Water was poured over a large oil fire to extinguish it. What would happen and why?

Nothing would happen, the fire would not stop and would keep burning. To stop the fire you would

Need a wet cloth to put over it.

I think that the fire will continue burning, because the oil and water don't mix and the water is heavier (denser) than oil, so the oil will go up and the fire with it. That's why because the gas station have sand instead of water