What is Methane hydrate?
'''Methane hydrate''', also called methane ice or methane clathrate, consists of [[methane]], which is enclosed in frozen water. The water [[molecules]] completely surround the [[methane]]. Methane hydrate is a common constituent of the shallow marine ([[ocean]]) [[geosphere]]. In 1971, it was first discovered in Black Sea. ==Definition and Characteristics== Methane hydrate consists of methane gas trapped inside cage-like crystal structures made up of water molecules. These “cages” have a size of atoms and molecules, far too small to see with the naked eye. Under normal temperature and pressure, one litre of methane hydrate is equal to 168 litres of methane gas. == Origin of methane hydrate == Methane hydrate is thought to be formed by dead organic matter trapped between the earth's layers, and then broken down by [[microorganisms]] and the earth's heat. The process is similar to the one that produces methane when organic waste is dumped at a [[garbage]] pit and covered with [[earth]], except that it occurs deep below the earth's surface. The organisms which produce methane by a process of [[fermentation]] are the [[methanogen|methaneogen]] [[Archaea|Archea]]. ==Natural resources== Areas where natural methane hydrate is thought to exist are generally areas under the ocean where continental plates meet. In depths between 500 to 1000 meter, where pressure is high and temperature low enough. ==Possible mining methods== ===Thermal recovery method=== * In this method, a well is drilled to the methane hydrate-bearing layer, and methane hydrate is dissociated by heating using a fluid (hot water or steam) heated at the surface in a boiler or similar device and circulated down through the well. This causes methane hydrate to decompose and generates methane gas. The methane gas mixes with the hot water and returns to the surface, where the gas and hot water are separated. ===Depressurization method=== * As with geological formation, methane hydrate bearing layers are subject to be pressurized by the combined overbu