The Nanuq Undefined Oil Pool was discovered in 2000 by the Nanuq 2 well, which tested 1,750 barrels of oil and 1.2 million cubic feet of gas per day from both Nanuq and Kuparuk reservoir sands.  The Colville River Unit CD1-NQ1 delineation well (subsequently renamed Colville River Unit CD1-229) was drilled during 2001, and it tested 460 barrels of oil and 6.5 million cubic feet of gas per day from a horizontal completion.  Sustained production is recorded from only CD1-229.  Between February and July of 2001, the well produced a total of 60 days, yielding 19,312 barrels of oil and 298 million cubic feet of gas, for an average rate of 332 barrels of oil per day and 4,869 million cubic feet of gas per day.

The reservoir consists of the Cretaceous-age Nanuq sands:  Nanuq 2 and CD1-229 encountered 50 and 19 vertical feet of oil-bearing sandstone, respectively.  Nanuq 2 also opened 9 vertical feet of Kuparuk reservoir sand for the commingled production test discussed above.   Oil gravity from Nanuq 2 and CD1-229 measured 40 and 41 degrees API, respectively.