Activation Rate of Seismicity for Hydraulic Fracture Wells in the Western Canada Sedimentary Basin

The rate of M >= 3 earthquakes associated with hydraulic fracturing (HF) in horizontal wells (HF wells) in the Western Canada Sedimentary Basin is estimated for the period from 2009 to 2019. The estimates are based on a statistical discrimination algorithm that uses an objective scoring function deduced from the observed spatiotemporal correlations between wells and earthquakes. A Monte Carlo simulation approach is used to test the efficacy of the scoring function in determining noncoincidental association rates, allowing for correction of the observed association rates for the expected number of false positives. The basin-wide average rate of association of M >= 3 earthquakes with HF wells (2009-2019) is similar to 0.8% on a per well basis. The susceptibility appears to vary by formation by more than an order of magnitude, ranging from similar to 6% for HF wells in the Duvernay Formation to similar to 0.07% for HF wells in the Cardium Formation. For some formations, there has been no observed association at the M >= 3 level to date, but this does not necessarily imply that such formations are immune to induced seismicity.