Oil shale
![](http://upload.wikimedia.org/wikipedia/commons/a/a3/Oilshale.jpg)
Oil shale is a fine-grained sedimentary rock, containing significant amounts of kerogen (a solid mixture of organic chemical compounds), from which liquid hydrocarbons can be manufactured. The name oil shale is something of a misnomer as the rock is not necessarily a shale and the hydrocarbon in it is not truly oil.[1] Deposits of oil shale are located around the world, including major deposits in the United States. Global deposits are estimated as equivalent to 2.8–3.3 trillion (2.8–3.3 x 1012) barrels of recoverable oil.[2][3][4][5]
The kerogen in oil shale can be converted to synthetic crude oil through the chemical process of pyrolysis. When heated to a sufficiently high temperature a vapor is driven off which can be distilled (retorted) to yield a petroleum-like shale oil—a form of non-conventional oil—and combustible shale gas (shale gas can also refer to gas occurring naturally in shales). Oil shale can also be burnt directly as a low-grade fuel for power generation and heating purposes, and can be used as a raw material in the chemical and construction materials industries.[6][7]
Oil shale has gained attention as an energy resource as the price of conventional sources of petroleum has risen, and as a way to secure independence from external suppliers of energy.[8][9]
Geology
Oil shale is an organic-rich sedimentary rock, which belongs to the group of sapropel fuels.[10] It is differentiated from bitumen-impregnated rocks (tar sands and petroleum reservoir rocks), humic coals and carbonaceous shale.[1] In oil shales, the kerogen has not yet been naturally cooked into petroleum by heat and pressure.[11]
Oil shales vary considerably in their mineral content, chemical composition, age, type of kerogen, and depositional history, and are derived from a number of different organisms.[12] One classification scheme is based on their composition, dividing them into three categories: Carbonate-rich shales, siliceous shales, and cannel shales.[13] Another classification is based on kerogen type, which is a function of the hydrogen, carbon, and oxygen content of their original organic matter.[12] Oil shales are also classified as terrestrial, lacustrine, or marine, based on the environment where the initial biomass was deposited. [6]
Reserves
Although oil shale resources occur in many countries, only 33 countries possess deposits of possible economic value.[14][15] The largest deposits in the world are found in the United States in the Green River basin, which covers portions of Colorado, Utah, and Wyoming; about 70 % of this resource is located on federally-owned or managed land.[16] Total world resources of oil shale were estimated in 2005 at 411 gigatons (411 x 109 tonnes), which is enough to yield 2.8 to 3.3 trillion (2.8 to 3.3 x 1012) U.S. barrels.[2][3][4][5] Among those, the United States accounts for 62 % of world resources; together, the United States, Russia and Brazil account for 86 % of the world's resources in terms of shale oil content.[14] These figures are considered tentative, as several deposits have not yet been explored.[6][17]
History
Oil shale has been in use since ancient times, since it will generally burn without any processing. However, modern industrial oil shale mining began in 1837 in Autun, France, followed by Scotland, Germany, and several other countries.[18][19] The first oil shale retort was constructed in the United States in 1855.[19] The oil shale industry started growing just before World War I, but was abandoned in most countries after World War II because of high processing costs and the availability of cheaper petroleum.[6][19][18][20] Following the 1973 oil crisis, world production of oil shale reached a peak of 46 million tonnes in 1980 before falling to about 16 million tonnes in 2000, due to competition from conventional petroleum which had remained at under US$30/barrel.[14][21] The global oil shale industry began to revive in the mid-1990s. In 2003, an oil shale development program was restarted in the United States, and a commercial leasing program for oil shale and tar sand was introduced in 2005.[22][23]
Extraction and processing
Oil shale is usually mined and then transported to be processed elsewhere (ex situ), although several newer technologies extract its useful components underground (in situ).[24] Several mining methods are used, which all begin by fragmenting the oil shale, so that it may be transported to a power plant or a retorting facility. The most-often used methods of surface mining are open pit mining and strip mining, while underground mining of oil shale employs the room-and-pillar method.[25]
After access to the shale is gained, either on-site or off-site, its kerogen is converted to synthetic crude oil and shale gas through the chemical process of pyrolysis. Most conversion technologies involve heating shale in the absence of oxygen to a temperature at which kerogen is decomposed (pyrolysed) into gas, condensable oil, and a solid residue; this takes place usually at 450 °C (842 °F) to 500 °C (932 °F) [26] Other technologies are based on the solvent processes of reactive fluids.[27]
Industry
Currently, oil shale is used industrially in Brazil, China, Estonia and to some extent in Germany, Israel, and Russia. At the beginning of the 21st century, several additional countries were assessing their reserves or had built experimental production plants, while others had phased out their oil shale industry.[19] Oil shales are used for oil production in Estonia, Brazil, and China, for power generation in Estonia, China, Israel, and Germany, for cement production in Estonia, Germany, and China, and by chemical industries in Estonia and Russia.[28][29][20] At present, Estonia alone accounts for about 70 % of the world's oil shale production.[30]
Applications and products
Oil shale can be used as a fuel for thermal power plants, where, like coal, it is burned to drive steam turbines; some of these plants employ the resulting heat for district heating of homes and businesses. Sizable oil shale-fired power plants are located in Estonia, which has an installed capacity of 2,967 megawatts (MW), Israel (12.5 MW), China (12 MW), and Germany (9.9 MW).[14][31] While some countries, such as Romania, have shut down their oil shale-fired power plants, others, including Russia, have switched to other fuel sources. Jordan and Egypt are planning to construct new oil shale-fired power plants, while Canada and Turkey plan to burn oil shale along with coal for power generation.[14] ||[32][7] Oil shale is used as the main fuel for the power generation only in Estonia, where its oil shale-fired Narva Power Plants accounted for 95 % of electrical generation in 2005.[33]
In addition to its use as a fuel, oil shale may also be used for production of specialty carbon fibers, adsorbent carbons, carbon black, phenols, resins, glues, tanning agents, mastic, road bitumen, cement, bricks, construction and decorative blocks, soil additives, fertilizers, rock wool insulation, glass, and pharmaceutical products.[34] However, oil shale use for production of these items is still small or only in its experimental stages.[6][7] Some oil shales yield sulfur, ammonia, alumina, soda ash, uranium, and nahcolite as shale oil extraction byproducts. Between 1946 and 1952, a marine type of Dictyonema shale was used for uranium production in Sillamäe, Estonia, and between 1950 and 1989 alum shale was used in Sweden for the same purposes.[6] Another of its proposed uses is as a substitute for natural gas, but at current price levels this is not economical.[35][36]
The oil derived from oil shale is not a direct substitute for crude oil in all applications. By comparison with West Texas Intermediate, the benchmark standard for crude oil in the futures contract market, shale oil sulfur content ranges up to 9.5% by weight, where West Texas Intermediate's sulfur content is limited to no more than 0.42%.[37][38] Shale oil also contains higher concentrations of olefins, oxygen, and nitrogen than conventional crude oil, as well as higher viscosities. It does not contain the full range of hydrocarbons used in modern gasoline production.[4]
Economics
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Oil_Prices_Medium_Term.png/300px-Oil_Prices_Medium_Term.png)
The various attempts to develop the world's oil shale deposits, over a period of over 150 years, have experienced successes when the cost of shale oil production in a given region was less than the price of crude oil or its other substitutes.[39] According to a survey conducted by the RAND Corporation, a surface retorting complex (comprising a mine, retorting plant, upgrading plant, supporting utilities, and spent shale reclamation) is unlikely to be profitable in the United States until crude oil prices range between US$70 to US$95 per barrel (in 2005 dollars).[25] Once commercial plants are in operation and experience-based learning takes place, costs are expected to decline in 12 years to US$35–US$48 per barrel. After production of 1,000 million barrels, costs are estimated to decline further to US$30 – US$40 per barrel.[34] Royal Dutch Shell has announced that its in-situ extraction technology in Colorado could be competitive at prices over US$30 per barrel, while other technologies at full-scale production assert profitability at oil prices even lower than US$20 per barrel.[40][41][42][43] To increase the efficiency of oil shale retorting, several co-pyrolysis processes have been proposed and tested.[44][45][46][47][48]
A critical measure of the viability of oil shale as an energy source is the ratio of the energy produced by the shale to the energy used in its mining and processing, a ratio known as "Energy Returned on Energy Invested" (EROEI). A 1984 study estimated the EROEI of the various known oil shale deposits as varying between 0.7-13.3.[49] Royal Dutch Shell has reported an EROEI of three to four on its in-situ development, Mahogany Research Project.[50][40][51] An additional economic consideration is the water needed in the oil shale retorting process, which may pose a problem in areas with water scarcity.
Environmental considerations
The oil shale industry can have a negative impact on the surrounding environments, if the risks associated with it are not managed correctly. Environmental concerns raised over the extraction of shale oil have caused the oil shale industry in some countries to come to a halt.[21][52] Opposition to the proposed Stuart Oil Shale Project in Australia resulted in its being put on hold in 2004.[52][53][54]
Surface-mining of oil shale deposits has the same environmental impacts as those of open-pit mining. In addition, combustion and thermal processing generate waste material, and the atmospheric emissions include carbon dioxide, a major greenhouse gas. Experimental in-situ conversion processes and carbon capture and storage technologies may reduce some of these concerns in the future, but at the same time they may cause other problems, including groundwater pollution.[55]
See also
- Abiogenic petroleum origin
- Bituminous coal
- Core research center
- Future energy development
- Green River Basin
- Mahogany research project
- Mitigation of peak oil
- Non-conventional oil
- Oil reserves
- Synthetic Liquid Fuels Program
- Tar sands
- World energy resources and consumption
Footnotes
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- ^ a b WEC (2007), p. 101-102
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Andrews, Anthony (2006-04-13). "Oil Shale: History, Incentives, and Policy" (PDF). Congressional Research Service. Retrieved 2007-06-25.
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Dyni, John R. (2006). "Geology and resources of some world oil-shale deposits. Scientific Investigations Report 2005–5294" (PDF). U.S. Department of the Interior. U.S. Geological Survey. Retrieved 2007-07-09.
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(help) - ^ a b c WEC (2004), p 85-90
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"Energy Security of Estonia" (PDF). Estonian Foreign Policy Institute. September 2006. Retrieved 2007-10-20.
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Ots, Arvo (2007-02-12). "Estonian oil shale properties and utilization in power plants" (PDF). Energetika. 53 (2). Lithuanian Academy of Sciences Publishers: 8–18. Retrieved 2007-11-07.
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Nield, Ted (2007-02-17). "Shale of the Century". Geological Society of London. Retrieved 2007-10-20.
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(help) - ^ a b Altun, N. E.; Hiçyilmaz, C.; Hwang, J.-Y.; Suat Bağci, A.; Kök, M. V. (2006). "Oil Shales in the world and Turkey; reserves, current situation and future prospects: a review" (PDF). Oil Shale. A Scientific-Technical Journal. 23 (3). Estonian Academy Publishers: 211–227. ISSN 0208-189X. Retrieved 2007-06-16.
- ^ Lee, Sunggyu (1990). Oil Shale Technology. CRC Press. p. 10. ISBN 0849346150. Retrieved 2007-07-09.
- ^ a b c d e Brendow, K. (2003). "Global oil shale issues and perspectives. Synthesis of the Symposium on Oil Shale. 18-19 November, Tallinn" (PDF). Oil Shale. A Scientific-Technical Journal. 20 (1). Estonian Academy Publishers: 81–92. ISSN 0208-189X. Retrieved 2007-07-21.
- ^ Qian, Jialin; Wang, Jianqiu; Li, Shuyuan (2003). "Oil Shale Development in China" (PDF). Oil Shale. A Scientific-Technical Journal. 20 (3). Estonian Academy Publishers: 356–359. ISSN 0208-189X. Retrieved 2007-06-16.
- ^ The Reserves in Colorada, if econimically feasible would produce more oil than the entire Middle East. Argonne National Laboratory. "About Oil Shale". Retrieved 2007-10-20.
- ^ WEC (2004), p.77
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Laherrère, Jean (2005). "Review on oil shale data" (PDF). Hubbert Peak. Retrieved 2007-06-17.
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Yin, Liang (2006-11-07). "Current status of oil shale industry in Fushun, China" (PDF). Amman, Jordan. Retrieved 2007-06-29.
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A. K. Burnham (2003-08-20). "Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-like Shale Oil" (PDF). Lawrence Livermore National Laboratory. UCRL-ID-155045. Retrieved 2007-06-28.
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"Nominations for Oil Shale Research Leases Demonstrate Significant Interest in Advancing Energy Technology. Press release". Bureau of Land Management. 2005-09-20. Retrieved 2007-07-10.
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(help) - ^ "What's in the Oil Shale and Tar Sands Leasing Programmatic EIS". Oil Shale and Tar Sands Leasing Programmatic EIS Information Center. Retrieved 2007-07-10.
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Burnham, Alan K.; McConaghy, James R. (2006-10-16). "Comparison of the Acceptability of Various Oil Shale Processes" (PDF). Golden: 26th Oil Shale Symposium. UCRL-CONF-226717. Retrieved 2007-06-23.
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Bartis, James T.; LaTourrette, Tom; Dixon, Lloyd; Peterson, D.J.; Cecchine, Gary (2005). "Oil Shale Development in the United States. Prospects and Policy Issues. Prepared for the National Energy Technology Laboratory of the U.S. Department of Energy" (PDF). The RAND Corporation. ISBN 978-0-8330-3848-7. Retrieved 2007-06-29.
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(help) - ^ Youngquist, Walter (1998). "Shale Oil - The Elusive Energy" (PDF). Hubbert Center Newsletter (4). Colorado School of Mines. Retrieved 2007-10-21.
- ^ Koel, Mihkel (1999). "Estonian oil shale". Oil Shale. A Scientific-Technical Journal (Extra). Estonian Academy Publishers. ISSN 0208-189X. Retrieved 2007-07-21.
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"Non-Nuclear Energy Research in Europe – A comparative study. Country Reports A – I. Volume 2" (PDF). European Commission. Directorate-General for Research. 2005. EUR 21614/2. Retrieved 2007-06-29.
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Qian, Jialin; Wang, Jianqiu; Li, Shuyuan. "One Year's Progress in the Chinese Oil Shale Business" (PDF). China University of Petroleum. Retrieved 2007-10-06.
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Hamarneh, Yousef (1998; 2006). "Oil Shale Resources Development In Jordan" (PDF). Amman: Natural Resources Authority of Jordan. Retrieved 2007-06-16.
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"Estonian Energy in Figures 2005" (PDF). Ministry of Economic Affairs and Communications. 2006. Retrieved 2007-10-22.
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(help) - ^ a b "A study on the EU oil shale industry viewed in the light of the Estonian experience. A report by EASAC to the Committee on Industry, Research and Energy of the European Parliament" (PDF). European Academies Science Advisory Council. May 2007. Retrieved 2007-11-25.
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(help) - ^ Schora, F. C.; Tarman, P. B.; Feldkirchner, H. L.; Weil, S. A. (1976), "Hydrocarbon fuels from oil shale", Proceedings, 1, American Institute of Chemical Engineers: 325–330, A77-12662 02-44
- ^ Ingo Valgma. "Map of oil shale mining history in Estonia". Mining Institute of Tallinn Technical University. Retrieved 2007-07-21.
- ^ Dyni, John R. (1983-04-01). "Distribution and origin of sulfur in Colorado oil shale". 16th Oil Shale Symposium Proceedings. U.S. Geological Survey,: 144–159. CONF-830434-. Retrieved 2007-10-22.
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Al-Harahsheh, Adnan; Al-Otoom, Awni Y.; Shawabkeh, Reyad A. (2003-10-16). "Sulfur distribution in the oil fractions obtained by thermal cracking of Jordanian El-Lajjun oil Shale". Energy. Elsevier (published November 2005). Retrieved 2007-10-22.
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Robert Rapier (2006-06-12). "Oil Shale Development Imminent". R-Squared Energy Blog. Retrieved 2007-06-22.
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Linda Seebach (2005-09-02). "Shell's ingenious approach to oil shale is pretty slick". Rocky Mountain News. Retrieved 2007-06-02.
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(help) - ^ Schmidt, S. J. (2003). "New directions for shale oil:path to a secure new oil supply well into this century: on the example of Australia" (PDF). Oil Shale. A Scientific-Technical Journal. 20 (3). Estonian Academy Publishers: 333–346. ISSN 0208-189X. Retrieved 2007-06-02.
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Leah Krauss (2006-11-07). "Analysis: Israel sees shale replacing oil". United Press International. Retrieved 2007-07-29.
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"Strategic Significance of America's Oil Shale Resource. Volume II Oil Shale Resources, Technology and Economics" (PDF). United States Department of Energy. 2004. Retrieved 2007-06-23.
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Tiikma, Laine; Johannes, Ille; Pryadka, Natalja (2002). "Co-pyrolysis of waste plastics with oil shale". Retrieved 2007-10-20.
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(help) - ^ Tiikma, Laine; Johannes, Ille; Luik, Hans (March 2006). "Fixation of chlorine evolved in pyrolysis of PVC waste by Estonian oil shales". Journal of Analytical and Applied Pyrolysis. Retrieved 2007-10-20.
- ^ Veski, R.; Palu, V.; Kruusement, K. (2006). "Co-liquefaction of kukersite oil shale and pine wood in supercritical water" (PDF). Oil Shale. A Scientific-Technical Journal. 23 (3). Estonian Academy Publishers: 236–248. ISSN 0208-189X. Retrieved 2007-06-16.
- ^ Aboulkas, A.; El Harfi, K.; El Bouadili, A.; Benchanaa, M.; Mokhlisse, A.; Outzourit, A. (2007). "Kinetics of co-pyrolysis of Tarfaya (Morocco) oil shale with high-density polyethylene" (PDF). Oil Shale. A Scientific-Technical Journal. 24 (1). Estonian Academy Publishers: 15–33. ISSN 0208-189X. Retrieved 2007-06-16.
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Cleveland, Cutler J.; Costanza, Robert; Hall, Charles A. S.; Kaufmann, Robert (1984-08-31). "Energy and the U.S. Economy: A Biophysical Perspective" (PDF). Science. 225 (4665). American Association for the Advancement of Science: 890–897. ISSN: 00368075. Retrieved 2007-08-28.
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"Oil Shale Test Project. Oil Shale Research and Development Project" (PDF). Shell Frontier Oil and Gas Inc. 2006-02-15. Retrieved 2007-06-30.
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Spencer Reiss (2005-12-13). "Tapping the Rock Field". WIRED Magazine. Retrieved 2007-08-27.
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Greenpeace Australia Pacific (2005-03-03). "Climate-changing shale oil industry stopped". Retrieved 2007-06-28.
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Renato Orsato (2004). "Eco-Activism: Greenpeace, the Oil Industry and the Stuart Oil Shale Project in Australia". Retrieved 2007-10-20.
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"Greenpeace happy with part closure of shale oil plant". 2004-07-22. Retrieved 2007-10-20.
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Jim Bartis, RAND Corporation (2006-10-26). "Unconventional Liquid Fuels Overview. 2006 Boston World Oil Conference" (PDF). Association for the Study of Peak Oil & Gas - USA. Retrieved 2007-06-28.
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References
- Survey of energy resources (PDF) (20 ed.). World Energy Council (WEC). 2004. ISBN 9780080444109. Retrieved 2007-07-20.
- Survey of energy resources (PDF) (21 ed.). World Energy Council (WEC). 2007. ISBN 0946121265. Retrieved 2007-11-13.
External links
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- Oil Shale. A Scientific-Technical Journal. Estonian Academy Publishers. ISSN 0208-189X
- Selected online oil shale publications by the U.S. Geological Survey
- Ullmann's Encyclopedia of Industrial Chemistry article on oil shale (requires registration). Retrieved on 2007-08-04
- The Scandinavian Alum Shales. 1985. p. 49. ISBN 9171583343. Retrieved 2007-10-20.
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ignored (help) - Mihkel Koel (1999). "Estonian oil shale". Retrieved 2007-10-20.
- 27th Oil Shale Symposium
- Daniel Fine (2007-03-08). "Oil Shale: Toward a Strategic Unconventional Fuels Supply Policy". Retrieved 2007-10-20.
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