Bosses at Total claim they have made “significant progress” towards stemming the highly explosive methane gas spewing out of the stricken Elgin platform.
In the last week the French energy giant has stepped up its preparations to start performing the two procedures which is hoped will permanently “kill” the leaking G4 well.
All 238 men had to be evacuated from the platform three weeks 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 seven tonnes of gas which is spewing from the North Sea installation every hour.
And bosses at Total said yesterday that so far everything has gone “according to plan”.
The first approach will see heavy mud being pumped down into the well from the top at high pressure using either The West Phoenix, a semi-submersible rig, or the Skandi Aker, a well intervention vessel.
Once the mud has blocked the gas and restored the normal pressure, cement will be poured into the well to seal it.
Simultaneously, drilling will 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.
This week Total carried out preparatory work for both of the options.
Another two flights, with teams from Total and Wild Well Control, visited the platform to carry out “essential cleaning” ahead of the well kill beginning.
Several more helicopter flights are likely to be required this week before the positioning of a well intervention support vessel alongside the Elgin.
On April 7 a supply plane brought specialist equipment for the well control operation, from Houston to Aberdeen and two rigs have been mobilised for the drilling of the relief wells.
The Sedco 714, which is expected to start drilling first, arrived at a standby location outside the Elgin exclusion zone.
The second rig, the Rowan Gorilla V, is currently suspending operations on the nearby West Franklin field before repositioning itself to drill the second relief well.
Meanwhile, environmental tests have been carried out by the Scottish Government and Greenpeace to determine the effect the gas condensate is having on the platform’s surroundings.
The results are due back this week.