P-S Seismic Inversion: Modeling, Processing, and Field Examples

Robert James Ferguson

ABSTRACT

This thesis presents methods to invert P-S stacking velocities and P-S reflectivity, to estimate shear-wave velocity (Vs). The methods are applied to synthetic data, as well as a survey from the Blackfoot oil field in Alberta, Canada. S-wave velocity estimates are computed using a P-S analogue of the Dix equation, and are found to be consistent with well-log velocities, for offset-depth ratios of about 1.0. Recursive amplitude inversions, using a weighted stack data, are derived. Missing low-frequency and phase error are found to distort inversion results.

Frequency-domain inversion, and constrained linear inversion, when applied to P-S weighted stacks, are use to restore low-frequency, and phase errors are corrected in processing. Frequency-domain inversion is applied to the Blackfoot field data, and the resulting Vs and Vp/Vs anomalies correlate compellingly with a productive oil reservoir in a Cretaceous sandstone.

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