Hubbert's Peak
The Hubbert peak theory posits that for any given geographical area, from an individual oil-producing region to the planet as a whole, the rate of petroleum production tends to follow a bell-shaped curve. It is one of the primary theories on peak oil.
Choosing a particular curve determines a point of maximum production based on discovery rates, production rates and cumulative production. Early in the curve (pre-peak), the production rate increases due to the discovery rate and the addition of infrastructure. Late in the curve (post-peak), production declines due to resource depletion.
The Hubbert peak theory is based on the observation that the amount of oil under the ground in any region is finite, therefore the rate of discovery which initially increases quickly must reach a maximum and decline. Extraction roughly follows the discovery curve after a time lag (typically about 35 years) for development. The theory is named after American geophysicist M. King Hubbert, who created a method of modeling the production curve given an assumed ultimate recovery volume.
"Hubbert's peak" can refer to the peaking of production of a particular area, which has now been observed for many fields and regions.
Peak oil as a proper noun, or "Hubbert's peak" applied more generally, refers to a singular event in history: the peak of the entire planet's oil production. After Peak Oil, according to the Hubbert Peak Theory, the rate of oil production on Earth will enter a terminal decline. Based on his theory, in a paper he presented to the American Petroleum Institute in 1956, Hubbert correctly predicted that production of oil from conventional sources would peak in the continental United States around 1965-1970. Hubbert further predicted a worldwide peak at "about half a century" from publication and approximately 12 gigabarrels (GB) a year in magnitude. In a 1976 TV interview[4] Hubbert added that the actions of OPEC might flatten the global production curve but this would only delay the peak for perhaps 10 years.
Hubbert curve
The standard Hubbert curve. For applications, the x and y scales are replaced by time and production scales.
U.S. Oil Production and Imports 1920 to 2005
Norway's oil production and a Hubbert curve approximating it.?In 1956, Hubbert proposed that fossil fuel production in a given region over time would follow a roughly bell-shaped curve without giving a precise formula; he later used the Hubbert curve, the derivative of the logistic curve, for estimating future production using past observed discoveries.
Hubbert assumed that after fossil fuel reserves (oil reserves, coal reserves, and natural gas reserves) are discovered, production at first increases approximately exponentially, as more extraction commences and more efficient facilities are installed. At some point, a peak output is reached, and production begins declining until it approximates an exponential decline.
The Hubbert curve satisfies these constraints. Furthermore, it is roughly symmetrical, with the peak of production reached when about half of the fossil fuel that will ultimately be produced has been produced. It also has a single peak.
Given past oil discovery and production data, a Hubbert curve may be constructed that attempts to approximate past discovery data, and used to provide estimates for future production. In particular, the date of peak oil production or the total amount of oil ultimately produced can be estimated that way. Cavallo[5] defines the Hubbert curve used to predict the U.S. peak as the derivative of:
where Q max is the total resource available (ultimate recovery of crude oil), Q(t) the cumulative production, and a and b are constants. The year of maximum annual production (peak) is:
The sum of multiple Hubbert curves can be used in order to model more complicated real life scenarios.
Definition of Reserves
Almost all of Hubbert peaks must be put in the context of high ore grade. Except for fissionable materials, any resource, including oil, is theoretically recoverable from the environment with the right technology. A current example would be biofuel. However, a genetically engineered organism that produces crude oil would not invalidate Hubbert's peak for oil. His research was about the "easy" oil, "easy" metals, and so forth that can be recovered before a society considers greatly advanced mining efforts and how to time the necessity of such resource acquisition advancements or substitutions by knowing an "easy" resource's probable peak. Also, as reserves become more difficult to extract there is the possibility that mining or alternatives are too expensive for developing countries.
The "easy" oil constraint also applies to "abiotic oil", a theory believed by virtually no notable U.S. geologists, although it is believed by some Russian and Ukrainian geologists. This theory states that some oil is created through other methods than conventionally understood biogenic processes. However, in order to have any effect on Hubbert peak theory applied to oil, this other creation of oil would have to occur at a rate comparable to current oil depletion, something that has not been credibly observed.
For heavy crude or deep water drilling attempts, such as Noxal oil field or tar sands or oil shale, the price of the oil extracted will have to include the extra effort required to mine these resources. According to the U.S. Minerals Management Service, areas such as the Outer Continental Shelf may also incur higher costs due to environmental concerns. So not all oil reserves are equal, and the more difficult reserves are predicted by Hubbert as being typical of the post-peak side of the Hubbert curve.
Reliability
US oil production (crude oil only) and Hubbert high estimate.Generally the only reliable way to identify the timing of any production peak, including the global peak, is in retrospect. United States oil production peaked in 1970, and this provides the greatest evidence to support the theory.
Hubbert, in his 1956 paper, made two predictions for the US conventional oil production (crude oil + condensate):
* a low estimate: a logistic curve with a logistic growth rate equals to 6%, an ultimate resource equals to 150 Giga-barrels (Gb) and a peak in 1965.
* a high estimate: a logistic curve with a logistic growth rate equals to 6% and ultimate resource equals to 200 Giga-barrels and a peak in 1970.
Forty years later, the high estimate has been proven to be remarkably accurate in terms of production level and cumulative production. In 2005, the US production was 1.55 Gb with a cumulative production of 176.4 Gb (crude oil + condensate) and the Hubbert model is predicting 1.17 Gb (24% lower) and 178.2 Gb respectively.