Summary: U.S. Crude Oil, Natural Gas, and Natural Gas Liquids Proved Reserves, 2009

摘要

The U.S. Energy Information Administration (EIA) provides annual estimates of the United States proved reserves of crude oil, natural gas, and natural gas liquids (NGL) based on filed responses to Form EIA-23, Annual Survey of Domestic Oil and Gas Reservesan annual survey of about 1,200 domestic operators. EIA defines proved reserves as those volumes of oil and natural gas that geologic and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic and operating conditions. Reserves estimates change from year to year as new discoveries are made, existing reserves are produced, and as prices and technologies change. Discoveries include new fields, identification of new reservoirs in old fields, and extensions. Extensions are reserve additions that result from additional drilling and exploration in previously discovered reservoirs. Extensions typically account for a large percentage of discoveries within a given year. While actual discoveries of new fields and reservoirs are important indicators of new resources, they usually account for a small percentage of reserve additions in a given year. Revisions occur primarily when operators change their estimates of what they will be able to produce from the properties they operate using existing technology and prices.