Effects of gamma rays on the low frequency dielectric dispersion of crude oil

Abstract

The relative permittivity of irradiated and non- irradiated crude oil was investigated in the frequency range 1 to 100kHz and room temperature of 27.0 0.5°C. Samples of crude oil of specific gravity 0.828 0.005 were irradiated for periods of 2 months, 4 months and 6 months respectively using a cobalt 60 (60Co) gamma radiation source at a dose rate of 0.65 mSv per hour. The dielectric measurement was made using a Marconi TF 1313 Universal Bridge, working in conjunction with a Philip Harris signal generator. Results for irradiated and non-irradiated samples showed a decrease of relative permittivity (e') with frequency from 1 to 100 kHz. However, the relative permittivity of the irradiated samples was found to differ distinctly from the non-irradiated samples. This difference has been attributed to the ionization and weakening of molecular bonds in the irradiated samples. Increase in irradiation time of the samples from two months to four and six months respectively resulted in further increase of the relative permittivity owing to increased level of ionization.

Keywords: dielectric, frequency, crude oil, dispersion, permittivity

Nigerian Journal of Physics Vol. 17, 2005: 99-102