BP Canada Energy Group recently reported an unauthorized discharge of drilling mud from the one of its drilling operations off the coast of Nova Scotia. The company estimated approximately 136,000 litres of drilling mud were discharged.
Anita Perry, BP Canada’s regional manager for Nova Scotia, said a preliminary look at the spill has led the company to believe the cause is mechanical failure, though the investigation is not complete.
Perry said this is not a common occurrence, but the organization has response plans in place to manage spills. She said that before drilling was done in the area, a survey was conducted to assess environmental risks.
“Prior to drilling we did not identify any corals or any species there that could be damaged. So we do not believe there will be any damage,” said Perry.
The company suspended drilling during the investigation of the cause of the spill.
Risks to the Environment
Stacy O’Rourke, the director of communications at the Canada-Nova Scotia Offshore Petroleum Board (CNSOPB) said the synthetic-based mud is dense and sinks rapidly to the sea floor and the synthetic-based oil in the mud has low toxicity.
Ms. O’Rourke added that the effects of these types of spills are usually limited to the area immediately surrounding the well and are associated with the physical smothering of the seabed due to coverage by the mud.
She said the spill happened earlier in the day on Friday, and both the board and coast guard were notified. As of Friday evening, O’Rourke said no one on the board was at the spill.
The incident occurred approximately 330 kilometres from Halifax on a drill rig called the West Aquarius.
CBC interviewed Tony Walker, a professor from the Dalhousie University School for Resource and Environmental Studies, about the potential impacts of the release of drilling mud on the environment. The Professor said that in looking at the project’s environmental assessment report, carried out by the Canadian Environmental Assessment Agency (CEAA), the drilling mud spill may still be cause for concern.
Professor Walker said while a water-based mud is available for use in this type of drilling, the assessment outlines BP’s decision to use the synthetic, because it can better handle potential gas buildup and temperature regulation.
“Certainly, a synthetic-based mud does contain chemicals and potentially oils and diesel and that sort of thing,” he told the CBC. Walker said he reviewed data from the report based on a 3D modelled test and scaled down the impacts based on the June 22 incident.
“It could [result in] impacts of a kilometre or more from the drilling site. It could actually cover and smother [ocean floor dwelling] organisms; it could impact fish species which have larvae and eggs on the seabed.”
Professor Walker told the CBC that the CEAA report also references data from past drill sites, where little to no spilling was reported, in which surrounding marine habitats took up to five years to recover from drilling.
“The kind of consistent thread or theme I get from the report … is that if there are releases, it’ll be localized and it’ll have short term impacts,” Walker told the CBC.
“A kilometre is quite a big area, and [the report] talks about a recovery period of about five years for recolonization. I wouldn’t call five years entirely short-term.”
Nova Scotia’s energy minister says he’s concerned about spill of the drilling fluids off the province’s coast. However, he also added that he remains committed to growing the oil and gas industry.
Geoff MacLellan said he has “complete confidence” in the Canada-Nova Scotia Offshore Petroleum Board’s investigation into BP Canada’s leak of 136 cubic metres of synthetic drilling mud on Friday.
Approval to drill was granted in the Spring
BP Canada Energy Group was given approval in the spring of 2018 to drill of the coast of Nova Scotia. At the time, the Aspy D-11 exploration well was the first in BP Canada’s Scotian Basin Exploration Project. It was estimated that up to seven exploration wells could be drilled off the southeast coast of Nova Scotia over a three-year period.
At the time of the issuance of the approval, Anita Perry of BP Canada Energy stated in a phone interview with Canada’s National Observer, “We’re confident we addressed all issues and risks for a safe drilling program.”