Alberta Energy Regulator has lifted some of the restrictions put on a Calgary-based energy company following an earthquake in March.
Vesta Energy has been cleared to resume operations north of Township Road 39, which is Hwy 11A east of Sylvan Lake and then becomes Hwy 11 as it heads west.
“The Alberta Geological Survey (AGS) has determined that these sites are at lower risk of seismic events,” said the AER in a recent update.
“All of Vesta’s hydraulic fracturing activity to the south of Township 39 will remain suspended until the AER and AGS complete their investigation into the March 4 earthquake.
“At this time, we do not know how long our review will take.”
A Vesta Energy spokesperson confirmed “we are going to be allowed to go back to work as per the AER” but declined to comment any further.
The 4.6 magnitude earthquake that shook homes and spooked many central Albertans just before 6 a.m. was the largest ever to hit the area, said Natural Resources Canada. It was located about 12 km south of Sylvan Lake.
A Geological Survey of Canada spokespeson said at the time the most powerful earthquakes in central Alberta usually top out at 3.8 to 4 on the Richter scale.
Many area residents felt the earthquake, reporting shaking rooms, rattling doors and windows. The tremors were so strong a number of people thought a vehicle had slammed into something nearby.
Vesta, which was conducting fracking operations in the area, detected and reported the earthquake and immediately shut down operations.
The regulator then ordered Vesta to suspend hydraulic fracturing operations at the site in order to protect the public and the environment.
March 15, AER issued a series of recommendations for all oil and gas operators working in the Duvernay Formation in the Red Deer region. It covers an area roughly 10 km wide from Wetaskiwin to about 10 km south of Red Deer.
It is recommended operators assess the potential for “induced seismicity” and develop a response plan before starting fracking operations.
If any 1.0 magnitude earthquake occurs within five kilometres of an active well, the plan should be implemented and AER notified. It is recommended fracking be suspended if any seismic event more than 3.0 magnitude is detected.
Hydraulic fracturing involves pumping chemicals and sand underground to break up rocks to help get oil and natural gas flowing.
An Alberta Geological Survey interactive map shows several dozen small earthquakes occurred south of Sylvan Lake in the first few months of the year. Most are well under the 3.0 magnitude that is typically detectable by people on the surface.
None appear to have been recorded since the early March seismic activity.