Ali Ranjbar

The measurement of shear wave velocity (Vs) using the dipole sonic imager (DSI) logging tool is regarded as a crucial physical parameter for rocks. However, not all wells have access to this data, making it essential to accurately and reliably estimate this parameter with minimal uncertainty to determine reservoir characteristics effectively. The Vs estimation approach in this study includes empirical methods and two rock physic models. In empirical methods, empirical correlations reported in studies have been used. In the second approach, two rock physics models, Gaussmann and Xu-Payne, which are more complicated than the experimental models, have been chosen to determine the characteristics of the Vs. The main innovation of this paper is the comparison of all the mentioned methods in Vs estimation. Correlation coefficient (R2) and Average Relative Error (ARE) were chosen as statistical comparison criteria. Based on the final findings, the Greenberg and Castagna method, incorporating Gaussmann fluid replacement theory, exhibited consistent performance and improved estimation accuracy of Vs with R2 and ARE values of 0.9067 and 3.2292, respectively. The suggested approach has the potential to be employed in various other oil and gas exploration fields and can provide accurate Vs estimates.