It could take six months for oil engineers to drill a relief well to the leaking gasfield under the platform in the North Sea that was evacuated after gas reached dangerous levels and became highly inflammable.
A 3.7km exclusion zone for shipping and a 4.8km exclusion zone for aircraft have been imposed around the Elgin wellhead platform and Rowan Viking drilling rig 240km off Scotland's east coast.
The incident occurred on Monday during work to plug and abandon the well, which was no longer in production. Although all nearby wells have been shut down, gas continues to seep to the surface, where there is a 10km "light sheen" of condensed gas on the water.
Total, the oil company that operates the platform, said it will drill the relief well to the leaking wellhead, which could be blocked with a concrete plug similar to the technique used to stem the Deepwater Horizon spill in the Gulf of Mexico.
Another possibility is to try to block the flow of gas by injecting mud back down the existing gas pipeline leading to the wellhead. However, the company is hoping the leak will peter out over the coming days or weeks, which it said was possible given that the gasfield was already depleted when the accident happened.