Estimation of dielectric properties of crude oils based on IR spectroscopy

•A method for estimation of dielectric properties of crude oils based on IR spectra•Experimental comparison of direct electrical measurement and estimates•Evaluation of the uncertainty of the method•Experimental data on biodegraded and non-biodegraded crude oils

Dielectric properties of crude oils play an important role in characterization and quality control. Measuring permittivity accurately over a wide range of frequencies is, however, a time-consuming task and existing measurement methods are not easily adapted for real-time diagnostics. IR spectroscopy, on the other hand, provides rapid measurements of fundamental molecular properties.In this paper we show that by using multivariate calibration tools such as PLS regression, it is possible to extract dielectric properties of crude oils directly from IR spectra, in addition to conventional interpretation of the spectra, hence reducing the need for direct electrical measurements. Results on 16 different oil samples show that the dielectric parameters obtained with the proposed method agree well with those obtained using direct permittivity measurements. The PLS regression method has also been extended with Monte Carlo simulation capabilities to account for uncertainties in the data.