I recently found out during my space exploration playthrough that oil rigs are not compatible with Dectorio.
The issue emerged when trying to place an oil rig on an oil deposit in deep or shallow water, by giving an error message "Error: Oil rigs can only be placed on water"
While debugging I remembered that Dectorio changes many entities' properties including water. I went and disabled Dectorio and attempted to place an oil rig once again and the issue seemed to vanish.
I'm not sure if and how this could be fixed, but it's just a shame that a great mod like Dectorio, that allowes such creativity doesn't mix with the great applications that come from Cargo Ships.

I tried this with just Cargo Ships and Dectorio installed and there was no problem. Seems like this is a result of more than just those two mods. What other mods are you using? Is everything up to date?

Yeah, I think I messed up while debugging or just got lucky. I think the problem is the mod "Water Ores".
It seems that Cargo Ships and Water Ores both can generate oil deposits on water. These deposits also have different sprites, the Cargo Ships deposits have more of a blue tint to them, but Water Ores deposits have the default sprite.
The Cargo Ships deposits can be extracted with oil rigs, but the Water Ores deposits have to be landfilled over and used up with pumpjacks.
Sorry for causing any trouble, I guess I have to look harder for a better oil deposit now and improve my debugging for the future.