Industry sources said the fire occurred when some oil ignited spontaneously in a power turbine on 4 April but this remains unconfirmed.
It is understood nobody was hurt.
A spokesman for the UK Health & Safety Executive (HSE) said: “HSE is aware of the incident following a statutory report from the dutyholder and will be considering the content.”
Apache did not respond to a request for comment by the time Upstream went to press.
Upstream reported in March that Apache is appealing against three safety warnings served by the HSE following a serious hydrocarbon leak on its Forties Alpha platform.