scholarly journals 13C Chemical Shift in Natural Gas Hydrates from First-Principles Solid-State NMR Calculations

2016 ◽  
Vol 120 (2) ◽  
pp. 1130-1136 ◽  
Author(s):  
Yuan Liu ◽  
Lars Ojamäe
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Natural Gas ◽  
Gas Hydrates ◽  
First Principles ◽  
Solid State Nmr ◽  
Natural Gas Hydrates ◽  
13C Chemical Shift

13C Chemical Shift and 13C–14N Dipolar Coupling Tensors Determined by 13C Rotary Resonance Solid-State NMR

2001 ◽  
Vol 148 (2) ◽  
pp. 298-308 ◽  
Author(s):  
Louise Odgaard ◽  
Mads Bak ◽  
Hans J. Jakobsen ◽  
Niels Chr. Nielsen
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Dipolar Coupling ◽  
13C Chemical Shift

Chemical shift reference scale for Li solid state NMR derived by first-principles DFT calculations

2018 ◽  
Vol 297 ◽  
pp. 33-41 ◽  
Author(s):  
S.S. Köcher ◽  
P.P.M. Schleker ◽  
M.F. Graf ◽  
R.-A. Eichel ◽  
K. Reuter ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Dft Calculations ◽  
First Principles ◽  
Solid State Nmr ◽  
Reference Scale

Phase diagrams for clathrate hydrates of methane, ethane, and propane from first-principles thermodynamics

2016 ◽  
Vol 18 (4) ◽  
pp. 3272-3279 ◽  
Author(s):  
Xiaoxiao Cao ◽  
Yingying Huang ◽  
Wenbo Li ◽  
Zhaoyang Zheng ◽  
Xue Jiang ◽  
...  
Keyword(s):  
Natural Gas ◽  
Phase Diagrams ◽  
Gas Hydrates ◽  
First Principles ◽  
Inclusion Compounds ◽  
Light Hydrocarbon ◽  
Clathrate Hydrates ◽  
Natural Gas Hydrates

Natural gas hydrates are inclusion compounds composed of major light hydrocarbon gaseous molecules (CH4, C2H6, and C3H8) and a water clathrate framework.

scholarly journals Analysis of Multi-Phase Mixed Slurry Horizontal Section Migration Efficiency in Natural Gas Hydrate Drilling and Production Method Based on Double-Layer Continuous Pipe and Double Gradient Drilling

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3792
Author(s):  
Yang Tang ◽  
Jiaxin Yao ◽  
Guorong Wang ◽  
Yin He ◽  
Peng Sun
Keyword(s):  
Solid State ◽  
Natural Gas ◽  
Double Layer ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Simulation Software ◽  
Natural Gas Hydrate ◽  
Horizontal Section ◽  
Natural Gas Hydrates ◽  
Drilling Method

In order to improve the recovery efficiency of natural gas hydrate in solid-state fluidized mining of natural gas hydrate, we solve drilling safety problems, such as narrow density of natural gas hydrate formation pressure window and poor wellbore stability caused by high upstream velocity during drilling and production. In this study—in order to increase the natural gas hydrate output and reduce production costs—based on the principle of the solid-state fluidized mining, a natural gas hydrate drilling method based on double-layer continuous-pipe double-gradient drilling was proposed to solve the above problems. The article introduces a drilling and production tool combination scheme and the mathematical model of wellbore-pressure dynamic regulation. Simulation software was used to study and compare the migration efficiency of multiphase mixed slurries of sediment and natural gas hydrates in the horizontal section of the double-layer continuous-pipe double-gradient drilling method and traditional drilling method. The results show that the transport efficiency of the multiphase mixed slurry of sediment and natural gas hydrate in the horizontal section of the double-layer continuous-pipe double-gradient drilling method is better than the traditional drilling method under the same conditions. When the double-layer continuous-pipe double-gradient drilling method is adopted, the multiphase mixed slurry of sediment and natural gas hydrate is transported in the pipe and has the function of the submarine lift pump, which effectively avoids the problem of the stability of the shaft wall caused by excessive flow velocity. This will also be more suitable for the transportation of large-diameter particles during the solid-state fluidized mining of natural gas hydrates.

Hydrogen bonding and chemical shift assignments in carbazole functionalized isocyanides from solid-state NMR and first-principles calculations

2011 ◽  
Vol 13 (28) ◽  
pp. 13082 ◽  
Author(s):  
Chandrakala M. Gowda ◽  
Filipe Vasconcelos ◽  
Erik Schwartz ◽  
Ernst R. H. van Eck ◽  
Martijn Marsman ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Chemical Shift ◽  
First Principles ◽  
Solid State Nmr ◽  
Chemical Shift Assignments ◽  
First Principles Calculations
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