North Sea gas leak plug 'achievable'
Experts inspected the wellhead for the first time since the platform's 238 crew were evacuated on March 25 when the leak was detected.
Fri, Apr 06, 2012 at 12:30 PM
LEAK: Specialists will revisit the platform in the coming days to develop detailed plans for pumping the problem G4 wellhead full of "heavy mud" at high pressure so as to seal it. (Photo: AFP)
A plan to plug a leaking North Sea platform well is "achievable," inspectors said Friday following a visit to a well head that is spewing a cloud of potentially explosive gas.
A team of experts spent four hours Thursday visiting the Elgin platform, which is operated by French energy giant Total.
It was the first time the wellhead had been inspected since the platform's 238 crew were evacuated on March 25 when the leak was detected.
"We achieved our goals. Everything went as we would have hoped and the planned well intervention is achievable," Texas-based outside experts Wild Well Control said after visiting the platform alongside staff from the rig who are familiar with its construction.
The firm said there were certainly no surprise obstacles to launching their operation.
Specialists will revisit the platform in the coming days to develop detailed plans for pumping the problem G4 wellhead full of "heavy mud" at high pressure so as to seal it.
In a statement, Total said the team found no gas on the the processing platform and the 90-meter bridge to the well head platform was also free of gas.
The structural condition of that platform, G4 and the surrounding rig were unchanged since the evacuation, as were safety situations.
"The visual inspection confirmed that the leak is coming from the G4 well head at Well Head Platform deck level. In parallel, a remote operated vehicle survey confirmed no underwater gas leak," Total said.
"The team was also able to identify piping and routing options plus tie-in points for well control equipment. Specialists plan to return to the platform within the coming days to complete the survey and develop detailed plans."
Simultaneous preparations are still proceeding for the drilling of a relief well and a backup relief well, Total said.
"In parallel, various indications such as regular visual observations from a nearby vessel and temperature measurements seem to suggest that the gas leak rate has decreased during the last few days."
Previously, some 200,000 cubic metres of highly flammable gas were estimated to be escaping from the platform in a leak which Total says is costing the company $2.5 million daily.
Meanwhile the Scottish government sent a marine research vessel Friday to carry out sampling around the platform.
Experts from Marine Scotland, the body which manages the country's waters, went to assess and monitor the impact of the leak.
The Alba na Mara ship will collect and analyse water, fish and sediment sampling over the weekend.
Scotland's environment secretary Richard Lochhead met Total managing director Phillipe Guys on Friday at the company's site in Aberdeen on the east coast of Scotland, for an update on progress.
He said Guys reassured him that the firm had the required "manpower, expertise and equipment" in place or on its way.
"Stopping the leak is the top priority and Total informed me that in the coming days efforts will begin to try and stop the flow of gas above the surface by putting heavy mud into the well," he said.
"Monitoring has shown that the gas cloud is naturally dispersing and the very thin sheen of gas condensate on the surface of the water is also dispersing.
"But while impact on the environment is still minimal, it's important we continue to gather as much information as possible as the situation continues."
Copyright 2012 AFP European Edition
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