The Elgin platform in the North Sea, 150 miles (240km) off Aberdeen, suffered a serious natural gas on Sunday.   It is expected at take several weeks, in the best case scenario, to shut off the leak. Some estimates suggest that it will take 6 months to control the leak.   The platform is operated by Total SA.  The leak is reported to be from a well, known as G4, that was drilled in 1997 and has now been shut for about one year.  The leak is estimated at 9 million cubic meters of gas per day or three percent of Britain’s natural gas output.

The U.K. coastguard has established exclusion zones around the area and Shell has evacuated some personnel from its nearby Shearwater platform and Noble Hans Deul drilling rig and suspended drilling operations as a precautionary measure. Shipping was being ordered to keep at least two miles away and there was a three-mile exclusion zone for aircraft.

Total considers relief well to end Elgin gas leak

Why is this leak so serious? It is not as bad as an oil leak – right?  Yes and no.  First, there is a significant explosion risk, if the gas is ignited.  When workers abandoned the platform they left a natural gas flare burning less than 100 meters from where the leaking natural gas is bubbling up to the surface.  The French oil giant Total dismisses the risk of explosion  if the gas continued to pour from the leak for some time.

The gas is also poisonous, containing hydrogen sulphide – familiar from the smell of rotten eggs. The gas should disperse in the atmosphere, but it poses a risk to anyone close to the source, making capping the well more complicated.

Longer term, the leaking natural gas is highly damaging to the ozone layer.  When natural gas is burned, it emits half as much carbon dioxide as coal.  Natural gas, itself, however, is mostly methane, which is 25 times more potent as a greenhouse gas than carbon dioxide. The indefinite venting of large quantities of natural gas from the Elgin rig could do considerable damage.

North Sea offshore well disaster worsens — poisonous explosive gas spreads

As natural gas production grows, questions arise about methane leaks

Thanks for Phil Leon for contributing to this post.