USGS stats

And here’s how much the USGC says is actually “usuable":

The total quantity of technically recoverable oil within the entire assessment area is estimated to be between 5.7 and 16.0 billion barrels (95-percent and 5-percent probability range), with a mean value of 10.4 billion barrels. Technically recoverable oil within the ANWR 1002 area (excluding State and Native areas) is estimated to be between 4.3 and 11.8 billion barrels (95- and 5-percent probability range), with a mean value of 7.7 billion barrels (table 1).

In anticipation of the need for scientific support for policy decisions and in light of the decade-old perspective of a previous assessment, the USGS has completed a reassessment of the petroleum potential of the ANWR 1002 area. This was a comprehensive study by a team of USGS scientists in collaboration on technical issues (but not the assessment) with colleagues in other agencies and universities. The study incorporated all available public data and included new field and analytic work as well as the reevaluation of all previous work.

Using a methodology similar to that used in previous USGS assessments in the ANWR and the National Petroleum Reserve—Alaska, this study estimates that the total quantity of technically recoverable oil in the 1002 area is 7.7 BBO (mean value), which is distributed among 10 plays. Most of the oil is estimated to occur in the western, undeformed part of the ANWR 1002 area, which is closest to existing infrastructure. Furthermore, the oil is expected to occur in a number of accumulations rather than a single large accumulation.

So we use 6.6 billion per year, and ANWR might give us 7.7 billion in a year. Think that's enough?