Imperial Oil says its fourth-quarter profit fell dramatically as a result of lower oil and gas prices, although some of its refinery and chemical operations weren't affected to the same degree.

The company earned $102 million or 12 cents per diluted share in the fourth quarter, down from $671 million of 79 cents per diluted share.

The result included a $289-million net loss for Imperial's upstream operations, which include oilsands, conventional oil and natural gas production.

Its downstream operations, which include refining and retailing operations, remained profitable but earned $352 million, down from $397 million.

Imperial's petrochemical business earned $74 million, up from $63 million in the fourth quarter of 2014.

The Calgary-based subsidiary of ExxonMobil says the average realized price for a barrel of synthetic oil was down 31 per cent compared with a year ago, while it was down 56 per cent for a barrel of bitumen.