Combating Snorre gas leak

Personnel on Statoil’s Snorre A platform in the North Sea pumped heavy drilling mud during the night into an injection well which has been leaking gas. This escape began around 19.00 yesterday, 28 November, and work on re-establishing barriers in the well will be continuing today.

“The mud is intended to push back the gas so that we can get at the well to halt the leak,” explains Øivind Reinertsen, senior vice president for Statoil’s Tampen business cluster.

Plans call for new personnel to be sent to the platform today in order to relieve the emergency response team which has been working through the night.

A total of 180 crew were evacuated by helicopter to surrounding platforms after the leak arose, leaving 36 people to combat the leak.

The plan is that evacuated personnel will be flown ashore today, debriefed about the incident and offered the opportunity to return home.

“This evacuation followed established procedures,” explains Mr Reinertsen.

“We quickly mobilised technical expertise in Stavanger, and these specialists have been in constant contact with the platform and drilling management on Snorre A.”

The problem arose during preparations to drill a sidetrack from injection well P-31 on the tension leg platform.

Although heavy mud had been introduced in advance to stabilise downhole conditions, gas nevertheless entered the mud when production tubing was pulled out.

That intrusion was registered topside, together with a gas leak from the seabed equipment.

“This is a very unusual and serious incident,” says Mr Reinertsen. “In such circumstances, we don’t want more people on the platform than are needed for emergency response.

“Production was shut down, and the decision taken to evacuate the installation.”

It became clear relatively quickly that gas was no longer reaching the platform topside, but that the seabed leak was continuing.

Mr Reinertsen is not prepared to comment on the underlying causes of the leak.

“This is a serious incident, which will be investigated in accordance with Statoil’s in-house routines,” he says.

It remains unclear at present when production can be resumed from the platform.

“The safety aspect has top priority at the moment,” says Mr Reinertsen. “All other considerations will have to wait.”

Click here to access facts about the Snorre field.