Predictions of shear-wave logs in wells that do not have dipole Sonics are challenging, particularly in heavy oil reservoirs. In this study, we utilized linear-regression, robust locally weighted scattering and smoothing (LOWESS), and several other approaches of iteratively re-weighted linear least- squares inversion (IRLS) techniques to estimate shear-wave logs. The developed computer codes were implemented using well logs from three different types of reservoirs (conventional oil, heavy oil, and tight shale oil) in WCSB. The proposed methods guard against outliers, and have shown improvements in predicting shear-wave sonic logs compared to standard linear relationships (Castagna et. al., 1985).
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