Well bore fault blamed for underground leak by Sheila Pratt with files from Brent Wittmeier, January 10, 2014, Edmonton Journal
Canadian Natural Resources was alerted to an underground leak in one of its wells by seismic equipment on the Primrose site near Cold Lake, says the Alberta Energy Regulator. A fault in the cement casing in the well allowed 27,000 litres of bitumen to seep into the adjacent rock layer on Jan. 3, and no bitumen came to the surface, said Darin Barter, AER spokesman. There are no underground aquifers in the area, so there are no concerns bitumen leaked into the groundwater, said Barter. “We are taking this very seriously,” said Barter. “We need to have confidence the company can resume production without problems.”
Company spokesperson Zoe Addington said the well bore fault occurred at 440 metres below surface at Pad 30 in the Primrose South area. In addition to the repair work, the company is also doing an investigation to determine cause of the event, she said. “We anticipate finding that the casing parted at a collar connection joint,” Addington said. The AER will be investigating whether the company’s high-pressure, cyclic steam process is implicated in the well bore failure, said Barter. “Our investigation will look into that,” he said. In this incident, the underground leak was stopped when the well was shut in.
That’s not the case at four leaking sites discovered on the CNRL Primrose field last spring where bitumen continues to come to the surface through deep fissures, albeit more slowly in the cold weather, noted Barter. The company has said those four surface leaks — one into a small lake — are also caused by well bore failure. But the regulator is looking into whether the company’s high pressure steam process is a factor, causing cracks in the caprock that allow bitumen to flow uncontrolled to the surface. In its process, CNRL pumps high temperature steam into the ground for weeks to soften the bitumen, which is then brought to the surface through the same wells. Mike Hudema of Greenpeace questioned whether CNRL should be allowed to continue to operate on Primose lease given there were also leaks in 2009. The regulator should consider suspending the operation, he said.
Meanwhile, in a second incident in the Cold Lake area, about 2,000 litres or two cubic metres of water-based “drilling mud” spilled outside a lease area operated by Cenovus Energy, said Barter. The spill wasn’t near wildlife or water, he added. The exact makeup of the substance is not yet known, though it’s not believed to have any contaminants. “It’s been cleaned up, scraped, and samples have already been taken to a lab,” said Barter. “We’re just awaiting results of the sampling.” Cenovus spokesman Reg Curren said the spill occurred when the company was drilling a type of exploratory well. The company cleaned up the spill with a vacuum truck. [Emphasis added]
Alberta regulator investigates CNRL well leak in troubled field by The Canadian Press, January 10, 2014, Calgary Herald
The Alberta Energy Regulator is investigating another leak from a Canadian Natural Resources (TSX:CNQ) bitumen well near Cold Lake. The regulator says 27,000 litres of crude bitumen were released underground on Jan. 3 at the company’s troubled Primrose field. But agency spokesman Darin Barter said the leak has been stopped.
“There was no release to surface,” Barter said Friday. “There’s no aquifers that have been impacted by this incident.” [It will take time for the release to move into aquifers] Barter said the release has been definitively attributed to a failed well casing, setting this leak apart from an earlier one in the same field last summer that also remains under investigation. In that leak, more than a million litres of bitumen has so far seeped to the surface. The spill continues, although cold weather has slowed the amount to almost nothing.
CNRL has said the earlier leak was also due to a well failure. “We don’t necessarily share that view of the incident,” said Barter. The regulator is investigating whether the bitumen escaped through cracks in the rock above the deposit and was driven to the surface by high-pressure steam pumped underground to soften it before being extracted. The company has been ordered to reduce the pressure of the steam it uses. The first leak remains the subject of a $40-million cleanup effort from CNRL. Barter said there’s no indication when the regulator’s report on that leak will be complete.
There were also bitumen leaks at the Primrose field in 2009. The regulator concluded those leaks were at least partially caused by high volumes and high pressures of steam. Mike Hudema with Greenpeace Canada said it is “incredible” that CNRL is still allowed to continue its operations. “If the Alberta government is serious about protecting Alberta’s environment, it has to pull CNRL’s approval for their Cold Lake operations,” Hudema said in a release. “How many more spills will it take before we see real action?” [Emphasis added]
Cenovus spills 1300 gallons at Cold Lake by Derrick, January 10, 2014, Westcoastnativenews
On January 8 Cenovus reported that a well incident cause approximately 1300 gallons of Drilling fluids spilled at there site, And 500 gallons ran down off the site. A vac truck was used to assist in the clean-up and a bobcat is being used to scape up the contaminated ice and snow. Sampling is being done to ensure that all fluids released are recovered. it is unknown at this time what caused the incident.
[Refer also to:
Where’s the regulator? CNRL releases into formation another 7000 gallons of Crude Bitumen at Primrose, Cold lake, does not yet know how to repair the problem, or past releases ]