Saturday, 31 March 2012

North Sea gas leak


Total mulls helicopter water drop to put out flare on North Sea platform
News comes as union claims French oil company 'fobbed off' workers worried about risk of gas leak four weeks ago.


30 March, 2012

The French oil company that operates the leaking North Sea gas platform is considering using a helicopter water drop to extinguish a flare that could ignite the explosive gas cloud.

The news came as reports emerged that platform-owner Total was warned about the risk of a gas leak four weeks ago. The Aberdeen Press and Journal said a local union claims workers' fears about high pressure in the 13,000ft deep reservoir were "fobbed off" a month ago.

The Department of Energy and Climate Change said: "Total has confirmed in their latest update to the government's inspectors that the flare remains lit but observations from the latest aerial surveillance suggest that the flame appears to be reducing in size."

Total, which originally failed to make clear that the flare was still alight, said other options to put it out included firefighting vessels and pumping nitrogen to starve the flame of oxygen.

On Thursday night Total said it had traced the leak to a gas pocket in a rock formation 4km (2.5 miles) below the seabed but 1km above the gas reservoir being tapped by the Elgin platform, which was evacuated on Sunday when the leak was discovered.

In an attempt to quell fears about the risks of explosion from the gas cloud which has settled above the area, it said there were now firefighting ships on standby at the edge of the two nautical mile (2.3 mile) exclusion zone.

Marine experts and oil industry unions are alarmed about the dangers of the gas cloud being ignited by the flare, about 100m from the leak, if the wind changes direction in coming days.

Union leaders have urged oil companies to evacuate every rig and platform within five miles of the Elgin as a precaution. Total said the wind was expected to continue blowing the gas away from the flare, which was well above the gas cloud, and predicted the flare could burn itself out within a few days.

In a statement on Thursday evening, the company said the flare was burning off evaporating liquids still in the platform's system. "As these liquids evaporate the flow of hydrocarbons to the flare will exhaust itself and the flare should burn out," it said.

Total disputed allegations that the gas was leaking from the seabed and that it was toxic. It said the gas was escaping from the deck level of the platform, about 25m above sea level, and was natural gas.

"This means that we now know the source of the leak, we know the problem," a company spokesman said. "We can now look at solving that problem as quickly as possible. All our focus is now on fixing it as soon as we can."





Source of North Sea gas leak found, says Total
Oil company says Elgin rig is still at risk of explosion but situation now 'bad case' rather than 'worst-case' scenario


29 March, 2012

Oil company Total believes it has found the source of the gas leak from its North Sea platform, as it sent two fire-fighting vessels to the edge of the emergency exclusion zone.

The French fuel group said it had traced the leak to a gas pocket in a rock formation 4km (2.5 miles) below the seabed but 1km above the gas reservoir being tapped by the Elgin platform, which was evacuated on Sunday when the leak was discovered.

In an attempt to quell fears about the risks of explosion from the gas cloud which has settled above the area, it said there were now fire-fighting ships on standby at the edge of the two nautical mile (2.3 mile) exclusion zone.

Marine experts and oil industry unions are alarmed about the dangers of the gas cloud being ignited by a flare still burning on the platform, about 100 metres from the leak, if the wind changes direction in coming days.

Union leaders have urged oil companies to evacuate every rig and platform within five miles of the Elgin as a precaution. Total said the wind was expected to continue blowing the gas away from the flare, which was well above the gas cloud, and predicted the flare could burn itself out within a few days.

In a statement on Thursday evening, the company said the flare was burning off evaporating liquids still in the platform's system. "As these liquids evaporate the flow of hydrocarbons to the flare will exhaust itself and the flare should burn out," it said.

Total disputed allegations that the gas was leaking from the seabed and that it was toxic. It said the gas was escaping from the deck level of the platform, about 25 metres above sea level, and was natural gas.

"This means that we now know the source of the leak, we know the problem," a company spokesman said. "We can now look at solving that problem as quickly as possible. All our focus is now on fixing it as soon as we can."

Frederic Hauge, head of Norwegian environment group Bellona, told Reuters: "The bad news is that the leak is continuing and that it reduces the possibility it could be plugged by sand or other material.

"The good news is that the flow rate of gas coming to the surface is not increasing."

Total has a team of engineers working on contingency plans, including the potential for drilling a relief well to siphon off the gas, or to suppress the leak by injecting mud down the well.

The site remains off-limits, however, because of the potentially explosive gas cloud.

Hauge said that since the leak appeared to come from a gas pocket at lower pressure and smaller volume than Elgin's main reservoir "we move from a worst case scenario to a bad case scenario. But this is not a good case scenario as long as gas is leaking."

In a question and answer session on the company's Facebook page for the Elgin emergency, Jacques-Emmanuel Saulnier, Total's head of communication, said: "The wind is pushing the gas cloud in the opposite direction [from the platform]. At this time, the circumstances are rather favourable."

He added: "A gas cloud is always a fire hazard."

Admitting there was still a risk of explosion, Saulnier added that the firm's first priority had been to evacuate the 238 workers on the platform. He added: "Now, our priority has to be stopping the leak in order to avoid all risk of explosion and also to limit the impact on the environment."


A good video from WSJ

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