Objective. To elucidate the dynamics of catagenetic processes that occurred in the Silurian sediments against the background of an oil and gas systems formation. Method. The method includes lithology-facies, mineralogical-petrographic, catagenetic, and litho-fluido-dynamic analyses. Results. The spatial-temporal development features of carbonate (bank-reefal facies), argillite (outer and inner shelf), and argillite-carbonate (transition facies) complexes located in the Silurian sediments (profile of boreholes: Lishchynska-1 – Peremyshlyany-1 – Baluchin-1 – Olesko-1) have been determined. The main post-sedimentary transformations of clayey compound rocks consistent in the formation of quartz, calcite, pyrite, as well in the formation of caverns and fractures, which in most cases are combined with thin channels forming a single system, have been studied. It has been established that during the Palaeozoic and Early Mesozoic, the regime of catagenesis of the Silurian sediments of the considered structures was identical. Its further differentiation caused by the individualization of various tectonic block development occurred. In the first catagenetic cycle, the Silurian deposits reached the temperature conditions of the main zone of gas formation. The hydrocarbon (HC) generation centre was located in the western part of the studied profile (the Lishynskaya area), and within the zone of hydrocarbon accumulation a number of lithogenetic reservoirs were localized, the formation of which took place at different catagenetic substages. The main phase of hydrocarbon accumulation is confined to the Late Cretaceous. At this time in the Lishchino-Peremyshlyanskaya area there was a knot of reservoirs pertaining to the heterogeneous morphology, genesis, and the time of their formation. The spatial superposition of these reservoirs and the presence of a multi-directional system of fractures led to the formation of a single fluid system. In the Palaeogene, the accumulated oil and gas accumulations were destroyed as a result of the regional fracture zone development. Hydrocarbon fluids migrated both laterally and vertically with their possible accumulation in structural or lithological traps in the Silurian and Devonian sediments. Scientific novelty. The novel periodization of the Silurian deposits catagenesis has been determined, and the difference in the regime of catagenesis which occurred in various tectonic structures has been established. Practical relevance. The hydrocarbon fluids migration stages and the history of conditions during the formation of the lithogenetic reservoirs have been determined, which allowed assessing specific aspects of the oil-and-gas potential of the Silurian and adjacent sedimentary complexes.
1. Belokon', A. V. (2005). Application of basin modeling technology to estimate oil and gas potential of deeply-burial deposits of the North of Western Siberia. New Ideas in the Geology and Geochemistry of Oil and Gas: M-ls of VII International. conf. Moscow: GEOS. (in Russian).
2. Dixon, S. A., Summers, D. M., & Surdam, R. C. (1989). Diagenesis and preservation of porosity in Norphlet Formation (Upper Jurassic), southern Alabama. AAPG Bulletin. 73(6), 707–728.
3. Dmitrievskij, A. N., Beljankin, N. A., & Karakin, A. N. (2007). One of the possible mechanisms for replenishing hydrocarbon reserves. Dokl. RAN. [Rep. RAS]. 415, 5, 678–681. (in Russian).
4. Dryhant, D. M. (2000). Lower and Middle Paleozoic of the Volyno-Podolian margin of the East-European platform and the Carpathian foredeep]. Nauk. zap. DPM NAN Ukrainy. Scientific notes DPM NAS of Ukraine. 15, 24–129. (in Ukrainian).
5. Hnidets, V. P., Hryhorchuk, K. H., Kurovets, I. M., Kurovets, S. S., Prykhodko, A. A., Hrytsyk, I. I., & Balandiuk. L. V. (2013). Upper Cretaceous geology of the Black sea-Crimean petroleum-bearing region Ukraine. CJ "Poly" Ltd., Lviv, (in Ukrainian).
6. Kurovets, I. M., Dryhant, D. M., Chepil, P. M., Chepusenko, P. S., & Shyra, A. I. (2010). Geological and petrophysical characteristics of the basin fine-grained rocks of the Silurian south-western margin of the East European Platform. Collection of scientific works of the Institute of Geological Sciences of the National Academy of Sciences of Ukraine. 3, 287–293. (in Ukrainian).
7. Hryhorchuk, K. H. (2010). Features of lithofluidodynamics of exfiltration catagenesis. Geology and geochemistry of combustible minerals. 1, 60–68 (in Ukrainian).
8. Hryhorchuk, K. H., & Senkovskyi, Yu. M. (2013). Discrete formation of reservoirs of "shale" gas in exfiltration catagenesis. Geodynamics. (14), 61–68. (in Ukrainian).
9. Ivanova, A. V. (2016). Influence of geotectonic conditions on the formation of carbonaceous formations of the Lviv and Predobrogean depressions. Geological journal, 1 (354), 36–50. (in Russian).
https://doi.org/10.30836/igs.1025-6814.2016.1.97284
10. Kartsev, A. A., Vagin, S. B., & Matusevich, V. M. (1986). Hydrogeology of oil and gas basins. M.: Nedra.
11. Kudel'skij, A. V. (1982). Lithogenesis, problems of hydrogeochemistry and energy of oil and gas basins. Lithology and mineral resources. 5, 101–116.
12. Krupskyi, Yu. Z., Kurovets, I. M., Senkovskyi, Yu. M., Mykhailov, V. A., Chepil, P. M., Dryhant, D. M, Shlapinskyi. V. E., Koltun, Yu. V. … & Bodlak, V. P. (2014). . Unconventional sources of hydrocarbons in Ukraine: monograph in 8 volumes. V. 2 Western oil and gas region. NJSC Naftogaz Ukrainy and others. Kyiv: Nika-Centr. (in Russian)
13. Leonov, Ju. G., & Volozha, Ju. A. (2004). Sedimentary basins: study method, structure and evolution. M.: Nauchnyj mir. (in Russian)
14. Minskij, N. A. (1972). The regularities of the formation of the belts of optimal collectors. Moscow: Nedra.
15. Naumko, I. M., Kurovets, I. M., Zubyk, M. I., Batsevych, N. V., Sakhno, B. E., & Chepusenko, P. S. (2017). Hydrocarbon compounds and plausible mechanism of gas generation in "shale" gas prospective Silurian deposits of Lviv paleozoic depression. Geodynamics, 1(22), 26–41.
16. Radkovets, N. (2015). The Silurian of south-western margin of the East European Platform (Ukraine, Moldova and Romania): lithofacies and palaeoenvironments. Geological Qurterly. 59, 1, 105–118.
https://doi.org/10.7306/gq.1211
17. Radkovets, N., Rauball, J., & Iaremchuk, I. (2017). Silurian black shales of the Western Ukraine: petrography and mineralogy. Estonian Journal of Earth Sciences. 66, 3, 161–173.
https://doi.org/10.3176/earth.2017.14
18. Radkovets, N., Kosakowski, P., Rauball, J., & Zakrzewski, A. (2018). Burial and thermal history modelling of the Ediacaran succession in Western and SW Ukraine and Moldova. Journal of Petroleum Geology, 41, 1, 85–106.
https://doi.org/10.1111/jpg.12694
19. Sidorova, V. A., Safronova, T. P., & Burova, E. G. (1991). Geochemical aspects of the migration of hydrocarbon systems and modern tectonic. Scientific and applied aspects of geochemistry of oil and gas. M.: IGIRGI, 100–105.
20. Schito, A., Andreucci, B., Aldega, L., Corrado, S., Di Paolo, L., Zattin, M., ... & Mazzoli, S. (2018). Burial and exhumation of the western border of the Ukrainian Shield (Podolia): a multi‐disciplinary approach. Basin Research, 30, 532–549.
https://doi.org/10.1111/bre.12235
21. Sokolov, B. A. (2002). Towards the creation of a general theory of the oil and gas potential of the entrails. New ideas in the geology and geochemistry of oil and gas: Proceedings of the VI International Conference. M.: GEOS,
22. Środon, J., Paszkowsky, M., Drygant, D., Anczkiewicz, A., & Banaś, M. (2013). Thermal history of Lower Paleozoic rocks on the Peri-Tornquist margin of the East European craton (Podolia, Ukraine) inferred from combined XRD, K-Ar and AFT data. Clays and Clay Minerals. 61, 2, 107–132
https://doi.org/10.1346/CCMN.2013.0610209
23. Yusupova, I. F., Abukova, L. A., & Abramova, O. P. (2005). Catagenic losses of rock organic matter as a factor of geodynamic destabilization. New ideas in geology and geochemistry of oil and gas: Proceedings of the VII International Conference. M.: GEOS.