"Alaska's existing oil costs an average of $50 a barrel to produce, not including taxes."In 1998, oil was about $9 a barrel and the producers were 
still making a profit.  I find it hard to believe 18 years later it costs that much to produce. 
The Tar Sands project in Canada did not become viable until oil prices raised above $49 a barrel. Now that it has been going for over a decade, they have found ways to cut production costs. Same with fracking.