1. Arnim B. Haase and Robert R. Stewart
Q-factor estimation
Q-factor estimation from borehole seismic data: Ross Lake, Saskatchewan
Arnim B. Haase and Robert R. Stewart bc
Arnim B. Haase

3. Outline: Introduction
Spectral ratio method applied to P-wave and S-wave
Drift correction method for P-wave and S-wave
S-wave Q from empirical equation
P-wave Q from modelling
Conclusions

4. Velocity as Function of Frequency (e.g. Kjartansson, 1979)

5. Spectral Ratio Method (e.g. Tonn, 1991)

14. , tP = d / V(ω2)
Delay Time Equation (Stewart et al., 1984)

15. Parameters and results for P-wave Q
Depth range is 340 m to 1180 m
Average transit time is between 0.4 and 0.45 ms/m
Delay time is 15 ms
Corner frequency is 70 Hz
36.7 ≤ QP ≤ 41.3

16. Shear Log

17. Parameters and results for S-wave Q
Depth range is 235 m to 355 m
Guesstimated transit time is about ms/m
Corrected S-wave travel time is about 179 ms
Corner frequency is 25 Hz
QS = 37

19. Empirical QS-QP Relation (Udias, 1999)

21. Summary:
Over a depth interval of m, P-wave Q is estimated to be 67 from the spectral ratio technique, about 40 from drift curves, and 80 from convolutional model data matching.
S-wave Q estimates over the same interval are 23 from the spectral ratio method, 37 from guesstimated drift curves, and 12 from an empirical equation.
The variance between estimates is considerable, but in keeping with results found in the literature.

22. Acknowledgements:
Thank you to all CREWES sponsors, and Husky Energy Inc., in particular Mr. Larry Mewhort, for release of the VSP-data and well-logs.