Natural gas hydrates are ice-like solids that consist of gas molecules (such as methane) which are enclosed within the cage-like structure of water molecules. Originally discovered in the laboratory of Sir Humphrey Davy in 1810, they exist in nature and are stable under certain conditions of temperature and pressure, such as those found in the sediments within and beneath the permafrost in the Beaufort-Mackenzie Basin. Very large amounts of gas may be stored as hydrate. One unit volume of hydrate may store or release 160 volumes of methane during its formation or decomposition. Thus gas hydrates may contribute to future energy supplies, but they may represent a significant source of greenhouse gas as well. This gas can be released to the atmosphere during hydrate decomposition in response to climate warming, or to sea-level rise particularly in coastal areas affected by contact with water of warmer temperature than the ground. Gas hydrates also present a hazard during exploration drilling or hydrocarbon production, because they could become unstable during the drilling or production process. Uncontrolled gas releases, blowouts, fires and instability of sediments at the well site may result without adequate safeguards; therefore it is important to have knowledge of the distribution and behavioural characteristics of natural gas hydrates.

Gas hydrate zones along the Beaufort Coastlands larger image [GIF, 18.9 kb, 525 X 443, notice]

Authors: S.L. Smith and A.S. Judge
Geological Survey of Canada

More information on gas hydrates.