Gas hydrates: a nice idea

ICE - LIKE CRYSTALS composed of water and gas occur in abundance in sediments on the floor of the deep-water Gulf of Mexico (GoM). For offshore operators, these structures – gas hydrates – can be hazardous. Yet they may be a significant future energy source, writes Anne Feltus.

Gas hydrates are formed when molecules of gas, primarily methane, which have been produced by the decomposition of organic material or have bubbled up to the subsurface from deep in the earth are diffused through sediments on the seabed. At the intense pressures and in the very low temperatures that occur in the GoM beyond a depth of about 1,450 feet, they become squeezed into cage-like structures of water molecules (called clathrates). Friend or foe? For drillers, the problem is this: gas hydrates act as a glue that bonds grains of sediment together, increasing the rigidity of the sedimentary layer. When hot oil from horizons deep below the seabed is pumped through drill pipes, it warms the