In connection with the recent geological modeling studies, an updated geological model of the Kolgan terrigenous strata of the Upper Devonian in the south of the Orenburg region is presented. The depth-velocity geologic model reveals a number of features of its structure. For the first time it was shown that the boundaries of the Kolgan formation spreading were delineated based on the results of interpretation of the common depth point method (CDPM)-3D seismic depth cube. The presence of the Kolgansko-Borisovsky paleo-trough was clarified and proved. It is noted that all deposits of the Kolgan formation are mainly located in the areas of tectonic faults and have structural-tectonic and lithological-sedimentary nature. The main productive reservoirs are made of terrigenous sandy sediments and have nomination Dkt1 - Dkt3, possibly in some wells there are Dkt4, Dkt5 reservoirs. At present 41 deposits have been discovered at 16 fields. As a result of this work, the zone of Kolgan deposits development within this paleo-fall was established, which is an additional tool for searching for hydrocarbon deposits in Dkt group formations. The boundaries of the Kolgan formation distribution can be clarified not only on the basis of well logging data, but also on the basis of seismic data. Based on the complex of data, the Kolgan strata thicknesses increase in the north and northeast directions from the territory of Zemlyansky license area, therefore, when planning further exploration in the region, attention should be paid to this fact when studying neighboring territories.
References
1. Pavlinova N.V., Usova V.M., Some features of composition and genesis of terrigenous rocks of kolganskaya strata (In Russ.), Vestnik Rossiyskogo universiteta druzhby narodov. Seriya: Inzhenernye issledovaniya = RUDN Journal of Engineering Research, 2012, no. 3, pp. 11–16.
2. Afanas’eva M.A., Kolgan thickness as perspective object for hydrocarbon prospecting in the limits of Buzuluk depression (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2011, no. 1, pp. 33–37.
3. Shibina T.D., Gmid L.P., Tatinskaya N.V., Nikitin Yu.I., Lithology and forecast of reservoirs in the Kolgan formation of the Vakhitovsky field of the Kichkasskaya area in the south of the Orenburg region (In Russ.), Neftegazovaya geologiya. Teoriya i praktika, 2007, V. 2.
4. Nikitin Yu.I., Rikhter O.V., Vilesov A.P., Makhmudova R.Kh., Structure and formation conditions of the Kolganian suite on the south of the Orenburg region (In Russ.), Neftegazovaya geologiya. Teoriya i praktika, 2014, no. 2, URL: http://www.ngtp.ru/rub/4/21_2014.pdf
5. Baranov V.K., Galimov A.G., Lithological criteria of oil-bearing capacity of Upper Devonian deposits in the south of the Orenburg region (In Russ.), Otechestvennaya geologiya, 1996, no. 7, pp. 5–17.
6. Poberezhnyy S.M., Afanas’eva M.A., Polyakova M.A., Yaroshenko A.V., Sedimentation models of the formation of the Kolgan strata of the East Orenburg ridge-like uplift (In Russ.), Geologiya, geografiya i global’naya energiya, 2010, no. 3, pp. 22–36.
7. Kosmynin V.A., Kuz’min D.A., Lithofacies analysis and assessment of oil and gas potential of Kolgan strata deposits in the south of the Orenburg region (In Russ.), Regional’naya geologiya i metallogeniya, 2013, no. 56, pp. 31–39.
8. Fomina G.V., Kaydalov V.I., Borisova E.V. et al., Search for non-anticlinal traps in terrigenous deposits of the Orenburg region (In Russ.), Geologiya nefti i gaza, 1988, no. 10, pp. 14–16.
9. Postoenko P.I., Cherepanov A.G., Prospects of oil bearing Frasnian - Lower Famennian deposits in the south-east of the Volga-Kama anteclise (In Russ.) Geologiya nefti i gaza, 1992, no. 2., pp. 10–14.
10. Yakhimovich G.D., Kolganskiy neftegazonosnyy basseyn i rol’ tektoniki v ego formirovanii (Kolgansky oil and gas basin and the role of tectonics in its formation), Collected papers “Geologiya i razrabotka neftyanykh i gazovykh mestorozhdeniy Orenburgskoy oblasti” (Geology and development of oil and gas fields in the Orenburg region), Orenburg: Orenburgskoe knizhnoe izdatel’stvo Publ., 1998, pp. 72-76.
11. Korotkov B.S., Medvedev N.F., Serebryakova E.S., Kolganskaya tolshcha – osobennosti rasprostraneniya i perspektivy neftegazonosnosti (Kolganskaya strata – features of distribution and oil and gas potential), In: Problemy geologii prirodnogo gaza Rossii i sopredel’nykh stran (Problems of natural gas geology in Russia and neighboring countries), Moscow: Publ. of VNIIGAZ, 2005, pp. 142–149.
