3.6 billion barrels, divided by 800,000 barrels per day, equals 4500 days, or 12.3 years... if no more deposits are discovered there, if no new technologies allow deeper drilling, and if no new methods improve extraction percentages.
The other variable is increased production and faster depletion. But that is a good rough number. Thanks.
You need to include the Three Forks as much of the new production is coming from that layer as well. It has been raised again to 7.4 billion barrels.
Bakken, Three Forks resources rise twofold in new USGS estimate
http://www.ogj.com/articles/print/volume-111/issue-5/general-interest/bakken-three-forks-resources-rise-twofold.html
05/06/2013
The latest assessment, which includes the Three Forks for the first time, found the Bakken has a 3.65 billion bbl estimated mean resource—unchanged from 5 years ago—and Three Forks has an estimated mean 3.73 billion bbl. The formations’ combined estimate ranges from 4.42 million bbl, with a 95% chance of production, to 11.43 billion bbl, with a 5% chance.