Study of the features of the formation, structure and hydrocarbon potential accounting of the Upper Cretaceous oil-water deposits (the Eastern Ciscaucasia)

UDK: 553.98
DOI: 10.24887/0028-2448-2022-3-12-16
Key words: underformed deposit, Upper Cretaceous, Paleogene, Eastern Stavropol, permeability, well testing, hydrophobicity, oil-generating parent rocks, well logging, chalk-like limestone, caven-fractured reservoir
Authors: A.A. Brailovskaya (NK Rosneft-NTC LLC, RF, Krasnodar), M.A. Naumova (NK Rosneft-NTC LLC, RF, Krasnodar), V.M Yatsenko (Rosneft Oil Company, RF, Moscow)

Scientists have been interested in studying the lithological composition, geological structure and stratification of sections, reservoir properties, saturation, conditions and history of the development of Upper Cretaceous deposits (K2) of the Eastern Caucasus for more than 70 years. The problem of further study of Upper Cretaceous deposits and associated hydrocarbon deposits is very complex and relevant. In previos work the authors showed the similarities and differences of the geological structure and conditions of the development of Upper Cretaceous deposits within a number of regions of the Eastern Caucasus: Eastern Stavropol, the Republique of Ingushetia, and the Chechen Republic. The deposits are differentiated by the depths of their occurrence, the conditions of formation and maturity, the types of reservoirs, the presence of discontinuous faults, the intensity and composition of fluid inflows. The formed mature high-amplitude (over 250-500 m), complicated by discontinuous disturbances of various order, including intrawater dislocations, Upper Cretaceous traps of the Chechen Republic and the Republique of Ingushetia are characterized by initial fluid flow rates up to 200-3000 t/day and practically anhydrous hydrocarbons tributaries. For low-amplitude (less than 50 m) underformed deposits of Eastern Stavropol and Plain Dagestan, not rich in intra-water faults, less representative fluid flow rates (more often under 100-150 t/day) with a high water content at all stages of development are characteristic. The tendency of the dependence of the intensity and composition of tributaries on the amplitude of Upper Cretaceous deposits and a number of other factors was traced by the authors within the Eastern Stavropol territory. The differentiation of "non-standard" traps of the region according to the features of the lithological and stratigraphic structure, the potential of carbonate reservoirs, taking into account the tectonic, geochemical and geological prerequisites for their formation, is carried out.

In this article specialists of Rosneft Company and its subsidiary Rosneft-NTC have identified and analyzed the signs of the most promising Maastricht zones of the Eastern Stavropol Region that are relevant when searching for missed traps, planning well interventions and contributing to improving the efficiency of the Company's field development. These features can be applied to other oil and gas bearing areas with similar geological conditions. Also, recommendations are given for optimizing the development processes of immature hydrocarbons deposits in carbonate cavern-crack rocks.


1. Braylovskiy A.L., Povyshenie effektivnosti geofizicheskikh issledovaniy skvazhin dlya izucheniya slozhnykh karbonatnykh kollektorov (na primere verkhnemelovykh otlozheniy Prikumskoy sistemy podnyatiy) (Improving the efficiency of well logging for the study of complex carbonate reservoirs (by the example of the Upper Cretaceous deposits of Prikumsk the uplifts)): thesis of candidate of geological and mineralogical science, Groznyy, 1985, 219 р.

2. Braylovskaya A.A., Miroshnichenko V.V., Oks L.S., Yatsenko V.M., A comprehensive approach to the re-evaluation of the geological structure of ‘low-pore’ deposits in a limited set and low quality of initial data on the example of deposits in the Republic of Ingushetia (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2020, no. 10, pp. 30–36, DOI: 10.24887/0028-2448-2020-10-30-36

3. Chepak G.N., Polosin B.A., Plotnikov M.S. et al., Reservoir properties of carbonate rocks of the Triassic and Upper Cretaceous of the Eastern Stavropol region (In Russ.), Neftegazovaya geologiya i geofizika, 1980, no. 12, pp. 6–9.

4. Stulov L.G., Tomashev D.V., Paporotnaya A.A., Features of the geological structure and location of oil deposits in the Cretaceous (Maastrichtian stage) natural reservoir (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2013, no. 2, pp. 33–35.

5. Nelepov M.V., Tektonicheskie usloviya formirovaniya zalezhey uglevodorodov mezozoyskikh otlozheniy Vostochnogo Predkavkaz'ya (Tectonic conditions for the formation of hydrocarbon deposits in the Mesozoic deposits of the Eastern Ciscaucasia): thesis of candidate of geological and mineralogical science, Stavropol, 2005, 188 р.

6. Neruchev S.G., Nefteproizvodyashchie svity i migratsiya nefti (Oil producing formations and oil migration), Leningrad: Nedra Publ., 1962, 224 р.

7. Panchenko A.S., Voprosy formirovaniya zalezhey uglevodorodov v mezozoyskikh otlozheniyakh Predkavkaz'ya (Issues of the formation of hydrocarbon deposits in the Mesozoic deposits of Ciscaucasia), Collected papers “Geologiya, razvedka i razrabotka gazovykh i gazokondensatnykh mestorozhdeniy Severnogo Kavkaza“ (Geology, exploration and development of gas and gas condensate fields in the North Caucasus), Proceedings of  SKF VNIIgaz, 1971, no. 4, pp. 61–71.

8. Mikhaylov N.N., Motorova K.A., Sechina L.S., Smachivaemost' neftegazovykh plastovykh sistem (Wettability of oil and gas reservoir systems), Moscow: Publ. of Gubkin University, 2019, 360 p.

9. Golf-Racht T., Fundamentals of fractured reservoir engineering, Amsterdam, New York: Elsevier, 1982, 608 р.

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