There's a city-state allied to me that just found oil. At least, I can see oil in their lands since I developed the relevant technology.
I'd like them to build a Well improvement over that tile, so that they'll connect the oil to my trade network.
But there's another improvement there (Trading Post), which would be destroyed if they built the well. They seem hesitant to build over it. There's an idle Worker just sitting in their city.
How can I get that well built?
I've tried taking one of my workers there, but I can't build outside of my territory.
I've tried taking a combatant there, but I can't pillage a non-enemy either.
War or culture bombs would not be worth it.
I'm about to build planes, perhaps I can bomb an ally?
Any other ideas?