scholarly journals Peculiarities of Stratigraphic Distribution and Paleoecology of Jurassic Bivalve Mollusks of the Pre-Сarpathian Foredeep

2021 ◽  
Vol 30 (4) ◽  
pp. 718-728
Author(s):  
Ihor V. Shaynoha ◽  
Vasyl V. Karabyn

Pre-Carpathian region is one of the oldest oil and gas producing regions of our country, which is attracting more and more attention of scientists. In the Outer zone of the Pre-Carpathian Foredeep, Jurassic deposits occur at considerable depths (up to 3,000 m), so we obtain almost all geological information about them exclusively during the study of core material selected during drilling. A comprehensive and detailed study of the Jurassic deposits of this zone during exploration drilling in the 1950s contributed to the discovery of the Kokhanivske and Sudovovyshnianske oil deposits and Rudkivske gas deposit, as well as a number of oil and gas manifestations. After that, the interest in the conditions of formation and stratification of Jurassic deposits increased. Researchers have begun to treat them as the promising objects for oil and gas exploration. Jurassic deposits in the Pre-Сarpathian Foredeep fill a single depression – the Stryi Jurassic deflection, covered by a thick layer of Cretaceous and Neogene rocks. The study of their geology and stratigraphy has acquired important applied and scientific significance, because stratigraphic research serves as a basis for clarifying the history of geological development of the region, performing tectonic constructions, reconstruction of paleogeographic and paleoecological conditions, comparison of productive horizons and specification of their stratigraphic position, search for new objects promising for hydrocarbons. Extremely rare finds of paleontological remains (which are not always well preserved) do not allow to unambiguously determining the age of the host rocks. It is still not always possible to clearly stratigraphically distinguish and correlate these rocks due to weak paleontological study and partial uncertainty in the interpretation of the geological structure of these strata. Despite the significant amount of research we have done, there are some debatable issues regarding the completeness of the section of these rocks and the presence of separate stratigraphic units in them. For many years, we have studied in detail and comprehensively bivalve mollusks found in the core of wells drilled in the Outer zone of the Pre-Carpathian Foredeep. As a result, the age of the host strata was specified and confirmed, as well as the thickness of individual stratigraphic units.

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (5) ◽  
pp. 283-292
Author(s):  
Tomasz Topór ◽  

The application of machine learning algorithms in petroleum geology has opened a new chapter in oil and gas exploration. Machine learning algorithms have been successfully used to predict crucial petrophysical properties when characterizing reservoirs. This study utilizes the concept of machine learning to predict permeability under confining stress conditions for samples from tight sandstone formations. The models were constructed using two machine learning algorithms of varying complexity (multiple linear regression [MLR] and random forests [RF]) and trained on a dataset that combined basic well information, basic petrophysical data, and rock type from a visual inspection of the core material. The RF algorithm underwent feature engineering to increase the number of predictors in the models. In order to check the training models’ robustness, 10-fold cross-validation was performed. The MLR and RF applications demonstrated that both algorithms can accurately predict permeability under constant confining pressure (R2 0.800 vs. 0.834). The RF accuracy was about 3% better than that of the MLR and about 6% better than the linear reference regression (LR) that utilized only porosity. Porosity was the most influential feature of the models’ performance. In the case of RF, the depth was also significant in the permeability predictions, which could be evidence of hidden interactions between the variables of porosity and depth. The local interpretation revealed the common features among outliers. Both the training and testing sets had moderate-low porosity (3–10%) and a lack of fractures. In the test set, calcite or quartz cementation also led to poor permeability predictions. The workflow that utilizes the tidymodels concept will be further applied in more complex examples to predict spatial petrophysical features from seismic attributes using various machine learning algorithms.


2021 ◽  
Vol 133 (2) ◽  
pp. 27-30
Author(s):  
D. A. Kobylinskiy ◽  

The work is devoted to the development of geochemical criteria for determining the nature of saturation for deep-adsorbed gases in the core. As the object of investigation used the core material selected in the fields in the Nadym-Pyrskoy oil and gas field. In each sample, 72 components were determined, namely, hydrocarbons of different material groups: normal, branched, polycyclic, and aromatic compounds from butane to dodecane. With respect to the quantitative distribution and correlation among the components, qualitative geochemical indicators of sediment productivity have been developed. The saturation character established by the criteria of deep-adsorbed gases was confirmed by the test results. In this regard, this research method significantly increases the effectiveness of diagnostics of prospective deposits, the application of which is relevant in the territory of the West Siberian oil and gas basin, especially when studying deep-submerged deposits of complex geological structure.


Formulation of the problem. Hydrocarbon pools in hydrodynamic traps are known within many oil and gas provinces. The Dnieper-Donets basin is one of the regions where non-vault traps of almost all types and associated with them hydrocarbon pools are widespread, while HT in DDD are not yet typical, although the geological structure of the region indicates the possibility of their formation. Thus, substantiation of the role of geological preconditions in the processes of hydrodynamic type traps formation is the main task of the work. Analysis of recent research and publications. In the monograph of O. Plotnikov (2001) among the promising regions for the search for HT defined DDD. The reason for this was the data on the presence in some productive horizons, in particular in the Sorochinsky and Rudenkivsky fields, of formation waters that lie above gas-bearing deposits. It is believed by some researchers, that the leading role in the formation of gas accumulations at these fields belongs to formation waters. According to the results of geological and geophysical study of the southern slope of the Kalmius-Torets depression and the Krasnoarmijska monocline in the south-eastern part of the DDD (A. Terdovidov (2000), S. Pavlov (2004), favorable geological prerequisites for the formation of HT in Paleozoic sediments established. Selection of previously unsolved parts of the overall problem. The general problem of searching for HT in the DDD as a whole task has not been solved so far. Formulation of the purpose of the article. Estimation of possibilities of a new direction of search and reconnaissance works in DDD, namely on non-traditional non-vault traps of hydrodynamic type substantiation. Results. The Visean dominant productive complex, regionally extended on the monocline slopes of the northern and southern sides of the depression and lithologically represented mainly by sandy horizons, was selected for priority research. The significant content of alluvial sandstones in Visean sediments section allowed the authors to consider them as special reservoirs of fluids, and paleoalluvial systems to study in the rank of independent search objects. Their territorial location is logically related to the existing deflections of the surface of the crystalline basement, most of which are associated with modern river systems, which indicates the current functioning of their relationship. The authors made an attempt to substantiate within the northern side of the DDD the following forecast water exchange systems: 1) expultional overflowing; 2) docking regime (both in the terminology of O. Plotnikov) in Paleozoic sediments; 3) infiltration water exchange in Mesozoic sediments, as necessary conditions for catching migrating upward hydrocarbons. The decrease in the infiltration waters velocity to insignificant values is interpreted by the authors as a typical phenomenon for "closed" monoclines, within which there was an equilibrium between the pressure of infiltrative waters and the resistance of expultional fluids. This equilibrium is seen as a term of creating conditions for hydrodynamic trapping. The conclusions emphasize the need for comprehensive research to confirm the predictive models of water exchange and obtain data for mapping piezometric minimums, where there is an presumable accumulation of hydrocarbons.


Author(s):  
Ад.А. Алиев ◽  
Г.Д. Етирмишли

Статья посвящена новым извержениям самых активных грязевых вулканов Шамахи-Гобустанского региона Восточного Азербайджана – Шихзарли и Гушчу, характеризующихся частыми проявлениями. Так, начиная с 1844 г. зарегистрировано 26 извержений грязевого вулкана Шихзарли, одно из которых, наиболее интенсивное произошло в феврале 1902 г. после катастрофического Шамахинского землетрясения. Цель исследования. Рассмотрены геологическая позиция грязевых вулканов, сейсмологические данные, определившие глубину очага и энергию извержения, дан краткий исторический обзор извержений. Методы исследования. Геологическое строение площадей расположения грязевых вулканов изложено на основе новых данных, полученных в последние годы о тектонике грязевулканических районов Азербайджана, в частности Гобустана, с выделением разломных структур и расположенных между ними микроблоков, а также тектонических единиц – аллохтон, паравтохтон и автохтон. В одном их таких микроблоков (Баянатинский) расположен грязевой вулкан Шихзарли, относящийся к паравтохтону. Почти все извержения грязевых вулканов Шихзарли и Гушчу, а также последние их проявления спровоцированы землетрясениями, происшедшими в близкорасположенных к ним районах и отмечены 5–7 сейсмостанциями. Предыдущее извержение грязевого вулкана Гушчу в Шамахинском районе в январе 2020 года явилось следствием подземных толчков в соседнем Исмаиллинском районе. В историческом обзоре рассматриваемых грязевых вулканов отмечены характерные и отличительные особенности их проявлений. Последнее (16-е) извержение грязевого вулкана Гушчу произошло из нового эруптивного центра, на расстоянии 700 м к северу от основного действующего более ста лет кратера вулкана. Результаты работы. Приведены результаты геохимического анализа вулканической брекчии, особенно нефтеносных пород – песчаников и горючих сланцев эоцен-миоценовых отложений для оценки перспектив нефтегазоносности площадей расположения изученных грязевых вулканов. В пределах Баянатинского микроблока нефтегазовые скопления могут быть открыты под грязевулканическим очагом The article is devoted to new eruptions of the most active mud volcanoes Shikhzarli and Gushchu in the Shamakhi-Gobustan region of East Azerbaijan. These volcanoes are characterized by frequent manifestations. Thus, since 1844, 26 eruptions of the Shikhzarli mud volcano have been recorded. The most intense eruption occurred in February 1902 after the catastrophic Shamakhi earthquake. Aim. The geological position of mud volcanoes, seismological data that determined the depth of the source and the energy of the eruption are considered. A brief historical review of the eruptions is given. Methods.The geological structure of the areas where mud volcanoes are located is presented on the basis of new data obtained in recent years on the tectonics of mud volcanic regions of Azerbaijan. In particular for this reason was used Gobustan, with the identification of fault structures and microblocks located between them, as well as tectonic units - allochthon, parautochthon and autochthon. In one of these microblocks (Bayanata), there is the Shikhzarli mud volcano, which belongs to the parautochthon. Almost all the eruptions of the Shikhzarli and Gushchu mud volcanoes, as well as their last manifestations, are induced by earthquakes that have occurred in the regions close to them and are registered by 5–7 seismic stations. The previous eruption of the Gushchu mud volcano in the Shamakhi region in January 2020 was the result of tremors in the neighboring Ismayilli region. In the historical review of the considered mud volcanoes, characteristic and distinctive features of their manifestations are noted. The last (16th) eruption of the Gushchu mud volcano occurred from a new eruptive center, at a distance of 700 m to the north of the main crater of the volcano that has been active for more than a hundred years. Results. The results of geochemical analysis of volcanic breccias, especially oil-bearing rocks - sandstones and oil shales of Eocene-Miocene deposits are presented to assess the prospects for oil and gas content of the areas where the considered mud volcanoes are located. Within the Bayanata microblock, oil and gas accumulations can be discovered under a mud volcanic chamber


2021 ◽  
pp. 32-47
Author(s):  
Yu. A. Zagorovsky

The article briefly describes current understanding of the tectonic regime of study area. It is related to the field geological practice of students of Industrial University of Tyumen. Study area is located at the western edge of Sukhoi Log town, Sverdlovsk region. The relevance of the work is related to the educational process. Information about the geological structure of the Devonian and Carboniferous formations of study area is collected. Some of the most characteristic outcrops of Paleozoic are described. Actual information about the Ural mountain genesis is given. The list of studied objects includes the outcrop of Eifelian reefal limestones near to the Shata waterfall and the ruins of a volcano. According to other researchers, it is a part of Middle Devonian volcanic arc, which was formed over the subduction zone. Here the Ordovician-Silurian Paleouralian Ocean were subducted under the collage of different-age terrains and paleocontinents (Paleozoic basement of the modern West Siberian Plate). A possible section across the Middle Devonian subduction zone of study area is presented. Similar objects associated with the oil and gas are known in the Pre-Jurassic basement of Western Siberia. The limestones and volcanic massifs exposed near the Sukhoi Log are good natural equivalents of the objects of oil and gas exploration in Western Siberia.


2013 ◽  
Vol 10 (7) ◽  
pp. 1830-1835 ◽  
Author(s):  
Dike U. Ike ◽  
Adoghe Anthony ◽  
Adoghe Anthony ◽  
Ademola Abdulkareem ◽  
Ademola Abdulkareem

Information and Communication Technology (ICT) is of great importance to almost all aspects of oil and gas operations, from upstream to downstream operations. ICTs help to optimize oil and gas processes and thus improves  the efficiency and viability of oil and gas operations. This paper presents the core areas of application of ICTs in the oil and gas industry using Nigeria’s oil and gas industry as a case study.


Author(s):  
І. R. Mikhayliv ◽  
А. P. Boiko

Although the Outer zone of the Precarpathian foredeep is one of the oldest gas extraction regions of Ukraine it is still promising for the exploration of new oil and gas deposits. The main gas deposits are open here in the Miocene, but the number of unidentified structures is rapidly shrinking. The development of unexplored Cretaceous deposits and the possibility of opening up their deposits of oil and gas can provide an increase in the resource base. In this case, the importance of the prospects of oil and gas bearing capacity of Cretaceous deposits is determined by a set of criterion features, including the determination of the nature of collectors and caprocks distribution, the establishment of favorable hydrogeological, structural and tectonic conditions for the formation and conservation of oil and gas deposits. The substantiated oil and gas prospect increases the search engine success, and therefore the development of the hydrocarbon potential of the Cretaceous deposits of the Outer zone can make a significant contribution to the fuel and energy supply of Ukraine with its own raw materials. Generalization, systematization, and analysis of new and reinterpretation of previously performed geological and geophysical studies and the results of deep drilling made it possible to substantiate the reliable geological structure of the cretaceous deposits of the studied region, which will increase the efficiency of prediction of oil-and-gas saturation and determine the priority oil and gas prospecting objects for detailed geological and geophysical works in order to search for new oil and gas deposits. Research results will increase the efficiency of search work, and the growth of promising and projected resources will be a significant contribution to the task of stabilizing and increasing oil and gas production in Ukraine.


2021 ◽  
Vol 3-4 (185-186) ◽  
pp. 16-32
Author(s):  
Halyna Medvid ◽  
Olga Teleguz ◽  
Vasyl Harasymchuk ◽  
Maria Kost’ ◽  
Solomiya Kalmuk

The hydrogeochemical parameters of the Lower Sarmatian aquifer of the north-western part of the Outer Zone of the Carpathian Foredeep have been studied. The waters of the chloride-calcium type (according to the classification of V. O. Sulin) are dominated. Other types of water are distributed locally. On the basis of the calculated genetic coefficients, the conclusion on sedimentogenic conditions of their forming during a geological history of the region is made. It is established that the general tendency for the deposits of the Outer Zone is increasing of TDS of water with depth and stratigraphy. The waters of the north-western part of the Outer Zone are characterized by reduced values of sulfate content and sulfation coefficient rSO42– • 100/rCl–, indicating the conditions of hydrogeological closed structures. The genetic index of formation water metamorphism (rNa+/rCl–) is mainly inversely dependent on TDS. Its values greater than one are inherent in waters of hydrocarbonate-sodium and sulfate-sodium types, which are not typical for the hydrocarbon deposits. The nature of fluctuations in the values of the chlorine-bromine coefficient is fully consistent with other hydrochemical parameters and the results of paleohydrodynamic reconstructions. A detailed analysis of the current hydrodynamic situation of Lower Sarmatian aquifer in combination with geochemical features and paleohydrodynamic reconstructions allowed to identify the perspective structures of the studying region. Our forecasts for the gas potential of the Krukenychy depression are consistent with the forecasts of researchers of Ivano-Frankivsk National Technical University of Oil and Gas. The results of their research are based on gravitational field anomalies.


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