I am dumbfounded, Can someone please explain?

The United States has an immense amount of oil (more so than the countries were getting oil from), the recent discovery of 3-5 billion gallons of oil in North Dakota alone is more that the largest oil plant in Saudi Arabia. As far as I know, environmentalist do not seem to have a problem drilling in NK. However, we are expected to have another increase of oil prices. I am oblivious to the resoning for this paradox. Can someone explain?