Dielectric Dispersion Responses for Clay-Bearing Rocks Based on Digital Cores and Numerical Simulation

The dielectric response of clay-bearing rocks is complex, which seriously affects the evaluation of oil saturation. This paper introduces the dual-Debye model to characterize the dielectric dispersion characteristics of pore water and the Debye model to establish the dielectric dispersion characteristics of water-absorbing clay minerals. A dielectric dispersion simulation method is established to study dielectric dispersion characteristics of 12 clay-bearing digital cores of the publicly available Berea sandstones. The results show that the numerical simulation method is perfectly verified by using a pure clay-bearing rock, and the established method can effectively characterize the dielectric dispersion phenomenon of clay-rich sandstones. The clay content has a strong influence on the dielectric dispersion characteristics of clay-bearing rocks. The higher the clay content, the stronger the dielectric dispersion, and the contribution of pore water also needs to be considered. It is also crucial to consider the dielectric dispersion anisotropy related to the distribution of rock components, which will be beneficial for the saturation evaluation of clay-bearing reservoirs based on dielectric dispersion.