Electromagnetic dispersion and sensitivity characteristics of carbonate reservoirs

ABSTRACTThe need to develop a new measurement method for the identification of favorable hydrocarbon-producing zones in carbonate reservoirs is of great importance due to their complex pore structure and lithology. We have evaluated fundamental experimental data acquired from carbonate formation samples in a buried-hill reservoir to demonstrate the magnitude of the complex resistivity (CR) dispersion effect in oil-saturated carbonate rocks and the possibility of identifying hydrocarbon-bearing carbonate sections. Our experimental data set included CR measurements on four carbonate core samples with various degrees of oil saturation, and at each saturation level, CR measurements were acquired in a frequency range between 10 Hz and 100 kHz. The experimental data indicated that the intensity of the CR dispersion effect increased with oil saturation above a specific critical excitation frequency. The experimental spectra of the carbonate samples were fitted with the Debye model and the Cole-Cole model (CCM), ...