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Winnipeg Free Press - PRINT EDITION

Fracking caused quakes: B.C. report

Only one of the events felt on the surface

By: Lauren Krugel

Posted: 09/7/2012 3:18 AM | Comments: 0

CALGARY -- A spate of small earthquakes in B.C.'s remote northeastern corner were caused by a controversial technique used to extract natural gas from shale rock, says a report by the province's energy regulator.

The B.C. Oil and Gas Commission launched its probe after a "number of anomalous, low-level seismic events" were detected in the Horn River Basin, a gas-rich shale formation that's attracted some of the industry's biggest players.

"The investigation has concluded that the events observed within remote and isolated areas of the Horn River Basin between 2009 and 2011 were caused by fluid injection during hydraulic fracturing in proximity to pre-existing faults," the agency said in a recent report.

In order to break the rock and free the gas trapped inside it, operators inject a combination of water, sand and chemicals into the ground at high pressure.

The process, known as hydraulic fracturing or fracking, has drawn concern from environmentalists and landowners because of the amount of water the process requires and because of potential contamination of groundwater.

Studies have also linked fracking to earthquakes around shale formations in England and Oklahoma.

Natural Resources Canada detected 38 events ranging in magnitude from 2.2 to 3.8. A quake of between 4.0 and 4.9 is considered light and may cause a noticeable shaking of indoor items and rattling noises.

Another 234 events were picked up by industry-deployed devices in the area that are capable of detecting much smaller shakes than Natural Resources Canada's equipment can.

"We wanted to make sure that we knew what was causing the events, and we wanted to make sure that the events would pose no risk to safety or the environment," said Ken Paulson, chief operating officer at the commission.

Only one quake was felt at the surface near the fracking.

"There was no risk posed to public safety or environment by any of the events that were looked at as part of this investigation," said Paulson.

The report said more than 8,000 fracking completions have been performed in northeastern B.C. that haven't been associated with unusual seismic activity. No quakes were recorded in the area before April 2009, the report said.

It said the events began after fracking took place. The quakes happened within five kilometres of fracking operations and within 300 metres of the depth at which the rock was being fractured.

The report's recommendations include improvements in seismic detection in the area, further study to identify pre-existing fault lines and stronger monitoring and reporting procedures.

It also calls for an examination of the relationship between hydraulic fracturing parameters and seismic activity. For instance, lower pump rates or injection volumes may be considered.

Geoscience BC is funding an update of the area's seismographic grid network to boost monitoring. The commission is undertaking further study with the University of British Columbia.

Dave Collyer, president of the Canadian Association of Petroleum Producers, said natural gas companies provided the commission with data for its study and support its conclusions. The industry is finalizing guidelines for operators and is financially supporting more seismic monitoring.

-- The Canadian Press

Republished from the Winnipeg Free Press print edition September 7, 2012 A16

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