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.
Keywords: Correlation; DTP, sonic log – compressional slowness; DTS, sonic log – shear slowness; Dynamic shear velocity estimation from compressional velocity logs in the Montney Formation; GR, gamma ray log; Log analysis; NNE, neural network estimation; RCW, reservoir characterization workflow; RHOB, bulk density; SSTVD, subsea true vertical depth in meters; Shale; Siltstone; Tight reservoir; Velocity; Vp, compressional sonic velocity; Vs DOL, shear velocity log estimated using Greenberg-Castagna [1] Dolomite lithology constants; Vs LST, shear velocity log estimated using Greenberg-Castagna [1] Limestone lithology constants; Vs MDRK, shear velocity log estimated using Castagna et al. [5] Mudrock lithology constants; Vs MJ Clavier, shear velocity log estimated using Marion & Jizba [11] method with Clavier et al. [12] fractional clay volume correction; Vs MJ Larionov, shear velocity log estimated using Marion & Jizba [11] method with Larionov [13] fractional clay volume correction; Vs MJ Stieber, shear velocity log estimated using Marion & Jizba [11] method with Stieber [14] fractional clay volume correction; Vs SH, shear velocity log estimated using Greenberg-Castagna [1] Shale lithology constants; Vs SST, shear velocity log estimated using Greenberg-Castagna [1] Sandstone lithology constants; Vs, shear sonic velocity; VsANN, shear velocity log estimated using artificial neural network techniques; VsRegress, shear velocity log estimated from the bivariate analysis of dipole sonic Vp and Vs logs; Vsh, Clavier, Clavier et al. [12] fractional clay volume correction; Vsh, Larionov, Larionov [13] fractional clay volume correction; Vsh, Stieber, Stieber [14] fractional clay volume correction.