Geometrization of East Siberia complex carbonate reservoirs with integration of well-testing and seismic surveys

Complex carbonate reservoirs of Eastern Siberia are highly heterogeneous and difficult to predict seismically because of intrusive bodies, thin-bedded strata, and salinization zones. This study aims to evaluate the effectiveness of an integrated reservoir geometrization approach for refining the boundaries of productive zones, improving production drilling success, and reducing geological risks using an oil and gas condensate field in the Irkutsk Region as a case study. The leading method is a retrospective analysis by integrating long-term well testing, interference testing, numerical 2D flow modeling in Kappa Ecrin Saphir, seismic attribute maps (acoustic impedance and Vp/Vs ratio), and seismic facies analysis. The results show that the productive reservoir is only partly associated with basement highs and does not fully conform to their boundaries. By combining dynamic reservoir data with seismic information, the authors define the lateral extent of vuggy porosity zones more accurately. Initial rates, reservoir pressure measurements, and pulse interference tests confirm authors' results. This approach can enhance drilling success from 78,4 % to 86,4 % and provides an effective tool for optimizing well placement and development programs.

1. Kayachev N. F., Nazarov D. V., Shutalev A. D., Dadakin N. M., Kotelnikov I. A., Kutukova N. M. Elision processes as main factors in formation of high-productive carbonate rocks of vendian-cambrian deposits in Eastern Siberia. Oil Industry. 2020;5:16–21. (In Russ.). https://doi.org/10.24887/0028-2448-2020-5-16-21

2. Kuznetsov V. G. Natural reservoirs of oil and gas in carbonate sediments. Moscow: Nedra; 1992. (In Russ.).

3. Lucia F. J. Carbonate reservoir characterization: an integrated approach. 2nd ed. Berlin; Heidelberg: Springer, 2007. 264 p. https://doi.org/10.1007/978-3-540-72742-2

4. Nelson R. A. Geologic analysis of naturally fractured reservoirs. 2nd ed. Houston : Gulf Professional Publishing, 2001. 349 p.

5. Tchistiakov A., Snegireva I., Spivakova M., Cheremisin A. DFN Modeling Approach in the Eastern Siberia Oil and Gas Condensate Carbonate Reservoir. First EAGE Workshop on Advances in Carbonate Reservoirs from Prospects to Development. European Association of Geoscientists & Engineers. 2024;(2024):1–5. https://doi.org/10.3997/2214-4609.2024634037

6. Kolesov V., Ter-Saakov S. Weak and Large Collector (Based on the Examples of the Eastern Siberia Carbonate Reservoirs). Progress’19. 2019. 2019;(1):1–5. European Association of Geoscientists & Engineers. https://doi.org/10.3997/2214-4609.201953051

7. Okpoli C. C., Arogunyo D. I. Integration of well logs and seismic attribute analysis in reservoir identification on PGS field onshore Niger Delta, Nigeria. Pakistan Journal of Geology. 2020;4(1):12–22. https://doi.org/10.2478/pjg-2020-0002

8. Kulpin L. G. Hydrodynamic methods of borehole research under elastic filtration conditions in confined formations : abstract of the dissertation for the degree of Candidate of Technical Sciences. Moscow: Moscow. in-t neftekhim. and the I. M. Gubkin Gas Industry; 1971. (In Russ.).

9. Deeva T. A., Kamartdinov M. R., Kulagina T. E., Mangazeev P. V., Pankov M. V. Hydrodynamic Research of Wells. Tomsk: Tomsk Polytechnic University Press, 2004. (In Russ.).

10. Okabe A., Boots B., Sugihara K., Chiu S. N. Spatial tessellations: concepts and applications of Voronoi diagrams. 2nd ed. Chichester; New York: Wiley; 2000.

11. Nikishin A. M., Startseva K. F., Verzhbitsky V. E., Cloetingh S., Malyshev N. A., Petrov E. I. [et al.]. Sedimentary basins of the East Siberian Sea and the Chukchi Sea and the adjacent area of the Amerasia Basin: seismic stratigraphy and stages of geological history. Geotectonics. 2019;53(6),635–657. https://doi.org/10.1134/S001685211906010

12. Bourdet D. Well test analysis: the use of advanced interpretation models. Amsterdam: Elsevier; 2002.

13. Bogannik G. N., Gurvich I. I. Seismic exploration. Tver: AIS; 2006. (In Russ.).