Based on well log correlation in the interval fr om the base of the Domanic horizon of Middle Devonian sediments to the top of Vereiskian horizon of middle Carboniferous deposits in the Samara and Orenburg regions by the block structure of the Kama-Kinel system of downfolds is confirmed. Changing the thickness between the wells in two adjacent blocks and taking into account the loss of significant thickness intervals allowed us to lim it each block assumed syndepositional faults. Subsequent analysis of the results of regional seismic surveys showed that the boundaries of blocks allocated for the correlation are confirmed by the seismic data.
Sequential paleoreconstruction of deposits the Kama-Kinel system of downfolds allowed the unambiguous answer questions regarding the time and nature formation of the Kosvinskian (mostly clay) sediments in the axial zone of the system of downfolds. The analysis of 10 consecutive paleoreconstructed cross sections it is shown that the formation of a very thick layer of predominantly clayey sediments was preceded by the blocks lifting in the axial zone of this system and the erosion of carbonate deposits of the Tournaisian and Famennian tiers the most part. The lifting completed in late Tournaisian time. Beginning in Visean time, the blocks immersion was accompanied by accumulation of terrigenous sediments Kosvinskian horizon, in the bottom of which was captured on top of the Tournaisian fauna.
The location of the Tournaisian fauna in the cross section Lower Carboniferous terrigenous strata is a consequence of the tectonic blocks dip during the formation of these strata after complete erosion of the overlying Tournaisian deposits in late Tournaisian time and has nothing to do with plicative nature of the bedding. The process of forming clinoforms is not typical for carbonates. It is associated with the formation of terrigenous strata of the Lower Carboniferous in the initial period of its formation.
Thus, the Kama-Kinel system of downfolds is a complex tectonically active structure between the arches with no doubt, confined to large rivers, due to deep-seated faults.
References
1. Kleshchev A.I., Kirov V.A., Petropavlovskiy V.V., On the age of the Saraylina terrigenous thickness of Tatarstan (In Russ.), Geologiya nefti, 1957, no. 12.
2. Pozner V.M., K stratigrafii nizhnego karbona Kamsko-Kinel’skoy vpadiny (To the stratigraphy of the Lower Carboniferous of the Kamsko-Kinel Basin), Proceedings of VNIGNI, 1959, V. XIV
3. Troyepol’skiy V.I., Ellern S.S., Badamshin E.Z., Napalkov V.N., Some data on the structure of the lower part of the terrigenous sequence of the Lower Carboniferous in the Aksubaevo-Melekess depression, the paleogeographic conditions of its formation and the prospects of oil content (In Russ.), Uchenyye zapiski KGU, 1959, V. 119, no. 2.
4. Tikhiy V.N., Novyye dannyye po stratigrafii i geologicheskoy istorii devona Volgo-Ural’skoy oblasti (New data on the stratigraphy and geological history of the Devonian of the Volga-Urals region, In: Neftegazonosnost’ Uralo-Volzhskoy oblasti (Oil and gas potential of the Ural-Volga region), Moscow: Publ. of USSR AS, 1956, pp. 127–134.
5. Kiligina M.L., Stratigrafiya kamennougol’nykh otlozheniy Tatarii (Stratigraphy of Carboniferous deposits of Tatarstan), In Neftegazonosnost’ Uralo-Volzhskoy oblasti (Oil and gas potential of the Ural-Volga region), Moscow: Publ. of USSR AS, 1956.
6. Markovskiy N.I., On the paleogeography of the Lower Visean time in the areas of the Middle Volga and trans-Volga region (In Russ.), DAN SSSR, 1955, V. 104, no. 4.
7. SHaronov L.V., On the comparison of the Yasnaya Polyana deposits of Tataria and some other territories (In Russ.), Tatarskaya neft’, 1957, no. 3, pp. 37–41.
8. Grachevskiy M.M., Dolitskiy V.A., Proiskhozhdeniye Kamsko-Kinel’skoy vpadiny (Origin of the Kamsko-Kinel Basin), In: Materialy po regional’noy tektonike SSSR (Materials on regional tectonics of the USSR), Moscow: Nedra Publ., 1964.
9. Mirchink M.F., KHachatryan R.O., Mkrtchyan O.M., Tektonika i proiskhozhdeniye Kamsko-Kinel’skoy sistemy progibov (Tectonics and the origin of the Kamsko-Kinelsky system of deflections), In: Voprosy tektoniki neftegazonosnykh oblastey (Issues of tectonics of oil and gas bearing areas), Moscow: Publ. of USSR AS, 1962, pp. 86–101.
10. Valeyev R.N., Tektonika Vyatsko-Kamskogo mezhdurech’ya (Tectonics of the Vyatka-Kama interfluve), Proceedings of KGI, 1968, V. 12, pp. 4–109.
11. Sokolova T.N., Faktory, opredelyayushchiye usloviya sedimentatsii otlozheniy achimovskoy tolshchi Zapadnoy Sibiri (Factors determining the sedimentation conditions of the deposits of the Achimov strata of Western Siberia), Collected papers “Prognoz mestorozhdeniy nefti i gaza” (Forecast of oil and gas fields), Moscow: Publ. of VNIGNI, 1989, pp. 135-142.
12. Egorov P.S., O diz”yunktivnom kharaktere dislokatsii nizhnego Prikam’ya (In Russ.), Geologiya nefti i gaza, 1963, no. 8, pp. 45–50.
13. Aleksandrov A.A., Surovikov E.YA., Sanarov S.V., Danilov B.A., Izucheniye radayevsko-bobrikovskikh plastov-kollektorov Dmitriyevskogo mestorozhdeniya nefti v svyazi s predstavleniyami o klinoformnom stroyenii terrigennoy tolshchi nizhnego karbona (The study of the Radaevsko-Bobrikov reservoirs of the Dmitrievsky oil field in connection with the views on the clinoform structure of the terrigenous sequence of the Lower Carboniferous), Moscow: Publ. of IGiRGI, 1995, 40 p.
14. Sanarov S.V., Sivkov N.R., Danilov B.A., Razrabotka geologicheskoy i seysmorazvedochnykh osnov poiskov zalezhey nefti v klinoformnykh lovushkakh terrigennoy tolshchi nizhnego karbona v zone yugo-zapadnogo borta Mukhano-Erokhovskoy vpadiny (Development of a geological and seismic basis for the search for oil deposits in the clinoform traps of the terrigenous sequence of the Lower Carboniferous in the zone of the southwestern side of the Mukhano-Erokhiv depression), Moscow: Publ. of IGiRGI, 1997, 211 p.
15. Gutman I.S., Korrelyatsiya razrezov skvazhin slozhnopostroyennykh neftegazonosnykh ob”yektov na osnove innovatsionnykh tekhnologiy (Well log correlation for complex oil and gas bearing objects on the basis of innovative technologies), Moscow: Publ. of Gubkin Russian State University of Oil and Gas, 2011, 116 p.вЃ
