Measures have been put in place to divert the highly-explosive methane gas spewing out of Total’s Elgin platform to make the area safer for stemming the leaking well.
A specially-made “diverter” has been fitted to the G4 wellhead and is carrying the leaking gas away from the platform.
The device carries the gas through four hoses and ensures there are no hydrocarbons accumulating around G4.
As before, the gas will continue to leak into the atmosphere and some condensates will also go into sea as the diverter only affects the direction of leaking gas, not the volume.
However, the estimated flow-rate is now believed to be less than a third of what it was in the initial stages of the leak. It is now predicted that just less than 2.5 tonnes of gas are escaping from the G4 well every hour, compared with the seven tonnes which started leaking on March 25.
Bosses at Total said the installation of the diverter will “maximise” the safety of the well intervention operations, alleviating restrictions on helicopter landings on the platform.
Preparations have been continuing this week to start performing the two procedures which it is hoped will permanently “kill” the leaking G4 well.
All 238 men had to be evacuated from the platform more than a month ago after the leak was first discovered.
Since then, plans have been put in motion to develop two technical solutions they will use to stem the gas. The first approach will involve heavy mud being pumped down into the well from the top at high pressure using the West Phoenix, a semi-submersible rig.
Once the mud has blocked the gas and restored the normal pressure, cement will be poured into the well to seal it.
Drilling will also begin on two relief wells to intercept the leak and pump in mud from the bottom. This back-up method, which will be deployed in case the first approach fails to work, will take up to six months to complete.