Methane hydrate stability in pore water: A simple theoretical approach for geophysical applications
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In this paper, the effect of salinity variation and chemical diagenesis on CH4 hydrate stability conditions in the marine environment can be evaluated by determining how these processes affect lnaw of pore water.Abstract:
Geophysicists have recently expressed an interest in understanding how pore water composition affects CH4 hydrate stability conditions in the marine environment. It has previously been shown in the chemical engineering literature that CH4 hydrate stability conditions in electrolyte solutions are related to the activity of water (aw). Here we present additional experimental data in support of this relationship and then use the relationship to address issues relevant to geophysicists. Pressure and temperature conditions of CH4 hydrate dissociation were determined for 10 solutions containing variable concentrations of Cl−, SO42− Br−, Na+, K+, Mg2+, NH4+, and Cu2+. The reciprocal temperature offset of CH4 hydrate dissociation between the CH4-pure water system and each of these solutions (and for other electrolyte solutions in literature) is directly related to the logarithm of the activity of water (lnaw). Stability conditions for CH4 hydrate in any pore water system therefore can be predicted simply and accurately by calculating lnaw. The effect of salinity variation and chemical diagenesis on CH4 hydrate stability conditions in the marine environment can be evaluated by determining how these processes affect lnaw of pore water.read more
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References
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Clathrate hydrates of natural gases
E. Dendy Sloan,Carolyn A. Koh +1 more
TL;DR: In this paper, the authors compared the properties of hydrates and ice with those of natural gas and showed the effect of thermodynamic inhibitors on the formation of hydrate formation and dissolution process.
Journal ArticleDOI
Early oxidation of organic matter in pelagic sediments of the eastern equatorial Atlantic: suboxic diagenesis
Philip N. Froelich,Gary P. Klinkhammer,Michael L. Bender,Nile A. Luedtke,G.R. Heath,Doug Cullen,Paul Dauphin,Doug Hammond,Blayne Hartman,Val Maynard +9 more
TL;DR: Pore water profiles of total CO 2, pH, PO 3−4, NO − 3 plus NO − 2, SO 2− 4, S 2−, Fe 2+ and Mn 2+ have been obtained in cores from pelagic sediments of the eastern equatorial Atlantic under waters of moderate to high productivity as mentioned in this paper.
Journal ArticleDOI
Gas hydrates—geological perspective and global change
TL;DR: In this article, the authors discuss three important aspects of gas hydrates: their potential as a fossil fuel resource, their role as a submarine geohazard, and their effects on global climate change.
Journal ArticleDOI
Dissociation of oceanic methane hydrate as a cause of the carbon isotope excursion at the end of the Paleocene
TL;DR: In this paper, the authors show that bottom water temperature increased by more than 4°C during a brief time interval (<104 years) of the latest Paleocene (∼55.6 Ma) and there also was a coeval −2 to −3‰ excursion in the δ13C of the ocean/atmosphere inorganic carbon reservoir.
Journal ArticleDOI
Methane hydrate — A major reservoir of carbon in the shallow geosphere?
TL;DR: The estimated amount of organic carbon in the methane-hydrate reservoir greatly exceeds that in many other reservoirs of the global carbon cycle as discussed by the authors, such as the atmosphere (3.6 Gt), terrestrial biota (830 Gt); terrestrial soil, detritus and peat (1960 Gt).