This crossplot is used to estimate an equivalent NaCl concentration from a chemical analysis data set. Ion concentrations are first summed to calculate total solids concentration. Total solids concentration is used to define ion multipliers which are then used to calculate the equivalent NaCl concentration.
Inputs are highlighted in yellow and outputs are in green. Ion multiplier values are also plotted on the crossplot. Some of the multipliers are fixed and do not vary appreciably at concentrations below 10,000 ppm. Some multipliers are not defined at total solids concentrations greater than 150,000 ppm.
Schlumberger's Industry Publication, "Log Interpretation Charts." Gen-8 Chart from 2000 Edition.