Hydrocarbon reserves of the Kuyumbinskoye field are concentrated in reservoirs with secondary voids of fracture and cavernous-fractured type. The latter were formed by chemical and physical weathering of carbonate rocks as they were brought to the surface (hypergenesis). This paper focuses on the methodology of studying the reservoirs with secondary voids formed by hypergenesis processes. Modeling of the hypergenesis zone was carried out. For the studied sediments within the hypergenesis zone, three vertical zones, named by the predominant processes in them, were identified: oxidation, leaching, cementation. The patterns of vertical change in capacity along the section of the hypergenesis zone were studied. The area forecast of cavernosity distribution was made. A predictive map of thicknesses of reservoir intervals with increased capacity was constructed on the basis of detailed structural interpretation of 3D seismic surveys and paleogeographic analysis. The paper shows that the distribution of high-capacity zones (cavernous intervals) is controlled by erosion-denudation processes. The reconstruction of the paleorelief of the pre-Vendian erosion surface and the conditions of denudation processes was carried out. The correlation of cavernosity development to the paleorelief elements was revealed. For the first time in this area, seismic data revealed depressional ring anomalies of the «karst sinkhole» type - a search criterion for zones of reservoirs with improved poroperm properties. As a result of these studies, a new approach to modeling of secondary formed voids (cavernous zones) in the area and section of the studied field was developed.
References
1. Kulishkina O.N., Konyaev D.N., Berin M.V., Ryazanov P.O., The study of the Riphean fractured reservoir in the zone of hypergenesis to increase the efficiency of oil production, Proceedings of 8th International Geological and Geophysical Conference and Exhibition «St. Petersburg 2018. Innovations in Geosciences - Opening Times», St. Petersburg, 09-12.04.2018, DOI: https://doi.org/10.3997/2214-4609.201800297
2. Kharakhinov V.V., Kulishkin N.M., Shlenkin S.I., Olyunin A.V., New approaches to the investigation of oil and gas potential for the Pre-Jurassic deposits in the West-Siberian oil and gas province (In Russ.),Geologiya nefti i gaza, 2015, no. 6, pp. 63-77.
3. Kharakhinov V.V., Shlenkin S.I., Afonasin V.V. et al., New approaches to geological modeling of fractured reservoirs in East Siberia (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 11, pp. 93–97.
4. Kharakhinov V.V., Shlenkin S.I., Afonasin V.V. et al., Some specific features of geological and hydrodynamic modeling of fractured reservoirs in ancient complexes of East Siberia (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2013, no. 2, pp. 11–20.
5. Kharakhinov V.V., Shlenkin S.I. et al., Treshchinnye rezervuary nefti i gaza (Fractured oil and gas reservoirs), Moscow: Nauchnyy mir Publ., 2015, 284 p.
6. Gvozdetskiy N.A.,Karst (Karst), Moscow: Mysl’ Publ., 1981, 214 p.
7. Malkov V.N., Gurkalo E.I., Monakhova L.B.et al., Karst i peshchery Pinezh’ya (Karst and caves of the Pinezhsky region), Moscow: EKOST Publ., 2001, 208 p.
