As I recall, Prudhoe Bay was ~13 GB, half again the estimated size of Tupi, and this in an onshore operation without the deepwater technological challenges.

I can see, at least in the first few years after the first oil gets flowing, a process similar to that which has taken place with Thunderhorse. Production by fits and starts as the realities of each challenge are met and resolved - or not.

It will be an interesting process given the 'limits of technology' and also that as the next few years go by a number of chaotic things will be happening including crazy oil prices and technological and logistical bottlenecks.

Purdhoe Bay is a interesting field.

http://www.evworld.com/article.cfm?storyid=968

In a sense it straddles the time between old technology and new. The original estimates using primitive to us technology and with production upgraded with newer technology including water injection.

http://www.aspousa.org/assets/pdf/Peak_Oil_Review_30_Jan_06.pdf

I wonder what the URR claims would be if the field was found today ? I happen to treat it and the North Sea production as straddling the cusp between estimates we can feel comfortable with and ones that are suspect. In general the trend seems to be to use OIP numbers as URR since about 1980 or so onwards and in some cases inflated OIP estimates.