Complex Resistivity Measurement and Inversion for Carbonate Hydrocarbon Reservoir

It’s of great need for geophysicist to develop a new measuring method for identification of the favorable hydrocarbon producing zones in carbonate reservoir, due to the complex pore structure and lithology. This study provides the fundamental experimental data acquired from carbonate core samples in a buried-hill reservoir, in order to demonstrate the magnitude of complex resistivity (CR) dispersion effect in oil saturated carbonate rocks and the possibility of identifying the hydrocarbon bearing carbonate sections. Our experimental data set includes CR measurements of two carbonate core samples with various oil saturations, and at each saturation level, CR measurements were acquired in frequency range between 10 Hz and 100 kHz. The experimental data show that the intensity of CR dispersion effect increases with oil saturation above a specific critical excited frequency. The experimental spectra of the carbonate samples have been fitted with the Debye model and the Cole-Cole model, which can be used for the interpretation of dispersion effect over a wide frequency range. Our experimental data and fitting result indicate that, measurement of CR dispersion effect can be an effective means in identifying carbonate hydrocarbon reservoir and evaluating the formation saturation quantitatively on favorable conditions.