This crossplot displays shale volumes calculated from the gamma ray log. Linear and non-linear equations are presented.
Inputs are highlighted in yellow and outputs are color coded, based on the equation used. Enter the average gamma ray log value over the interval of interest, as well as gamma ray log values for clean (no shale) and shale (completely shale) intervals. The linear output is known as the gamma ray index, which is used as input to the non-linear equations.
Data points associated with output values are plotted on the cross plot for reference and are also color coded.