Oil well in the gulf the potential for on going disasters .?

ok but what happens to a depleted undersea oil well ? how do the engineers stop the weight of the sea from collapsing the cavern roof ? so with the uncontrolled eviction of oil once the gas has been depleted will the great weight of the water at that depth not force water in at great pressure widening the hole and collapsing the undersea roof of the cavern ,could this happen with the gulf well ? does not the gas in the oil help support the structure of the undersea well ? Is there not a balance between the oil below and the sea above ? So oil is spewing out uncontrollably ok ,but there is going to come a time when the oil is spent ,and i do not believe the media about the amounts of oil that is escaping not one word ,i think it is much more serious than being reported,so when the oil has finished spewing ,will not the sea water start filling this empty space with great force ? the gas in the oil causes the fountain of oil to shoot into the air ,when this force is spent what will happen .