Vast quantities of methane are trapped in oceanic hydrate deposits, and there is concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of methane into the atmosphere. The recent discovery of active methane gas venting along the landward limit of the gas hydrate stability zone (GHSZ) on the shallow continental sl...

A gas hydrate reservoir, identified by the presence of the bottom simulating reflector, is located offshore of the Antarctic Peninsula. The analysis of geophysical dataset acquired during three geophysical cruises allowed us to characterize this reservoir. 2D velocity fields were obtained by using the output of the pre-stack depth migration iteratively. Gas hydrate amount was estimated by seism...

Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has ...

Gas hydrates, or more generally clathrate hydrates, are a type of inclusion compound and take the form of nonstoichiometic solid crystalline materials formed from water and small guest molecules. Under sufficient pressure of the guest material and at specific temperatures, 3D hydrate structures are formed by the stacking of polyhedral cages of hydrogenbonded water molecules. Suitably sized gues...

An isobaric flow loop added to the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) is being investigated as a means of rapidly forming methane hydrate in watersaturated sand from methane dissolved in water. Water circulates through a relatively warm source chamber, dissolving granular methane hydrate that was pre-made from seed ice, then enters a colder hydrate growth chamber wher...

The investigation of surface tension is a very important task for gas hydrate studying. Surfactants can effectively reduce the surface tension, improve the gas storage capability of hydrate and increase the formation rate, shorten the induction time. The objective of this study were to obtain a better understanding of the role of surface tension on hydrate formation and build gas hydrate models...

Hydrate-bearing sediment cores were retrieved from the Joetsu Basin (off Joetsu city, Niigata Prefecture) at the eastern margin of the Japan Sea during the MD179 gas hydrates cruise onboard R/V Marion Dufresne in June 2010. We measured molecular and stable isotope compositions of volatiles bound in the gas hydrates and headspace gases obtained from sediments to clarify how the minor components ...

The kinetics of nucleation of one-component gas hydrates in aqueous solutions are analyzed. The size of the hydrate nucleus and the work for nucleus formation are determined as functions of the supersaturation Dm: Expressions for the stationary rate J of hydrate nucleation are derived. These expressions describe the JðDmÞ dependence for homogeneous nucleation and for heterogeneous nucleation at...

The JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate research well was drilled to 1166 m through about 200 m of subpermafrost gas-hydrate-bearing sediments under the Mackenzie Delta, Canada. An extensive logging program was completed to characterize in situ the physical properties of the sediments where gas hydrate fills as much as 80% of the pore space. Analysis of sonic logging waveform show th...

An integrated lipid biomarker–carbon isotope approach reveals new insight to microbial methane oxidation in the Gulf of Mexico gas-hydrate system. Hydrate-bearing and hydrate-free sediments were collected from the Gulf of Mexico slope using a research submersible. Phospholipid fatty acids consist mainly of C16–C18 compounds, which are largely derived from bacteria. The phospholipid fatty acids ...