M.D. Balagurov
Lower Vendian deposits in south-western slope of Nepsky Arch (Eastern Siberia): lithology and depositional settings
DOI 10.31087/0016-7894-2022-5-51-61
Key words: Vendian deposits; lithology; sandstone; evaporite; mineral assemblage; salinization; Acoustic Impedance.
For citation: Balagurov M.D. Lower Vendian deposits in south-western slope of Nepsky Arch (Eastern Siberia): lithology and depositional settings. Geologiya nefti i gaza. 2022;(5):51–61. DOI: 10.31087/0016-7894-2022-5-51-61. In Russ.
In one of the large East Siberian oil and gas field situated in the south-western part of the Nepsky Arch, exploratory drilling with total coring of the main oil and gas bearing intervals was carried out, including the coring of the basal part of sedimentary cover composed of the Nepsky Fm Vendian sediments. The core was subjected to laboratory studies with the purpose of detailed description of the lightly saline Lower Vendian Nizhnenepsky reservoir intervals, and they are the subject of research in this work. This paper mainly presents the results of the laboratory studies of the Nizhnenepsky rock lithology. A sequence of the cycle members composing the basal, middle, and upper series of the Nizhnenepsky Member is identified. Each rock group has different lithological and sedimentological characteristics, reservoir properties, degree of salinization and silting. Fine- and medium grained mesomictic sandstone from the middle section of the member are the most saline and carbonated, and fine-grained arkosic sandstone of the upper section are lesser saline and carbonated. A number of relatively approximate wells in the center of the study area are similar in terms of high content of mainly sulphate group of evaporites and carbonate minerals in the rocks of the middle section of the Nizhnenepsky Member. Among the carbonate minerals, dolomite that entirely composes individual layers is dominating. It is also present as cement in sandstone lenses and interlayers, in certain samples its content exceeds 90 %. In the well drilled in the marginal western segment of the study area, the section pattern in the middle interval is markedly different. Clastic halite-saline deposits were encountered throughout the section of the target interval. Basing on the integrated analysis of the available geological and geophysical data, lithologies of the rocks are described, and salt occurrence intervals are identified in the well columns. In addition, a methodological approach to predicting zones of salinization of terrigenous rocks and zones promising for exploratory drilling is proposed that can be used as early as the initial interpretation of 3D seismic data.
Maxim D. Balagurov
Chief Specialist
Lomonosov Moscow
State University,
1, Leninskiye gory, GSP-1, Moscow, 119991, Russia
e-mail: maxim_balagurov@mail.ru
ORCID ID: 0000-0002-3640-2293
1. Vorobyev V.S., Chekanov I.V., Klinovaya Ya.S. The distribution model of terrigenous reservoirs and saline sand-gravelite deposits within the fields of the central part of the Nepal arch. Geologiya neft i i gaza. 2017;(3):47–60. In Russ.
2. Shemin G.G. Geologiya i perspektivy neftegazonosnosti venda i nizhnego kembriya tsentral’nykh raionov sibirskoi platformy (Nepsko- Botuobinskaya, Baikitskaya anteklizy i Katangskaya sedlovina) [Geology and petroleum potential of Vendian and Lower Cambrian of the central Siberian Platform regions (Nepsky-Botuobinsky, Baikitsky anteclises, and Katangsky saddle)]. Novosibirsk: Izd-vo SO RAN; 2007. 467 p. In Russ.
3. Vassoevich N.B. Izbrannye trudy. Litologiya i neftegazonosnost’ [Selectas. Lithology and petroleum potential]. Moscow: Nauka; 1990. 264 p. In Russ.
4. Krasheninnikov G.F. Uchenie o fatsiyakh [Theory of facies]. Moscow: Vysshaya shkola; 1971. 368 p. In Russ.
5. Shantzer E.V. Principles of the studies of genetic types of continental sedimentary formations [Essays on the doctrine of genetic types of sedimentary continental formations]. Moscow: Nauka; 1966. 240 p. In Russ.
6. Mel’nikov N.V. Vend-kembriiskii solenosnyi bassein Sibirskoi platformy. (Stratigrafiya, Istoriya razvitiya) [Vendian-Cambrian salt-bearing basin of Siberian Platform (stratigraphy, history of evolution)]. Novosibirsk: Izdatel’stvo SO RAN; 2009. 148 p. In Russ.
7. Konoval’tseva E.S. Secondary processes in reservoir rocks of productive sediments of Yaractinski deposit. Neftegazovaya geologiya. Teoriya i praktika. 2010;(5):1–11. In Russ.
8. Burlin Yu.K., Konyukhov A.I., Kornyushina E.E. Litologiya neftegazonosnykh tolshch [Lithology of oil and gas bearing sequences.]. Moscow: Nedra, 1991; 290 p. In Russ.
9. McDonald G.J.F. Anhydrite-gypsum equilibrium relations. American Journal of Science. 1953;(251):247–272. DOI: 10.2475/ajs.251.12.884.
10. Antsiferov A.S. Formirovanie neftegazovykh zalezhei i metodika ikh poiskov v yuzhnykh raionakh Sibirskoi platformy [Oil and gas pool formations and methodology of prospecting for them in the southern regions of Siberian Platform]. Geologiya nefti i gaza. 1976;(12):5–8. In Russ.
11. Gurova T.I., Chernova L.S., Potlova M.M. et al. Litologiya i usloviya formirovaniya rezervuarov nefti i gaza Sibirskoi platform [Lithology and settings of formation of oil and gas reservoirs in Siberian Platform]. Moscow: Nedra; 1988. 254 p. In Russ.
12. Karnyushina E.E., Korobova N.I., Stupakova A.V., Sautkin R.S. Ehtapy rannevendskoi sedimentatsii na vostochnom sklone Baikitskoi anteklizy [Stages of Early Vendian sedimentation in the eastern slope of the Baikitsky Anteclise]. In: Novye idei v geologii nefti i gaza — 2017 : mat-ly mezhdunarodnoi nauchno-prakticheskoi konferentsii (Moscow, 25–26 May, 2017). Moscow; 2017. pp. 126–127. In Russ.
13. Mukhidinov Sh.V., Vorobyev V.S. Methodical features of petrophysical study salinization clastic rocks of oil and gas fields Chong Group. PROneft . 2017;(1):32–37. In Russ.
Section: Oil and gas reservoirs