Specialist equipment has arrived in Scotland to help stop the gas leak at the Elgin platform in the North Sea.
A team from operators Total flew out to inspect the leak last week.
The equipment, which will be used as part of the company's "dynamic kill" plan to plug the well with mud, was flown into Prestwick airport from Houston, Texas.
The Scottish government is also starting its assessment of the environmental impact of the leak.
Marine research vessel, Alba na Mara, spent the weekend collecting samples in the area around the rig, 150 miles east of Aberdeen.
Marine scientists expect to have the results from the tests on fish samples on Tuesday.
The findings from analysis of the sea water are expected later in the week.
Total said it expected to fly experts back to the installation with the next few days.
After returning from their reconnaissance mission last week, the oil company suggested a planned "top fill" operation, which would see the leaking well head plugged with mud, could go ahead.
The specialised equipment brought to Scotland from the US will be used for "well intervention operations".
Alternative plans to drill two relief wells to bring the situation under control are also still being prepared.