BC Regulator Rules Fracking Caused November Quakes

The BC Oil & Gas Commission said December 21 its investigation into three earthquakes in the northeast part of the province on November 29 were caused by a nearby Canadian Natural Resources Limited (CNRL) fracking operation.

The three events, which measured 3.4, 4.0 and 4.5 magnitude occurred over a 45-minute period, between about 6:27 pm and 7:15 pm. The commission received 14 “felt event” reports of the tremors and CNRL immediately suspended its hydraulic fracturing operations.

The commission’s investigation included a review of operational and seismological data within a 10-km radium of the epicentre of the quakes, and focused on current and previous fracking operations targeting the lower Montney formation from CNRL’s pad 5-22.

Seven wells had been fracked in May and June, and resulted in no seismic events larger than magnitude 2.5. Pre-assessment reports relating to expected seismicity on the two wells being fracked on November 29 concluded that induced seismicity was likely to occur, but were not expected to exceed magnitude 3.0.

CNRL has met the requirements to resume fracking operations at other well pads in the area, but fracking operations targeting the lower Montney from the 5-22 pad will remain suspended until a detailed technical review is completed, the commission said.

Other companies in the area have been allowed to resume fracking operations, but the commission reminded that they are all required to submit revised induced seismicity assessments taking into account the findings of the commission’s investigation into the 5-22 events, with particular attention to the lower Montney.

“Completions targeting the lower Montney formation…appear to have increased susceptibility for induced seismic events and operators should be prepared to implement mitigation measures if seismic monitoring indicates an increase in the frequency or magnitude of events,” the commission said.