Anomalies of hydrogen index in the bottom sediments of the Black Sea shelf as possible sign of presence of hydrocarbon deposits in the depths

UDK: 551.351.2 : 553.381/982
DOI: 10.24887/0028-2448-2020-2-8-11
Key words: hydrogen index, bottom sediment, hydrocarbon fluid, continental outskirts, Gudauta uplift
Authors: S.G. Parada (Southern Scientific Centre of RAS, RF, Rostov-on-Don)

The variations of hydrogen index pH in the bottom sediments of North-Eastern outskirts of the Black Sea in the region of the Gudauta uplift are studied. Here the potentially oil- and gas-bearing structures and carbonaceous reef-forming buildings are singled out by seismic data. The sampling of bottom sediments was carried out in the course of the maritime science-research expedition in the August of 2010. The sampling stations were placed at 7 profiles oriented perpendicular to the coast line, 1500 m further on. The profiles were placed at the distance 3000 m from each other. In all, 260 samples were picked out. The pH measurement was carried out by potentiometric method using the analyzer Expert-001, measuring electrode and chlorine-silver comparison electrode. The established pH values are in the interval of 7.68–9.3. The median value makes 8.16, modal – 8.1, mean arithmetical – 8.26, at inaccuracy of average estimation – 0.037. The planar interpolation of pH values of bottom sediments was carried out in the environment ArcGis 9.1 with use of function kriging. It was established that marine sediments in the limits of Gudauta uplift are characterized by increased values of pH (7.86–9.27), in comparison with sediments of other sections of continental outskirts of Black Sea (7.55 – 8.4 at the Crimean shelf, 7.14 – 8.7 at the South-Eastern continental slope), i.e. are more alkaline. For all that, anomalous values of pH do not depend on the composition of sediments and coincide with the shelf zone and leveled parts of continental slope. It is established that the anomalous pH values of bottom sediments, according to published data, can be tied with the flows of carbohydrate fluids, ascending from industrial deposits. These fluids are oxidized at the interaction with oxygen of the seawater bicarbonate and also with methane-oxidizing bacteria. Therefore, the established by us spatial coincidence of areas of anomalously increased pH indices of bottom sediments of Gudauta uplift with areas of development of potentially oil- and gas-bearing geological structures, revealed earlier by seismic data, is connected with possible existence of carbohydrate deposits in them.

References

1. Matishov G.G., Matishov D.G., Berdnikov S.V. et al., The risks of geological survey and oil-and-gas production projects realization in conditions of hydrogen-sulphidous zone of the Black Sea (In Russ.), Vestnik Yuzhnogo nauchnogo tsentra RAN, 2011, V. 7, no. 1, pp. 59–63.

2. Timofeev V.A., Timofeev A.A., Parada S.G., The theoretical premises of oil and gas capacity of Cis-Caucasian Paleozoic complexes (In Russ.), Vestnik Yuzhnogo nauchnogo tsentra RAN, 2009, V. 5, no. 4, pp. 50–61.

3. Matishov G.G., Parada S.G., Davydenko D.B., The technologies of forecasting carbohydrate fields and mineral deposits of the future Russia (on example of the Southern Region) (In Russ.), Geologiya i geofizika yuga Rossii, 2011, no. 1, pp. 20–31.

4. Davydenko D.B., Davydenko E.D., Isaev V.S. et al., An attempt of detection and study of the zones of endogenous fluidization with the set of remote and gas-geochemical methods (In Russ.), Vestnik Yuzhnogo nauchnogo tsentra, 2014, V. 10, no. 1, pp. 25–34.

5. Parada S.G., Kholod Yu.V., Shishkalov I.Yu., Geochemistry of secondary dispersion halos of the Malka-Musht ore deposit block (the Northern Caucasus) (In Russ.), Nauka Yuga Rossii, 2011, V. 7, no. 3, pp. 55–60.

6. Parada S.G., Alekseenko V.S., Vozmozhnosti ispol'zovaniya velichiny rN donnykh osadkov dlya otsenki neftegazonosnosti shel'fa Chernogo morya (Possibilities of using the pH value of bottom sediments to assess the oil and gas potential of the Black Sea shelf), Collected papers “Okruzhayushchaya sreda i chelovek. Sovremennye problemy genetiki, selektsii i biotekhnologii” (Environment and people. Modern problems of genetics, selection and biotechnology), Proceedings of International scientific conference and youth scientific conference in memory of the corresponding member of the RAS D.G. Matishov, Rostov-na-Donu, 2016, pp. 221–223.

7. Serebrennikova O.V., Geokhimicheskie metody pri poiske i razvedke mestorozhdeniy nefti i gaza (Geochemical methods in the search and exploration of oil and gas fields), Khanty-Mansiysk: Publ. of YuSU, 2008, 172 p.

8. Kondratov L.S., Fokina L.M., New opportunities for searching oil and gas fields by adsorbed form of gas of rocks and bottom deposits of water areas (In Russ.), Vesti gazovoy nauki, 2010, no. 2(5), pp. 124–134.

9. Lein A.Yu., Bogdanova O.Yu., Bogdanov Yu.A., Magazina L.O., Mineralogical and geochemical features of authigenic carbonates on seepings and hydrothermal fields (By the examples of the Black Sea reefs and the mounds of the lost city field) (In Russ.), Okeanologiya, 2007, V. 47, no. 4, pp. 577–593.

10. Afanasenkov A.P., Nikishin A.M., Obukhov A.N., Geologicheskoe stroenie i uglevodorodnyy potentsial Vostochno-Chernomorskogo regiona (Geological structure and hydrocarbon potential of the East Black Sea region), Moscow: Nauchnyy mir Publ., 2007, 172 p.

11. Geologiya SSSR (Geology of the USSR), Part Kh, Moscow, 1964, 656 p.

12. Esina L.A., Khvoroshch A.B., Structural plan and prospective petroleum potential of the Jurassic sediments of the Gudauty Rise in the Black Sea (In Russ.), Okeanologiya, 2014, V. 54, no. 1, pp. 89–96.

13. Kiryukhina L.N., Gubasaryan L.A., Biogeochemical characters of Crimean shelf’s bottom sediments from the Black Sea (In Russ.), Ekologiya morya, 2000, V. 50, pp. 18–21.

14. URL: http://www.chernomorneftegazcompany.com/reports/EcologicalStudiesSouth WestBlackSeaArea.

The variations of hydrogen index pH in the bottom sediments of North-Eastern outskirts of the Black Sea in the region of the Gudauta uplift are studied. Here the potentially oil- and gas-bearing structures and carbonaceous reef-forming buildings are singled out by seismic data. The sampling of bottom sediments was carried out in the course of the maritime science-research expedition in the August of 2010. The sampling stations were placed at 7 profiles oriented perpendicular to the coast line, 1500 m further on. The profiles were placed at the distance 3000 m from each other. In all, 260 samples were picked out. The pH measurement was carried out by potentiometric method using the analyzer Expert-001, measuring electrode and chlorine-silver comparison electrode. The established pH values are in the interval of 7.68–9.3. The median value makes 8.16, modal – 8.1, mean arithmetical – 8.26, at inaccuracy of average estimation – 0.037. The planar interpolation of pH values of bottom sediments was carried out in the environment ArcGis 9.1 with use of function kriging. It was established that marine sediments in the limits of Gudauta uplift are characterized by increased values of pH (7.86–9.27), in comparison with sediments of other sections of continental outskirts of Black Sea (7.55 – 8.4 at the Crimean shelf, 7.14 – 8.7 at the South-Eastern continental slope), i.e. are more alkaline. For all that, anomalous values of pH do not depend on the composition of sediments and coincide with the shelf zone and leveled parts of continental slope. It is established that the anomalous pH values of bottom sediments, according to published data, can be tied with the flows of carbohydrate fluids, ascending from industrial deposits. These fluids are oxidized at the interaction with oxygen of the seawater bicarbonate and also with methane-oxidizing bacteria. Therefore, the established by us spatial coincidence of areas of anomalously increased pH indices of bottom sediments of Gudauta uplift with areas of development of potentially oil- and gas-bearing geological structures, revealed earlier by seismic data, is connected with possible existence of carbohydrate deposits in them.

References

1. Matishov G.G., Matishov D.G., Berdnikov S.V. et al., The risks of geological survey and oil-and-gas production projects realization in conditions of hydrogen-sulphidous zone of the Black Sea (In Russ.), Vestnik Yuzhnogo nauchnogo tsentra RAN, 2011, V. 7, no. 1, pp. 59–63.

2. Timofeev V.A., Timofeev A.A., Parada S.G., The theoretical premises of oil and gas capacity of Cis-Caucasian Paleozoic complexes (In Russ.), Vestnik Yuzhnogo nauchnogo tsentra RAN, 2009, V. 5, no. 4, pp. 50–61.

3. Matishov G.G., Parada S.G., Davydenko D.B., The technologies of forecasting carbohydrate fields and mineral deposits of the future Russia (on example of the Southern Region) (In Russ.), Geologiya i geofizika yuga Rossii, 2011, no. 1, pp. 20–31.

4. Davydenko D.B., Davydenko E.D., Isaev V.S. et al., An attempt of detection and study of the zones of endogenous fluidization with the set of remote and gas-geochemical methods (In Russ.), Vestnik Yuzhnogo nauchnogo tsentra, 2014, V. 10, no. 1, pp. 25–34.

5. Parada S.G., Kholod Yu.V., Shishkalov I.Yu., Geochemistry of secondary dispersion halos of the Malka-Musht ore deposit block (the Northern Caucasus) (In Russ.), Nauka Yuga Rossii, 2011, V. 7, no. 3, pp. 55–60.

6. Parada S.G., Alekseenko V.S., Vozmozhnosti ispol'zovaniya velichiny rN donnykh osadkov dlya otsenki neftegazonosnosti shel'fa Chernogo morya (Possibilities of using the pH value of bottom sediments to assess the oil and gas potential of the Black Sea shelf), Collected papers “Okruzhayushchaya sreda i chelovek. Sovremennye problemy genetiki, selektsii i biotekhnologii” (Environment and people. Modern problems of genetics, selection and biotechnology), Proceedings of International scientific conference and youth scientific conference in memory of the corresponding member of the RAS D.G. Matishov, Rostov-na-Donu, 2016, pp. 221–223.

7. Serebrennikova O.V., Geokhimicheskie metody pri poiske i razvedke mestorozhdeniy nefti i gaza (Geochemical methods in the search and exploration of oil and gas fields), Khanty-Mansiysk: Publ. of YuSU, 2008, 172 p.

8. Kondratov L.S., Fokina L.M., New opportunities for searching oil and gas fields by adsorbed form of gas of rocks and bottom deposits of water areas (In Russ.), Vesti gazovoy nauki, 2010, no. 2(5), pp. 124–134.

9. Lein A.Yu., Bogdanova O.Yu., Bogdanov Yu.A., Magazina L.O., Mineralogical and geochemical features of authigenic carbonates on seepings and hydrothermal fields (By the examples of the Black Sea reefs and the mounds of the lost city field) (In Russ.), Okeanologiya, 2007, V. 47, no. 4, pp. 577–593.

10. Afanasenkov A.P., Nikishin A.M., Obukhov A.N., Geologicheskoe stroenie i uglevodorodnyy potentsial Vostochno-Chernomorskogo regiona (Geological structure and hydrocarbon potential of the East Black Sea region), Moscow: Nauchnyy mir Publ., 2007, 172 p.

11. Geologiya SSSR (Geology of the USSR), Part Kh, Moscow, 1964, 656 p.

12. Esina L.A., Khvoroshch A.B., Structural plan and prospective petroleum potential of the Jurassic sediments of the Gudauty Rise in the Black Sea (In Russ.), Okeanologiya, 2014, V. 54, no. 1, pp. 89–96.

13. Kiryukhina L.N., Gubasaryan L.A., Biogeochemical characters of Crimean shelf’s bottom sediments from the Black Sea (In Russ.), Ekologiya morya, 2000, V. 50, pp. 18–21.

14. URL: http://www.chernomorneftegazcompany.com/reports/EcologicalStudiesSouth WestBlackSeaArea.


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