Any oil or gas leak from a North Sea field is bad news – not just from a people or environmental perspective, but potentially also for the British economy.
Fortunately, in the case of this week’s revelation that “hydrocarbons” have been detected on the Cormorant Alpha platform, the leakage was both located and contained aboard this massive structure.
And that’s important, as it should make fixing the problem a lot easier than, for example, leaking pipework at the bottom of the North Sea where simple issues quickly become major challenges – witness last year’s problems in the Dunlin field.
What is utterly vital is that Cormorant Alpha’s operator Taqa carries out repairs rapidly but effectively and, above all, safely, bearing in mind that this platform is what I have sometimes referred to as the “gatekeeper” to the Brent and Ninian pipeline systems and a whole bunch of other platforms in the northern North Sea.
Cormorant Alpha is relatively old, a reinforced concrete behemoth that is known in the trade as a “condeep” and which was built in the UK around the mid-1980s.
The superstructure of the platform sits on a concrete gravity base comprising a battery of concrete oil storage tanks and four stout, hollow legs.
Pipework from the production wells and other fields passes up through these legs, as does the start of the 91-mile Brent export line to Sullom Voe in Shetland.
The Brent line currently transports about 90,000 barrels per day to Sullom Voe – that’s pretty close to its original designed capacity of 100,000 barrels and that 90,000 barrels is a significant chunk of current UK oil output, whichhas lately been bumping along at little more than just 1million barrels per day.
It happens that much of the oil exported through Sullom Voe travels by tanker to Rotterdam for refining and then to market as road fuels and feedstock for petrochemicals manufacturers in Europe.
Importantly for Britain, even with the North Sea now heavily depleted, we are still about 68% self-sufficient in oil.
The balance has to be imported, whether from Norway or the Middle East or wherever.
Take out 8% of home production for any more than a few days and this will inevitably lead to more oil imports, that’s expensive.
Just the 90,000 barrels that daily passes across Cormorant Alpha and through the Brent system is worth around $10million – £6.25million at today’s exchange rates.
Say repairs take a week – the value of oil not produced would be the thick end of £50million. A month and it’s more or less £200million.
That’s not counting any collateral impact on quantities of gas flowing to the St Fergus terminal in the north-east.
The North Sea is home to a spider’s web of pipelines that link fields together and the whole lot to various terminals along the coastline.
So, when a key hub such as Cormorant Alpha is disabled or shut down because of a problem, others are impacted too – inthis case some 20 other fields.
That said the oil and gas is not lost, it will eventually get to market – but when is anyone’s guess right now.