Would you be able to add an option to not have oil in the starting area? It would be nice as I wouldn't have to unzip your mod just to change that one thing to a 0 probability in the vanilla config.
From what I noticed if you set oil to very small it might not spawn in starting area too.
It has nothing to do with the option - it's basically so poor that doesn't reach minimum spawn threshold.
If you have map settings on normal then please post save or map exchange string on forums and I'll take a look.