A reader asks me to compare the North Dakota field with ANWR. On a quick Google it looks like ANWR has about 10 bbl, i.e. three or so times the Bakken estimate. However, as several readers have explained to me, you really have to look at the price / yield curves to get a proper picture. To put it, ah, crudely: If a field has 10 bbl, but the last 5 bbl will cost you $500 a barrel to extract, you aren’t going to extract them until world prices go over $500. (Which, the way prices are headed, should be about next Tuesday.)