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Methane hydrates

Context and definition

Within the framework of the Deepwater Horizon incident, the aborted attempt to install a containment chamber on the main leak in May 2010 was due to the formation of methane hydrates crystals. They appear as ice-like crystals. Methane molecules are in fact trapped in “cages” comprised of water molecules. This type of structure can only be seen in areas of high pressure and/or low temperature.
Observations suggest that in the open environment, hydrates do not form visible structures in a long-lasting way. It is only when they come up against an obstacle that they form crystals.

 

Molecular structure of methane hydrate
Molecular structure of methane hydrate

 

Natural deposits

There are two main types of natural methane hydrate deposits:

  • oceanic deposits which may be located in the depths of marine sediments or on continental slopes
  • continental deposits in Arctic permafrost.
     

Risks related to extraction

Natural deposits of methane hydrates are a potential energy source capable of satisfying the world’s energy requirements for thousands of years.
 
 However, extracting this substance generates environmental and safety-related problems. First, using more methane would mean releasing even more greenhouse gases into the atmosphere. Secondly, trapped methane hydrates must be handled extremely carefully as if the gas is suddenly discharged, there is a risk of massive release.

Last update: 28/05/2010