Tuesday, March 27, 2012

Events in the North Sea

Yesterday it was an also ran news item. Today its bearerly the top of the headlines. I predict that unless the operator has a significant amount of luck they'll be on Newsnight very shortly. ( They should perhaps thank the News Corp sting on the Conservative party for keeping them of the headlines so far.)

The event ? The gas condensate leak on the Elgin platform.

Why is this serious ?

  1. Any release of volatile hydrocarbons ( that's gas and LPG type gases ethane, propane and butane )  is very serious as it can lead to a cloud that can ignite a cause a massive explosion.
  2. The leak is from below the water surface ( reports of the sea boiling ) and hence has got around the metal casing and well heads (I assume the well heads are on the sea floor - though its possible they are in the platform itself ) that should contain it. This is bad as it means the options for using techniques like pumping heavy materials into the well are perhaps limited. ( Already talk is about drilling a relief well. )
  3. Maybe the leak is outside of the well casing itself ? If so you could see a progressive increase in leak rate and even potentially loss of the platform as its foundations as undermined.  (I think this is very unlikely.)
  4. Reports suggest this happened during well abandonment operations. This means cementing plug placing. This may mean that materials are in the well that make regaining control very hard indeed. Some, esp in the US, may find this scenario familiar.
  5. This is a HPHT field - that means High Pressure High Temperature. Why does that matter ? Well high temperature means that steel loses its strength, high pressure means steel needs its strength even more. When you lose well control you have the possibility of seeing reservoir pressures and temperatures at the surface. Can the materials at the surface cope with this ? This will make control very hard - and has been a major focus of research and engineering effort. I have no idea how the company concerned went about dealing with this in this case, probably some exotic materials, but its still a major challenge.
  6. Remember - as the MSM hasn't so far - this is the location (block 22/30b) that the Ocean Odyssey has a blowout at with the loss of life of their radio operator ( ordered back to man the radio. )
The operator really have their work cut out sorting this problem. This may take months and will probably require drilling a relief well from some distance from the platform.

To the operator's credit they have put men before profit and taken them to safety.

The reaction of the public to this should be understanding. Its all too easy to start demanding this must never happen again, but stop driving your car - heating your house - using plastics or pharmaceuticals first please. There will be lessons to learn, but it is also a reminder of the thousands of hardly ever thought about people who work in our seas winning the energy we live by and always at some risk to themselves. ( The most risky thing is oddly enough the helicopter transfer to and from the platform, as helicopters themselves are inherently risky things and have the aerodynamic characteristics of a brick when anything stops the engine. )

Its strange the place in the heart coal miners have, but oil workers don't.

Update: Documentation puts the reservoir pressure at potentially up to 1100bar ( that's over 1000 atmosphere's - or the pressures that Mr Cameron has been diving in this week. ) and temperatures at 200'C. ( Normal North Sea is about 300bar and 90'C .) - source Elgin Franklin brochure here.

Further: It appears Elgin has a separate wellhead platform. However the jackup along side isn't in position over it ( at least not in the picture in the Daily Telegraph - but comment below suggests it is and was performing the well abandonment). It may be being used solely for accommodation.

Hydrogen Sulphide is in the gas ( which is about 25% as toxic as Hydrogen Cyanide - ie very ). This, as well as the explosive nature of any gas cloud is going to be a big problem.

The operator are already talking about a relief well, but acknowledge there may be a problem having a drilling platform anywhere near the  leak. ( Horizontal drilling technology makes this possible up to almost a mile away, but its ups the cost and control issues with killing the leaking area of the field ).

The media will shortly start to realise that as well as the condensate which appears on the surface large amount of methane are being lost. The green house impact of methane is about 20 times that of CO2. How much is being lost will have to be an estimate - there really is no other way of dealing with an out of control situation like this as there are no possibilities for instrumentation and only simulation can give estimates.

This could go on for 6 months.

We are lucky its going to happen over Summer ( good sea states, low gas demand ).

But stay calm. Blowouts, and this looks like a loss of well control that is what constitutes a blowout, happen all over the world a few every year. They get dealt with, and the phone of some of the worlds best experts in all this will have been ringing for a few days. They will arrive to sort this out.

We need to keep a sense of perspective and remember just how massive the contribution of North Sea Oil and Gas has been to our life as a nation.

Here we go: The Daily mail is calling it The Well From Hell .. the PR department at Total will be wanting to cancel all leave. The greenies are making the predictable song and dance - but the real debate is where to gas is originating ( the operator hinted at an unproductive layer of the well - in which case it may reduce or the main reservoir itself in which case its communicating with the surface outside of the casing. If this is the case it will get worse, much worse and potentially lead to structural damage as the material around the well is eroded. ( A case have been known when an entire land rig has disappeared with this type of lose of control of a well. )

1 comment:

Anonymous said...

The Jack-Up (The Rowan Viking) is indeed over the well-head platform (I have just left it). It is the Viking that is carrying out the well abandonment.

This will definitely complicate matters.