Western Hemisphere Subtotal 67 Billion Barrels
There is good agreement between forecast future discoveries by region and the total extrapolated from the global creaming curve.
The principle flaws or criticisms of extrapolation from creaming curves include: 1) The creaming curve represents only past experience, and doesn't include potential from new regions. Large oilfields might be found offshore Greenland, in parts of the Pacific, the Black Sea, the Arctic, or even in the Eastern Gulf of Mexico, 2) The creaming curve doesn't account for possible new exploration or production technologies, or 3) The creaming curve doesn't account for large volumes on unconventional resources, such as shale oil or tar sands.
It is possible that any of these, or some combination of these, may result in a reversal of historical trends, and that large and economic volumes of oil will be found and brought to market.
However, it is worth remembering that the historical record ALREADY includes discoveries and production from new regions, notably the revolutions of offshore exploration, deep water exploration, and arctic exploration. Substantial improvements in technology are also already part of the existing historical record. And while unconventional resources are only beginning to have a substantial impact on global production, realizing large gains from these resources will require the slow accumulation of financial and physical capital, and may be subject to limits in the availability of enabling resources, such as natural gas and water.
In sum, historical trends of exploration results (particularly on the global scale) form a legitimate basis for forecasting the volume of future oil discoveries.
As a final point, we should compare our forecast of new discoveries to the year 2030 to the volume expected to be produced through the year 2030. Global production in 2010 was about 31.7 billion barrels (about 87 million barrels per day). Assuming the IEA (International Energy Agency) estimate of 1.4% annual growth in production and demand, production in the year 2030 will total 41.9 billion barrels. And cumulative production from 2010 to 2030 will be 768 billion barrels. Production to the year 2030 will exceed the volume of new reserves discovered by about 4-fold. There is no reasonable extrapolation of historical discovery trends that would allow reserve replacement on a global scale.