Geology, geography and global energy

Scientific and Technical Journal

To the prospects of oil - and gas bearing capacity of the Northern part of Zilair synclinorium

2013. №3, pp. 9-26

Kazantseva Tamara T.  - D.Sc. in Geology and Mineralogy, Academician of the Academy of Sciences of the Republic of Bashkortostan, Institution of Russian Academy of Sciences Institute of geology of the Ufimian scientific centre, 16/2 K. Marx st., Ufa, Republic of Bashkortostan, 450000,,

The sediments of the Frasnian layer domanik of Upper Devonian are located within the platform Bashkiria and Pre-Ural foredeep. Peculiarities of their content, stratigraphic location, the structural characteristics and oil-and-gas-generating properties have been described in details in multiple publications. To the contrary, formations of infradomanik of Afonin horizon of the Eifelian stage (Middle Devonian) known to be the facial analog of the Frasnian layer domanik have been observed in single locations of the Eastern Pre-Ural. At the same time, nowadays the search for the slate-like structure of oil-and-gas-generating series became urgent due to the great importance of the slate-like gas worldwide. The present study presents the author’s data of infradomanik expansion, its development in the platform Paleozoic open-casts sufficiently characterized by the guided fauna on the East, on the Western descent of the Southern Ural, in the Northern part of Zilair synclinorium. The prospects of oil-and-gas-bearing capacity of the studied region have been validated on the basis of the structural and stratigraphic geology study, as well as of layer-wise description of several regional successions from Asha series stacks till Famennian layer of Upper Devonian. The general geological state of the mentioned synclinorium, the peculiarities of its structure, increased rocks bituminosity within the Paleozoic, the slate structure of distinct horizons (Afonin horizon, in particular), the presence of layers possessing collector properties and caprocks give the possibility to suggest the mentioned territory as the perspective one for the search of carbohydrate deposits. The peculiar attention was placed toward infradomanik due to its consideration as oil-and-gas-generating object analogous to the Frasnian layer domanik of Upper Devonian. The main attention was directed toward its areal expansion and sealing by retainers of ophiolite allochthone of the Kraka mountains consisting of ultrabasite rocks of rather small thickness. They were serpentinized at the edge and bottom zones and completely transformed into serpentinites. Serpentine possessing impenetrability at high extent due to the crystal matrix structure is the major rock-generating mineral of serpentinites.

Key words: domanikits,oil- and gas-bearing capacity,Afonin horizon,carbonates,mudstones,organic substance,allochthone