Estimating shear-wave velocity logs using P-S seismic inversion

Robert James Ferguson, Robert R. Stewart, Henry C. Bland

A method is developed to estimate S-wave velocity logs from pre-stack seismic data. The method requires converted-wave CCP gathers, a P-wave sonic log, and a P-wave macro velocity model. A band-limited S-wave sonic log section and a relative change in S-wave velocity section are produced. The procedure was first tested by computing the S-wave velocity of a single synthetic CCP gather. The synthetic test showed the inversion program to be working correctly. The S-wave velocity inversion was then applied to line EKW-002 of the Lousana multi-component data set. The S-wave sonic section derived from the inversion of the Lousana data set correlated well with the known geology. The effect of frequency band-limiting, and input data scaling were found to have an effect on inversion quality.