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UDC 553.98:552.54(571.5)

https://doi.org/10.26516/2541-9641.2025.4.133

EDN: RVGZVL

Influence of Tectonic Faults on the Formation of Secondary Calcitization of the Osinsky Horizon within the Nepa-Botuoba Anteclise

A.R. Valiullin¹, V.A. Zakharova²

¹Gazprom neft company group, Saint Petersburg, Russia

²Tyumen State University, Tyumen, Russia

Abstract. The osinsky horizon (Reservoir B1) of the Nepa-Botuoba Anteclise is characterized by complex geology and widespread secondary processes, among which calcitization significantly deteriorates reservoir properties. Identifying factors controlling the spatial distribution of secondary calcitization zones is crucial for improving reservoir quality prediction. This research aims to establish a relationship between tectonic fault development and the intensity of secondary calcitization in Reservoir B1 of the osinsky horizon. An integrated approach was used, including analysis of lithological (LithoScanner), and microimager (FMI) logging data from 12 wells, interpretation of seismic and electro-tomography data, and results from basin and geomechanical modeling. The comprehensive analysis revealed not only an inverse relationship between the proximity to the Tympuchikan Thrust and the secondary calcite content but also a coincidence between the strike of conductive fractures and the thrust direction. This provides direct evidence that the tectonic faults acted as a drainage system for the migration of mineralized fluids, which prevented calcite precipitation. It is concluded that the proximity to the thrust is a qualitative criterion for predicting zones with improved reservoir properties in Reservoir B1, offering opportunities for effective exploration planning in understudied areas with similar structural settings.

Keywords: osinsky horizon, secondary calcitization, tectonic faults, Tympuchikan Thrust, reservoir properties, reservoir, LithoScanner, basin modeling

References

Gorodnov A.V. Determination of filtration-capacity properties of salinized reservoirs in terrigenous deposits of the Nepa Arch of Eastern Siberia / A.V. Gorodnov, V.N. Chernoglazov, O.P. Davydova // Scientific and Technical Bulletin "Karotazhnik". Tver : 2012. Vol. 12 (222). P. 25-41.

Vorobiev V.S. Model of distribution of terrigenous reservoirs and salinized sandy-gravelly deposits within the fields of the central part of the Nepa Arch / V.S. Vorobiev, I.V. Chekanov, Ya.S. Klinovaya // Geology of Oil and Gas. Moscow : 2017, No. 3. P. 47–60.

Vorobiev V.S. Patterns of distribution of reservoirs and salinization intervals in the Vendian terrigenous complex of the Chonsk group of fields (Eastern Siberia) / V.S. Vorobiev, L.N. Shakirzyanov, E.A. Zhukovskaya // Abstracts of the conference "Problems and Experience in Developing Hard-to-Recover Reserves of Oil and Gas Condensate Fields". Saint Petersburg : 2015.

Melnikov N.V. Vendian-Cambrian Salt-Bearing Basin of the Siberian Platform (Stratigraphy, History of Development) / N.V. Melnikov. 2nd ed. Novosibirsk : SNIIGGiMS Publishing House, 2018. 177 p.

Valiullin Artur Rasimovich,

Gazprom neft company group,

3–5, Pochtamtamtskaya st., 190000, Saint Petersburg, Russia,

Main Specialist,

tel: +7(3452) 685 670 (доb. 6392),

еmail: Valiullin.ar@gazprom-neft.ru

Zakharova Valeriia Aleksandrovna,

Tyumen State University,

6, Volodarskogo str. 625003, Tyumen, Russia,

Specialist,

еmail: Zakharova.va@contractor.gazprom-neft.ru