Efforts to completely block the leaking G4 well on Total’s Elgin platform should be completed next month.
The installation was shut down and evacuated on March 25 after gas started spewing out of a well on the platform 150 miles off Aberdeen.
The leak was eventually plugged in May but efforts have been ongoing to permanently secure the well with concrete.
After months of not being able to keep staff on the installation overnight, first for safety reasons, 120 people moved back on to the platform in June after vital systems such as power generators were restarted.
A spokesman for the company said last night this number had now increased to 138 people and the installation was fully re-manned.
All essential functions onboard the Rowan Viking drilling rig, which sits adjacent to the Elgin complex, have also been recovered and 60 workers are now also staying onboard.
The Rowan Viking will be used to pump the cement into the well to permanently plug it.
A spokesman for Total said recent investigations indicated the overall environmental impact of the incident had been “minimal” as the majority of the condensate released evaporated.
What did fall to the sea also evaporated or dispersed completely within days.
An estimated 3,096 tonnes of gas and 3,076 tonnes of condensate were released. Most of the condensate evaporated, leaving an estimated 407 tonnes on the surface of the sea.
An investigation into the cause of the leak is ongoing. Total will not be able to resume production until the investigations are completed.