BP has temporarily shut down its Clair oil platform, located about 75km to the west of Shetland Islands, following a leak.
The energy giant confirmed that a quantity of oil in water was released to the sea from the Clair platform.
The most likely volume of oil to be spilled over the sea surface is calculated to be around 95 tonnes based on the platform data.
It said that the leakage was due to a technical issue with the system designed to separate the mixed production fluids of water, oil and gas.
BP said: “The release was stopped within an hour once the issue had been identified and Clair production was taken offline.
“We are investigating the cause of the technical issue and the field will remain offline for the time being.”
The company said that its oil spill and environmental experts are working with Oil Spill Response Limited (OSRL) and the Department for Business, Energy and Industrial Strategy (BEIS) to gauge any potential environmental impacts.
BP is monitoring the movement of the oil that has been observed on the sea surface.
It said: “At present, we believe the most appropriate response is to allow the oil to disperse naturally at sea, but contingencies for other action are being prepared.
“Both direct observation and oil spill modelling indicate the oil to be moving in a northerly direction away from land.”
BP added that its recent surveillance flight indicated a significant dispersal of the oil at the surface.