Continental Resources/CEO increases estimated ultimate recovery by 20%, from 430,000 to 518,000 boe per well. Note: EOG has EUR of 700,000/section in its very, very good Parshall wells. Dual laterals are said to increase EUR from each section by 400,000 boe if I remember correctly.
With new technology and lessons learned, this does not surprise me in the least.
USGS survey in 2008 (or analysts following the survey) suggested 2 - 4% of total Bakken reserves recoverable; since then some folks suggesting they are bringing up as much as 7%.
Remember: going from 2% to 4% is doubling the total number of barrels. Two percent doesn't sound like much; doubling sounds huge. It is.