A study on microwave dielectric properties of solid bitumen

Microwave complex dielectric constants were measured with the cavity perturbation method for natural bitumens of various degrees of metamorphism as well as for bitumen samples subjected to thermal metamorphism under lab conditions. The results show a positive correlation between microwave complex dielectric constant and metamorphic degree and that the magnitude of variation in this parameter is greater than that of H/C,R _max, free radical concentration,d ₀₀₂ value, back-peak temperature in organic DTA and density. Microwave complex dielectric constant can be used as an indicator of oil-gas-generating threshold. For bitumen from oil- generating areas,ε′<5 andε″<0.070; and for that from oil-pyrolyzed gas areas,ε′=5?15 andε″=0.07?0.03.