This paper describes observations of seismicity and casing failures associa
ted with steam stimulation operations at Imperial Oil Ltd.'s Cold Lake oil
held in Alberta, Canada. A total of 11 oil-producing pads were monitored ov
er a 1-2 year period using 3-component geophones cemented at depths ranging
from 160 m to 400 m and data acquisition systems with a hat frequency resp
onse up to 1.5 kHz. Most of the seismicity was detected during the steaming
operations and was located in the formation overlying the oil-bearing laye
r. Some activity was observed in the shales above, however, the reservoir i
tself showed almost no evidence of seismicity. The estimated seismic moment
of the observed events was in the range 10(5)-10(7) N.m(-2.7 < M < - 1.3).
According to a theoretical model (TALEBI et at., 1998) and in situ observa
tions, the seismic source corresponding to casing failure events should be
well described by a dipole registering seismic moment in the order of 2.10(
6) N.m. Seismic signals of a total of four observed casing failures were an
alyzed. The partial failures produced seismic moments slightly lower than t
his value while total failures were stronger by about one order of magnitud
e. The use of the SV/SH amplitude ratio, in conjunction with accurate sourc
e locations, provided a robust technique for the detection of casing failur
es.