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Peak oil, an event based on M. King Hubbert's theory, is the point in time when the maximum rate of extraction of petroleum is reached, after which it is expected to enter terminal decline. Peak oil theory is based on the observed rise, peak, fall, and depletion of aggregate production rate in oil fields over time. It is often confused with oil depletion; however, peak oil is the point of maximum production, while depletion refers to a period of falling reserves and supply. Some observers, such as petroleum industry experts Kenneth S. Deffeyes and Matthew Simmons, predict negative global economy implications following a post-peak production decline and oil price increase because of the high dependence of most modern industrial transport, agricultural, and industrial systems on the low cost and high availability of oil. Predictions vary greatly as to what exactly these negative effects would be. Oil production forecasts on which predictions of peak oil are based are often made within a range which includes optimistic (higher production) and pessimistic (lower production) scenarios. Optimistic〔 estimations of peak production forecast the global decline will begin after 2020, and assume major investments in alternatives will occur before a crisis, without requiring major changes in the lifestyle of heavily oil-consuming nations. Pessimistic predictions of future oil production made after 2007 stated either that the peak had already occurred,〔 〕 that oil production was on the cusp of the peak, or that it would occur shortly. Hubbert's original prediction that US peak oil would be in about 1970 seemed accurate for a time, as US average annual production peaked in 1970 at 9.6 million barrels per day.〔(【引用サイトリンク】title=US Field Production of Crude Oil )〕 However, the successful application of massive hydraulic fracturing to additional tight reservoirs caused US production to rebound, challenging the inevitability of post-peak decline. In addition, Hubbert's original predictions for world production proved premature. ==Peak theory== (詳細はUnited States Geological Survey, wrote of US petroleum: "... the peak of production will soon be passed, possibly within 3 years."〔David White, "The unmined supply of petroleum in the United States," ''Transactions of the Society of Automotive Engineers'', 1919, v.14, part 1, p.227.〕 In 1953, Eugene Ayers, a researcher for Gulf Oil, projected that if US ultimate recoverable oil reserves were 100 billion barrels, then production in the US would peak no later than 1960. If ultimate recoverable were to be as high as 200 billion barrels, which he warned was wishful thinking, US peak production would come no later than 1970. Likewise for the world, he projected a peak somewhere between 1985 (one trillion barrels ultimate recoverable) and 2000 (two trillion barrels recoverable). Ayers made his projections without a mathematical model. He wrote: "But if the curve is made to look reasonable, it is quite possible to adapt mathematical expressions to it and to determine, in this way, the peak dates corresponding to various ultimate recoverable reserve numbers"〔Eugene Ayers,"U.S. oil outlook: how coal fits in," ''Coal Age'', August 1953, v58 n.8 p 70–73.〕 By observing past discoveries and production levels, and predicting future discovery trends, the geoscientist M. King Hubbert used statistical modelling in 1956 to accurately〔Deffeyes, Kenneth S (2002). Hubbert's Peak: The Impending World Oil Shortage. Princeton University Press. ISBN 0-691-09086-6.〕 predict that United States oil production would peak between 1965 and 1971. Hubbert used a semi-logistical curved model (sometimes incorrectly compared to a normal distribution). He assumed the production rate of a limited resource would follow a roughly symmetrical distribution. Depending on the limits of exploitability and market pressures, the rise or decline of resource production over time might be sharper or more stable, appear more linear or curved.〔 That model and its variants are now called Hubbert peak theory; they have been used to describe and predict the peak and decline of production from regions, countries, and multinational areas. The same theory has also been applied to other limited-resource production. In a 2006 analysis of Hubbert theory, it was noted that uncertainty in real world oil production amounts and confusion in definitions increases the uncertainty in general of production predictions. By comparing the fit of various other models, it was found that Hubbert's methods yielded the closest fit over all, but that none of the models were very accurate.〔 In 1956 Hubbert himself recommended using "a family of possible production curves" when predicting a production peak and decline curve. More recently, the term "peak oil" was popularized by Colin Campbell and Kjell Aleklett in 2002 when they helped form the Association for the Study of Peak Oil and Gas (ASPO). In his publications, Hubbert used the term "peak production rate" and "peak in the rate of discoveries". 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「peak oil」の詳細全文を読む スポンサード リンク
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