Experimental Study on the Relationship Among Complex Resistivity, Water Saturation, and Salinity in the Jiaozuo Anthracite Reservoir.

In order to investigate the electrical response characteristics of anthracite coal reservoirs and their correlation with water saturation, salinity, and porosity, the complex resistivity of Zhaogu No. 2 mine anthracite coal was measured across a frequency range of 1 Hz to 100 kHz. The experimental findings indicate that as water saturation, salinity, and porosity increase, the amplitude of both the real and imaginary components of the complex resistance of the coal sample gradually decreases, leading to a decrease in the dispersion degree and an increase in the interface polarization frequency. By analyzing the experimental data and studying the polarization mechanism of coal in a sodium chloride solution, this study proposed an enhanced model that integrates the aspects of the Cole-Cole model and the Warburg model to overcome the limitations of the traditional first-order model, which can fit only single-peak curves. The second-order series Cole-Cole model not only delves into microscopic mechanisms underlying the low-frequency polarization effect of coal samples but also provides a highly accurate fit for complex resistivity dispersion curves under varying conditions. This research offers both an experimental foundation and a theoretical framework for leveraging the electrical properties of anthracite coal reservoirs in assessing the pore structure and permeability of coal seams.