The article presents a concept to a full study of the lithological-facies conditions of the accumulation of carbonate reef sediments, replaced up the section by mixed terrigenous-carbonate coastal-marine sediments which in turn are replaced by terrigenous transitional and continental sediments. The relevance of studying Permian-Triassic deposits is obvious, since they compose one of the oil and gas complexes identified in Timan-Pechora oil and gas province. Previously, the study of Permian-Triassic complex was not carried out at the R. Trebs and A. Titov fields, as well as in the nearby areas.
This article provides a brief description of the algorithm for studying complex terrigenous-carbonate deposits of Permian-Triassic complex which include deposits of Asselian-Sakmarian stage, Artinskian and Kungurian stages, poorly defined Upper Permian complex, as well as Charkabozh suite of Lower Triassic. For the first time, for the indicated deposits, an analysis of the core material available for the deposits was carried out, maps of attributes were constructed using 3D seismic data and lithological-facies maps were constructed as well. Sediments were accumulating in different facies conditions, gradually replacing each other from marine conditions to continental ones. Asselian-Sakmarian complex was accumulating under the conditions of the carbonate platform with the development of chain-type organogenic structures. In Artinskian-Kungurian time interval the setting changed to the conditions of a mixed terrigenous-carbonate coastline where terrigenous-carbonate deposits accumulated. Upper Permian sediments were accumulating during the formation of the deltaic system. The sediments of Charkabozh formation were accumulating in continental conditions during the formation of an alluvial system of the intertwined type. The lithological typification of the section was carried out and together with the data of geophysical studies of wells and seismic survey made it possible to establish the main regularities of the deposits formation.
References
1. Dunham R.J., Ham W.E., Classification of carbonate rocks according to depositional texture, Classification of carbonate rocks, Proceedings of Symposium of American Association of Petroleum Geologists, 1962, no. 1, pp. 108–121.
2. Baraboshkin E.Yu., Prakticheskaya sedimentologiya. Terrigennye kollektory (Practical sedimentology. Terrigenous reservoirs), Tomsk: Publ. of TPU, 2011, 159 p.
3. Zhemchugova V.A., Rezervuarnaya sedimentologiya karbonatnykh otlozheniy (Reservoir sedimentology of carbonate deposits), Moscow: Publ. of EAGE, 2014, 232 p.
4. URL: https://www.google.ru/maps
5. Selley R.C., Ancient sedimentary environments and their sub-surface diagnosis, Cornell University Press,1970.
6. Logvinenko N.V., Petrografiya osadochnykh porod (s osnovami metodiki issledovaniya) (Petrography of sedimentary rocks (with the basics of research methods)), Moscow: Vysshaya shkola Publ., 1984, 416 p.
7. Nichols G., Sedimentology and stratigraphy, 2009, Wiley-Blackwell, 432 p.
