The majority of researchers believe that formation of heavy oil traps in Permian deposits of Cheremshano-Bastrykskaya area is attributed to Devonian and Carboniferous oil reservoirs which resulted fr om vertical migration of hydrocarbons through natural fractures and faults. Heavy oil traps are originally related to coastal-marine sands of Late Ufimian basin wh ere coastal sand bars formed due to geodynamic processes.
To analyze heavy oil traps genesis in Cheremshano-Bastrykskaya area, neotectonic investigations were carried out on top of Asselian deposits and the topographical relief. Identifying the base of Sheshminskian anticlinal structures in Lower Permian deposits has been attempted, involving studies of 73 heavy oil traps.
Correlation of Sheshminskian anticlines horizontal location with neotectonic genesis of Asselian deposits showed that most of these structures have no base in the underlying Permian deposits and can be classified as non-tectonic structures. Coincidence of sand unit top and overburden rock structural geometries is attributed to irregular compaction of lithologically different rocks, rather than to tectonic processes.
The initial stage of Permian deposits topography formation is associated with enveloping the core of reef carboniferous structures with younger rocks; or it may attributed to some other sedimentary processes or to the buried paleogeomorphic features reflected on the ground surface.
Suspending heavy-oil production will entail changes in oil traps location. Recommencing of production will require identifying their horizontal location, and this data can be provided by neotectonic investigations.
References
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2. Uspenskiy B.V., Valeeva I.F., Geologiya mestorozhdeniy prirodnykh bitumov Respubliki Tatarstan (Geology of natural bitumen deposits of the Republic of Tatarstan), Kazan': GART Publ., 2008, 347 p.
3. Uspenskiy B.V., Borovskiy M.Ya., Vafin R.F., Petrov S.I., Geologicheskie kriterii i geofizicheskie metody podgotovki mestorozhdeniy prirodnykh bitumov k osvoeniyu (Geological criteria and geophysical methods for the preparation of natural bitumen deposits to development), Collected papers “Osobennosti razvedki i razrabotki mestorozhdeniy netraditsionnykh uglevodorodov” (Features of exploration and development of non-traditional hydrocarbons deposits), Proceedings of Scientific and Practical Conference, Kazan', 2–3 September 2015, Kazan': Ikhlas, 2015, pp. 294–296.
4. Mingazov M.N., Otsenka perspektiv neftenosnosti osadochnoy tolshchi Tatarstana na osnove neotektonicheskikh issledovaniy (Estimation of oil-bearing prospects of sedimentary thickness of Tatarstan on the basis of neotectonic studies), Moscow: Publ. of VNIIOENG, 2005, 160 p.
