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Where are Natural Methane Hydrates Found?

Methane Hydrate is stable on land in polar regions and at sea in water deeper than a few hundred meters, and likely exists on all continental margins. The triangles here show actual discoveries (updated from Kvenvolden, 1988).

 

The crystalline structure of water ice may change significantly in the presence of impurities, (e.g. methane). If the impurities, or guest molecules are of the proper size a clathrate or cage structure forms around them holding them through Van derWaals forces. (Sloan, 1990)

Historical Perspective

1810

Sir Humphrey Davy discovers chlorine hydrate.

1888

Villard measured hydrates of CH4, C2H6, C2H4, C2H2, and N2O.

1930's

Hammerschmidt determines hydrates are blocking gas lines, and investigates inhibitor gasses.

1940's

Soviets hypothesize the existence of natural methane hydrates in cold northern climates. 

1960's

Molecular structure of hydrate is determined ("clathratus ~ to encage).  Soviets recognize methane hydrate as a possible energy source, discover and produce the first major hydrate deposit in permafrost.

1970's

A bottom simulating reflector is drilled and is found to be associated with the base of hydrate stability.

1990's

Initial characterization and quantification of methane hydrate deposits in deep water. 

2000

Efforts to quantify location and abundance of hydrates begin.  Large-scale efforts to exploit hydrates as fuel begin.

 

 

Stability Field

Biogenic methane is generated 0 to 100's of mbsf and forms hydrate where temperatures are low (< ~25 C). As burial continues, hydrate dissociates at the BSR where methane may accumulate.

 

Abundance

Even the lower estimate of the amount of methane hydrates in the world show that this source of carbon is significant, (Kvenvolden 1988).