The existing ideas about limiting the potential of the Priirtysh petroleum bearing region only to the most submerged parts of the basin - troughs with the Devonian-Carboniferous filling complex are not complete and do not take into account / do not assume the existence of an underlying forearc basin of the Early Paleozoic, which is capable of generating hydrocarbons in the study area. The fundamental element of this area is the Seletinskaya island arc of the Early Cambrian inception. The developed concept for the development of the region implies a two-story structure of the Priirtysh Caledonides. The first stage is associated with the formation of a fore-arc basin in the Late Cambrian in the front of the Seletinskaya island arc, with a complex of filling with siliceous-terrigenous facies of Ordovician and Silurian age. The basin was characterized by conditions of hemipelagic sedimentation.
With the development of the northern part (in modern coordinates) of the Zharma-Saur island arc, the second stage of the development of the basin on the Caledonian base is associated, namely, the fore-arc basin that developed in the front of the Seletinskaya island arc is replaced by a back-arc basin, which was laid in the rear of the Zharma-Saur arc Devonian age. It is assumed that the oceanic crust of the Ob-Zaisan Ocean subsided under the continental crust of the Caledonides, which had already formed by that time.
In general, back-arc basins have a greater potential than fore-arc ones, but in this case, the main generation potential is associated with the most mature deep-immersed lower Paleozoic potential source rocks, since the main problem of this petroleum bearing region is due to relatively shallow depths and, as a result, an obstacle to the start of generation processes less submerged strata enriched in organic matter. To study the territory, deep drilling and seismic surveys are required, the multiplicity of which should be chosen taking into account the illumination of the structure of the Lower Paleozoic part.
References
1. Votsalevskiy E.S., Kuandykov B.M., Pilifosov V.M. et al., Karta prognoza neftegazonosnosti Kazakhstana (Forecast map of oil and gas potential of Kazakhstan): edited by Daukeev S.Zh. et al., Almaty: Publ. of Kazgeoinform, 2002.
2. Vinogradov A.P., Paleogeografiya SSSR (Paleogeography of the USSR), Part 1, Moscow: Nedra Publ., 1974, 276 p.
3. Khafizov S., Syngaevsky P., Dolson J.C., The West Siberian Super Basin: The largest and most prolific hydrocarbon basin in the world, AAPG Bulletin, 2022, V. 106, no. 3, pp. 517-572, DOI: https://doi.org/10.1306/11192121086
4. Akchulakov U.A., Urdabaev A.T., Azhgaliev D.K., Kompleksnoe izuchenie osadochnykh basseynov Respubliki Kazakhstan. Priirtyshskiy basseyn (Comprehensive study of sedimentary basins of the Republic of Kazakhstan. Irtysh basin). Part 1, Astana: Publ. of RTsGI Kazgeoinform, AO NK KazMunayGaz, 2012, 234 p.
5. Daukeev S.Zh. et al., Glubinnoe stroenie i mineral’nye resursy Kazakhstana (Deep structure and mineral resources of Kazakhstan), Collected papers “Neft’ i gaz” (Oil and gas), Part III, Almaty: Publ. of Kazgeoinform, 2002, 248 p.
6. Korobkin V.V., Smirnov A.V., Paleozoic tectonics and geodynamics of volcanic arcs in Northern Kazakhstan (In Russ.), Geologiya i geofizika, 2006, V. 47, no. 4, pp. 462-474.
7. Samygin S.G., Kheraskova T.N., Kurchavov A.M., Tectonic evolution of Kazakhstan and Tien Shan in Neoproterozoic and Early-Middle Paleozoic (In Russ.), Geotektonika, 2015, no. 3, pp. 66-92, DOI: https://doi.org/10.7868/S0016853X1406006X
8. Korobkin V.V., Buslov M.M., Tectonics and geodynamics of the Western Central Asian fold belt (Kazakhstan Paleozoides) (In Russ.), Geologiya i geofizika, 2011, V. 52, no. 12, pp. 2032-2055.
9. Stepanets V.G., Antonyuk R.M., Tektonicheskoe rayonirovanie i palinspasticheskie rekonstruktsii razvitiya kaledonid Tsentral’nogo Kazakhstana (Tectonic zoning and palinspastic reconstructions of the development of the Caledonides of Central Kazakhstan), Proceedings of International scientific conference “Geodinamika formirovaniya podvizhnykh poyasov Zemli” (Geodynamics of the formation of the mobile belts of the Earth), Ekaterinburg, 24-26 April 2007.
10. Nikitin I.F., Ordovician siliceous and siliceous-basalt complexes of Kazakhstan (In Russ.), Geologiya i geofizika, 2002, V. 43, no. 6, pp. 512-527.
11. Tsay D.T., Regional’naya zonal’naya shkala ordovika po graptolitam (Ordovician regional zoning scale based on graptolites): thesis od doctor of geological and mineralogical science, Novosibirsk, 1988, 29 p.
12. Miletenko N.V., Fedorenko O.A., Atlas litologo-paleogeograficheskikh, strukturnykh, palinspasticheskikh i geoekologicheskikh kart Tsentral’noy Evrazii (Atlas of lithological-paleogeographic, structural, palinspastic and geoecological maps of Central Eurasia), Almaty: Publ. of Research Institute of Natural Resources YuGGEO, 2002.
13. Zou C. et al., Formation and distribution of volcanic hydrocarbon reservoirs in sedimentary basins of China, Petroleum Exploration and Development, 2008, V. 35, no. 3, pp. 257-271.
