Relief well to stem gas leak at evacuated offshore rig could take six months to drill

 

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.

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksAn introduction to the ground rules of British democracy
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Web Developer - Junior / Mid Weight

£15000 - £25000 per annum: Recruitment Genius: To support their continued grow...

Recruitment Genius: Marketing Data Specialist

£22000 - £25000 per annum: Recruitment Genius: They are the go-to company for ...

Recruitment Genius: Search Marketing Specialist - PPC / SEO

Negotiable: Recruitment Genius: This is an opportunity to join the UK's leadin...

Recruitment Genius: Sales Administrator

Negotiable: Recruitment Genius: This caravan dealership are currently recruiti...

Day In a Page

Is this the future of flying: battery-powered planes made of plastic, and without flight decks?

Is this the future of flying?

Battery-powered planes made of plastic, and without flight decks
Isis are barbarians – but the Caliphate is a dream at the heart of all Muslim traditions

Isis are barbarians

but the Caliphate is an ancient Muslim ideal
The Brink's-Mat curse strikes again: three tons of stolen gold that brought only grief

Curse of Brink's Mat strikes again

Death of John 'Goldfinger' Palmer the latest killing related to 1983 heist
Greece debt crisis: 'The ministers talk to us about miracles' – why Greeks are cynical ahead of the bailout referendum

'The ministers talk to us about miracles'

Why Greeks are cynical ahead of the bailout referendum
Call of the wild: How science is learning to decode the way animals communicate

Call of the wild

How science is learning to decode the way animals communicate
Greece debt crisis: What happened to democracy when it’s a case of 'Vote Yes or else'?

'The economic collapse has happened. What is at risk now is democracy...'

If it doesn’t work in Europe, how is it supposed to work in India or the Middle East, asks Robert Fisk
The science of swearing: What lies behind the use of four-letter words?

The science of swearing

What lies behind the use of four-letter words?
The Real Stories of Migrant Britain: Clive fled from Zimbabwe - now it won't have him back

The Real Stories of Migrant Britain

Clive fled from Zimbabwe - now it won’t have him back
Africa on the menu: Three foodie friends want to popularise dishes from the continent

Africa on the menu

Three foodie friends want to popularise dishes from the hot new continent
Donna Karan is stepping down after 30 years - so who will fill the DKNY creator's boots?

Who will fill Donna Karan's boots?

The designer is stepping down as Chief Designer of DKNY after 30 years. Alexander Fury looks back at the career of 'America's Chanel'
10 best statement lightbulbs

10 best statement lightbulbs

Dare to bare with some out-of-the-ordinary illumination
Wimbledon 2015: Heather Watson - 'I had Serena's poster on my wall – now I'm playing her'

Heather Watson: 'I had Serena's poster on my wall – now I'm playing her'

Briton pumped up for dream meeting with world No 1
Wimbledon 2015: Nick Bollettieri - It's time for big John Isner to produce the goods to go with his thumping serve

Nick Bollettieri's Wimbledon Files

It's time for big John Isner to produce the goods to go with his thumping serve
Dustin Brown: Who is the tennis player who knocked Rafael Nadal out of Wimbeldon 2015?

Dustin Brown

Who is the German player that knocked Nadal out of Wimbeldon 2015?
Ashes 2015: Damien Martyn - 'England are fired up again, just like in 2005...'

Damien Martyn: 'England are fired up again, just like in 2005...'

Australian veteran of that Ashes series, believes the hosts' may become unstoppable if they win the first Test