(NAS Colloquium) Geology, Mineralogy, and Human Welfare (1999) / Chapter Skim
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Potential Effects of Gas Hydrate on Human Welfare
Potential Effects of Gas Hydrate on Human Welfare
Pages 3420-3426
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From page 3420... ...
Assessments of gas hydrate as an energy resource have often been overly optimistic, based in part on its very high methane content and on its worldwide occurrence in continental margins. Although these attributes are attractive, geologic settings, reservoir properties, and phase-equilibria considerations diminish the energy resource potential of natural gas hydrate.
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From page 3421... ...
In the 1960s, naturally occurring gas hydrate was found in the Siberian Messoyakha gas field (19) , and in the 1970s it was recognized that gas hydrate occurs naturally not only in polar continental regions but also in shallow sediment under deep water of the oceanic outer continental margins (24, 25~.
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From page 3422... ...
, the energy density (volume of methane at standard conditions per volume of sediment) of methane hydrate is 10-fold greater than the energy density of other unconventional sources of gas, such as coal beds, tight sands, black shales, and deep aquifers, and 2- to 5-fold greater than the energy density of conventional natural gas.
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From page 3423... ...
Therefore, all of these discouraging factors, such as low permeability sediments, decreasing enrichment factor with depth, lack of sustained gas-industry interest, current limited gas-industry infrastructure at most gas-hydrate locations, and no good field example yet of successful methane production from gas hydrate, diminish the potential for gas hydrate becoming a significant energy resource. As far as human welfare is concerned, methane hydrate as an energy resource is not of immediate interest.
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From page 3424... ...
Therefore, the potential role for gas hydrate in global climate change is diminished because of the possibility of rapid oxidation of the released methane to carbon dioxide, thus enhancing the solubility of the methane carbon in the ocean water. Scenarios of past global climate change caused by methane released from gas hydrate are all very speculative; one test in the Arctic of methane release during the current climate cycle failed to show much methane from gas hydrate; one GCM study demonstrated little impact of gas hydrate on future global warming; and records of excursions of methane concentrations during the Paleocene and Holocene, although possibly caused by gas-hydrate dissociation, do not provide compelling evidence that this methane actually affected global climate.
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From page 3425... ...
Of these three issues, only the third is considered here to be important at the present time for human welfare. It is argued that gas hydrate as a future energy resource has received overly optimistic assessments because of inadequate evaluation of the reservoir qualities of the geologic settings in which oceanic gas hydrate is found.
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From page 3426... ...
Potential Supply of Natural Gas in the United States (as of December 31, 1980) (Potential Gas 39.
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