B.C.’s Oil and Gas Commission (OGC) has concluded that a trio of earthquakes in the area around Fort St. John at the end of November were caused by hydraulic fracturing (fracking) operations.
The quakes struck about 20 kilometres south of the city on Nov. 29. The OGC said they were a result of fracking operations conducted by Canadian Natural Resources Ltd. (CNRL)
The quakes were recorded as magnitude 3.4, 4.0 and 4.5.
The OGC said it made its determination based on the fact that CNRL was conducting hydraulic fracturing at the time of the quakes, and that the epicentres of the quakes and strongest “felt” reports were near the company’s ‘G’ and ‘H’ wells.
The OGC said CNRL performed well bore integrity assessments, and did not report any problems. In the wake of the quakes, it said the company immediately suspended its fracking operations and has subsequently cooperated with regulators.
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According to the OGC, CNRL was drilling in the natural gas-rich lower Montney formation when the quakes occurred.
The company had drilled seven other upper Montney wells earlier this year, but never recorded a seismic event over magnitude 2.5 in that time.
It says the company submitted a pre-assessment report for a pair of wells in the lower Montney formation, which did conclude “seismicity was likely to occur, but events larger than magnitude 3 were not expected.”
The OGC said fracking operations at CNRL’s 5-22 well pad remain suspended while it conducts a detailed technical review, however other companies operating in the area may resume operations.
Companies planning to resume work must submit revised induced seismicity reports.
The regulator said it is also working with area operators to catalogue known geologic faults and is conducting a third-party review of geo-mechanical properties, hydraulic fracture design and seismologic data to improve its assessment of induced seismicity hazards.
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