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Petroleum Reserves            
Last Updated: February 2008
Next Update: January 2009

What are proved reserves?

Proved reserves of crude oil are the estimated quantities which geological and engineering data demonstrate with reasonable certainty can be recovered in future years from known reservoirs, assuming existing economic and operating conditions. Proved reserves make up the domestic production base and are the primary source of oil and gas used in the United States. Total proved reserves of crude oil in the United States, as of year-end 2006, are 20.97 billion barrels, a 3.6 percent decrease from those of 2005.

What States contain crude oil reserves?

Thirty-one States have crude oil reserves. The top five are:

  • Texas, with 4.9 billion barrels
  • Alaska, with 3.9 billion barrels
  • California, with 3.4 billion barrels
  • Wyoming, with 706 million barrels
  • New Mexico, with 696 million barrels.

Also, there are substantial crude oil reserves located in Federal Offshore fields: 3.7 billion barrels in the Gulf of Mexico and 441 million barrels in the Pacific. Offshore refers to that geographic area that lies seaward of the coastline. In general, the coastline is the line of ordinary low water along with that portion of the coast that is in direct contact with the open sea or the line making the seaward limit of inland water.

Crude Oil Proved Reserves by Area, 2006

Crude Oil Proved Reserves by Area, 2006

click on image to enlarge

What is not included in estimates of proved crude oil reserves?

Estimates of proved crude oil reserves do not include the following:

  • "Indicated additional reserves," a category of oil that is reported separately and may become available from known reservoirs through the application of improved recovery techniques using current technology
  • Natural gas liquids (including lease condensate)
  • Oil of doubtful recovery because of uncertainty as to geology, reservoir characteristics, or economic factors
  • Oil that may occur in undrilled prospects
  • Oil that may be produced from oil shales, coal, Gilsonite (asphalt), and other such sources

 

What about stored crude oil?

Volumes of crude oil placed in underground storage, such as those in the Strategic Petroleum Reserve, are not considered proved reserves. The Strategic Petroleum Reserve was created to diminish the impact of disruptions in petroleum supplies and to carry out obligations of the United States under the International Energy Program. In 1975, Public Law 94-163 (the Energy Policy and Conservation Act) established the Strategic Petroleum Reserve of up to one billion barrels of petroleum supplies. These petroleum stocks are to be maintained by the Federal Government for use during periods of major supply interruptions.


More information on this subject can be found in the following EIA publications:
    bullet item U.S. Crude Oil, Natural Gas, and Natural Gas Liquids Reserves
    bullet item Annual Energy Review
    bullet item Petroleum (Oil) - A Fossil Fuel