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How ANWR Works

How Much ANWR Oil Are We Talking About?

In 1998, the U.S. Geological Survey (USGS) examined ANWR's coastal plain, specifically Area 1002, to estimate the amount of technically recoverable oil. Based on the geology, the USGS projected that there could be anywhere from 5.7 billion to 16 billion barrels of oil (average = 10.4 billion barrels). Of this potential oil, 74 percent lies on federal lands, with the remaining oil on state and native lands. So 7.7 billion barrels of oil might be located on the federal portion of ANWR (based on the average numbers). For comparison, the rest of the undiscovered, recoverable oil within the United States is estimated at 120 billion barrels [source: U.S. DOE]. Therefore, the estimated oil within Area 1002 is about 8.7 percent of the total undiscovered, recoverable oil within the United States. Since 1998, there have been no further surveys of ANWR oil.

How does ANWR's oil compare to other Alaska oil fields on the north slope? Its estimated oil reserves fall below Prudhoe Bay's 13.6 billion barrels, but are similar to the National Petroleum Reserve of Alaska's (NPRA's) 10.6 billion barrels [source: U.S. DOE].

Comparison of the 1998 ANWR and 2002 NPRA U.S. Geological Survey assessments.
Volumes are technically recoverable oil.

Oil, millions of barrels

Size of area

Entire area1




(million acres)

ANWR assessment





NPRA assessment





Federal area

ANWR assessment





NPRA assessment





1 includes federal and native lands, as well as state offshore areas; F95 indicates the USGS's more conservative estimate for oil; Me indicates the mean estimate; F05 indicates the USGS's least conservative estimate.

Source: USGS

In 2007, Alaska Sen. Ted Stevens asked the U.S. Energy Information Administration (EIA) to revise its assessments of the potential oil production from ANWR and its impact on oil production, imports and world oil prices. The EIA based its analysis on the USGS estimates within ANWR. The agency projected that it would take a minimum of 10 years from the time oil exploration and drilling in ANWR was approved until oil production could begin (barring any legal challenges).

Uncertain Estimates?
The EIA noted several uncertainties in its projections. For instance, the estimated oil reserves and the size of individual oil fields are not known for sure. In addition, the quality of ANWR oil isn't known but assumed to be similar to nearby Prudhoe Bay. If it were more viscous, it would be harder to extract and production would be lower.

­Why the long delay? For one, oil companies could only drill wells during the winter (a span of three to four months), and heavy equipment could only be transported to and from ANWR drilling sites by ocean barges during the summer (a window of two to three months). Add the time it would take to obtain leases, drill exploratory wells and construct producing wells, and 10 years have slipped by. Under that reasoning, oil production could begin in 2018 if drilling were approved today.

If oil production began around 2018, the EIA anticipates that ANWR oil production would add to U.S. oil production and peak around 2027 or 2028 (most U.S. oil production comes from the lower 48 states and offshore resources). When the EIA considers the mean oil estimate, ANWR would contribute about 2 percent of total U.S. daily oil production in 2020 and increase to about 10 percent of U.S. daily oil production by 2030 (cumulative 2.6 billion barrels of oil from 2018 to 2030).

So what would be the economic impact of opening ANWR to oil production?

  • ANWR oil reserves would represent 0.4 to 1.2 percent of world oil consumption by 2030, so ANWR oil would have little impact on world oil prices.
  • At its peak, ANWR oil would contribute about 0.8 million barrels per day to U.S. oil production, but America would still import about 10.6 million barrels of oil per day.
  • The total amount of money that the United States spent on foreign oil between 2018 and 2030 would be cut by $202 billion (2006 dollars) if ANWR were opened to oil production.
­[source: U.S. DOE]