Trap magmatism effect on oil and gas horizons (south of the Siberian platform)

The lack of determination of the hydrocarbon distribution regularities in the areas with widely developed basalt complexes significantly complicates the estimation of the prospects for the oil and gas potential of the ancient platforms. This is a challenge for the researchers of the Siberian Platform, which has recently become a new Russian oil and gas extraction base. For a long time, preceding the mass introduction of trap magma, the platform was subjected to intense deflection compensated by sedimentation with the formation of a large number of hydrocarbon deposits in the lower horizons of the sedimentary cover. The influence degree of widely manifested within the Siberian platform trap magmatism on the ontogenesis of oil and gas deposits has become the goal of the studies, which involve identification of the dependence between the thickness of the Osa production horizon and reservoir intrusions of dolerites, dependence of the phase state of deposits and the temperature gradient in individual fields in the south of the Siberian platform. The study uses the correlation methods for the lithologic and stratigraphic sections of the largest hydrocarbon deposits: Verkhnechonsky, Yaraktinsky, Kovykta, Srednebotuobinsky and others. The information is represented graphically in the diagrams. Having analyzed the data obtained according to the results of deep drilling in the known fields in the south of the Siberian platform, the authors have built linear graphs of the relationship between the thicknesses of the Osa productive horizon, salt-bearing fluid seal of Usolskaya suite and reservoir intrusions of Usolsky sill dolerites. Also the graphs of deposit phase state dependence on the temperature of fluid generation are constructed on the basis of the calculation of the possible formation depth of the field. There is a direct relationship between the thicknesses of fluid seal and reservoir intrusions of dolerites. It means that the horizon is preserved in the case when the fluid seal thickness increases as dolerite reservoir thickness increases. Gas condensate deposits are formed at higher temperatures.

trap magmatism, Osa horizon, Siberian platform, sill, fluid seal

1. Feoktistov G.D. Petrologiya i usloviya formirovaniya trappovykh sillov [Petrology and formation conditions of trap sills]. Novosibirsk: Nauka Publ., 1978, 166 p. (In Russ.).

2. Skripin A.I., Alekseev E.B. Evolution of trap magmatism in the southern part of the Siberian platform. Geologiya i geofizika [Russian Geology and Geophysics], 1981, vol. 22, no. 11, pp. 12–17. (In Russ.).

3. Tonkikh M.E., Baryshev A.S., Egorov K.N., Kashkarev D.L. Structural position of traps in the south of Siberian platform. Vestnik Irkutskogo gosudarstvennogo tekhnicheskogo universiteta [Proceedings of Irkutsk State Technical University], 2011, no. 12 (59), pp. 65–73. (In Russ.).

4. Vasil'ev Yu.R., Zolotukhin V.V., Feoktistov G.D., Prusskaya S.N. Estimation of volumes and genesis of Permian-Triassic trap magmatism on the Siberian platform. Geologiya i geofizika [Russian Geology and Geophysics], 2000, vol. 41, no. 12, pp. 1696–1705. (In Russ.).

5. Antsiferov A.S., Bakin V.E., Vorob'ev V.N. Nepsko-Botuobinskaya antekliza – novaya perspektivnaya oblast' dobychi nefti i gaza na Vostoke SSSR [Nepa-Botuoba anteclise as a new promising field of oil and gas production in the East of the USSR]. Novosibirsk: Nauka Publ., 1986, 245 p. (In Russ.).

6. Zamaraev S.A., Geletii N.K., Malykh A.V. On the temperature effect of traps on potassium salts of the Nepa potassium-bearing basin in Eastern Siberia. Geologiya i geofizika [Russian Geology and Geophysics], 1985, vol. 26, no. 4, pp. 42–47. (In Russ.).

7. Gazhula S.V. Features of a trap magmatism in connection with the oil and gas potential of the Siberian platform. Neftegazovaya geologiya. Teoriya i praktika [Petroleum Geology – Theoretical and Applied Studies], 2008, vol. 3, no. 1, pp. 1–8. Available at: http://www.ngtp.ru/rub/4/10_2008.pdf (10 February 2019).

8. Odintsova T.V., Drobot D.I. Trap magmatism and oil and gas potential of the Vendian terrigenous complex of the Lena oil and gas region. Geologiya nefti i gaza [Oil and Gas Geology], 1983, no. 7, pp. 6–10. (In Russ.).

9. Starosel'tsev V.S. Tektonika bazal'tovykh plato i neftegazonosnost' podstilayushchikh otlozhenii [Basaltic plateau tectonics and oil and gas potential of underlying sediments]. Moscow: Nedra Publ., 1989, 259 p. (In Russ.).

10. Abrosimova O.O., Kulagin S.I. Structural features of the deposits of the Cambrian complex within the Mirnyi protrusion (Nepa-Botuoba anteclise). Izvestiya Tomskogo politekhnicheskogo universiteta [Bulletin of the Tomsk Polytechnic University], 2010, vol. 316, no. 1, pp. 48–52. (In Russ.).

11. Levin F.D. Ob"emnaya geologo-geofizicheskaya model' Verkhnechonskogo mestorozhdeniya UV [3-D geological and geophysical model of the Verkhnechonsk hydrocarbon field]. Sovremennye aerogeofizicheskie metody i tekhnologii [Modern aero geophysical methods and technologies]. Iss. 1, vol. 1. Moscow: СС “GRPE ‘Aerogeofizika’” Publ., 2009, pp. 195–225. (In Russ.).

12. Vassoevich N.B. Teoriya osadochno-migratsionnogo proiskhozhdeniya nefti (istoricheskii obzor i sovremennoe sostoyanie) [Theory of the sedimentary-migration origin of oil (historical review and current state)]. Izvestiya Akademii nauk SSSR. Seriya geologicheskaya [Bulletin of the USSR Academy of Sciences. Geological series], 1967, no. 11, рр. 135–156. (In Russ.).