scholarly journals Geological and structural prerequisites of gas-bearing capacity and gas hydrate formation in the World Ocean (in terms of the Black Sea)

2018 ◽  
Vol 27 (2) ◽  
pp. 294-304
Author(s):  
E. Maksymova ◽  
S. Kostrytska

Gas hydrates occurring in the World Ocean are considered as the additional and perspective non-traditional resource of hydrocarbon materials. The proposed classification of deposits as for mining and geological conditions of their occurrence as well as methodological approach to their development and calculation of technological parameters of methane extraction from the World Ocean floor with minimum impact upon the Earth’s hydrosphere is of considerable importance in the context of current studies of new and most prospective source of energy in terms of the available experience gap as for the development of gas hydrate deposits. The approach to search for and explore gas hydrate deposits occurring on and under the World Ocean floor has been suggested; the approach is based upon the regularities of gas hydrate distribution in lithological varieties and geological structures. The necessity to take into consideration the pore space enclosing gas hydrate thicknesses to calculate their reserves has been substantiated. The overview of scientific literature sources summarizingthe results of marine expeditions as well as the analysis of publications of world scientific community dealing with the studies of gas hydrates has made it possible to determine that gas hydrate deposits are associated to the zones of jointing of continental plates and oceanic troughs. In their turn, those zones, due to different genesis, are made up of the corresponding various products of sedimentary rock accumulations. Detailed analysis of the Black Sea floor structure has been performed. Three geomorphological zones have been singled out; basic types of gas-bearing capacity manifestation and methane liberation from the interior have been represented. Quantitative evaluation of methane content in gas hydrate deposits has been given taking into account the detected ones. Data concerning gas-bearing capacity of the Black Sea floor proved by the map of mud volcanoes location within the areas of gas hydrate sampling have been considered. That was the basis to analyze peculiarities of the formation of bottom-sediment gas hydrates basing upon genetic origin of lithological composition of their enclosing rocks and their structures in terms of the Black Sea floor. Relation between the features of the World Ocean floor structure and the distribution of gas hydrate deposits has been determined. Theoretical approach to search for and explore gas hydrate deposits both in the Black Sea and in the World Ocean has been developed and proposed. Interaction between different zones of the World Ocean floor and types of gas hydrate deposits based upon the compositions of their enclosing rock has been shown. Lithological composition of the rocks enclosing gas hydrates has been analyzedin detail. That will make it possible to determine the type of any specific deposit and elaborate technological scheme to open and develop methane-containing gas hydrate deposits.

2021 ◽  
Vol 2021 (2) ◽  
pp. 43-55
Author(s):  
Andrey Vitalievich Makagon

The article considers the modern problems and prospects of the development of technologies of transporting the natural gas by sea due to the fact that gas hydrate deposits are found on the bottom of Lake Baikal, the Black Sea, the Caspian Sea and the Okhotsk Sea. It has been stated that despite the proved gas hydrate deposits the fields have not been explored yet. Introducing the technology for transporting gas by sea in gas hydrate form is being substantiated. Comparative analysis of LNG, CNG and NGH technologies for sea transportation of natural gas proved that the transport component of the NGH technological chain has significant advantages over LNG and CNG technologies. The process of converting thermal energy of the ocean has been proposed to use for increasing the energy efficiency of methane production from subsea gas hydrate deposits in the gas hydrate cycle, which can save 10-15% of the produced methane for electricity generation. A schematic and technological solution of a gas production complex is presented, according to which carbon dioxide is introduced into the gas hydrate layer to extract methane from gas hydrates. To improve the kinetics of replacing methane with carbon dioxide in gas hydrates it is proposed to recycle a portion of CO2. Due to the specific and diversified geographic, economic, political and other conditions the conventional technologies for pipeline transportation of gas and LNG cannot fully meet the requirements of gas export and production projects. It has been inferred that NGH technology is most suitable for solving the problem of diversifying natural gas supplies from the Arctic regions, the Black Sea and in the development of offshore gas and oil fields.


Author(s):  
S. V. Goshovskyi ◽  
Oleksii Zurian

In the bowels of the Earth and in the oceans of the World Ocean, there are practically unlimited resources of natural gas in the solid hydrate state, available to most countries of the world community. The development of gas hydrate deposits is based on the process of dissociation (separation), in which the gas hydrates break down into gas and water. In these technologies, three methods for the development of gas hydrate deposits are proposed: pressure reduction, heating and inhibitor input. Based on the systematized data, the above methods are suggested to be attributed to traditional methods, as the most studied and classical ones. It is proposed to identify a number of methods that imply the same results, but use other physical approaches and designate them as unconventional. 1. Decomposition of methane hydrates by nanoparticles. In this method, the use of nanoparticles commensurate with the gas hydrate cell (supplied as part of a hydrodynamic jet) is proposed for efficient and safe destruction of the gas hydrate. The application of nanotechnology provides effective and consistent study of the entire surface of the aquatic deposit of gas hydrates, with the necessary rate of their destruction and the production of planned volumes of methane. 2. Decomposition of methane hydrates by microorganisms (bacteria). In this process, in the process of the life of the bacteria, a gas must be released, replacing in the clathrate structure a molecule of methane per molecule of the given gas. In addition, the process must be controlled by the use of external factors that provide nutrition to the bacteria and at the same time, light, chemicals, electromagnetic radiation, etc. can be stopped at any time, which is absent in the natural conditions of formation of the gas hydrate.


2019 ◽  
Vol 28 (3) ◽  
pp. 395-408
Author(s):  
V. Bondarenko ◽  
K. Sai ◽  
M. Petlovanyi

The actuality has been revealed of the necessity to attract the gas hydrate depos- its of the Black Sea into industrial development as an alternative to traditional gas fields. This should be preceded by the identification and synthesis of geological and thermobaric peculiarities of their existence. It was noted that the gas hydrates formation occurs under certain thermobaric conditions, with the availability of a gas hydrate-forming agent, which is capable of hydrate formation, as well as a sufficient amount of water necessary to start the crystallization process. The gas hydrate accumulation typically does not occur in free space – in sea water, but in the massif of the sea bed rocks. The important role in the process of natural gas hydrates formation is assigned to thermobaric parameters, as well as to the properties and features of the geological environment, in which, actually, the process of hydrate formation and further hydrate accumulation occurs. It was noted that the source of formation and accumulation of the Black Sea gas hydrates is mainly catagenetic (deep) gas, but diagenetic gas also takes part in the process of gas hydrate deposits formation. The main component of natural gas hydrate deposits is methane and its homologs – ethane, propane, isobutane. The analysis has been made of geological and geophysical data and literature materials devoted to the study of the offshore area and the bottom of the Black Sea, as well as to the identification of gas hydrate deposits. It was established that in the offshore area the gas hydrate deposits with a heterogeneous structure dominate, that is, which comprises a certain proportion of aluminosilicate inclusions. It was noted that theBlack Sea bottom sediments, beginning with the depths of 500 – 600 m, are gassy with methane, and a large sea part is favourable for hydrate formation at temperatures of +8...+9oC and pressures from 7 to 20 MPa at different depths. The characteristics of gas hydrate deposits are provided, as well as requirements and aspects with regard to their industrialization and development. It is recommended to use the method of thermal influence on gas hydrate deposits, since, from an ecological point of view, it is the safest method which does not require additional water resources for its implementation, because water intake is carried out directly from the upper sea layers. A new classification of gas hydrate deposits with a heterogeneous structure has been developed, which is based on the content of rocks inclusions in gas hydrate, the classification feature of which is the amount of heat spent on the dissociation process.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1345
Author(s):  
Oleg Bazaluk ◽  
Kateryna Sai ◽  
Vasyl Lozynskyi ◽  
Mykhailo Petlovanyi ◽  
Pavlo Saik

Ukraine is an energy-dependent country, with less that 50% of its energy consumption fulfilled by its own resources. Natural gas is of paramount importance, especially for industry and society. Therefore, there is an urgent need to search for alternative and potential energy sources, such as gas hydrate deposits in the Black Sea, which can reduce the consumption of imported gas. It is necessary to refine the process parameters of the dissociation of gas hydrate deposits with a heterogeneous structure. The analyzed known geological–geophysical data devoted to the study of the offshore area and the seabed give grounds to assert the existence of a significant amount of hydrate deposits in the Black Sea. An integrated methodological approach is applied, which consists of the development of algorithms for analytical and laboratory studies of gas volumes obtained during the dissociation of deposits with a heterogeneous structure. These data are used for the computer modelling of the dissociation zone in the Surfer-8.0 software package based on the data interpolation method, which uses three methods for calculating the volumes of modelling bodies. A 3D grid-visualization of the studied part of the gas hydrate deposit has been developed. The dissociation zone parameters of gas hydrate deposits with different shares of rock intercalation, that is, the minimum and maximum diameters, have been determined, and the potentially recoverable gas volumes have been assessed. The effective time of the process of gas hydrate deposit dissociation has been substantiated. The obtained research results of the dissociation process of gas hydrate deposits can be used in the development of new technological schemes for gas recovery from the deep-water Black Sea area.


2018 ◽  
Vol 12 (2) ◽  
pp. 104-115 ◽  
Author(s):  
V Bondarenko ◽  
◽  
K Sai ◽  
K Prokopenko ◽  
D Zhuravlov ◽  
...  

Author(s):  
Н. Есин ◽  
N. Esin ◽  
Н. Есин ◽  
N. Esin ◽  
О. Сорокина ◽  
...  

A method of calculation on local curves of the World ocean eustatic (absolute) variations is presented in this paper. It is shown that vertical motions of the Earth's Crust considerably distort eustatic curve of the sea level change (up to the contrary result). Thus, the local curves present little volume of information. A method of extraction of tectonic component from local curves is proposed. The World ocean level change in Holocene is calculated on local curves of the Mediterranean Sea. It was ascertained that the process of an active erosion of the Black Sea shelf began 3–4 ka.


2000 ◽  
Vol 1 (1) ◽  
pp. 105 ◽  
Author(s):  
A. GUBANOVA

It was reported for the first time that Acartia tonsa was present in the Black Sea as early as in 1976. A.tonsa was found in the Mediterranean Sea in 1985. So, this copepod was initially introduced to the Black Sea and did not invade here from the Mediterranean. Probably A.tonsa was transferred to the Black Sea with ship's ballast water from some other region of the World Ocean. Differences in seasonal dynamics and size structure of A.clausi and A.tonsa in the Bay of Sevastopol in 1976 are discussed.


2021 ◽  
Author(s):  
Oleksii Batyrev ◽  
Olga Andrianova ◽  
Radomir Belevich ◽  
Michael Skipa

<p>Coastal zone research is becoming increasingly important because the impact of climate change is most significant here. The state of coastal regions is determined by the variability in three contact media (geological, water, and air). Evaluation of level changes on the coasts of various parts of the World Ocean (the Mediterranean, Black, Baltic and North Seas, and the Atlantic coasts in Brazil and France) over a long period of time shows various fluctuations with an upward trend in recent decades.</p><p>To highlight the factors that determine the seashores' level fluctuations, three contact media parameters were considered on the example of the western part of the Black Sea. Calculations, analysis, and comparison of trends in the variability of hydrometeorological characteristics (air and water temperatures, precipitation, and river discharge) and sea level over a period of more than 100 years have been carried out.</p><p>To assess the intensity of fluctuations of the coastal land along the western coast of the Black Sea, the series of level heights were considered at 6 Ukrainian stations: Vylkove, Chornomorsk (Ilyichevsk), Odesa-port, port Yuzhne, Ochakiv and Sevastopol (partially used as a benchmark), at 2 stations on the Romanian coast: Constanta and Sulina, and 2 stations on the Bulgarian coast: Burgas and Varna. Estimates of the dynamics of the land for the stations of this region's coastal zone for more than a 100-year period are calculated, and it is shown in which way changes in sea level are a consequence of the processes occurring in the coastal land and at the bottom.</p><p>Comparison of the years with extreme fluctuations in the sea level with the years of the global El Niño phenomenon showed that one of the causes of the observed disturbances in the water and air environments is the distant manifestations of this phenomenon.</p><p>Level fluctuations, both in the Black Sea and in the World Ocean, are synchronous at low-frequency scales (their period is more than 5 years) since global climatic processes on our planet influence them; short-term fluctuations are distinguished by regional features and are created under the influence of local factors (tectonic, geophysical, hydrostatic, etc.).</p><p>Modeling and predicting changes in the coastal zone of various parts of the World Ocean requires continuation of systematic observations of sea-level fluctuations, hydrometeorological characteristics, and seismic conditions in regions with the longest data series; it's crucial for the Black Sea as well for the Mediterranean, Baltic, North Seas, and Atlantic shores.</p>


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