What is more, is that the money is generated from private industry operating on the free market and does not come from tax on citizens.  Representative Don Young of Alaska as Minority Chair of the House Natural Resources Committee released the following press release with his comments of the figures. 

View press release. (pdf)

The OMB figures however are actually somewhat inaccurate in that they are based upon oil reserve estimates made by the 1998 USGS report on the 10-02 Area.  Those numbers generated by the USGS deliberately omitted known accumulations of oil below a certain size due to the lack of technology available at the time.  Today’s technology allows for the production of those fields neglected in the ’98 report thus increasing the base reserve estimates.  The 1998 USGS report also used an average estimated recovery rate of 35% in generating its final figures.  Today, rates of 65% are common. This fact alone would double the USGS figures.  The USGS report estimates that at prices above $30 per barrel that all oil from the 10-02 Area of ANWR could be recovered.  The total figures in the 1998 USGS report for estimated reserves in place were between 11.6 to 31.5 billion barrels of oil with a mean estimate of 20.7 billion barrels of oil.

For more information see the CRS Report

View USGS report. (pdf) 

And …

The 2001 review of the USGS 1998 report

And…

USGS 1998 Report (pdf)