Patent ID: 8076950
Filing Date: 2011-12-13
Classification: G01N

Abstract:
1. A method for determining the water conductivity and water volume fraction of a multi-component mixture of water and further fractions of at least one non-aqueous additional liquid and a gas in a pipe, the method comprising the following steps: a. measure electromagnetic phase difference at at least two pre-determined frequencies in the pipe, b. assume a value for the conductivity of the water in the multi-component mixture, c. determine the pressure and temperature of the multi component mixture, d. calculate the real and imaginary dielectric constant of water of the mixture for the first measurement frequency based on the result from step a-c, e. calculate the ratio between the real and imaginary dielectric constant of water of the mixture obtained in the previous step, f. calculate the real part of the dielectric constant of the multi-component mixture based on the result from step a, at least one of calibration constant obtained empirically by measuring the phase vs. frequency for saline water with known water conductivity and a multiplication factor obtained empirically by measuring the phase difference vs. frequency for water samples of known water salinity, and the result from step e, g. calculate the imaginary part and effective part of the dielectric constant of the multi-component mixture based on the result from steps f and e, h. calculate the volume fraction of water of the mixture based on knowledge of the dielectric constant of the non-aqueous liquid(s), gas and the result from step d, i. repeat step d-h for the other pre-determined frequencies from step a, j. repeat step a-i for another water conductivity and repeat step b-j until the entire expected water conductivity range have been covered, and k. determine the water volume fraction of the multi-component mixture and water conductivity of the water fraction by identifying the water conductivity from step b and water fraction from step h which gives the most similar water fraction for all pre-defined measurement frequencies.