The C-NLOER does a very good job of informing the public about offshore incidents, even those that are relatively minor, in a timely manner. The information below is excerpted from their report.
On October 29, 2026 Cenovus reported a spill of approximately 1,400 litres (370 gallons, 8.8 barrels) of synthetic-based mud (SBM) from the West White Rose Platform.
The release occurred during completions operations through the cuttings discharge chute, approximately 63 metres below sea level. No indication of the release was observed at the sea surface from the platform or the standby vessel, which conducted a sweep of the area.
As a precaution, operations were suspended on the West White Rose on October 29 while Cenovus investigated the circumstances surrounding the release. Operations resumed the next day with measures in place to prevent recurrence. C-NLOER Environmental Protection and Well Operations staff were engaged by Cenovus prior to the resumption of operations and are continuing to monitor Cenovus’s investigation and response.
SBM is a dense fluid used during drilling and well operations. It is a mixture of synthetic base fluid, a food-grade oil, and various weighting agents and additives. The synthetic base fluid has very low toxicity in marine environments, with the potential to biodegrade when sufficient oxygen is present. Because of its density, SBM generally sinks and settles, with effects due to the seabed coverage near the release, limited to within tens of metres of the discharge location.
