The platform was first shut down Saturday after a remotely operated vehicle discovered the leak.
The platform was shut again on Monday after problems during an attempted restart.
A total of 33 people were evacuated from the facility as a precautionary measure, spokesman Orjan Heradstveit said.
103 crew members stayed on board the platform.
Heradstveit said the spill was a “very small amount”, but had no time estimate for putting the platform back on line.