Oil shale reserves
Oil shale deposits range from small presently economically unrecoverable to large potentially recoverable resources.
[2] For comparison, at the same time the world's proven oil reserves are estimated to be 1.6976 trillion barrels (269.90 billion cubic metres).
[8] Oil shale formation takes place in a number of depositional settings and has considerable compositional variation.
Much of the organic matter in oil shale is of algal origin, but may also include remains of vascular land plants.
[10][7] Most oil shale deposits were formed during Middle Cambrian, Early and Middle Ordovician, Late Devonian, Late Jurassic, and Paleogene times through burial by sedimentary loading on top of the algal swamp deposits, resulting in conversion of the organic matter to kerogen by diagenetic processes.
[3][13] There are a wide variety of extraction methods, which yield significantly different quantities of useful oil.
[14] A 2008 estimate set the total world resources of oil shale at 689 gigatones—equivalent to yield of 4.8 trillion barrels (760 billion cubic metres) of shale oil, with the largest reserves in the United States, which is thought to have 3.7 trillion barrels (590 billion cubic metres), though only a part of it is recoverable.
[15] According to the 2010 World Energy Outlook by the International Energy Agency, the world oil shale resources may be equivalent of more than 5 trillion barrels (790 billion cubic metres) of oil in place of which more than 1 trillion barrels (160 billion cubic metres) may be technically recoverable.
[2] For comparison, at the same time the world's proven oil reserves are estimated to be 1.6976 trillion barrels (269.90 billion cubic metres).
They may also resemble the deposits found along the eastern American seaboard, which were the product of a shallow sea, in that they may be quite thin but laterally expansive, covering thousands of square kilometers.
Although reserves in Tarfaya and Timahdit are well explored, the commercial exploitation has not started yet and only a limited program of laboratory and pilot-plant research has been undertaken.
[15][14] The principal Chinese oil shale deposits and production lie in Fushun and Liaoning; others are located in Maoming in Guangdong, Huadian in Jilin, Heilongjiang, and Shandong.
[7] According to some reports, also Uzbekistan has major oil shale deposits of 47 billion metric tons, mainly located at Sangruntau but also at Baysun, Jam, Urtabulak, Aktau, Uchkyr and Kulbeshkak.
There are oil shale reserves also in Germany, Luxembourg, Spain, Bulgaria, Hungary, Poland, Serbia, Austria, Albania, and Romania.
[7][20] Most of Israel's deposits are located in the Rotem Basin region of the northern Negev desert near the Dead Sea.
[7][21] At 301 billion metric tons, as estimated in 2005, the oil shale deposits in the United States are the largest in the world.
[24] In 2010, it was estimated by the World Energy Council that the United States resource could be equal to 3.7 trillion barrels (590 billion cubic metres) of shale oil.
[15] In 2016, their estimation was that the resource may even consist of up to 6 trillion barrels (950 billion cubic metres) of shale oil.
