Gas Permeability Variation During Methane Hydrate Dissociation by Depressurization in Marine Sediments

2021 ◽  
Author(s):  
Haijun Wang ◽  
Xuelian Pan ◽  
Weiguo Liu ◽  
Xiang Sun ◽  
Yanghui Li ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Methane Hydrate ◽  
Gas Permeability ◽  
Hydrate Dissociation ◽  
Permeability Variation

TEMPERATURE CHANGES FOR METHANE HYDRATE DISSOCIATION IN DIFFERENT CLASS DEPOSITS BY DEPRESSURIZATION

2018 ◽  
Author(s):  
Mingjun Yang ◽  
Yi Gao ◽  
Hang Zhou ◽  
Bingbing Chen ◽  
Yongchen Song
Keyword(s):  
Methane Hydrate ◽  
Hydrate Dissociation ◽  
Temperature Changes

scholarly journals Formation of a Low-Density Liquid Phase during the Dissociation of Gas Hydrates in Confined Environments

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 590
Author(s):  
Lihua Wan ◽  
Xiaoya Zang ◽  
Juan Fu ◽  
Xuebing Zhou ◽  
Jingsheng Lu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Methane Hydrate ◽  
Phase State ◽  
Solid Phase ◽  
Potential Method ◽  
Methane Hydrates ◽  
Low Density ◽  
Hydrate Dissociation ◽  
State Of Water ◽  
Confined Environment

The large amounts of natural gas in a dense solid phase stored in the confined environment of porous materials have become a new, potential method for storing and transporting natural gas. However, there is no experimental evidence to accurately determine the phase state of water during nanoscale gas hydrate dissociation. The results on the dissociation behavior of methane hydrates confined in a nanosilica gel and the contained water phase state during hydrate dissociation at temperatures below the ice point and under atmospheric pressure are presented. Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) were used to trace the dissociation of confined methane hydrate synthesized from pore water confined inside the nanosilica gel. The characterization of the confined methane hydrate was also analyzed by PXRD. It was found that the confined methane hydrates dissociated into ultra viscous low-density liquid water (LDL) and methane gas. The results showed that the mechanism of confined methane hydrate dissociation at temperatures below the ice point depended on the phase state of water during hydrate dissociation.

X-ray Computed Tomography Observation of Methane Hydrate Dissociation

2002 ◽  
Author(s):  
Liviu Tomutsa ◽  
Barry Freifeld ◽  
Timothy J. Kneafsey ◽  
Laura A. Stern
Keyword(s):  
Computed Tomography ◽  
Methane Hydrate ◽  
Hydrate Dissociation ◽  
X Ray ◽  
X Ray Computed

Geomechanical Responses During Gas Hydrate Production Induced by Depressurization

2016 ◽  
Author(s):  
Ah-Ram Kim ◽  
Gye-Chun Cho ◽  
Joo-Yong Lee ◽  
Se-Joon Kim
Keyword(s):  
Methane Hydrate ◽  
Fossil Fuel ◽  
Gas Production ◽  
Field Scale ◽  
Production Well ◽  
Physical Processes ◽  
Hydrate Dissociation ◽  
Thermal Changes ◽  
New Energy ◽  
Hydrate Bearing Sediments

Methane hydrate has been received large attention as a new energy source instead of oil and fossil fuel. However, there is high potential for geomechanical stability problems such as marine landslides, seafloor subsidence, and large volume contraction in the hydrate-bearing sediment during gas production induced by depressurization. In this study, a thermal-hydraulic-mechanical coupled numerical analysis is conducted to simulate methane gas production from the hydrate deposits in the Ulleung basin, East Sea, Korea. The field-scale axisymmetric model incorporates the physical processes of hydrate dissociation, pore fluid flow, thermal changes (i.e., latent heat, conduction and advection), and geomechanical behaviors of the hydrate-bearing sediment. During depressurization, deformation of sediments around the production well is generated by the effective stress transformed from the pore pressure difference in the depressurized region. This tendency becomes more pronounced due to the stiffness decrease of hydrate-bearing sediments which is caused by hydrate dissociation.

scholarly journals Numerical simulation of CH4 hydrate formation in fractures

2018 ◽  
Vol 36 (5) ◽  
pp. 1279-1294 ◽  
Author(s):  
Sheng-Li Li ◽  
You-Hong Sun ◽  
Kai Su ◽  
Wei Guo ◽  
You-Hai Zhu
Keyword(s):  
Methane Hydrate ◽  
Hydrate Formation ◽  
Growth Behavior ◽  
Fractured Media ◽  
Initial Condition ◽  
Insulation Layer ◽  
Hydrate Dissociation ◽  
Fracture Size ◽  
The Media ◽  
Gas Supply

Fracture-hosted methane hydrate deposits exist at many sites worldwide. The growth behavior of CH4 hydrate in fractured media was simulated by TOUGH + HYDRATE (T + H) code. The effects of fracture size, initial condition, and salinity on the growth behavior of hydrate in fractures were investigated. In general, the hydrate layer grew from the two ends and gradually covered on the surface of the fracture. With the formation of hydrate in fractures, the temperature increased sharply since the hydrate acted as a thermal insulation layer. In longer fractures, fast growth of hydrate at the ends of the fracture led to the formation of hydrate plugs with high saturation (called as stopper). In narrower fractures, hydrate dissociation occurred in the middle of the fracture during hydrate growing in the whole fracture due to the cutoff of gas supply by the stopper at the ends. At a low initial subcooling, hydrate formed both on the surface and in the micropores of the media, which was different from that at higher subcooling. In salt solution, the formation of hydrate stopper was inhibited by the salt-removing effect of hydrate formation and the growth of hydrate was more sustainable.

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