The hidden treasure: locations of shale oil resources

Where shale oil resources are located worldwide?

Shale oil resources are still being appraised and assessed worldwide. Every year new estimates are released by national geological surveys of particular countries and oil exploration companies. The assessment efforts are a difficult task as black shales formed many times in the history of Earth, in various environments and locations around the world.

The map of the appraised and potential shale gas and oil resources is presented below.

Shale gas and oil occurrence areas worldwide (source: EIA/ARI, 2013)

The latest data on total and recoverable shale oil resources are presented in the report by EIA (US Energy Information Agency) and ARI (Advanced Research Institute) Amerykańska Agencja Informacji do Spraw Energii) i ARI (Advanced Research Institute) of 2013. Top ten countries in terms of estimated recoverable resources are presented in the report. The distribution of potentially recoverable resources is shown in the following graph (source: EIA/ARI, 2013).

Russia is the leading country with its recoverable resources estimated at 75 billion barrels of oil (bbl). Huge Russian resources make Europe the leading continent in terms of shale oil resources.

Europe is followed by:

North America (mainly US resources),
South America,
Asia,
Africa,
Australia.

Estimated shale oil resources and shale oil plays (basins in which shale sediments and the oil-forming organic matter debris were deposited) are discussed in the following sections.

East Europe

The largest European resources are found in Russia within the West Siberian Basin. They are located in the shales of the Late Jurassic/Early Cretaceous Bazhenov Formation. Both rocks and organic matter are of marine origin there.

Poland boasts the second largest shale oil reserves in East Europe. However, they are much smaller than the Siberian ones. Considering their importance, they are discussed in a separate chapter.

The resources of Russia's exclave of Kaliningrad and of Lithuania are an extension of Poland's Baltic Basin. Like in Poland, the oil occurs in a Silurian shale formation of marine origin.

The resources of Bulgaria, Romania and Ukraine are located in late Carboniferous shales of the Dnepr-Donetsk Basin, late Silurian shales of the Moesian Platform and in late Jurassic Etropole Formation. It should be noted that only condensate (a mix of oil and freshly formed gas) was reported from the Moesian Platform. All of these resources occur in rocks of marine origin.

West Europe

The largest oil reserves were found in the shales of Paris Basin (France). Crude oil occurs in both early Jurassic marine sediments and Carboniferous/Permian shales of lacustrine origin.

In the Netherlands, shale oil is potentially present in the West Netherlands Basin within Carboniferous lacustrine sediments of the Epen Formation, marine Carboniferous Geverik Formation and the Jurassic Posidonia shales.

In the United Kingdom, shale oil occurs in early Jurassic (Liassic) marine shales of the South England Basin.

In Germany, shale oil accumulations were found in the Lower Saxony Basin within marine Posidonia shale (Jurassic) and the Cretaceous lacustrine Wealden formation.

In Spain, oil condensate occurs in the Basque-Cantabrian Basin within Liassic (Lower Jurassic) marine sediments.

North America

The United States have the largest shale oil resources in North America.

The most important accumulations are those located in Montana and North Dakota within Devonian - early Carboniferous marine sediments of the Bakken Formation (Williston Basin). The Formation extends to Saskatchewan and Manitoba in Canada.

The world's only commercially developed shale oil plays are located in the Bakken Formation. In 2011, 2000 oil wells operated there producing up to 75.000 barrels of oil per day. According to the gazlupkowy.pl website, 233,000 barrels of oil were produced daily from the Bakken Formation.

In Mexico, shale oil resources are located in the following basins:

Burgos (middle to late Cretaceous Eagle Ford Shale Formation),
Southeastern Tampico Basin (the Jurassic Pimienta Formation),
Tuxpan Basin (middle Cretaceous Tamaulipas Formation and an extension of the Pimienta Formation),
Veracruz Basin, late Cretaceous Maltrata shales.

All of the Mexican shale oil formations are of marine origin.

Asia

China boasts the largest reserves in Asia. Shale oil accumulations occur in the Jianghan Basin within late Silurian Longmaxi Formation. These are almost exclusively oil condensate deposits.

In the Jianghan Basin, oil occurs within the Permian Qixia/Maokou Formation. Some of the deposits are located, again in the form of oil condensate, are located within the Greater Subei Basin (late Ordovician/early Silurian) and a late Permian shale formation. The sediments of these formations were deposited in marine environments. In the Chinese basins of Tarim (late Triassic Ketuer Formation), Junggar (Permian Pingdiquan/Lucaogou Formation and Triassic shales) and Songliao (Cretaceous Quingshankou Formation), oil is present in shale rocks of lacustrine origin.

Oil accumulations in the Indonesian basins of Sumatra, Kutei and Tarakan occur in lacustrine sediments, too. All of the Indonesian oil-bearing rocks formed in the Quaternary.

In Pakistan and India, shale oil accumulations occur in the following basins:

Cambay (late Cretaceous/Tertiary Cambay Formation),
Krishna-Godavari (Permian-Triassic),
Cauvery (Cretaceous Sattapadi-Andimadam Formation),
Damodar Valley Basin (Permian-Triassic Barren Measure Formation), and
Lower Indus Basin, late Cretaceous Sembar and Paleocene Ranikot Formations.

All of the above accumulations occur in marine sediments.

In Turkey, shale oil is present in the Southeast Anatolia Basin (marine Silurian-Devonian Dadas Formation) and in the Thrace Basin (Middle/Upper Eocene Hamitabat Formation). The deposits are of marine origin.

Mongolian oil shales are found in the East Gobi and Tamtsag Basins. In both basins, they occur as a single late Cretaceous Tsagaantsav Formation of lacustrine origin.

In Jordan, shale oil accumulations occur in the Wadi Sirhan Basin, within Silurian Batra Formation of marine origin.

South America

Argentina possesses the largest potential oil shale deposits in South America. Oil shales occur in the following four basins:

Neuquen (late Jurassic/early Cretaceous Los Molles and Vaca Muerta Formations),
San Jorge (Pozo D-129 Formation of lacustrine origin),
South Magellan Basin (Late Inoceramus- Magnas Verdes Formation),
Parana (Ponta Grossa Formation).

In Brazil, oil shales occur in the following basins:

Parana (Ponta Grossa Formation),
Solimões (Jandiatuba Formation)
Amazonia (Barreirinha Formation).

All of the above mentioned formations were deposited in a marine environment.

In Bolivia, Paraguay and Uruguay, the deposits occur within two huge basins:

Parana (Ponta Grossa and Cordobes Formations)
Chaco (Los Monos Formation).

The oil is present in Devonian shales deposited in a marine environment.

Chile's resources are located in late Cretaceous marine Estratos con Favrella Formation (the Magellan Basin).

Africa

Libya boasts the largest estimated shale oil resources of the African continent. They occur in the following basins:

Ghadames (Silurian Tannezulf Formation, a late Devonian formation),
Sirte (late Cretaceous Sirte/ Rachmat Shale and Etel Shale Formations),
Murzuq (an extension of the Silurian Tannezulf shale formation).

All of these formations were deposited in marine environments.

Algerian resources include primarily oil shales of the Ghadames Basin. Other Algerian basins (Illizi, Ahnet, Reggae, Tindouf) and the Silurian shale facies of the Ghadames Basin contain condensate rather than mature crude oil. All Algerian oil-or condensate-bearing shales were formed in marine environments.

Egyptian shale oil resources occur in marine Middle Jurassic Khatabha Formation that extends over four basins:

Abu Gharadig,
Shoushan-Matruh,
Alamein, and
Natrun.

In the former two basins oil occurs in the form of the condensate.

Tunisian shale oil resources are located in the Ghadames Basin that Tunisia shares with Libya. They occur in Silurian facies of the Tannezulf Formation (as condensate) and in late Devonian shales.

Late Silurian oil-bearing shales extend to Morocco (the Tindouf Basin).