scholarly journals Formation and Accumulation of Pore Methane Hydrates in Permafrost: Experimental Modeling

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 467 ◽  
Author(s):  
Evgeny Chuvilin ◽  
Dinara Davletshina
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Pore Space ◽  
Hydrate Formation ◽  
Methane Hydrates ◽  
Frozen Soils ◽  
Geological Models ◽  
Negative Temperatures ◽  
Thermobaric Conditions ◽  
Ice Content

Favorable thermobaric conditions of hydrate formation and the significant accumulation of methane, ice, and actual data on the presence of gas hydrates in permafrost suggest the possibility of their formation in the pore space of frozen soils at negative temperatures. In addition, today there are several geological models that involve the formation of gas hydrate accumulations in permafrost. To confirm the literature data, the formation of gas hydrates in permafrost saturated with methane has been studied experimentally using natural artificially frozen in the laboratory sand and silt samples, on a specially designed system at temperatures from 0 to −8 °C. The experimental results confirm that pore methane hydrates can form in gas-bearing frozen soils. The kinetics of gas hydrate accumulation in frozen soils was investigated in terms of dependence on the temperature, excess pressure, initial ice content, salinity, and type of soil. The process of hydrate formation in soil samples in time with falling temperature from +2 °C to −8 °C slows down. The fraction of pore ice converted to hydrate increased as the gas pressure exceeded the equilibrium. The optimal ice saturation values (45−65%) at which hydrate accumulation in the porous media is highest were found. The hydrate accumulation is slower in finer-grained sediments and saline soils. The several geological models are presented to substantiate the processes of natural hydrate formation in permafrost at negative temperatures.

scholarly journals Modeling of stability of gas hydrates under permafrost in an environment of surface climatic change – terrestrial case, Beaufort-Mackenzie basin, Canada

2011 ◽  
Vol 7 (5) ◽  
pp. 2863-2891
Author(s):  
J. Majorowicz ◽  
J. Šafanda ◽  
K. Osadetz
Keyword(s):  
Surface Temperature ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Pore Space ◽  
Hydrate Formation ◽  
Type I ◽  
Depth Range ◽  
Mackenzie Basin ◽  
Gas Hydrate Formation ◽  
Heat Effects

Abstract. Modeling of the onset of permafrost formation and succeeding gas hydrate formation in the changing surface temperature environment has been done for the Beaufort-Mackenzie Basin (BMB). Numerical 1-D modeling is constrained by deep heat flow from deep well bottom hole temperatures, deep conductivity, present permafrost thickness and thickness of Type I gas hydrates. Latent heat effects were applied to the model for the entire ice bearing permafrost and Type I hydrate intervals. Modeling for a set of surface temperature forcing during the glacial-interglacial history including the last 14 Myr was performed. Two scenarios of gas formation were considered; case 1: formation of gas hydrate from gas entrapped under deep geological seals and case 2: formation of gas hydrate from gas in a free pore space simultaneously with permafrost formation. In case 1, gas hydrates could have formed at a depth of about 0.9 km only some 1 Myr ago. In case 2, the first gas hydrate formed in the depth range of 290–300 m shortly after 6 Myr ago when the GST dropped from −4.5 °C to −5.5. °C. The gas hydrate layer started to expand both downward and upward subsequently. These models show that the gas hydrate zone, while thinning persists under the thick body of BMB permafrost through the current interglacial warming periods.

scholarly journals Peculiarities of geological and thermobaric conditions for the gas hydrate deposits occurence in the Black Sea and the prospects for their development

2019 ◽  
Vol 28 (3) ◽  
pp. 395-408
Author(s):  
V. Bondarenko ◽  
K. Sai ◽  
M. Petlovanyi
Keyword(s):  
Natural Gas ◽  
Black Sea ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
The Black Sea ◽  
Heterogeneous Structure ◽  
Offshore Area ◽  
Thermobaric Conditions ◽  
Gas Hydrate Deposits

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.

Thermodynamic Modelling of Gas Hydrate Formation in the Presence of Inhibitors and the Consideration of their Effect

2014 ◽  
Vol 14 (1) ◽  
pp. 45
Author(s):  
Peyman Sabzi ◽  
Saheb Noroozi
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Low Temperatures ◽  
Hydrate Formation ◽  
Transportation Systems ◽  
Flow Lines ◽  
Main Approach ◽  
Efficient Inhibitor ◽  
System A ◽  
Gas Hydrate Formation

Gas hydrates formation is considered as one the greatest obstacles in gas transportation systems. Problems related to gas hydrate formation is more severe when dealing with transportation at low temperatures of deep water. In order to avoid formation of Gas hydrates, different inhibitors are used. Methanol is one of the most common and economically efficient inhibitor. Adding methanol to the flow lines, changes the thermodynamic equilibrium situation of the system. In order to predict these changes in thermodynamic behavior of the system, a series of modelings are performed using Matlab software in this paper. The main approach in this modeling is on the basis of Van der Waals and Plateau's thermodynamic approach. The obtained results of a system containing water, Methane and Methanol showed that hydrate formation pressure increases due to the increase of inhibitor amount in constant temperature and this increase is more in higher temperatures. Furthermore, these results were in harmony with the available empirical data.Keywords: Gas hydrates, thermodynamic inhibitor, modelling, pipeline blockage

scholarly journals Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3615
Author(s):  
Florian Filarsky ◽  
Julian Wieser ◽  
Heyko Juergen Schultz
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Synthetic Natural Gas ◽  
Operation Conditions ◽  
Gas Hydrate Formation ◽  
Gas Conditioning ◽  
And Storage ◽  
Economic Considerations ◽  
High Storage

Gas hydrates show great potential with regard to various technical applications, such as gas conditioning, separation and storage. Hence, there has been an increased interest in applied gas hydrate research worldwide in recent years. This paper describes the development of an energetically promising, highly attractive rapid gas hydrate production process that enables the instantaneous conditioning and storage of gases in the form of solid hydrates, as an alternative to costly established processes, such as, for example, cryogenic demethanization. In the first step of the investigations, three different reactor concepts for rapid hydrate formation were evaluated. It could be shown that coupled spraying with stirring provided the fastest hydrate formation and highest gas uptakes in the hydrate phase. In the second step, extensive experimental series were executed, using various different gas compositions on the example of synthetic natural gas mixtures containing methane, ethane and propane. Methane is eliminated from the gas phase and stored in gas hydrates. The experiments were conducted under moderate conditions (8 bar(g), 9–14 °C), using tetrahydrofuran as a thermodynamic promoter in a stoichiometric concentration of 5.56 mole%. High storage capacities, formation rates and separation efficiencies were achieved at moderate operation conditions supported by rough economic considerations, successfully showing the feasibility of this innovative concept. An adapted McCabe-Thiele diagram was created to approximately determine the necessary theoretical separation stage numbers for high purity gas separation requirements.

scholarly journals Investigation on Gas Hydrates Formation and Dissociation in Multiphase Gas Dominant Transmission Pipelines

2020 ◽  
Vol 10 (15) ◽  
pp. 5052 ◽  
Author(s):  
Sayani Jai Krishna Sahith ◽  
Srinivasa Rao Pedapati ◽  
Bhajan Lal
Keyword(s):  
Crude Oil ◽  
Phase Behavior ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Formation Rate ◽  
Water System ◽  
Hydrate Formation ◽  
Multiphase System ◽  
Gas Hydrate Formation ◽  
Water Cut

In this work, a gas hydrate formation and dissociation study was performed on two multiphase pipeline systems containing gasoline, CO2, water, and crude oil, CO2, water, in the pressure range of 2.5–3.5 MPa with fixed water cut as 15% using gas hydrate rocking cell equipment. The system has 10, 15 and 20 wt.% concentrations of gasoline and crude oil, respectively. From the obtained hydrate-liquid-vapor-equilibrium (HLVE) data, the phase diagrams for the system are constructed and analyzed to represent the phase behavior in the multiphase pipelines. Similarly, induction time and rate of gas hydrate formation studies were performed for gasoline, CO2, and water, and crude oil, CO2, water system. From the evaluation of phase behavior based on the HLVE curve, the multiphase system with gasoline exhibits an inhibition in gas hydrates formation, as the HLVE curve shifts towards the lower temperature and higher-pressure region. The multiphase system containing the crude oil system shows a promotion of gas hydrates formation, as the HLVE curve shifted towards the higher temperature and lower pressure. Similarly, the kinetics of hydrate formation of gas hydrates in the gasoline system is slow. At the same time, crude oil has a rapid gas hydrate formation rate.

Investigating the dynamics of gas hydrates in a gas dominant flow loop

2011 ◽  
Vol 51 (2) ◽  
pp. 734
Author(s):  
Yutaek Seo ◽  
Mauricio Di Lorenzo ◽  
Gerardo Sanchez-Soto
Keyword(s):  
Steady State ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Transient Flow ◽  
Hydrate Formation ◽  
Hydrodynamic Condition ◽  
Gas Pipelines ◽  
Flow Loop ◽  
Offshore Pipelines

Offshore pipelines transporting hydrocarbon fluids have to be operated with great care to avoid problems related to flow assurance. Of these possible problems, gas hydrate is dreaded as it poses the greatest risk of plugging offshore pipelines and other production systems. As the search for oil and natural gas goes into deeper and colder offshore fields, the strategies for gas hydrate mitigation are evolving to the management of hydrate risks rather than costly complete prevention. CSIRO has been developing technologies that will facilitate the production of Australian deepwater gas reserves. One of its research programs is a recently commissioned investigation into the dynamic behaviour of gas hydrates in gas pipelines using a pilot-scale 1 inch and 40 m long flow loop. This work will provide experimental results conducted in the flow loop, designed to investigate the hydrate formation characteristics in steady state and transient flow. For a given hydrodynamic condition in steady state flow, the formation and subsequent agglomeration and deposition of hydrate particles appear to occur more severely as the subcooling condition is increasing. Transient flow during a shut-in and restart operation represents a more complex scenario for hydrate formation. Although hydrates develop as a thin layer on the surface of water during the shut-in period, most of the water is quickly converted to hydrate upon restart, forming hydrate laden slurry that is transported through the pipeline by the gas flow. These results could provide valuable insights into the present operation of offshore gas pipelines.

Insights into CO2 Capture by Flue Gas Hydrate Formation: Gas Composition Evolution in Systems Containing Gas Hydrates and Gas Mixtures at Stable Pressures

2018 ◽  
Vol 6 (5) ◽  
pp. 5732-5736 ◽  
Author(s):  
Aliakbar Hassanpouryouzband ◽  
Jinhai Yang ◽  
Bahman Tohidi ◽  
Evgeny Chuvilin ◽  
Vladimir Istomin ◽  
...  
Keyword(s):  
Co2 Capture ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Flue Gas ◽  
Hydrate Formation ◽  
Gas Mixtures ◽  
Gas Composition ◽  
Gas Hydrate Formation

scholarly journals Mathematical modeling of the equilibrium complete replacement of methane by carbon dioxide in a gas hydrate reservoir at negative temperatures

2020 ◽  
Vol 6 (2) ◽  
pp. 63-80
Author(s):  
Stanislav L. Borodin ◽  
Denis S. Belskikh
Keyword(s):  
Carbon Dioxide ◽  
Mathematical Model ◽  
Gas Hydrates ◽  
Hydrate Formation ◽  
Complete Replacement ◽  
Hydrate Reservoir ◽  
Negative Temperatures ◽  
Gas Hydrate Reservoir ◽  
Promising Source ◽  
Methane Carbon

Gas hydrates, which contain the largest amount of methane on our planet, are a promising source of natural gas after the depletion of traditional gas fields, the reserves of which are estimated to last about 50 years. Therefore, it is necessary to study the methods for extracting gas from gas hydrates in order to select the best of them and make reasoned technological and engineering decisions in the future. One of these methods is the replacement of methane in its hydrate with carbon dioxide. This work studies the construction of a mathematical model to observe this method. The following process is considered in this article: on one side of a porous reservoir, initially saturated with methane and its hydrate, carbon dioxide is injected; on the opposite side of this reservoir, methane and/or carbon dioxide are extracted. In this case, both the decomposition of methane hydrate and the formation of carbon dioxide hydrate can occur. This problem is stated in a one-dimensional linear formulation for the case of negative temperatures and gaseous carbon dioxide, which means that methane, carbon dioxide, ice, methane, and carbon dioxide hydrates may be present in the reservoir. A mathematical model is built based on the following: the laws of conservation of masses of methane, carbon dioxide, and ice; Darcy’s law for the gas phase motion; equation of state of real gas; energy equation taking into account thermal conductivity, convection, adiabatic cooling, the Joule — Thomson effect, and the release or absorption of latent heat of hydrate formation. The modelling assumes that phase transitions occur in an equilibrium mode and that methane can be completely replaced by carbon dioxide. The results of numerical experiments are presented.

scholarly journals Numerical Simulation on the Dissociation, Formation, and Recovery of Gas Hydrates on Microscale Approach

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5021
Author(s):  
Mar’atus Sholihah ◽  
Wu-Yang Sean
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Pore Networks ◽  
Mechanisms Of Formation ◽  
Pressure Concentration ◽  
Micro Modeling ◽  
Multi Phase ◽  
Saturation Rate ◽  
Process Method

Investigations into the structures of gas hydrates, the mechanisms of formation, and dissociation with modern instruments on the experimental aspects, including Raman, X-ray, XRD, X-CT, MRI, and pore networks, and numerical analyses, including CFD, LBM, and MD, were carried out. The gas hydrate characteristics for dissociation and formation are multi-phase and multi-component complexes. Therefore, it was important to carry out a comprehensive investigation to improve the concept of mechanisms involved in microscale porous media, emphasizing micro-modeling experiments, 3D imaging, and pore network modeling. This article reviewed the studies, carried out to date, regarding conditions surrounding hydrate dissociation, hydrate formation, and hydrate recovery, especially at the pore-scale phase in numerical simulations. The purpose of visualizing pores in microscale sediments is to obtain a robust analysis to apply the gas hydrate exploitation technique. The observed parameters, including temperature, pressure, concentration, porosity, saturation rate, and permeability, etc., present an interrelationship, to achieve an accurate production process method and recovery of gas hydrates.

scholarly journals Formation of submarine gas hydrates

1994 ◽  
Vol 41 ◽  
pp. 86-94
Author(s):  
V. Soloviev ◽  
G. D. Ginsburg
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Deep Sea ◽  
Hydrate Formation ◽  
Coarse Grained ◽  
Necessary Condition ◽  
Dissolved Gas ◽  
Scale Levels ◽  
Bottom Sampling ◽  
Gas Bearing

Submarine gas hydrates have been discovered in the course of deep-sea drilling (DSDP and ODP) and bottom sampling in many offshore regions. This paper reports on expeditions carried out in the Black, Caspian and Okhotsk Seas. Gas hydrate accumulations were discovered and investigated in all these areas. The data and an analysis of the results of the deep-sea drilling programme suggest that the infiltration of gas-bearing fluids is a necessary condition for gas hydrate accumulation. This is confirmed by geological observations at three scale levels. Firstly, hydrates in cores are usually associated with comparatively coarse-grained, permeable sediments as well as voids and fractures. Secondly, hydrate accumulations are controlled by permeable geological structures, i.e. faults, diapirs, mud volcanos as well as layered sequences. Thirdly, in the worldwide scale, hydrate accumulations are characteristic of continental slopes and rises and intra-continental seas where submarine seepages also are widespread. Both biogenic and cat­agenic gas may occur, and the gas sources may be located at various distances from the accumulation. Gas hydrates presumably originate from water-dissolved gas. The possibility of a transition from dissolved gas into hydrate is confirmed by experimental data. Shallow gas hydrate accumulations associated with gas-bearing fluid plumes are the most convenient features for the study of submarine hydrate formation in general. These accumulations are known from the Black, Caspian and Okhotsk Seas, the Gulf of Mexico and off northern California.

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