Natural Gas Hydrates – A Review of the Resources Offshore Nigeria and around the Globe

2011 ◽  
Vol 4 ◽  
pp. 27-33
Author(s):  
U.P. Igboanusi ◽  
J.U. Okere
Keyword(s):  
Climate Change ◽  
Natural Gas ◽  
Geographical Distribution ◽  
Gas Hydrates ◽  
Co2 Sequestration ◽  
Large Scale ◽  
Continental Margins ◽  
Natural Gas Hydrates ◽  
Pure Methane ◽  
Permafrost Regions

Natural gas hydrates are ice-like materials which exist in permafrost regions and in the continental margins of oceans. They constitute a huge unconventional reservoir of natural gas around the globe including offshore Nigeria. The paper is a review of this important global resource with particular focus on the Nigerian deposits. The reasons for the interest on hydrates are discussed including the potential for the recovery of large quantities of methane, the climate change and ocean floor instability that may result from their dissociation. They may also be exploited for large-scale CO2 sequestration. The geographical distribution of hydrates deposits on earth, the thermodynamics of why they occur in those particular places and source of the methane gas that is eventually enchlathrated into hydrates are discussed. The natural gas in the Nigerian hydrate is essentially biogenic in origin and is almost pure methane (more than 99% methane). The hydrates exist in finely disseminated or massive aggregate forms within clay-rich sediment.

scholarly journals Clathrate Ices—Recent Results

1978 ◽  
Vol 21 (85) ◽  
pp. 33-49
Author(s):  
D. W. Davidson ◽  
J. A. Ripmeester
Keyword(s):  
Natural Gas ◽  
Ethylene Oxide ◽  
Gas Hydrates ◽  
Time Scale ◽  
Water Molecules ◽  
Guest Molecules ◽  
Natural Gas Hydrates ◽  
Change Effect ◽  
Line Narrowing ◽  
Permafrost Regions

AbstractThe last five years have seen an increasing interest in clathrate ices as a result of the discovery of extensive deposits of natural gas hydrates in permafrost regions. Twenty-six new clathrate hydrates have been identified, mainly by NMR, including a tetragonal hydrate of dimethyl ether. N-butane and neopentane have been found to be enclathrated in natural gas hydrates, the former as a gauche conformer. As a result of their high symmetries, encaged neopentane, CF4, SF6, and SeF6 exhibit a Resing apparent-phase-change effect in the temperature range of NMR line narrowing. There is increasing evidence that reorientational jumps of water molecules are more frequent than translational jumps in clathrate ices. This is certainly so for ethylene oxide-d4 and tetrahydrofuran-d8 hydrates for which two regions of proton line narrowing and two T1ρ minima have been observed. The reorientational motions of most guest molecules in structure II hydrates only become isotropic on a time scale long enough to permit the cage configurations to be averaged to 43m symmetry by reorientation of the water molecules. The orientations of the water molecules remain disordered to the lowest temperatures.

scholarly journals Assessment of Marine Gas Hydrates and Associated Free Gas Distribution Offshore Uruguay

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Juan Tomasini ◽  
Héctor de Santa Ana ◽  
Bruno Conti ◽  
Santiago Ferro ◽  
Pablo Gristo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Probabilistic Approach ◽  
Mean Value ◽  
Continental Margins ◽  
Gas Distribution ◽  
Free Gas ◽  
Natural Gas Hydrates ◽  
Bottom Simulating Reflectors ◽  
Thermobaric Conditions

Natural gas hydrates are crystalline solids formed by natural gas (mainly methane) and water that are stable under thermobaric conditions of high pressure and low temperature. Methane hydrate is found in polar areas of permafrost and in offshore basins of continental margins. These accumulations may represent an enormous source of methane. Based on global estimations of methane concentration in natural gas hydrates, the methane content may be several times greater than those of technically recoverable, conventional natural gas resources. In the continental margin of Uruguay, seismic evidence for the occurrence of gas hydrate is based on the presence of (bottom simulating reflectors) BSRs in 2D seismic reflection sections. Here we present results regarding gas hydrates and associated free gas distribution assessment offshore Uruguay, based on BSR mapping and applying a probabilistic approach. A mean value of 25,890 km2 for the area of occurrence shows a great potential for this nonconventional resource, encouraging further research.

scholarly journals Clathrate Ices—Recent Results

1978 ◽  
Vol 21 (85) ◽  
pp. 33-49 ◽  
Author(s):  
D. W. Davidson ◽  
J. A. Ripmeester
Keyword(s):  
Natural Gas ◽  
Ethylene Oxide ◽  
Gas Hydrates ◽  
Time Scale ◽  
Water Molecules ◽  
Guest Molecules ◽  
Natural Gas Hydrates ◽  
Change Effect ◽  
Line Narrowing ◽  
Permafrost Regions

Abstract The last five years have seen an increasing interest in clathrate ices as a result of the discovery of extensive deposits of natural gas hydrates in permafrost regions. Twenty-six new clathrate hydrates have been identified, mainly by NMR, including a tetragonal hydrate of dimethyl ether. N-butane and neopentane have been found to be enclathrated in natural gas hydrates, the former as a gauche conformer. As a result of their high symmetries, encaged neopentane, CF4, SF6, and SeF6 exhibit a Resing apparent-phase-change effect in the temperature range of NMR line narrowing. There is increasing evidence that reorientational jumps of water molecules are more frequent than translational jumps in clathrate ices. This is certainly so for ethylene oxide-d4 and tetrahydrofuran-d8 hydrates for which two regions of proton line narrowing and two T 1ρ minima have been observed. The reorientational motions of most guest molecules in structure II hydrates only become isotropic on a time scale long enough to permit the cage configurations to be averaged to 4 3m symmetry by reorientation of the water molecules. The orientations of the water molecules remain disordered to the lowest temperatures.

Natural gas hydrates: myths, facts and issues

2004 ◽  
Vol 336 (9) ◽  
pp. 751-765 ◽  
Author(s):  
Benoı̂t Beauchamp
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Natural Gas Hydrates
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