This crossplot allows the user to quickly calculate Wyllie sonic porosity, tied to a compressional sonic slowness value, using custom matrix and fluid compressional slowness values, along with a compaction factor.
Inputs are highlighted in yellow and the custom sonic porosity output is in green.
For reference, sonic porosity functions using sandstone, limestone and dolomite matrix compressional slowness values are presented (orange, blue and purple lines). The data point associated with the custom inputs is plotted on the crossplot.
Wyllie, M.R.J., Gregory, A.R. and Gardener, L.W., "Elastic Wave Velocities in Heterogeneous and Porous Media." Geophysics, Volume 21, Number 1, January 1956: 41-70.
Wyllie, M.R.J., "The Fundamentals of Well Log Interpretation." Third Edition, Academic Press, New York, 1963.