North Sea gas leak threat subsides

02/04/2012

Gas has continued to leak from the Total oil company’s gas rig and a two mile exclusion zone has been imposed to protect shipping in the area.

Previously, misinformation had been given to the press that the flare on top of the rig could safely be extinguished remotely. This information is now redundant after the flame extinguished itself naturally.

The major risk had always been that a change in wind direction would cause the leaking gas to blow onto the flame and cause an explosion.

Energy Minister Charles Hendry said:

“Total confirmed to me this morning that the flare on the Elgin platform has naturally extinguished itself. This comes as very welcome news and a considerable relief. Although the platform was designed to use the prevailing wind to keep the flare from the escaping gas, the fact the flare is out removes a major risk from the equation.

“The task now is very clear – every effort must be made to locate and stop the gas leak. Following my visit to Total’s emergency control room yesterday, I know they have some of the best expertise in the world on hand to consider their options. The Government continues to monitor the situation very closely to ensure this incident can be resolved as quickly and with as little risk to human life and the environment as possible.”

It now means that Total engineers can get on with solving the problem which it is believed originates from gas being released from the well system to the environment at the platform deck level and therefore above water, following the reduction in risk.

This means it is likely a failure of the well system has allowed gas to enter another part of the well not normally designed to handle it.

It has been estimated that the point of entry is at a point some 4000m below the seabed and this is allowing gas to travel contained within the well system to the platform. There is also no apparent evidence that gas is being released below sea level.

Total are now facing two options to tackle the gas release. The first option is to drill a relief well. Total are mobilising two drill rigs to drill a well to intersect the main well and then shut off the flow of gas or blocking the well with ‘heavy mud’. This can be achieved by using a mixture containing mineral compounds to be pumped into the well to suppress the flow of gas.

The events of the last few days have caused a rethink about the way such occurrences should be dealt with. If the wind had changed direction when the rig was fully manned, a serious disaster, similar to that of Piper Alpha, a gas rig which exploded in 1988 killing 167 people might have been the result.

A plan to deal with incidents in the Elgin field was published by the Department of Energy and Climate Change in January and this has now been amended to ensure immediate publication of any incident details.

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