Husky Energy: Rain and poor soil likely cause of leak

By Geoff Lee

November 22, 2016 12:00 AM

ANATOMY OF A LEAK This photo from Acuren Group's metallurgical report shows the location of the oil spill from a buckled section of the pipleine on Husky's Saskatchewan Gathering System then entered the North Saskatchewan River on July 21. The cause of the pipeline failure is attributed to the ground giving way due to heavy rainfall and weak sub soils. SUPPLIED PHOTO

More than 225,000 litres into river and on land

Husky Energy Inc. says heavy rain and weak sub soil are the likely causes of a pipeline rupture that dumped 225,000 litres of heavy oil and diluent into the North Saskatchewan River and on land.
“The break was a sudden, one-time event in a section of the pipe that had buckled due to the force of ground movement,” said the company in its final report on Nov. 17.
Husky reports the break occurred on land about 160 metres from the south slope of the river.
Of the total volume of crude oil released from the pipeline, about 60 per cent has been recovered from soil around the leak site.
“The remaining 40 per cent (90,000 litres) migrated into the river and was largely deposited along the shore banks, with the heaviest concentration in the first 20 kilometres,” said Husky spokesperson, Mel Duvall.
Husky noted 210,000 litres had been accounted for when the cleanup concluded in October.
The company has also filed its final geotechnical and metallurgical reports prepared by Stantec Consulting Ltd and Acuren Group Inc. to regulators in Saskatchewan for review.
“This afternoon (Nov. 17) we filed an update to the province’s Integrated Resource Information System, which included the cause of the incident, as well as a summary of the investigation and two supporting reports which, provided a geotechnical and metallurgical analysis,” said Duvall.
Husky says the pipeline break was caused by geotechnical activity.
The Stantec reports noted about 95 mm of rain fell in the area on July 11, nine days before the spill that may have been a contributing factor.
“Given the available data to date, the most recent movement affecting the pipelines was likely triggered by a high precipitation event, surface topography that impedes drainage and the weak pre-sheared foundation of Cretaceous clay shales,” stated Stantec.
The Acuren metallurgical report concluded the break in the pipeline was not the result of materials defects, deficiencies or corrosion.
In response to the Husky pipeline report being release, NDP Environment critic Cathy Sproule said more must be done to avoid a similar spill from occurring.
“We are reaffirming our call to move away from having companies police themselves when it comes to pipeline inspections,” said Sproule.
“The spill showed how devastating an incident like that can be to the water that many families drink and use in everyday life, but it also showed what little work is being done by the Sask. Party government to make pipeline safety a priority. The government only conducted 78 pipeline inspections last year, while the government of Alberta conducted more than 2,000. That will have to change moving forward.”
In its own summary, Husky said when the pipeline was installed in 1997, a geotechnical assessment prepared for the company by a third party concluded the ground was intact.
“While the investigation has concluded the pipeline was designed and constructed in accordance with applicable standards and operators responded appropriately, it is our intention to use these findings to further enhance our systems,” said Duvall.
“Our overall objective is to continuously improve the integrity of our systems and operations.”
The spill forced communities downstream from the spill, including North Battleford and Prince Albert, to shut off their water intakes and temporarily find alternate sources of potable water.
“We know the impact this incident had on communities and would like to acknowledge the extraordinary assistance we’ve received throughout,” said Duvall. “From the beginning we have taken full responsibility and continue to do so.”
Duvall also said that based on Husky’s findings, the company is moving forward with a number of immediate actions while regulators continue with their review.
The company aims to make improvement to its leak detection processes and operating procedures after it faced some criticism during the spill for not detecting it quicker.
Husky said prior to the spill, work was underway in the area to tie-in a new condensate line and update leak detection systems and work that required two pressure transmitters to be blocked in. The company said in such circumstances it is common for the leak detection system to register anomalies.
“The investigation has concluded that during the event, the operators responded appropriately to the data being observed and took proper steps to investigate,” said Husky.
Husky noted its leak detection systems and operator response are routinely tested.
To improve performance, the company is adjusting variables on the leak detection systems to reduce the number of false alarms. Husky says it will ensure geotechnical risks are addressed and re-assessed over the life of a pipeline with mitigation and monitoring strategies.
They are also reviewing and consolidating existing leak detection processes and procedures among other enhancements.

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