By Karolin Schaps and Muriel Boselli
LONDON/PARIS (Reuters) - French oil company Total
The energy firm will on Monday meet experts from Britain's Health and Safety Executive (HSE) to discuss the risks involved in sending people to the platform which is enveloped in a huge gas cloud.
"The company has prepared risk assessments for landing a helicopter on the platform and sending a team to carry out observations at the site of the gas release," a spokesman for the body said.
The danger of entering the abandoned platform became somewhat smaller on Saturday, when Total confirmed that a flare, lit during the evacuation process to burn off excess gas, had gone out on its own accord.
The authority is expected to give Total advice to proceed with plans to staunch the leaking well, industry sources said on Sunday.
"Authorization for both options should land early next week, perhaps on Monday," one of the sources said.
The HSE's role is to give the platform operator advice on how to comply with the law, not to give permission to send people aboard the facility, the spokesman said.
The flare that had been burning only 100 metres from where the gas is leaking was finally confirmed to have extinguished on its own without intervention on Saturday, reducing the threat of explosion.
Attention has now shifted to getting on with stopping the leak.
In the first process, Total will inject drilling mud to "kill" the well using the weight of the mud to stop the gas flow, but is potentially dangerous given that it would require workers to return to the wellhead platform.
This operation could start within 7-10 days of Total deciding to this process is appropriate.
The second process - safer, but slower and costly - involves digging two relief wells, which could take six months and cost up to $3 billion.
Relief drilling would require boring down 4 kilometres to intercept the gas pocket at exactly the right point, engineers say.
Total had originally hoped the leak would run itself dry as reservoir pressure dropped, removing the need to bore a hole.
But the discovery that the source is just 1.5 kilometers away from the main gas reservoir, one of the world's deepest, suggested that the amount of gas feeding the leak may be larger than first thought.
FLAME IS OUT
The gas flare, which had been lit as part of the initial emergency response to relieve pressure on the well as workers were evacuated, had been causing concern that it might ignite the leaking gas. But the UK Department of Energy said that Total had assured it that the prevailing winds were blowing the gas away from the flare. The leak, which started a week ago, has been spewing an estimated 200,000 cubic metres a day of natural gas into the air, forming a potentially explosive gas cloud around the platform.
It began after pressure rose in a well that had earlier been capped.
Total evacuated its 238 platform workers on March 25, and set up a two-mile exclusion zone for safety reasons, with fire-fighting ships on standby.
A senior union official said on Friday that Total had repeatedly assured workers a leak was impossible until just hours before evacuating them.
(Editing by Alexandria Sage and Greg Mahlich)