CALGARY – The Alberta Energy Regulator said on Monday it is implementing additional requirements at Canadian Natural Resources Ltd’s Primrose oilsands project after concluding excessive steaming caused a 6,648-barrel bitumen emulsion leak in 2013.
The requirements include permanent limits around the steam volumes the company is permitted to use to extract bitumen from underground reservoirs along with a requirement that CNRL seek approval for each steaming cycle at its Primrose East site.
“The restrictions do amount to a permanent ongoing decrease in the concentration of the company’s operations. The company will not be able to pursue its original operating strategy at Primrose,” said Kirk Bailey, executive v . p . of operations in the AER.
CNRL has been operating under steam restrictions at Primrose since the seepage is discovered.
Bitumen emulsion – a combination of bitumen, sand and water – was discovered oozing towards the surface at two locations at CNRL’s Primrose project in northern Alberta in May 2013. Two more leaks were found over the next month, prompting the AER to impose restrictions on the site and launch an investigation.
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In July 2013, company President Steve Laut said the work was producing about 10,000 barrels per day (bpd) less than previously expected consequently.
Bitumen seepage towards the surface because of oilsands operations is not permitted under Alberta energy regulations. Numerous animals died as a result of the leak, which continued for months, including birds, mammals and amphibians.
The investigation, explained Bailey as one of the most complicated ever undertaken by the AER, concluded the seepages were brought on by excessive steam volumes along open conduits for example wellbores, natural fractures and faults and hydraulically-induced fractures.
CNRL said the regulator’s report was consistent with its own findings at the 100,000-110,000 bpd project.
“Our enhanced operational practices and techniques – in position since July 2013 – includes modified steaming strategies, enhanced pressure monitoring and response strategies as well as remediation of wellbores to mitigate the chance of future seepages,” the organization said inside a statement.
Cyclic steam simulation involves injecting high-pressure steam into an oil well to liquefy viscous bitumen so it can flow to the surface.
The AER said it looked at other producers using the same technology for oil sands extraction, such as Imperial Oil, and concluded those projects posed no risk of comparable seepages.
? Thomson Reuters 2016
