Glad you had a good game!
Yes, I imagined the Oil discovery should happen quite fast but that didn't end up being how the city events system decided to work. The events trigger is 100% likely, but the selection for a city to receive an event depends on several factors I don't fully understand and so sometimes the events happen at a delay. I think I tried making the event ignore the global event cooldown but it didn't seem to accelerate matters. I think there is probably a time delay between city events that can be changed in the base VP but I decided not to mess with that.
