based on the location.
When refining, "Crude Oil" would be the same as it is now, but "Sweet Crude Oil" would produce more fuel/plastic per barrel.
"Sour Crude Oil" would require you convert it into "Crude Oil", producing less total barrels with a byproduct of fertalizer (sulfur based fertalizer).
The market effect would be that Sweet Crude would be highly sought after and Sour much less so. However you could make it so boats can optionally run on Sour Crude Oil as real life freighters run on cheap sulfur rich heavy oil.
To top off the idea, you can have skill specialization to focus oil refinary on one specific type of crude oil, so you could make Sour Crude Oil convert much more favorably into Crude Oil or you could go all in on Sweet Crude Oil. This would reflect how oil refinaries in the real world specialize in different types of crude oil.
An interesting senario could be that if the spawn rate of Sweet Crude Oil is low, you could end up with a petro-state where the town/player always has the lowest price oil, (although at a limited quantity) and uses that as the basis of government funding/taxes.
Pending
It's probably too complicated for Eco but I would honestly love a more involved fractioning/cracking system for oil. This is a step in that direction. It would be interesting if Sour was easier to process into 'Diesel' and 'Lubricants', while Sweet was easier to process into Plastic, Nylon, and Rubber.