Reсonstruction of sandstone sedimentation environments: new insights gained from mathematical analysis of granulometric data

UDK: 551.3.051

DOI: 10.24887/0028-2448-2025-12-8-14

Key words: granulometric analysis, sandstones, hydrodynamic conditions, sedimentological environments

Authors: M.V. Shaldybin (RN-Upstream design LLC, RF, Tomsk); S.А. Redikultsev (ROSPAN INTERNATIONAL JSC, RF, Novy Urengoy); А.А. Nikolaev (RN-BashNIPIneft LLC, RF, Ufa); V.М. Yatsenko (Rosneft Oil Company, RF, Moscow)

The analysis of the size distribution of particles in sandy rocks is a crucial sedimentological approach that enables us to understand the hydrodynamic conditions in aquatic environments, as well as the methods of transportation and deposition of these rocks. However, in Russia, this technique is not given much attention, with most research focusing on the quantification of the fine pelitic fraction and using these results to plan the bottomhole screen for well completion. Various methods such as grain-size statistical parameters, bivariate analysis, linear discriminate functions, Passega and Ludwikowska diagrams were used to reveal the depositional processes, sedimentation mechanisms, hydrodynamic energy and facies conditions. All studies were performed for fields and sandy deposits that are actively being studied by Rosneft's laboratory centers. The results of the discriminant analysis showed that Cretaceous sandstones from the BS and Achimov formations were formed in shallow-water environments under the influence of active internal tides. Jurassic sandstones, on the other hand, have a wide distribution of possible sedimentological environments, including coastal facies and beaches. The Bobrikov Horizon sandstones tend to be near-shore facies, but also can be considered as aeolian dunes, while the Vendian B-8 sandstones may have formed as aeolian deposits when they were actively discharged and deposited into shallow sea waters.

References

1. Bikkenin V.T., Rozhkov G.F., A critical review of genetic diagrams in granulometry (In Russ.), Litologiya i poleznye iskopaemye, 1982, no. 6, pp. 3–14.

2. Romanovskiy S.I., Fizicheskaya sedimentologiya (Physical sedimentology), Leningrad: Nedra Publ., 1988, 240 p.

3. Burleva O.V., Genetic interpretation of granulometric data of sandy-silty rocks of the Yu1 horizon in the southeast of the West Siberian Plate (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2001, no. 10, pp. 95–100.

4. Vakulenko L.G., Predtechenskaya E.A., Chernova L.S., Experience of using granulometric analysis for reconstructing the formation conditions of sandstones in productive strata of the Vasyugan horizon (Western Siberia) (In Russ.), Litosfera, 2003, no. 3, pp. 99–108.

5. Kudryashova L.K., Granulometric analysis as the main method for substantiating the conditions of formation of reservoirs YuK2-5 of the Em-Egovskaya area (Western Siberia) (In Russ.), Izvestiya TPU. Inzhiniring georesursov, 2015, V. 326, no. 10, pp. 143–149. 6. Folk R.L., Ward W., Brazos river bar: a study in the significance of grain size parameters, Journal of Sedimentary Petrology, 1957, V. 27, pp. 3–26, DOI: https://doi.org/10.1306/74D70646-2B21-11D7-8648000102C1865D

7. Folk R.L., A review of grain-size parameters, Sedimentology, 1966, V. 6, pp. 73–93, DOI: https://doi.org/10.1111/j.1365-3091.1966.tb01572.x

8. Sahu B.K., Depositional mechanism from the size analysis of elastic sediments, Journal of Sedimentary Petrology, 1964, V. 34, pp. 73–83,

DOI: https://doi.org/10.1306/74D70FCE-2B21-11D7-8648000102C1865D

9. Baiyegunhi C., Liu K., Gwavava O., Grain size statistics and depositional pattern of the Ecca Group sandstones, Karoo Supergroup in the Eastern Cape Province, South Africa Open Geoscience, 2017, V. 9, pp. 554–576, DOI: https://doi.org/10.1515/geo-2017-0042

10. Sinha A., Rais S., Granulometric analysis of Rajmahal inter-trappen sedimentary rocks (Early Cretaceous), Eastern India, implications for depositional history, International Journal of Geosciences, 2019, V. 10, pp. 238–253, DOI: https://doi.org/10.4236/ijg.2019.103015

11. Sahu B.K., Multigroup discrimination of depositional environments using size distribution statistics, Indian Journal of Earth Sciences, 1983, V. 10, pp. 20–29.

12. Passega R., Grain size representation by C-M pattern as a geological tool, Journal of Sedimentary Petrology, 1964, V. 34, pp. 830–847,

DOI: https://doi.org/10.1306/74D711A4-2B21-11D7-8648000102C1865D

13. Mycielska-Dowgiałło E., Ludwikowska-Kędzia M., Alternative interpretations of grain-size data from Quaternary deposits, Geologos, 2011, V. 17(4), pp. 189–203,

DOI: https://doi.org/10.2478/v10118-011-0010-9

14. Shaldybin M.V., Wilson M.J., Wilson L. et al., Jurassic and Cretaceous clastic petroleum reservoirs of the West Siberian sedimentary basin: Mineralogy of clays and influence on poro-perm properties, Journal of Asian Earth Sciences, 2021, V. 222, DOI: https://doi.org/10.1016/j.jseaes.2021.104964

15. Cacchione D.A., Pratson L.F., Ogston A.S., The shaping of continental slopes by internal tides, Science, 2002, V. 296(5568), DOI: https://doi.org/10.1126/science.1069803

16. Shaldybin M., Kvachko S., Rudmin M. et al., Ancient Aeolian reservoirs of the East Siberia Craton, Geosciences, 2023, V. 13(8), DOI: https://doi.org/10.3390/geosciences13080230