The Oil and Gas Potential of the Ordovician–Lower Frasnian Megacomplex of the Pechora Sea Shelf

2021 ◽  
Vol 76 (5) ◽  
pp. 538-549
Author(s):  
A. D. Dzyublo ◽  
V. V. Sidorov ◽  
M. S. Zonn ◽  
I. G. Agadzhanyants
Author(s):  
E. B. Rile ◽  
◽  
A. V. Ershov ◽  
A. V. Ershov ◽  

The research is based on the three-layer natural hydrocarbon reservoirs theory, which allocates 3 layers in a natural reservoir – the genuine seal, the productive part and the intermediate layer situated between them - the false seal. The Middle Ordovician-Lower Frasnian terrigenous complex variable in thickness, composition and stratigraphic completeness sub-regional natural reservoir was identified in the northern part of the Timan-Pechora oil and gas province adjacent to the Pechora Sea. It includes several zonal and local natural reservoirs (Middle Ordovician-Lower Devonian, Middle Ordovician-Eiffelian, Zhivetian-Lower Frasnian and others). The distribution areas of these natural reservoirs were extrapolated to the Pechora Sea offshore. The areas with the highest prospects of oil and gas potential of the Pechora Sea offshore were delineated, basing on the Timan-Pechora oil and gas potential analysis. These are the northwest extensions into the Pechora Sea of the Denisov trough, the Kolva megaswell, as well as the Varandei-Adzva structural zone and the Karotaiha depression. Keywords: natural reservoir; genuine seal; false seal; field; pool; hydrocarbons.


Author(s):  
A.A. Timirgalin ◽  
M.G. Butorina ◽  
N.O. Novikov ◽  
G.V. Volkov ◽  
I.R. Mukminov ◽  
...  

The resource base of Western Siberia needs to be replenished to maintain the current development indicators. The reserves associated with the classic structural traps were diagnosed and mapped for the main horizons in Western Siberia. Replenishment of the resource base at the expense of such reserves is ineffective due to the fact that undiscovered traps of these types are thin, or lie at great depths, which ultimately negatively affects the quality of the resource base and the economic efficiency of their involvement in development. The driver of the growth and replenishment of the resource base under current conditions is the Achimov deposits, which are ubiquitous in this area at depths of 2500–3500 m and are genetically deep-water deposits of fans. The advantage of involving these deposits in development is often associated with the confinement to existing assets, where production is carried out from above and below-lying geological objects, the complexity is associated with the lithological type of traps, which is not diagnosed by direct analysis of seismic materials, as well as the extremely poor knowledge of the deposits over the area. Considering that the variability of properties over the area is a distinctive feature of Achimov deposits, the factor of poor knowledge by drilling significantly complicates the understanding of the potential of the deposits. In order to identify and assess the most promising areas for involvement in the development of the Achimov deposits, in PJSC Gazprom Neft the work “Regional assessment and zonal study of the prospects for oil and gas potential of the Achimov formation in the Western Siberia” was carried out. The goal and objectives is to form a reliable tool for searching and forecasting potential options using the generated regional maps of criteria (various characteristic properties and their combinations) built on the basis of data generalization throughout Western Siberia.


Author(s):  
С.К. Курбаниязов

В начале барремского времени море отступило и до начала позднего альба территория представляла собой низменную аккумулятивную равнину, в пределах которой происходило накопление аллювиальных и озерно-аллювиальных отложений: красно-коричневых глин, алевролитов с прослоями коричневых песчаников и песков и линзами темно-серого лигнита. В основании толщи отмечаются гравелиты и конгломераты. В раннемальбе произошла кратковременная трансгрессия моря, однако территория современного Восточного Приаралья не была затоплена и представляла собой прибрежно-морскую равнину, где накапливались глины, алевролиты и песчаники. К концу позднего альба море регрессировало, и территория вновь стала представлять собой низменную аллювиально-озерную равнину. По всей территории происходило накопление пестроцветных глин, зеленовато-серых алевролитов, песков и песчаников, а также углей. При проведении иследовательских работ были обоснованы наиболее перспективные типы ловушек углеводородного сырья по стратиграфическим уровням и выявлена зональность их распространения. Дана оценка перспектив района на выявление залежей нефти и газа. Выделены информативные и качественные признаки (критерии) нефтегазоносности. Обоснованы площади и конкретные структуры для постановки детальных поисковых работ на выявление залежей нефти и газа. Рассчитана оценка потенциальных ресурсов углеводородного сырья. At the beginning of the Barremian time, the sea receded and until the beginning of the late Alb, the territory was a low-lying accumulative plain, within which the accumulation of alluvial and lacustrine-alluvial deposits occurred: red-brown clays, siltstones with layers of brown sandstones and sands and lenses of dark gray lignite. Gravelites and conglomerates are noted at the base of the strata.In the Rannemalba, there was a short-term transgression of the sea, but the territory of the modern Eastern Aral Sea region was not flooded and was a coastal-sea plain, where clays, siltstones and sandstones accumulated. By the end of the Late Alb, the sea regressed and the area again became a low-lying alluvial-lacustrine plain. There was an accumulation of variegated clays, greenish-gray siltstones, sands and sandstones, as well as coals throughout the territory. During the research work, the most promising types of hydrocarbon traps were justified by stratigraphic levels and the zoning of their distribution was revealed. The assessment of the prospects of the area for the identification of oil and gas deposits is given. Informative and qualitative signs (criteria) of oil and gas potential are identified. The areas and specific structures for setting up detailed search operations to identify oil and gas deposits are justified. The estimation of potential resources of hydrocarbon raw materials is calculated.


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