A working method for estimating dynamic shear velocity in the montney formation

Abstract

In this paper, we present a customized method for estimating sonic shear velocity (Vs) from compressional velocity (Vp) logs in the Montney Formation, in wells lacking dipole sonic data. Following a multi-scenario analysis that comprised of assessing empirical Vs estimation relations [including lithology, porosity (Ø), and volume of clay (Vsh)-based Vs estimation techniques], bivariate statistics, and machine learning, we found that the Greenberg & Castagna (1992) shale lithology constants yield Vs log estimates that best match the measured Montney Formation Vs in our study area, with a regional correlation coefficient of 0.8. We have therefore customized the Vs estimation method in our study to use the Greenberg & Castagna (1992) shale lithology constants. Our working method: • Improves the efficacy of Vs log estimation from Vp logs in the study area • Demonstrates the importance of calibrating empirical relations for Vs estimation to a specific formation, and • Provides a more accurate complementary Vs log dataset for subsequent regional reservoir characterization studies Method name: Dynamic shear velocity estimation from compressional velocity logs in the Montney Formation, Keywords: Log analysis, Velocity, Correlation, Tight reservoir, Siltstone, Shale