The operation to pump heavy mud into the leaking well began yesterday and successfully halted the leak 12 hours later.
The well had been leaking since March 25, causing 238 personnel to be evacuated from the Elgin complex and the adjacent drilling rig Rowan Viking.
Over the next few days, Total and its specialist teams will monitor the G4 well to confirm that the intervention has worked.
Yves-Louis Darricarrère, Total’s president of Exploration & Production, said: “Today, a major turning point has been achieved. Our absolute priority was to stop the gas leak safely and as quickly as possible. Since March 25, we have been working closely with the authorities and we have communicated transparently and will continue to do so. We shall now fully complete the ongoing task and take into account the lessons learnt from this incident.”