Velocity Uncertainties in Surface and Downhole Monitoring

Previous work in modeling positional uncertainty for both surface and downhole passive monitoring approaches has largely ignored the uncertainty in velocity estimates. Incorporation of velocity uncertainty in the model produces more realistic error estimates, that tend to agree with case studies showing large positional differences in results processed by different analysts. Velocity uncertainty is analyzed within a maximum likelihood framework, where uncertainties for estimated parameters can be computed for a variety of imaging constraints and approaches.