В статье приводятся результаты оценки начальных суммарных ресурсов нетрадиционных источников УВ в отложениях доманикового типа, хадумской и баженовской свит. Обоснована целесообразность проведения оценки ресурсов УВ в этих отложениях объемным методом. Приведен стратиграфический интервал их распространения. Изложена методика нефтегазогеологического районирования на основе картирования структурно-фациальных зон, степени катагенетической преобразованности ОВ, граничных значений мощности углеродистых пород в разрезе. Определены критерии выделения продуктивных интервалов, составляющих эффективную часть разреза. Обоснован выбор таких параметров, как коэффициент пористости, коэффициент извлечения нефти, коэффициент нефтенасыщенности, пересчетный коэффициент и плотность нефти. Для каждого комплекса отложений в расчет суммарных геологических ресурсов введены поправки, связанные с особенностями геологического строения подсчетных объектов, условиями их залегания и степенью геолого-геофизической изученности. Приведены объемы суммарных геологических и извлекаемых ресурсов нетрадиционных источников УВ для Волго-Уральской, Тимано-Печорской, Причерноморско-Северо-Кавказской, Западно-Сибирской и Лено-Тунгусской НГП. Проведенные исследования обосновали значительные ресурсы, добыча которых может компенсировать снижение объемов нефти из традиционных залежей. The estimation results of the initial total unconventional resources of hydrocarbon in Domanik type sediments, the Khadum and Bazhenov formations are provided. The reasonability of estimating hydrocarbon resources in these deposits by the volumetric method is substantiated. The stratigraphic interval of their distribution is given. The technique of oil and gas geological zoning based on the mapping of structural and facies zones, the degree of catagenetic transformation of organic matter, and the boundary values of the thickness of carbonaceous rocks in the section is described. The criteria for the allocation of pay intervals that make up the effective part of the section are determined. The choice of parameters such as porosity coefficient, oil recovery coefficient, oil saturation coefficient, correction factor and oil density is justified. For each complex of deposits, adjustments related to the features of the geological structure of the estimation targets, the conditions of their occurrence and the degree of geological and geophysical study have been introduced into the estimation of total geological resources. The volumes of total geological and recoverable resources of unconventional hydrocarbon sources for the Volga–Ural, Timan–Pechora, Black Sea–North Caucasus, West Siberian and Lena–Tunguska oil and gas provinces are given. The conducted research has rationalized extensive resources, the recovery of which can compensate for the decrease in oil volumes from traditional deposits.

Today there is no verified methodology to calculate oil reserves in the Bazhenov Formation, which makes it impossible to identify any references for the initial oil reserves. Therefore, the analog approach that is usually applied for quantitative assessment of petroleum potential becomes inapplicable. The paper considers different approaches to assessment of the petroleum potential of the Bazhenov Formation in West Siberia. Since oil distribution in the formation is determined by the initial content and catagenetic maturity of organic matter in the rock and controls the formation of an effective reservoir, it becomes apparent that estimating the oil resources and reserves requires geochemical studies. The proposed methodological approaches consider separation of net oil pays using the Rock-Eval data, well log data, and results of oil-promising objects survey and the principles of differentiated assessment of oil resources and territory ranking by the compositions of saturating hydrocarbons.

The paper deals with the South Kara regional depression covering the southern part of the Kara Sea and presents a comparative analysis of the geologic structure of potential exploration targets in the offshore and onshore regions of the study area. Regional tectonic processes are considered, and the main stages of the formation of large tectonic elements are reconstructed. A comparison of the anticline traps in the onshore parts of the study area and offshore Kara Sea regions is made.

The paper presents approaches to characterization of shale source rocks using geochemical data for the case of the Bazhenov petroleum system in West Siberia. Regional patterns of oil distribution in the Bazhenov shale are shown to depend on their original total organic carbon (TOC) content and thermal maturity. The existing thermal maturity model for the Bazhenov Formation based on vitrinite reflectance (R-vt(o)) of nearby beds has been updated using parameters measured by Rock-Eval pyrolysis (T-max, HI, PC, and RC) for the shale itself. The results were used to quantify hydrocarbon resources in different maturity zones. The relationship between TOC and the presence of para-autochthonous oil found for logged zones in the Bazhenov section allows allocating and quantifying oil resources in unlogged beds. (C) 2017, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.

Numerical models are developed to predict the generation, accumulation, and escape of hydrocarbons at the time of sediment accumulation (basin modeling) in the West Siberian geosyneclise during the Jurassic, Cretaceous, and Cenozoic. A theoretical framework for such computer models is presented with a special emphasis on modeling of gas generation during early catagenesis. The study provides a description of the algorithm used for interpretation of simulation results and considers the stages of formation of a shale cap rock during lithogenesis. Peak oil generation began in the Aptian and continued for about 80 Myr until Eocene–Miocene times; gas generation in the late catagenetic window took place from the Valanginian to the Maastrichtian. Numerical simulations show that the major oil-prone source rocks in the South Kara kitchen area were, in the decreasing order of potential, the Bazhenovo (Yanov Stan), Kiterbyut, and Malyshevka Formations. The Upper Jurassic regional rock unit generated over 60% of liquid hydrocarbons and heterocyclic compounds (oils). The major gas-prone source rocks in the area were, in the decreasing order of potential, the Kiterbyut, Malyshevka, Alym, and Bazhenovo (Yanov Stan) Formations. The Lower and Middle Jurassic regional rock units generated about 65% of hydrocarbon gases. Results are presented to quantify the amount of hydrocarbons dissipated due to either the absence or poor effectiveness of confining seals and to explore the role of Cenozoic tectonic processes in the formation of petroleum accumulations in the basin.

This study provides a comprehensive sedimentologic analysis of the J2 prospective horizon (Middle–Late Bathonian) in the central West Siberian Basin. Based on the extensive dataset, it was established that structural complexity of this horizon is largely caused by a variety of depositional environments. Sedimentary facies of this horizon pass upward from widespread continental at the base, through deltaic or coastal-continental, to marginal-marine at the top. Change in the paleohypsometry of the study area reflects the distribution of depositional environments, in terms of the proportions of continental, transitional, and marine deposits. The study also shows that facies variability and change in depositional settings can have a significant control on reservoir quality, as well as its vertical and lateral distribution. Using a combination of detailed GDE reconstructions, structure contour mapping on the top and base of the J2 horizon, analyses of well test data, probability of reservoir presence, distribution of average porosity and permeability within different subenvironments, a composite map showing variations in the reservoir effectiveness in the J2 horizon was generated.