Building academy on oil tile - Auto acquire oil?

Solution 1:

Yes, you'll gain the oil.

Great Person improvements count as improving strategic resources. This is so players don't have to replace them (wasting a great person) if they unknowingly put them on a strategic resource.

Solution 2:

Great People tiles will always give you strategic resources as long as you meet the prerequisites for accessing that strategic resource.

The reason for this is that strategic resources don't show up on the map until certain technologies have been unlocked. If you pop a Great Person to make a tile improvement, and then later you realize you have to build something else there, that'd be a huge bummer.

Thus, the game counts it as having built the special tile improvement on top.