Выполнен анализ результатов современных региональных сейсморазведочных работ и глубокого бурения в Присаяно-Енисейской перспективной нефтегазоносной области и на прилегающих тер­риториях Лено-Тунгусской нефтегазоносной провинции. Построены структурные карты по опорным отражающим горизонтам рифея, венда и нижнего кембрия, а также карты толщин рифейского и вендского­ терригенного сейсмогеологических комплексов. Построена тектоническая карта венд-палеозойского структурного яруса Присаяно-Енисейской синеклизы. Выполнено нефтегазогеологическое районирование Присаяно-Енисейской перспективной нефтегазоносной области, выделено восемь перспективных нефтегазоносных районов и выполнена количественная оценка перспектив нефтегазоносности. Начальные суммарные геологические ресурсы углеводородов Присаяно-Енисейской перспективной нефтегазоносной области оценены в 3 млрд 231 млн т УУВ, в том числе газа в 3 трлн 39 млрд м3 и конденсата в 192.7 млн т. Показано, что за 15—20 лет в Присаяно-Енисейской перспективной нефтегазоносной области могут быть подготовлены значительные запасы газа — до 1 трлн м3. Предложено рассматривать в качестве будущего центра газохимии и переработки газа пос. Богучаны. This study presents the results of recent regional seismic exploration and deep drilling efforts in the Sayan–Yenisei syneclise and adjacent areas of the Lena–Tunguska petroleum province. These results were used to build a series of structure maps for Riphean, Vendian and Lower Cambrian reflectors; thickness maps of the Riphean and Vendian terrigenous geoseismic sequences within the syneclise, and a tectonic map of the Vendian–Paleozoic structural stage of the Sayan–Yenisei syneclise. The proposed oil and gas geological zoning of the Sayan–Yenisei potential petroleum area enabled us to identify eight potential petroleum regions and perform a quantitative assessment of the hydrocarbon potential. The original in-place resources of the Sayan–Yenisei potential petroleum area are estimated to be 3 billion 231 million tons of hydrocarbon equivalent, including 3 trillion 39 billion m3 of gas and 192.7 million tons of condensate. It is shown that over next 15–20 years, up to 1 trillion m3 gas reserves can be explored in the Sayan–Yenisei potential petroleum area. It is proposed to consider the Boguchany village as a large gas conversion and helium production center.

—The results of regional geological exploration over the past 18 years within the Aldan–Maya potential petroleum area were used as the basis for the refinement of the geological structure of the study area. The study considers the key structural features of the sedimentary cover of the Aldan–Maya region and major tectonic events that affected its structure. The generalization and interpretation of regional seismic survey data provided the basis for building a series of geoseismic sections and structure maps, which, in turn, were used in structural tectonic zoning of the study area. The map showing outcrops of Riphean formations and groups on the pre-Vendian erosion surface was complied. Tectonic schemes for three structural levels (upper Karelian–Lower Riphean, Middle–Upper Riphean and Vendian–Cambrian) confirmed their fundamental difference. In particular, the large Maya inclined swell was detected only in the topography of the Lower Riphean and is absent in the overlying structures of Middle Riphean–Vendian age, which are represented by weakly differentiated monoclines. The parameters of the major tectonic elements were determined.

The article discusses the debatable issues of well log correlation of the Riphean, Vendian, Cambrian and Mesozoic sections, promising for the search for oil and gas in the Aldan-Maya potentially petroleum bearing region. The author's proposed correlation version is based on the interpretation of well logging data, seismic surveys, studying of deep well cores, stock and published data. The results obtained can be used to refine the stratigraphic correlations of wells and build maps. The history of studying the geological structure of the territory of the Aldan-Maya potentially petroleum bearing region was also analyzed, during which numerous indications of oil and gas potential were identified. The generalization of the performed exploration actitvity made it possible to identify Proterozoic and Phanerozoic oil and gas bearing strata. The characteristics of these sections are given. It is shown that the prospects for the discovery of oil and gas accumulations in the Aldan-May area are estimated quite highly.

The reproduction of the mineral resource base of oil and gas is associated with the discovery of new deposits and is based on the results of the stages of search and exploration at the expense of subsoil users. For successful licensing and exploration work, monitoring is necessary in order to identify the most effective methods both in individual areas of the distributed subsoil fund and in the region as a whole. The article summarizes the results of subsurface licensing in the Krasnoyarsk region of the Leno-Tunguska oil and gas bearing province as of 2022. Currently, licenses for the search, exploration and operation of oil and gas fields have been issued for 61 sites of the distributed subsoil fund. 16 companies have been registered. The largest volume of exploration work was carried out by Slavneft-Krasnoyarsk Oil Company, Vostsibneftegaz JSC and Gazprom PJSC. There are 16 sites of distributed subsurface resources on the territory of the Baikitskaya anteclise. In the period from 2004 to 2014, 10 oil and gas fields were discovered by subsoil users.

The Vendian deposits of the Siberian Platform are represented by four regional horizons (from bottom to top): Nepa, Vilyuchan, Tira, and Danilovka. The TDS of brines in the Nepa and Vilyuchan horizons varies from 170.3 to 470.1 g/L, and the TDS in the overlying Tira and Danilovka horizons, from 84.6 to 583.1 g/L. Brines of Cl Na, Cl Na-Ca, Cl Ca-Na, Cl Ca, and Cl Ca-Mg types have been identified. The pH values of the brines vary from 3.0 to 7.0; acidic and weakly acidic brines (pH = 3.0-5.5) prevail. The redox potential Eh varies from -440 mV (highly reducing conditions) to +130 mV (oxidizing conditions), averaging -176 mV. Areal regional hydrogeochemical zoning is controlled by the outer (on the periphery of the Siberian Platform, where infiltration of meteoric waters took place) and inner feeding areas. The outer feeding areas bear infiltrogenic brines of different ages (group I), mostly of Cl Na composition. They are characterized by TDS = 280 g/L, rNa/rCl = 1.55, Cl/Br = 2512, and average Ca/Cl = 0.3. The average values of the integrated brine metamorphization index S (according to S.L. Shvartsev) range from 50 to 200. In the intraplatform feeding areas, there are several phases of brines that underwent gravitational sinking into the Vendian horizons in the periods when Cambrian salt-bearing basins existed on the platform. These brines were metamorphosed during filtration along the fracture and fault zones. The intrusion of traps in the late Permian-early Triassic was accompanied by hydrothermal activity. The waters of the enclosing Cambrian dolomite horizons were heated to 800-1000 degrees C; their subsequent interaction with carbonate rocks and evaporites (in particular, chlorides) resulted in extrastrong saturated brines. These brines were also subjected to gravitational sinking into the Vendian reservoirs, which was the main cause of the inverse vertical hydrogeochemical zoning in the hydrogeologic subsalt formation. The brine metamorphism processes and temperature changes in the rock horizons during the intrusion of traps and their subsequent cooling led to a significant alteration of the enclosing rocks under interaction with brines and to salinization of the reservoirs, an increase in the total salinity of the brines, and catagenetic changes in their composition. The brines closest to the maximum saturation with halite were found in reservoir zones with the highest salinization and near faults and boundaries of intrusive bodies. During the pre-Vilyuchan, pre-Nepa, pre-Tira, and pre-Danilovka sedimentation breaks, infiltrogenic waters penetrated into the Vendian sediments. Geochemically, the sedimentogenic, infiltrogenic, and metamorphic strong brines (group II) have a predominantly Cl Ca or Cl Ca-Mg composition with TDS > 350 g/L. They are characterized by low rNa/rCl ratios (on average, 0.3), Cl/Br = 100, high Ca/Cl values (on average, 0.4), and S > 250.

The paper carried out analysis of petroleum licensing the western region of the Republic of Sakha (Yakutia). As of 01.03.2021, on this territory there are 76 subsoil plots and registered about 23 companies involved in prospecting, exploration and production of hydrocarbons. The largest subsoil user is PJSC "Surgutneftegas" - it owns 21 licensed areas. During the period of operation, 42 358 km of 2D seismic activity, 22 963 km2 were completed for the geological and exploration activity programs seismic survey 3D. Drilling of 349 wells with a volume of 669,705 m was carried out. The largest volume of exploration activity was carried out by PJSC "Surgutneftegas" and "Rosneft". In the period from 2009 to 2020 years, the 15 fields of oil and gas has been opened.

The article provides an analysis of geological exploration in Eastern Siberia and the Sakha Republic (Yakutia).In total, 85 oil and gas fields were discovered, 39 of them during the licensing period from 2004 to 2019: 28 in the Irkutsk region, 7 in the Krasnoyarsk region, 4 in the Sakha Republic (Yakutia).In this study the data of the deep drilling volumes are given too.In recent years, there has been a general trend of decreasing 2D seismic exploration and increasing of 3D seismic exploration.The largest volume of exploratory drilling is observed in the Sakha Republic (Yakutia).

Riphean and Vendian terrigenous complexes are not affected by trap injections within the South-Tunguska petroliferous region and thus can be considered a priority for further prospecting for hydrocarbon accumulations. Although these strata are not exposed with wells and are not characterized by core samples, their wide distribution is proved by seismic data. The obtained data and previous paleogeographic reconstructions show similar depositional environments of terrigenous sediments for the South-Tunguska and Baikit petroliferous regions. These facts substantiate criteria for the prediction of sand reservoirs within the study area. Taking into account the complex geologic structure of the South-Tunguska petroliferous region, ambiguity of seismic data interpretation, and problems of deep-drilling technology, we provide recommendations for the geological exploration.

Cumulative production, reserves prospective resources are obtained from the Government's balance sheet of reserves as of 01.01.2009, and inferred resources are corrected by expertise by the value of change in balance reserves and prospective resources. These estimates form the basis of zoning of the territory by types of hydrocarbon fluids and density resources for Riphean, Nepa, Tira, Lower-Middle Danilovo, Upper Danilovo and Lower Cambrian complexes.