Geology, geography and global energy

Scientific and Technical Journal

The Geoenvironmental and Geochemical Characteristics of the Caspian Sea: an Oil and Gas-filled Region

2012. №4, pp. 55-61

Serebryakov Andrey O. - Senior Lecture, Astrakhan State University, 20a Tatishchev st., Astrakhan, Russian Federation, 414000, geologi2007@yandex.ru

Abdrahmanova Nadiya R. - Post-graduate student, Astrakhan State University, 20a Tatishchev st., Astrakhan, Russian Federation, 414000, geologi2007@yandex.ru

The article relates that the Vostochnokaspiysky oil and gas region runs from the Caspian Sea through Mangyshlak and adjacent areas. The Eastern Caspian has a geological context encompassing rocks from the Paleozoic, Triassic, Jurassic, Cretaceous and Tertiary ages. The paper adds that oil deposits are generally confined to the Jurassic age sandstones, while gas deposits are normally found in the Cretaceous. Oil and gas flows have issued from the Lower Cretaceous deposits of Dunga-Espelisay, located in the western part of the Sea’s Beke-Bashkudukskogo periclinal shaft. The Eastern Caspian oil fields contain large multilayer deposits. A characteristic feature is the high wax content (from 10 to 20%). This determines their oil pour point (25–30° C), making their pumping a difficult feat to accomplish. In low-sulfur oil (from 0.20–0.45% sulfur), the tar content – which includes silica gel resins – is only 1–17.5%. The output fractions, for boiling up to 200° C, are from 13–19.5%, while for boiling up to 350° C they are from 31–40.5%. The document notes that gasoline fractions boiling in the range of n. C. to 200° C are dominated by paraffinic hydrocarbons, ranging from 63–73% and having a low aromatic content of 6-8%. The pure octane number of the fractions runs from 35-38%. Finally, the blueprint says that good raw material for catalytic reforming can be obtained from boiling oil fractions at a temperature of 62–120° C. The raw material generally contains 29–37% naphthenes (cycloalkane hydrocarbons) and traces of sulfur.

Key words: oil,gas,oil and gas region Vostochnokaspiysky,fallow age,Gremyachinskoye field

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