Description

Four seismic (earthquake) monitoring stations were installed surrounding Norman Wells to monitor seismic activity in the oil and gas leases in the Central Mackenzie Valley. Information on the frequency, intensity and location of earthquakes in the valley is being collected.

Location

The array is designed to accurately locate earthquakes in the Mackenzie Valley surrounding Norman Wells

Justification

In 2012, a potential tight oil play identified in the Norman Wells area, precipitated the acquisition of several exploration licenses by a number of petroleum companies. Residents of Tulita, Fort Good Hope and Norman Wells identified concerns that hydraulic fracturing associated with the play could cause earthquakes in the area. We didn’t really know a lot about earthquakes in the region, so we developed a research program to find out more.

In the event that commercial tight oil development were to go forward in the area, the data will serve as excellent baseline data to highlight any changes in the earthquake regime in the area and allow regulators to locate re-injection wells in areas where earthquakes are infrequent.

Approach

In order to understand the seismicity of an area a lot of earthquakes must be recorded. Small low-energy earthquakes, that are too small for humans to feel, are much more common than larger earthquakes, that humans can feel. Closely spaced seismic stations allow very low energy earthquakes close to the stations to be accurately located. Four small solar powered seismic observation stations were installed surrounding Norman Wells to allow us to detect and locate very small tremors. Using this we will understand where earthquakes occur in the area, and why.

Schedule

Four seismometers were installed in late 2013. Data is collected from the stations once or twice a year and analyzed. A good description of the installation and initial results are available.  More results and some initial interpretations of the data with respect to potential induced seismicity are also available.

No detectable changes to the background seismicity were noted before during or after a small Conoco-Phillips Canada test frack in the area. Data has been collected for several years, and an excellent baseline record of seismicity in the area has now been recorded.  NTGS expects to remove and redeploy the array summer 2019. Having a high-resolution seismic baseline for the area will allow regulators to accurately assess any induced seismic risks should exploration activities resume in the area.

Partners and Support

• Geological Survey of Canada: David Snyder, Honn Kao, Amir Mansour Farahbod, Andy Tran • Conoco-Phillips Canada: Sandy Crawford, Larry Matthews • Husky Energy: Darren Brown • Nanometrics: Peter Devanney