scholarly journals Geodynamics and geothermics of Pre-Caspian Depression and eastern segment of Caucasus region

Author(s):  
В.Б. Свалова

Актуальность работы определяется важностью оценки и прогноза нефтегазового потенциала глубоких осадочных бассейнов, в частности, глубоких горизонтов структур, не всегда доступных глубокому бурению в поисковых и разведочных целях. Цель и методы исследования. Наряду с прикладными вопроса- ми целью исследования являются фундаментальные вопросы теоретической геодинамики формирования и эволюции осадочных бассейнов в связи с подъемом мантийных диапиров на основе методов механи- ко-математического моделирования. Прикаспийская впадина и восточный сегмент Кавказского региона, включая Каспийское море, могут рассматриваться как регионы окрестности восточной части Альпийского пояса, который в свою очередь является западной частью Альпийско-Гималайского пояса, простирающе- гося от западной оконечности Средиземного моря до Тихоокеанского побережья. Каспийское море пере- секает с севера на юг серию широтных структурных зон юго-восточной окраины древней докембрийской Восточно-Европейской платформы, молодой эпигерцинской Скифско-Туранской платформы и современ- ного Альпийско-Гималайского орогенного пояса. Прикаспийская и Южно-Каспийская впадины являются глубокими осадочными бассейнами с толщиной осадочного чехла более 20 км, обладающими высоким нефтегазовым потенциалом и большим народно-хозяйственным значением. Формирование и эволюция осадочного бассейна служат ключом для определения зон нефтегенерации осадочного чехла, что делает задачу изучения геодинамики осадочных бассейнов крайне важной и необходимой. Геодинамика релье- фа поверхности определяется глубинными мантийными движениями. Механико-математическая модель динамики литосферы дает возможность количественно связать параметры формирующегося осадочного бассейна с подъемом мантийного диапира. Анализ геофизических полей геологических структур позволя- ет оценить подъем астеносферы, а разработанная самосопряженная термогравиметрическая модель ли- тосферы делает эти оценки надежными и достоверными. Геодинамика и история развития геологических структур определяют магматизм, вулканизм, сейсмичность, геотермические характеристики, геотермаль- ную активность, нефтегазоносность, опасные природные процессы региона, что в свою очередь является обоснованием создания системы комплексного экологического мониторинга на фундаментальной научной базе, прогноза и предупреждения природных бедствий и катастроф, а также поиска полезных ископаемых, включая углеводороды. Результатом работы является количественная оценка подъема астеносферы под осадочным бассейном на примере Прикаспийской впадины The relevance of the work is determined by the importance of assessing and predicting the oil and gas potential of deep sedimentary basins, in particular, deep horizons of structures that are not always accessible to deep drilling for prospecting and exploration purposes. The aim and research methods. Along with applied questions, the aim of the study is the fundamental questions of the theoretical geodynamics of the formation and evolution of sedimentary basins in connection with the rise of mantle diapirs based on the methods of mechanical and mathematical modeling. Pre-Caspian Depression and eastern segment of Caucasus region, including Caspian Sea, can be considered as regions of area of eastern part of Alpine belt, which is western part of Alpine-Himalayan belt disposed from Mediterranean sea to Pacific Ocean. Caspian sea crosses from North to South the series of structural zones of East European platform, Scythian-Turan platform and Alpine-Himalayan belt. Pre-Caspian Depression and South Caspian Depression are deep sedimentary basins with thickness of sedimentary cover more than 20 km which have high oil-gas potential and big industrial importance. Formation and evolution of sedimentary basin is the clue for oil-gas generation zones of sedimentary cover, that makes the problem of sedimentary basins geodynamics of great importance one. Geodynamics of relief is defined by deep mantle movements. Mechanical-mathematical model of the lithosphere dynamics gives possibility to link the basin parameters with mantle diaper upwelling. Analysis of geophysical fields gives opportunity to evaluate the asthenosphere upwelling, and elaborated self-conjugated thermo-gravimetric model makes this evaluation reliable and trustworthy one. Geodynamics and evolution history of geological structures determine magmatism, volcanism, seismicity, geothermics, geothermal manifestations, oil-gas potential, natural hazards of region, that is basement for monitoring system creation and construction on fundamental scientific base, forecast and prognosis of natural catastrophes and oil-gas potential researches. The result of this work is a quantitative assessment of the rise of the asthenosphere under the sedimentary basin using the example of the Pre-Caspian Depression

Neft i gaz ◽  
2020 ◽  
Vol 6 (120) ◽  
pp. 20-34
Author(s):  
О.S. TURKOV ◽  

The Caspian Basin is a unique geological object, the most notable features of which are the anomalously large thickness of the sedimentary cover and its enormous hydrocarbon potential. It is generally known that the main reserves in the identified fields and the prospects for discovering new large deposits of oil, gas and gas condensate here are associated with a subsalt complex of terrigenous and carbonate strata, submerged in the central part of the basin to depths of over 10 km. To date, this complex has been most studied in the edges of the depression at depths of 4-5 km. Confident forecasting of oil prospecting operations for deeper-lying objects is constrained by low researched of their structural, lithological, thermobaric and other parameters. In the debate about these very complex problems, one rarely recalls such a simple and at the same time crucial fact as direct signs of oil and gas potential. Indeed, every year we receive more and more new data on the “breathing of resources”, on the hydrocarbons migration from subsalt sediments into post-salt reservoirs, but we do not give them due attention. The article provides convincing, in the author's opinion, examples of the formation of post-salt deposits on salt domes due to the vertical migration of hydrocarbons. Taking this process into account, recommendations were made both НЕФТЬ И ГАЗ 2020 6 (120) 21 ГЕОЛОГИЯ on the general method of oil prospecting in subsalt deposits, and specific proposals for the search for subsalt and post-salt deposits of oil and gas.


2021 ◽  
Vol 132 (1) ◽  
pp. 25-29
Author(s):  
N. T. Thinh ◽  

The sedimentary basin Song Hong is one of the largest Cenozoic oil and gas bearing sedimentary basins, in which the center of the basin covers a large part. It elongates from block 105 to block 115. This article presents the geological structure, history of geological development, oil and gas potential and characteristics of reservoirs f the central basin, where the thickness of the basin deposits reaches more than 16 000 m.


Author(s):  
A. Khuduzade ◽  
Sh. Akhundov ◽  
S. Shabanova ◽  
T. Imamalili ◽  
O. Ismaylov

The article continues the series of publications devoted to the forecast of oil and gas potential in the Middle Kura Depression. Systematization and analysis of published materials show that the effectiveness of prospecting and exploration for oil and gas depends on the fairness and accuracy of scientific ideas about the origin and patterns of hydrocarbon localization. The established heterogeneity of the structure of sedimentary basins and the uneven distribution of oil and gas deposits in them allows us to make a predictive assessment of territories based on historical-geological methods and a synthes analysis of criteria for assessing the prospects of oil and gas. These methods are based on fundamental research in geology, the most important of which are structural-tectonic analysis and the genesis of oil and gas-bearing structures, the study of geological and geochemical factors in the simulation model “Uniform continuous lowering”, the study of the staged conversion of organic matter in the catagenetic process and show the oil and gas windows, prediction of collector and overlying seal zones, study of organic substances dissolved in water and other hydrogeological factors contributing to the formation and prevent of oil and gas deposits. Analysis of the geological history of the first stage of research,the assessment of petroleum potential of the region. Based on the results of seismic surveys, we carried out paleotectonic reconstructions for the northwestern zone of the Ganja oil and gas-bearing region, which illustrate the maps of total thickness in the form of isopachic triangle, paleotectonic profiles and graphic of subsidence size. Modeling of structural surfaces made it possible to establish the historical development of not only local structures, but also to notice new features in the formation of chronostratigraphic surfaces, and to judge the tectonic regime of the sedimentation basin, to justify the mechanism of formation in the sedimentary cover of the Middle Kura depression, both of plicative dislocation and faulting as well as zones of oil and gas accumulation associated with them. The study can be considered as a positive argument when choosing the location of the prospecting well.


2020 ◽  
Vol 245 ◽  
pp. 505-512
Author(s):  
Evgeny Gusev ◽  
Alexey Krylov ◽  
Dmitry Urvantsev ◽  
Yury Goremykin ◽  
Petr Krynitsky

Until recently, the North of the Kara Shelf was completely unexplored by seismic methods. Seismic and seismo-acoustic data that have appeared in recent years have made it possible to decipher features of the regional geological structure. This study solves the urgent problem of determining the prospects for the oil and gas potential of the North Kara sedimentary basin. The relevance of the research is associated with determining the prospects of the oil and gas potential of the North Kara sedimentary basin. The aim of the study is to clarify the age of the reflecting horizons using data on the geology of the island, as well as to determine the tectonic position of the sedimentary cover and basement structures in the north of the Kara shelf. The sedimentary cover is divided into three structural levels: Cambrian-Devonian, Middle Carboniferous-Cretaceous, Miocene-Quarter. The Cambrian-Devonian complex fills the deep troughs of the North Kara shelf. The most noticeable discontinuity is the base of Carboniferous-Permian rocks, lying on the eroded surface of folded Silurian-Devonian seismic complexes. The blanket-like plate part of the cover is composed of thin Carbon-Quarter complexes. The authors came to the conclusion that the fold structures of the Taimyr-Severozemelskiy fold belt gradually degenerate towards the Kara sedimentary basin and towards the continental slope of the Eurasian basin of the Arctic Ocean. A chain of narrow uplifts within the seabed relief, which correspond to narrow anticlines is traced to the West of the Severnaya Zemlya islands. Paleozoic rocks have subhorizontal bedding further to the West, within the Kara shelf. Mesozoic folding in the North of the Kara Sea is expressed exclusively in a weak activation of movements along faults. At the neotectonic stage, the shelf near Severnaya Zemlya was raised and the Mesozoic complexes were eroded. The modern seismic activity of the North Zemlya shelf is associated with the ongoing formation of the continental margin.


2019 ◽  
Author(s):  
Alan Bischoff ◽  
Andrew Nicol ◽  
Jim Cole ◽  
DDarren Gravley

Large volumes of magma emplaced and deposited within sedimentary basins can have an impact on the architecture and geological evolution of these basins. Over the last decade, continuous improvement in techniques such as seismic volcano-stratigraphy and 3D visualisation of igneous bodies has helped increase knowledge about the architecture of volcanic systems buried in sedimentary basins. Here, we present the complete architecture of the Maahunui Volcanic System (MVS), a middle Miocene monogenetic volcanic field now buried in the offshore Canterbury Basin, South Island of New Zealand. We show the location, geometry, size, and stratigraphic relationships between 25 main intrusive, extrusive and sedimentary architectural elements, in a comprehensive volcano-stratigraphic framework that explains the evolution of the MVS from emplacement to complete burial in the host sedimentary basin. The plumbing system of the MVS comprises saucer-shaped sills, dikes and sill swarms, minor stocks and laccoliths, and pre-eruptive strata deformed by intrusions. The eruptive and associated sedimentary architectural elements define the morphology of volcanoes in the MVS, which comprise deep-water equivalents of crater and cone-type volcanoes. After volcanism ceased, the process of degradation and burial of volcanic edifices formed sedimentary architectural elements such as inter-cone plains, epiclastic plumes, and canyons. Understanding the relationships between these diverse architectural elements allows us to reconstruct the complete architecture of the MVS, including its shallow (<3 km) plumbing system, the morphology of the volcanoes, and their impact in the host sedimentary basin during their burial. Insights from the architecture of the MVS can be used to explore for geoenergy resources such as oil, gas and geothermal energy in buried and active monogenetic volcanic systems elsewhere.


2014 ◽  
Vol 1010-1012 ◽  
pp. 1399-1403
Author(s):  
Wei Wei Zhou ◽  
Wei Feng Wang ◽  
Zhou Jie

Subtle fault zones are caused by the weak deformation generated in the sedimentary cover of a sag due to the influence of regional or local stress fields or basement faults. They are too subtle to be easily identified by conventional exploration methods and technologies and are thus usually ignored. Research results prove that there are two basement faults in the Jinhu sag referred to as the NE-and NW-trending basement faults. Parts of the NE-trending basement fault are intense enough to control sag formation and evolution (such as the faults in Yangcun and Shigang, etc.). However, the NW-trending and the rest of the NE-trending basement faults show weak activity and exert little influence on sedimentary cover deformation. These faults merely yield some weakly-deformed trend zones in the sedimentary cover, such as small en-echelon faults, small faults intermittently distributed along fixed directions, buried alluvial fans, zonal or stringy oil-gas traps, or linear structures (such as local folds, narrow and deep half-grabens, etc.). Apart from the two aforementioned types of subtle fault zones, intermittent and stringy NS-trending subtle fault zones are also induced by the EW-trending extrusion stress component in the sag generated by the regional dextral stress field. Keywords: Jinhu sag; basement faults; subtle fault zones; tectonic evolution; en-echelon; trap distribution


2021 ◽  
Author(s):  
Mikhail Kaban ◽  
Alexei Gvishiani ◽  
Roman Sidorov ◽  
Alexei Oshchenko ◽  
Roman Krasnoperov

<p><span>A new model has been developed for the density and thickness of the sedimentary cover in a vast region at the junction of the southern part of the East European Platform, the Pre-Caucasus and some structures adjacent to the south, including the Caucasus. Structure and density of sedimentary basins was studied by employing the approach based on decompensation of gravity anomalies. Decompensative correction for gravity anomalies reduces the effect of deep masses providing compensation of near-surface density anomalies, in contrast to the conventional isostatic or Bouguer anomalies. . The new model of sediments, which implies their thickness and density, gives a more detailed description of the sedimentary thickness and density and reveals new features which were not or differently imaged by previous studies. It helps in better understanding of the origin and evolution of the basins and provides a background for further detailed geological and geophysical studies of the region.</span></p>


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