Editing Oil shale (section)

== Resource ==
{{Main|Oil shale reserves}}
[[File:OilShaleFossilsEstonia.jpg|thumb|Fossils in Ordovician oil shale (kukersite), northern Estonia]]

As source rocks for most conventional [[Petroleum reservoir|oil reservoir]]s, oil shale deposits are found in all world oil provinces, although most of them are too deep to be exploited economically.<ref name="weo2010 165">[[#weo2010|IEA (2010)]], pp. 165–169</ref>  As with all oil and gas resources, analysts distinguish between oil shale resources and oil shale reserves. "Resources" refer to all oil shale deposits, while "reserves" represent those deposits from which producers can extract oil shale economically using existing technology. Since extraction technologies develop continuously, planners can only estimate the amount of recoverable kerogen.<ref name=csm>
{{Cite journal
 | last = Youngquist | first = Walter
 | title = Shale Oil – The Elusive Energy
 | journal = Hubbert Center Newsletter
 | publisher = [[Colorado School of Mines]]
 | issue = 4
 | year = 1998
 | url= http://hubbert.mines.edu/news/Youngquist_98-4.pdf
 | access-date =17 April 2008}}
</ref><ref name=dyni/> Although resources of oil shale occur in many countries, only 33&nbsp;countries possess known deposits of potential economic value.<ref name=symposium>
{{Cite journal
 | last = Brendow | first = K.
 | title = Global oil shale issues and perspectives. Synthesis of the Symposium on Oil Shale. 18–19 November, Tallinn
 | journal = [[Oil Shale (journal)|Oil Shale. A Scientific-Technical Journal]]
 | publisher = Estonian Academy Publishers
 | volume =20
 | issue =1
 | pages =81–92
 | year = 2003
 | doi = 10.3176/oil.2003.1.09
 | s2cid = 252652047
 | url=http://www.kirj.ee/public/oilshale/9_brendow_1_03.pdf
 | issn = 0208-189X
 | access-date =21 July 2007}}
</ref><ref name=china>
{{Cite journal
 | last1 =Qian | first1 =Jialin
 | last2 =Wang | first2 =Jianqiu
 | last3 =Li | first3 =Shuyuan
 | title =Oil Shale Development in China
 | journal = [[Oil Shale (journal)|Oil Shale. A Scientific-Technical Journal]]
 | publisher = Estonian Academy Publishers
 | volume =20
 | issue =3
 | pages =356–359
 | year =2003
 | doi =10.3176/oil.2003.3S.08
 | s2cid =130553387
 | url=http://www.kirj.ee/public/oilshale/9_qian_2003_3s.pdf
 | issn = 0208-189X
 | access-date =16 June 2007}}
</ref> Well-explored deposits, potentially classifiable as reserves, include the [[Green River Formation|Green River]] deposits in the [[western United States]], the Tertiary deposits in [[Queensland]], Australia, deposits in Sweden and Estonia, the El-Lajjun deposit in Jordan, and deposits in France, Germany, Brazil, China, southern Mongolia and Russia. These deposits have given rise to expectations of yielding at least 40&nbsp;liters of shale oil per tonne of oil shale, using the [[Fischer Assay]].<ref name=dyni/><ref name=turkey/>

A 2016 estimate set the total world resources of oil shale equivalent to yield of {{convert|6.05|Toilbbl|e9m3|abbr=off}} of shale oil, with the largest resource deposits in the United States accounting more than 80% of the world total resource.<ref name="wec2016 16"/>  For comparison, at the same time the world's proven [[oil reserves]] are estimated to be {{convert|1.6976|Toilbbl|abbr=off}}.<ref name="wec2016 14">[[#wec2016|WEC (2016)]], p. 14</ref> The largest deposits in the world occur in the United States in the Green River Formation, which covers portions of [[Colorado]], [[Utah]], and [[Wyoming]]; about 70% of this resource lies on land owned or managed by the United States federal government.<ref>{{Cite web
 |title        = About Oil Shale
 |url          = http://ostseis.anl.gov/guide/oilshale/index.cfm
 |publisher    = [[Argonne National Laboratory]]
 |access-date   = 20 October 2007
 |archive-url  = https://web.archive.org/web/20071013075329/http://ostseis.anl.gov/guide/oilshale/index.cfm
 |archive-date = 13 October 2007
 |url-status     = dead
 |df           = dmy-all
}}</ref> Deposits in the United States constitute more than 80% of world resources; other significant resource holders being China, Russia, and Brazil.<ref name="wec2016 16"/> The amount of economically recoverable oil shale is unknown.<ref name="weo2010 165" />