Geological features for the formation of gas-geochemical fields, including helium and hydrogen, in the water and sediments at the Vietnamese part of the South-China Sea

The paper presents the results of a complex joint Russian-Vietnamese geological, geophysical and oceanographic expedition in the South-China Sea (R/V “Akademik M.A. Lavrentyev”, cruise 88, 2019), as well as related joint RussianVietnamese marine and land researches in the area of north and south Vietnam under a series of local FEB RAS – VAST grants. The organizers of the marine expedition are the V. I. Ilyichev Pacific Oceanological Institute of the Far Eastern Branch of the Russian Academy of Sciences (POI FEB RAS) and the Institute of Marine Geology and Geophysics of the Vietnam Academy of Science and Technology (IMGG VAST). In comparison with the Sea of Japan and the Sea of Okhotsk, it can be noted that the active bottom degassing on the on the Vietnamese shelf and slope have is a local, although the intensity of gas-geochemical anomalies is comparable to similar zones in the Far Eastern Seas. For the first time, anomalous methane fields (up to 5000 nl/l) were found in the water column of the SouthChina Sea, which are comparable to anomalies on the oil and gas shelf and the gas-hydrate-bearing slope of Sakhalin Island.
Metamorphosed sedimentary and volcanic rocks were discovered for the first time in the southern part of Catba Island (Gulf of Tonkin), which indicates the introduction of an endogenous body into the sedimentary strata and its further transformation. In connection with the discovery in 2020 of the large Ken Bau gas field at the southern end of the sedimentary basin of the Red River, the forecast of POI scientists about the presence of significant hydrocarbon reserves in this area was confirmed.
The work was carried out within the framework of the joint Vietnam-Russia Laboratory for Marine Sciences and Technology (V. I. Ilyichev Pacific Oceanological Institute of the Far Eastern Branch of the Russian Academy of Sciences and the Institute of Marine Geology and Geophysics Vietnam Academy of Science and Technology). The expedition of the R/V “Akademik M.A. Lavrentyev” (cruise 88) is part of a series of expeditions in accordance with the UN Decade dedicated to the Ocean Science for Sustainable Development.

1. Akulichev V.A., Obzhirov A.I., Shakirov R.B., Mal’tseva E.V., Syrbu N.S., Polonik N.S., Van Phach P., Trung N.N., Hung D.Q., Anh L.D. (2015). Anomalies of natural gases in the Gulf of Tonkin (South China Sea). Doklady Earth Sciences, 461(1), pp. 203–207. https://doi.org/10.1134/S1028334X15030010

2. Areshev E.G., Gavrilov V.P., Dong Ch.L., Zao N., Popov O.K., Pospelov V.V., Shan N.T., Shnip O.A. (1997). Geology and oil and gas content of the Sunda shelf basement. Moscow, 285 p. (In Russ.)

3. Dolginov E.A., Bashkin Yu.V., Belousov T.P., Kao D.T., Le V.Z. (2010). Rift and epirift structures of northwestern Vietnam and their probable analogues. Izvestiya vuzov. Geologiya i razvedka = Proceedings of higher educational establishments. Geology and Exploration, 5, pp. 3–8. (In Russ.)

4. Duong Quoc Hung, Renat Shakirov, Iosif Iugai, Nguyen Van Diep, Le Duc Anh, Mai Duc Dong, Bui Van Nam, Yury Telegin (2019). A study on the relationship between gas-geochemical field and tectonic fault activities in the rivermouth of Gulf of Tonkin. Vietnam Journal of Marine Science and Technology, 19(2), pp. 191–198. https://doi.org/10.15625/1859-3097/19/2/14036

5. Ershov V.V., Shakirov R.B., Mel’nikov O.A., Kopanina A.V. (2010). Variations in the parameters of mud volcanic activity and their relationship with the seismicity of the south of Sakhalin Island. Regional’naya geologiya i metallogeniya = Regional Geology and Metallogeny, 42, pp. 49–57. (In Russ.)

6. Es’kova A.I., Ponomareva A.L., Legkodimov A.A., Kalgin V.Yu., Shakirov R.B., Obzhirov A.I. (2020). The Characteristics and Distribution of Indicator Microorganisms in the Marine Sediments from the South-China Sea. Izvestiya Irkutskogo Gosudarstvennogo Universiteta. Seriya: Nauki o zemle = The Bulletin of Irkutsk State University. Series Earth Sciences, 33, pp. 33–43. (In Russ.) https://doi.org/10.26516/2073-3402.2020.33.33

7. Geological map of Vietnam. (1986). Scale 1: 1 500 000. General Dpt. of Geology, Hanoi.

8. Kravtsov A.I., Voitov G.I., Fridman A.I. et al. (1967). Hydrogen content in free jets in the Khibiny. Doklady Akademii Nauk SSSR, 5, pp. 1190–1192. (In Russ.)

9. Kudrin I.V., Orlyankin V.N., Kudrin K.I. (2006). Method of searching of gaseous hydrogen and helium clusters in earth interior. Patent RF RU2316028. (In Russ.)

10. Kulinich R.G. Obzhirov A.I. (1985). On the structure and current activity of the junction zone of the Sunda shelf and the South China Sea basin. Tikhookeanskaya geologiya = Russian Journal of Pacific Geology, 3, pp. 102–106. (In Russ.)

11. Le Duc Anh, Nguyen Hoang, Phung Van Phach, Malinovskii A. I., Kasatkin S. A., Golozubov V. V. (2018). Geochemistry and petrogenesis of volcanic rocks and their mantle source in the East Vietnam Sea and adjacent regions in the Cenozoic. Vietnam Journal of Marine Science and Technology, 17(4), pp. 406–428. https://doi.org/10.15625/1859-3097/17/4/9258

12. Nguyen Nhu Trung. (2013). Basement structure of the Bac Bo Basin based on the 3D interpretation of satellite gravity and magnetic data. Proceedings of the 11th SEGJ International Symposium. https://doi.org/10.1190/segj112013-034

13. Regulatory and methodological support for the protection of atmospheric air (1995). Perm: Intereko, 249 p. (In Russ.)

14. Obzhirov A.I. (1993). Gas-geochemical fields of the bottom layer of seas and oceans. Moscow: Nauka, 139 p. (In Russ.)

15. Perevozchikov G.V. (2012). PHydrogen field at the Gazli field according to geochemical studies in the oil and gas region of Central Asia. Neftegazovaya geologiya. Teoriya i praktika = Oil and gas geology. Theory and practice, 7(1), pp. 1–13. (In Russ.)

16. Pollak H.N., Hurter S.J., Johnson J.R. (1991). New global heat flow compilation. University of Michigan, USA.

17. Porotov G.S. (1977). Mathematical methods in searching and prospecting for minerals. Leningrad: Leningrad Mining Institute, 106 p. (In Russ.)

18. Shakirov R.B. (2016). Gas-geochemical fields of the marginal seas of the Far Eastern region: distribution, genesis, connection with geological structures, gas hydrates and seismotectonics. Abstract Sci. Diss. Vladivostok: Il’ichev POI FES RAS, 49 p. (In Russ.)

19. Shakirov R.B. (2018). Gas-geochemical fields of the seas of East Asia. Moscow: GEOS, 341 p. (In Russ.)

20. Shakirov R.B., Hung D.Q., Anh L.D., Syrbu N.S., Obzhirov A.I., Borzova O.V., Okulov A.K., Nam B.V., Diep N.V., Dong M.D., Legkodimov A.A., Shakirova M.V., Ponomareva A.L., Bakunina M.S. (2019). Features of the gasgeochemical abnormal fields distribution in the Red River rift (Tonkin gulf, South-China sea). Doklady Earth Sciences, 484, Part 2, pp. 181–184. https://doi.org/10.1134/S1028334X19020065

21. Shakirov R.B., Li N.S., Obzhirov A.I., Valitov M.G., S”edin V.T., Telegin Yu.A., Proshkina Z.N., Okulov A.K., Storozhenko A.V., Ivanov M.V., Shvalov D.A., Legkodimov A.A., Es’kova A.I., Lipinskaya N.A., Bovsun M.A., Makseev D.S., Kalgin V.Yu., Yakimov T.S., Nguen Chun Tkhan’, Le Dyk An’. (2020). Integrated Russian-Vietnamese geological-geophysical and oceanographic expedition in the South China Sea (R/V “Akademik M.A. Lavrentyev”, cruise 88, 2019). Vestnik of Far Eastern Branch of Russian Academy of Sciences, 3, pp. 138–152. (In Russ.)

22. Shakirov R.B., Obzhirov A.I., Syrbu N.S., Nguen Nu Chung, Zyong Kuok Khyn, Mal’tseva E.V., Sorochinskaya A.V., Yugai I.G., Le Duc Anh, Fueg Van Fat, Polonik N.S., Bui Van Nam, Nguen Van Diep. (2015). Features of the distribution of natural gases in bottom sediments and water in the northwestern part of the Gulf of Tonkin (South China Sea, Vietnam). Geografiya i prirodnye resursy, 4, pp. 178–188. (In Russ.)

23. Shakirov R.B., Sorochinskaya A.V., Syrbu N.S., Nguen Nu Chung, Fung Van Fat, Le Duc Anh, Chon Tkhan’ Fi. (2017). Gas-geochemical features of sediments in the Tonkin Gulf (South China Sea). Vestnik of Far Eastern Branch of Russian Academy of Sciences, 4, pp. 33–42. (In Russ.)

24. Shakirov R.B., Syrbu N.S., Obzhirov A.I. (2016). Distribution of helium and hydrogen in sediments and water on the Sakhalin slope. Lithology and Mineral Resources, 51(1), pp. 61–73. (In Russ.) https://doi.org/10.1134/S0024490216010065

25. Shnip O.A. (2012). Composition and oil and gas content of the basement of the shelf of Northern and Central Vietnam. Trudy RGU Nefti i gaza imeni I.M. Gubkina, 31, pp. 53–55. (In Russ.)

26. Smirnov B.V. (1983). Probabilistic forecasting methods in engineering geology. Moscow: Nedra, 134 p. (In Russ.)

27. Syrbu N.S., Shakirov R.B., Le Duc Anh, Kholmogorov A.O., Iakimov T.S, Kalgin V.Yu. (2020). Formation of abnormal gasgeochemical fields of methane, helium and hydrogen in Northern Vietnam, its coastal and adjacent water areas. Lithology and Mineral Resources, 55(6), pp. 512–527. https://doi.org/10.1134/S0024490220060097

28. Tsunogai U., Kosaka A., Nakayama N., Komatsu D., Konno U., Kameyama S., Nakagawa F., Sumino H., Nagao K., Fujikura K., Machiyama H. (2010). Origin and fate of deep sea seeping methane bubbles at Kuroshima Knoll, Ryukyu forearc region, Japan. Geochemical Journal, 44, pp. 461–476. https://doi.org/10.2343/geochemj.1.0096

29. Tuyen N.H., Phach Ph.V., Shakirov R.B., Trong C.D., Hung Ph.N., Anh L.D. (2018). Geoblocks Recognition and Delineation of the Earthquake Prone Areas in the Tuan Giao Area (Northwest Vietnam). Geotectonics, 52(3), pp. 359–381. https://doi.org/10.1134/S001685211803007X

30. Voitov G.I., Dobrovol’skii I.P. (1994). Chemical and isotopic carbon instabilities of natural gas flows in seismically active regions. Fizika Zemli = Izvestiya, Physics of the Solid Earth, 3, pp. 20–31. (In Russ.)