West Siberian Province Research Articles

Application of the block factor analysis in the implementation of hydraulic fracturing during oil fields development

The relevance of this study is due to the need to optimize the oil production process in the fields of the West Siberian province. At the moment, the actual oil recovery factor often deviates from the design values, which leads to inefficient production and loss of resources. Therefore, the purpose of the study is to develop a meth-odology for optimizing the process of monitoring and regulating an oil field development facility using block factor analysis and de-signing hydraulic fracturing cracks. The work uses methods such as block factor analysis, 3D modeling, hydrodynamic modeling, and mathematical modeling. The result of the study is a developed methodology for optimizing the process of monitoring and regulat-ing an oil field development facility. The article also discusses the main reasons for the deviation of actual oil production from calcu-lated values, including hydraulic fracturing technology. Unsuccess-ful cases of this procedure and their causes were identified. The features of the block factor analysis tool and the proactive analysis method are described, as well as how to use it at the design and modeling stage of hydraulic fracturing to improve the efficiency of the well-stimulation operation. Successful implementation of hy-draulic fracturing allows one to approximate the actual oil recovery factor to design values, which is important for increasing the effi-ciency of production at the field and optimizing the use of re-sources.

Paleotectonic, lithological, geochemical criteria for the oil exploration in the Neocomian deposits, the Uvat region, on the example of the BS<sub>8</sub> formation, the Ust-Balyk suite

The Uvat project is one of the exploration projects of PJSC NK-Rosneft in the south of the West Siberian province. The high efficiency was achieved using modern technologies for the interpretation of 3D seismic and the involvement of a full range of well logging in daily work. Now, about 60 % of the territory is covered by 3D seismic surveys, during the period from 2004 to 2021, 27 medium and small fields were discovered, about 250 exploration wells were drilled. Gradually, the volume of the identified resource base is reduced and the urgent task for the "Uvat project" is to replenish it. Based on a comprehensive interpretation of all geological and geophysical materials and many years of experience in geological exploration activities, priority search targets for the territory of the Uvat project have been identified. According to modern estimates, the Neocomian oil and gas complex in the Uvat district accounts for at least 25% of all estimated resources, so it is one of the objects of hydrocarbon growth with potentially oil-bearing traps in the Achimov and offshore formations. The paper analyzes the criteria that had the greatest impact on the oil content of the Sarmanov clinoform reservoir (strata BS8-9). Such an analysis helps to assess not only the risks of hydrocarbon deposits in the BS8 reservoir of the Ust-Balyk suite, but also to adjust the exploration strategy.

Improving the Efficiency of Managing the Development of the West Siberian Oil and Gas Province Fields on the Basis of Differentiation and Grouping

Abstract —Using image recognition methods (principal component method (PCM) and discriminant analysis) made it possible to group and identify more than 500 research objects developed in five oil and gas areas of the West Siberian oil and gas province (WSOGP), which are confined to 13 large tectonic structures and 10 productive horizons. The grouping was made according to 19 parameters characterizing the mode of oil and gas occurrence and the geologic–physical and physicochemical properties of the reservoirs and hosted fluids exerting a prevailing influence on the recovery of oil reserves and used on projecting the development of research objects. The performed study has identified 19 relatively homogeneous groups of objects, each having a specific set of geologic–physical properties. It is shown that the parameters reflecting the geologic–physical and physicochemical properties of the reservoirs and fluids within the identified groups of objects exert different effects on the recovery of oil reserves. This requires differentiation and grouping of the objects during the solution of various development problems. It has been established that the specific features of groups of objects are determined primarily by areal, tectonic, and stratigraphic factors and that grouping must be performed separately in each stratigraphic system. Algorithms are proposed for grouping the developed oil and gas fields and for searching for groups of analogous objects in fields out of exploration that are most similar to the developed ones. The performed grouping and the results obtained provide the necessary information about the research objects and increase its reliability, thus making it possible to improve the efficiency of managing the oil company assets, i.e., the WSOGP oil fields.

НОВЫЕ СВЕДЕНИЯ ПО БИОСТРАТИГРАФИИ И ФОРАМИНИФЕРАМ АЛЬБА ЗАПАДНОЙ СИБИРИ

Foraminifera and ostracods similar to the Samotlor ones of the Middle and Upper Albian were found in the section of a newly drilled well in the Severnaya area of West Siberia. Host rocks are marine facies of the Khanty-Mansikian horizon, distributed in the northern paleobiogeographic district of the West Siberian Province. Foraminifera of the Middle Albian in this district are identified as the assemblage with Ammobaculites fragmentarius, Gaudryinopsis filiformis; the Upper Albian ones – the assemblage with Ammotium braunsteini, Verneuilinoides borealis assanoviensis. Layers with these assemblages are identified as foraminiferal zones of the Albian stage, belonging to the middle series of the Cretaceous System.

Jurassic paleogeography and sedimentation in the northern West Siberia and South Kara Sea, Russian Arctic and Subarctic

Abstract The study is focused on the depositional history of Jurassic oil- and gas-bearing sedimentary rocks, which currently occur at 3–6 km depth below the surface in the northern West Siberian Basin, the South Kara Basin and the western Yenisei-Khatanga Basin. Using data from deep wells, such as paleontological data and bedding geometries, lithology of rocks derived from cores and well log data, sediment thicknesses, results of detailed correlation of sedimentary cyclic units, and regional multichannel seismic reflection profiles, the authors produced 13 litho-paleogeographic maps of the studied region accompanied by W-E cross-sections. The maps present paleogeographic environments that existed during the deposition of each of 12 regional stratigraphic stages, namely: Lower Jurassic Zimniy (Hettangian – lowermost Upper Pliensbachian), Levinskiy (middle Upper Pliensbachian), Sharapov (uppermost Pliensbachian), Kiterbyut (lowermost Toarcian), Lower-Middle Jurassic Nadoyakh (uppermost Lower Toarcian – lowermost Aalenian), Middle Jurassic Laida (uppermost Lower Aalenian – lowermost Upper Aalenian), Vym (uppermost Aalenian – lowermost Bajocian), Leont'evskiy (uppermost Lower Bajocian – lowermost Upper Bajocian), Malyshev (uppermost Bajocian – lowermost Upper Bathonian), Middle-Upper Jurassic Vasyugan (uppermost Bathonian – lowermost Oxfordian), Upper Jurassic Georgiev (uppermost Oxfordian – lowermost Tithonian) and Bazhenov (uppermost Lower Tithonian – earliest Berriasian). The maps show the extent of exposed land, continental (alluvial plains), transitional (nearshore and coastal flood plains) and marine (water depth The presented results provide a more reliable framework for the re-evaluation of existing Jurassic hydrocarbon plays and identification of new plays in the West Siberian province.

Новые данные об арсенатах зоны гипергенеза Шерловогорского рудного района (Восточное Забайкалье)

The similarity in systematic composition of the new foraminiferal assemblages and litological affinity of such stages as Aptian, Al-bian, Cenomanian and Turonian have given opportunity to establish the Middle order of Cretaceous system. The first time these forami-niferal assemblages have been found in borehole sections of Samotlorskaya, Van-Eganskaya, South-Russkaya, Parusovaya and several areas of Yamal peninsula, which keep to Northern paleobiogeographical district of West Siberian province. The related connecting between species of foraminiferal assemblages of four stages have been united in one association of these taxons. Holding rocks of Vicu-lian, Chanty-Mansian, Uvatskian horizons consisting of similar on litology argilit-alevrolit-silks have been united in Pocurskaya series of deposits, without opoka and carbonate infusions. Due to similarity in foraminiferal assemblages Kusnetsovskian horizon also offer to Middle Cretaceous. New data on Foraminifera and Biostratigraphy of each stage have been received during study kern specimens from borehole sections of these areas. Some species, subspecies and vicariant in foraminiferal assemblages have known in such age formations of Canadian province. On this base West Siberian and Canadian provinces belong to Arctic paleobiogeographical Realm of same name circum pole Belt.

Геологическая модель Предъенисейского верхнепротерозой-палеозойского осадочного бассейна на юго-востоке Западно-Сибирской провинции

Геологическая модель Предъенисейского верхнепротерозой-палеозойского осадочного бассейна на юго-востоке Западно-Сибирской провинции

Cenomanian-Turonian Foraminiferal Zones of West Siberian Province and Their Correlation with Canadian Province

Data on Late Cenomanian and Early Turonian foraminiferal assemblages in the northern palaeo biogeographical district of the West Siberian province are summarized in the paper. In addition, the section of borehole 1016 of the Parusovaya area located in the far north of the province is considered. New information on the foraminiferal zones of this stratigraphic level along with the previously known sections of the Tazovskaya, Purpeiskaya, Van-Eganskaya areas provided an opportunity to carry out a correlation of these zones between the West Siberian and the Canadian provinces (Western Canada, Northern Alaska). The West Siberian Late Cenomanian Trochammina wetteri tumida, Verneuilinoides kansasensis and the Early Turonian Gaudryinopsis angustus foraminiferal zones have their analogues as similar zones in the Canadian province. Due to the provided correlation of the micropalaeontological (foraminiferal) zones, their age in the West Siberian province has been clarified. Besides, similarity of the conditions of dwelling within the boundaries of the entire Arctic palaeobiogeographical realm has been observed.

Middle Jurassic floras of Mongolia: Composition, age, and phytogeographic position

Floras of Oshin-Boro-Udzyur-Ula, Tsagan-Ovoo, and Nariin-Sukhait of Mongolia are reviewed. Their composition suggests a Middle Jurassic age for these floras. They resemble the synchronous floras of the West Siberian Province of the Siberian Paleofloristic Region. The boundary between this province and North Chinese Province of the same region should be drawn further to the south than was previously thought. The Middle Jurassic floras of Mongolia existed in a warm temperate, humid climate.

Early Middle Jurassic (possibly Aalenian) Tsagan-Ovoo Flora of Central Mongolia

The Tsagan-Ovoo Flora from terrigenous, coal-bearing deposits of the Bakhar Formation, central Mongolia, is documented for the first time. The Tsagan-Ovoo Flora contains 32 megafossil plant taxa belonging to horsetails, ferns, cycadaleans, ginkgoaleans, leptostrobaleans, conifers and gymnosperms of unknown systematic affinity. The floristic composition of the plant-bearing beds allows us to date them as early Middle Jurassic (possibly Aalenian). This flora is typical of the West Siberian Province of the Siberian Region and corroborates our previously obtained conclusion that the boundary between this province and the North Chinese Province of the same region should be positioned further south than its previous placement. The plants of the Tsagan-Ovoo Flora probably formed a mosaic of communities that inhabited swampy lowlands and lake margins. The flora reflects a wet, most probably warm-temperate climate with some seasonality in temperature and/or precipitation. Three new ginkgoalean species of the Tsagan-Ovoo Flora are described: Ginkgo badamgaravii Kostina et Herman, Pseudotorellia gobiense Kostina et Herman, and Pseudotorellia mongolica Kostina et Herman.

New data on middle and late Albian foraminifera and biostratigraphy of the northern palaeobiogeographical district of western Siberia

Abstract The present paper discusses foraminiferal assemblages and biozones established on the basis of studies of samples from ten borehole sequences of the Khanty-Mansiysk Horizon in the Samotlor area of the northern palaeobiogeographical district of western Siberia (Russia). In this region, middle and late Albian foraminiferal assemblages were first distinguished in western Siberia. Levels from which these assemblages have been recovered, are here referred to the following foraminiferal zones, the Ammobaculites fragmentarius-Gaudryinopsis filiformis Zone (middle Albian) and the Ammotium braunsteini-Verneuilinoides borealis assanoviensis Zone (upper Albian). Zonal assemblages are dominated by representatives of the orders Ammodiscida, Textulariida and Ataxophragmiida. Species of the ataxophragmiid genera Verneuilinoides, Pseudoverneuilina and Gaudryinopsis are the most characteristic, inclusive of several key index forms. Foraminiferal tests consist of agglutinated quartz-silica, the wall microstructure being almost exclusively medium and coarse grained. In specific composition, the Albian assemblages from the Samotlor area are similar to those from Transuralia (Russia) and to the Canadian Province, which, together with West-Siberian Province, forms the Arctic palaeobiogeographical realm

Low-frequency amplitude analysis for oil detection within the Middle Jurassic sediments in the southern part of Western Siberia

The structural element of a prospect is not a key factor in the detection of hydrocarbon deposits within the Jurassic formations of the southern parts of the West Siberian province. We investigated a method of mapping oil-saturated zones within the Middle Jurassic reservoirs. We evaluated the quantitative criteria between oil-saturated versus water-saturated zones. The methodology was based on amplitude analysis of seismic data and information obtained from the data and well testing.

Растительный покров подтаежных ландшафтов предгорной равнины правобережья реки Оби

Vegetation of the right bank of the Ob River in the limits of Novosibirsk area consists of southern taiga, subtaiga and forest-steppe elements. More over, in comparison with neighboring areas on the West Siberian Plain, it contains the significant amount of mountain elements (Kuminova, Vagina, Lapshina, 1963). Natural vegetation of the area belongs to the forest-steppe subzone of the West Siberian province (Il’ina, 1985). Low percentage of forest coverage is caused by anthropogenic deforestation and wide distribution of meadows (Lapshina, 1963). This is the most endangered vegetation in Novosibirsk area. Spatial vegetation structure was studied by using the model of the Ob River basin covered 184 square kilometers. Well-developed system of ravines and small creeks caused a presence of relatively large areas with very low anthropogenic impact which potentially could be the refuges of pristine zonal vegetation. Main vegetation type of this basin is forest which covered about 31% of the area. Forest diversity of model area consists of four syntaxa of association and subassociation ranks belonging to the Brachypodio pinnati–Betuletea pendulae class. Meadow vegetation is presented by five syntaxa from the Molinio-Arrhenatheretea class and mire vegetation — by two syntaxa from the Alneteae glutinosae class. Two subassociations and four variants are described for the first time. The ravine systems could be considered as low-level landscape structures which are the natural refuges with high level of biodiversity and habitats of rare and endangered species. The slope vegetation organized in ecological rows consists of three up to four syntaxa changing from the top to the ravine bottom. The Ob River Basin flora is characterized by insignificant amount of meadow steppe species, well-represented mire flora and a presence of mountain and taiga elements. The most specific floristic features are the presence of ephemeroid species, taiga species and Siberian tertiary nemoral relics (Polozhiy, Krapivkina, 1985). All these features allow us to refer the river basin vegetation to the low-mountain subtaiga type.

The Middle Jurassic flora of South Mongolia: Composition, age and phytogeographic position

The Nariin-Sukhait Flora from the terrigenous, coal-bearing deposits of the Orgilokhbulag Formation in the Nariin-Sukhait Coalfield, southernmost Mongolia, is documented for the first time. The Nariin-Sukhait Flora contains 57 fossil plant species belonging to liverworts, horsetails, ferns, cycadaleans, bennettitaleans, ginkgoaleans, leptostrobaleans, conifers and plants of an unknown affinity. Its floristic composition allows us to date the Orgilokhbulag Formation as Middle Jurassic. This flora is typical of the West Siberian Province of the Siberian Region. The boundary between this province and the North Chinese Province of the same region should be positioned further south than its previous placement, and the Nariin-Sukhait Flora existed close to this boundary. The parent plants grew in an alluvial plain characterised by rivers, oxbow lakes and swamps. The flora reflects a wet, most probably warm-temperate climate with some seasonality in temperature and/or precipitation. Two new fern species of the Nariin-Sukhait Flora are described: Coniopteris gurvantesensis Kostina et Herman and Sphenopteris gobiensis Kostina et Herman.

The Meso-Cenozoic tectonics and petroleum potential of West Siberia

The relationship between the petroleum potential of the West Siberian province and the Mesozoic to Cenozoic tectonic processes is analyzed. The studies were based on structural and isopach maps of seismogeologic megacomplexes compiled from generalized geological and geophysical data on the province at the Trofimuk Institute of Petroleum Geology and Geophysics as well as on the results of interpretation of regional seismic CDP (common depth point) profiles. The main stages of formation of structures of different ranks and faults have been established. It is shown that the petroleum potential of the province was determined mainly by its structure and tectonic processes at the Cenozoic stage of evolution. At that time, the Koltogory–Urengoi megatrench formed, which became the main zone of hydrocarbon generation, as well as large positive structures—petroleum accumulation zones. Also, disjunctions originated, which served as channels for hydrocarbon migration from the oil source rocks of the Bazhenovo Formation to the main Neocomian and Aptian–Albian–Cenomanian petroleum reservoirs of the province.

Natural Gas in the Context of Russia's Energy System

In Russia, as elsewhere, energy is used not in an abstract fashion but in concrete geographic space and, except in mobile machines, in a locationally concentrated manner. It is also consumed in a concrete world of existing equipment and specific technological applications. Energy production is similarly specific and particular, both in its various primary forms (raw fuels and hydro- and nuclear power) and in its location. However, the different primary forms in which energy is produced are not uniformly transportable nor uniformly applicable, efficient, or environmentally acceptable in the diverse technological processes. Energy demand, and the transport-delivery infrastructure to satisfy it, is, therefore, subject to pronounced inertia. The ghost of geography, which burdened the Soviet energy system in its last decade, also haunts that system in Russia today. In the 1980s, 65-70 percent of all fuels used in the European regions (the Urals included) of the USSR had to be shipped from Siberia and Central Asia; in today's Russia, also with three-fourths of the population in its European parts and the Urals, the share is significantly larger.The enormous spatial discrepancy between consumption and production that characterized the energy complex of the late Soviet era, specifically the oil and gas sector, remains. Indeed, its significance has increased because a much larger share of oil and gas output is exported today, and these exports account for a greater portion of Russia's economy than ever before. Roughly one-half of the oil and one-third of the natural gas were exported in recent years, overwhelmingly through Black Sea and Baltic ports and pipelines to Europe. The sharp rise in prices and the increased volumes, at least until the middle of the present decade, lifted the contribution of energy exports (nearly all of it oil and gas) to approximately 23 percent of Russia's GDP in the first seven months of 2006.1 To plug the huge domestic deficit in European Russia and fill export pipelines and tankers, Moscow still depends on its West Siberian province and a pipeline system largely developed in Soviet times. Russian oil companies did increase production, construct and expand tanker terminal capacity, and build a few hundred kilometers of pipeline. The anemic growth in the gas sector, however, is due entirely to independent producers who work on small fields and to oil companies, both of which extract mostly fat gas-that is, gas high in heavier hydrocarbon molecules that need to be removed before interregional pipeline transport. Gazprom, the Russian gas monopoly, continues to live off its Soviet inheritance.2 Although Gazprom's reserves have grown, much less has been done to access and prepare them for production and tap them with new pipelines.Geographic and structural rigidities in the consumption pattern will therefore circumscribe the scope of change, possibly for a generation. The population and settlement structure on the one hand and the sectoral-technological structure of consumption on the other set severe limits on feasible shifts. Within these limits, adjustments, conservation, and substitution in a market economy will proceed to the extent that price signals convey correct information. Political exigencies, however, circumscribe such adjustments everywhere, at least in the short term. This is doubly true in Russia, still a very distorted market economy, in which the oil and gas sector fueled the recent boom in personal consumption and which faces momentous parliamentary and presidential elections in 2007 and 2008.3This article focuses on natural gas, but in the context of boiler and furnace fuel use as a whole, particularly electric power generation. In 2005, Russia's aggregate fuel-energy consumption (including primary electricity-that is, hydro, nuclear, and geothermal power) amounted to 29.5 quads or 7,423,500 million kilocalories, roughly 30 percent of the U.S. total. Boiler and furnace use plus primary electricity are essentially equivalent to stationary consumption and in that year composed 76 percent of Russia's aggregate energy demand. …

Inorganic geochemistry of the oil of west Siberia: First ICP-MS data

The evolution in innovation technologies and analytical devices has raised geochemistry to a higher level. As is known, modern petroleum geochemistry is mainly composed of organic geochemistry. The trace element composition of oils was studied usually in combustion products, whereas works on direct determination of the trace element composition of hydrocarbons are scanty and generally related to a very small number of elements and/or heavy fractions [1]. The rapid progress in the method of mass spectrometry with inductively coupled plasma (ICP-MS) has made it possible to study the trace element composition of not only rocks, but also complex organic compounds, for instance, oil and its derivatives. A series of works has recently been reported on the geochemistry of asphaltenes and bitumens, i.e., solid components of oil [2, 3]. We analyzed for the first time the trace element composition of crude oil from West Siberia by the ICP-MS method. More than 50 trace, rare earth, and other elements were determined in oils from the Shaim and Srednii Ob fields (see [4‐6] for geological data). The analyses were conducted using an ELEMENT2 highresolution mass spectrometer following the technique developed at the Laboratory of Radiogeology (Zavaritskii Institute of Geology and Geochemistry) [7, 8]. The measurement results are shown in the table. Oils from West Siberia are characterized by extremely low contents of the majority of elements. The PM-normalized trace element contents are equal to ~0.1 u for the most depleted ultramafic rocks and ~0.001 for oils. It should be noted that the PM-normalized contents of trace elements in Triassic basalts of The table shows that crude oils of the Shaim and Srednii Ob fields have relatively high contents (>1 g/t) of major (Mg, Al, Fe, Na, Ti) and transition elements (Cr, V, Ni, Cu, Zn). In the Ni‐Cu‐Cr diagram [3] for the resinous‐asphaltene fractions, these oils belong to the chromium type. Their data points fall at the continuation of the trend outlined by the authors of [3] for the West Siberian province. The contents of other trace elements in these crude oils are lower (<1 g/t), but often higher than in some rocks. The Cs, Rb, Sr, and Zr contents in the oils are comparable with those in ultramafic rocks. The U content in oils is similar to that in the basaltoids and significantly higher than that in ultramafic rocks, chondrites, and intermediate rocks [9]. Such a high U content in oils is presumably related to the reducing conditions and, correspondingly, to the presence of a geochemical barrier. These conditions could also promote the high Pb content (up to 0.3 ppm). The Ag content is also relatively high (up to 0.1 ppm), while the Au content is low (<0.002 ppm).

Petroleum Habitat of East Siberia, Russia

East Siberia comprises three petroleum provinces—Lena-Tunguska, Lena-Vilyuy, and Yenisey-Anabar—that occupy the area of the Siberian craton. Petroleum has been generated and has accumulated in Precambrian rifts beneath the sedimentary basins and, more importantly, within the section of the basin itself. The platformal deposits of the basins extend beneath overthrusts on the east and south and are covered by sedimentary rocks of the West Siberian overthrusts on the east and south and are covered by sedimentary rocks of the West Siberian province on the west. Permafrost and gas hydrate deposits are present throughout most of East Siberia. In the Lena-Tunguska province, rifts that developed during Riphean time are filled by thick sedimentary rocks, in which petroleum deposits have formed. In Early Cambrian time a barrier reef extended across the East Siberian craton from southeast to northwest. A lagoon to the west of this reef was the site of thick rhythmic salt deposits, which are the main seal for petrole...

Models of Hydrocarbon-Bearing Sequences of West Siberia

The West Siberian province located within a young plate (platform) is one of the largest in the world in size, reserves, number of unique fields, and hydrocarbon production. The southern, central, and western areas of the province are dominantly oil-bearing, the northern portion gas-bearing. All commercial reserves are within the Devonian-Cenomanian stratigraphic interval. Small accumulations in fractured-vuggy Devon-Carboniferous rocks are located in the zone of unconformity between this sequence and the Jurassic. The potential of the pre-plate middle Paleozoic, platform upper Paleozoic, and Triassic sequences recognized by seismic data in the northern, deepest, part of the plate is not known yet. Most hydrocarbon pools are located in the Jurassic-Cretaceous hydrocarbon-bearing sequences (HBS) within the plate cover. Structural-depositional oil accumulations with very changeable flow rates, a large stratigraphic-depositional accumulation in high permeability basal (quartz) reservoirs, and an oil-condensate and a multiple-pool structural gas field are discovered in the Middle Jurassic composed of potential continental coal-bearing and marine deposits. In most HBS, there is still a prospect of discovering new hydrocarbon pools including pools in more complex traps.