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

• Published in: MethodsX Vol. 6; pp. 1876 - 1893
• Main Authors: Iwuoha, Sochi C., Pedersen, Per K., Clarkson, Christopher R., Gates, Ian D.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2019; Elsevier
• Subjects: Correlation; Dynamic shear velocity estimation from compressional velocity logs in the Montney Formation; Earth and Planetary Science; Log analysis; Shale; Siltstone; Tight reservoir; Velocity; DTP; DTS; Correlation; NNE; RCW; Shale; Vs SH; Vs MJ Stieber; Vs MJ Larionov; Siltstone; Vs LST; Vs MDRK; Vs SST; VsRegress; SSTVD; Vp; Vsh, Clavier; Vs; Vsh, Stieber; Log analysis; GR; Velocity; RHOB; Vsh, Larionov; Tight reservoir; VsANN; Dynamic shear velocity estimation from compressional velocity logs in the Montney Formation; Vs DOL; Vs MJ Clavier; Vs MJ Clavier, shear velocity log estimated using Marion & Jizba method with Clavier et al. fractional clay volume correction; NNE, neural network estimation; Vsh, Stieber, Stieber fractional clay volume correction; RCW, reservoir characterization workflow; Vs SH, shear velocity log estimated using Greenberg-Castagna Shale lithology constants; Vs MJ Larionov, shear velocity log estimated using Marion & Jizba method with Larionov fractional clay volume correction; DTS, sonic log – shear slowness; SSTVD, subsea true vertical depth in meters; VsRegress, shear velocity log estimated from the bivariate analysis of dipole sonic Vp and Vs logs; Vs MJ Stieber, shear velocity log estimated using Marion & Jizba method with Stieber fractional clay volume correction; GR, gamma ray log; Vs, shear sonic velocity; DTP, sonic log – compressional slowness; Vs SST, shear velocity log estimated using Greenberg-Castagna Sandstone lithology constants; Vp, compressional sonic velocity; Vs MDRK, shear velocity log estimated using Castagna et al. Mudrock lithology constants; Vs DOL, shear velocity log estimated using Greenberg-Castagna Dolomite lithology constants; Vs LST, shear velocity log estimated using Greenberg-Castagna Limestone lithology constants; RHOB, bulk density; VsANN, shear velocity log estimated using artificial neural network techniques; Vsh, Clavier, Clavier et al. fractional clay volume correction; Vsh, Larionov, Larionov fractional clay volume correction
• ISSN: 2215-0161; 2215-0161
• DOI: 10.1016/j.mex.2019.08.013

[Display omitted] 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