Estimated ultimately recoverable reserves

Whatever the ultimate recoverable reserves may be, current estimates of proven reserves of natural gas comprise about 50 percent of U.S. proven reserves of total petroleum energy. 

A final term used to define total oil reserves is estimated ultimately recoverable (EUR) reserves, which includes cumulative production to date, current reserve estimates, and those reserves that remain to be found and exploited. In Figure 2.11, the EUR would make up a portion of the resource base plus cumulative production to date. 

Estimated ultimately recoverable (EUR)—technical term describing the total amount of crude oil that will ultimately be recovered. This number is difficult to calculate and fluctuates frequently. Oil reserves are typically underestimated and are adjusted as additional information and new technology become available. Most experts believe that 1.2 trillion barrels (without oil sands) and 3.74 trillion barrels (with oil sands) reflect the world s total endowment of oil. 

A number of trends are anticipated in oil production in the next 20 years, including the Big Rollover (when oil production peaks, and begins to decline). Many oil experts believe this will occur within the next 10 to 15 years. Most experts agree that the earth s estimated ultimately recoverable oil reserves are about 1.2 trillion (short-scale) barrels without oil sands and 3.74 trillion barrels with oil sands. Present global consumption is 84.6 million barrels a day or 30.7 billion barrels per year. The United States produces 4.9 billion barrels per year and refines more than 8.5 billion barrels per year, while importing more than 16 billion barrels per year for commercial needs. These reserves cannot be replaced once they are used, and some projections indicate that, at our present rate of consumption, our oil reserves will be depleted during the next 38.8 years to 122.2 years. At the end of 2008, the world had consumed 1.12 trillion barrels. 

The following terms are often used in the context of quantifying reserves and resources of fossil fuels the Estimated Ultimate Recovery (EUR), also called Ultimate Recoverable Resources (URR), is the sum of past cumulative production, proved reserves at the time of estimation and the possibly recoverable fraction of undiscovered resources. The remaining potential, i.e., the sum of reserves and resources, is the total amount of an energy source that is still to be recovered. The mid-depletion point is the point of time when approximately 50% of the EUR (at field, country or world level) has been produced. 

FIGURE F-2 Annual production scenarios for the mean resource estimate showing sharp and rounded peaks, 1900-2125. Growth rate leading to either peak is 2 percent. Sharp peak occurs in 2037 followed by decline at reserve to production ratio of 10. Rounded peak occurs in 2030 followed by decline at 5 percent. U.S. volumes were added to the USGS (2000) foreign volumes estimate to obtain a world total of 3,000 billion barrels (mean value) of ultimately recoverable resources. SOURCE EIA (2000). 

In April 1969 the Canadian Petroleum Association estimated the ultimate potential raw recoverable natural gas reserves of Canada to be 720.9 Tcf (at 14.73 psia and 60°F). If the total raw recoverable gas discovered through 1970 is subtracted from this value, a remaining undiscovered potential of 634.8 Tcf of raw gas is derived. Much of this undiscovered potential is attributed to Canada s frontier areas comprised of Northern Canada, Arctic Islands, Mackenzie Delta, Hudson Bay, and the continental shelf areas off the Atlantic, Paciflc, and Arctic Coasts. 

Estimates suggest there could be as many as 1.7 trillion barrels of oil trapped in the ground in Alberta (Woynillowicz et al. 2005), more than the total oil reserve estimates discussed earlier. However, current estimates suggest that out of this, only 315 billion barrels ultimately may be recoverable, and only 174 billion barrels can be classified as "reserves" based on existing technology and economics. Nevertheless, this is a very large reserve. Including the oil sand reserves, Canada is second only to Saudi Arabia in reserves. ... 

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