Relief well to stem gas leak at evacuated offshore rig could take six months to drill
Steve Connor is the Science Editor of The Independent. He has won many awards for his journalism, including five-times winner of the prestigious British science writers’ award; the David Perlman Award of the American Geophysical Union; twice commended as specialist journalist of the year in the UK Press Awards; UK health journalist of the year and a special merit award of the European School of Oncology for his investigative journalism. He has a degree in zoology from the University of Oxford and has a special interest in genetics and medical science, human evolution and origins, climate change and the environment.
Tuesday 27 March 2012
It could take another six months for oil engineers to drill a relief well to the leaking gas field beneath the offshore platform in the North Sea that was evacuated over the weekend when highly inflammable and toxic gas reached dangerous levels.
A two-mile exclusion zone for shipping, and a three-mile exclusion zone for aircraft, have been imposed around the Elgin Well Head Platform and Rowan Viking Drilling Rig situated 150 miles off the coast of Aberdeen on the east coast of Scotland.
The incident occurred on Sunday during work to plug and abandon the gas well which was no longer in production. Although all nearby wells have been shut down, gas continues to seep to the surface where a six-mile “light sheen” of condensed gas has been spotted on the water nearby.
Total, the oil company that operates the platform, said it will drill the relief well to the leaking well head, which could then be blocked with a concrete plug similar to the plugging technique used to stem the Deepwater Horizon spill in the Gulf of Mexico.
Another possibility is to try to block the flow of gas by injecting mud back down the existing gas pipeline leading to the well head. However, the company is hoping that the gas leak will begin to peter out over the coming days or weeks, which it said is possible given that the gas field was already depleted when the accident happened.
“The gas is flammable but the platform power was turned off to minimise risk of ignition, but clearly there is a risk,” said David Hainsworth, Total's manager for health, safety and environment.
“We have taken away a series of risks but there is always a possibility, it's low but you never say never. The best-case scenario is that the gas in this area is not very productive and it dies off in the coming days and weeks,” Mr Hainsworth said.
“At the moment there is no real evolution of the sheen on the sea but if that was to change ... then the exclusion zone may be increased,” he added.
Simon Boxall of the National Oceanography Centre in Southampton said that the gas coming to the surface is a “sour” mixture of methane, hydrogen sulphide - which are both flammable - and carbon dioxide.
“If this gas is bubbling from the seabed the hydrogen sulphide will be dissolving in the water column and that could kill any nearby fish. However, it is likely only to be a localised problem and there is little risk for anyone on the mainland,” Dr Boxall said.
“This is a fantastically advanced platform designed to pull sour gas from five kilometres below the seabed. They've evacuated the workforce safely, but I wouldn't want to be the one who goes in and tries to deal with this. One spark could cause an explosion,” he said.
After the leak was discovered on Sunday, Total ordered the evacuation of 219 workers from the Elgin platform and the nearby Rowan Viking drilling rig. As a precautionary measure, Shell has also reduced staffing levels on its Nobel Hans Deul rig four miles away.
Belle Knox: How the porn star student from Duke University became bigger than Justin Bieber
Oscar Pistorius trial: Neighbour feared athlete would use gun that killed his girlfriend Reeva Steenkamp to shoot himself
Top 10 most expensive cities in the world: Singapore named costliest place to live – but what about London?
Oscar Pistorius trial: Athlete 'cheated on me' with Reeva Steenkamp, former girlfriend Samantha Taylor tells Pretoria court
Channel 4 announces two-hour TV show to be broadcast 'Live from Space' later this month
Apple's Tim Cook: Business isn’t just about making profit
Thousands of young people forced to go without food after benefits wrongly stopped under 'draconian' new sanctions regime
Ukraine crisis: New navy chief 'defects' and surrenders Crimean HQ as Putin claims ultranationalists forced intervention
Britain's top vet sparks controversy with call for ban on slashing animals' throats in 'ritual' slaughters for halal and kosher meat products
Ukraine crisis: Russia dismisses '3am ultimatum' as 'total nonsense'
If you're horrified by a flame-roasted dog, you should be shocked at a hog roast
- 1 The future of sex: The first female condoms were derided, mistrusted and shunned - but will their modern counterparts catch on?
- 2 South African rhino finally put down after roaming Kruger park for days with horn hacked off and bullet in brain
- 3 Italian pensioner hires an escort who turns out to be his son's girlfriend
- 4 Orgasm machine to deliver climax at the push of a button
- 5 Channel 4 announces two-hour TV show to be broadcast 'Live from Space' later this month
£12000 per annum: Inspiring Interns: A small but growing chain of boutique hot...
£12000 per annum: Inspiring Interns: The company works with Tier 1 FTSE 100 Ba...
£45 - 60k Per Annum: Charter Selection: Highly profitable leisure brand, marke...
£30000 - £50000 per annum + Highly Competitive Salary: Austen Lloyd: Residenti...