The Effect of Water Saturation and Salinity on Dielectric Constant Using Laboratory Wideband Measurement Method

The array dielectric tool (ADT) can be used in situations where the formation water resistivity is variable or unknown. However, few laboratory measurements of the dielectric dispersion properties at wide frequencies (20 MHz–1 GHz) have been reported to date, which hinders our understanding of the petrophysical mechanisms. In this study, we introduce the dielectric constant measurements of a sweep frequency in the range of 20–1000 MHz based on the parallel-disk capacitor method. In order to control the variables, artificial rocks were manufactured from glass beads. The relationships between the rock dielectric constant and the frequency, saturation, salinity were investigated in the MHz to GHz range. It is shown that the frequency, water saturation, salinity control the dielectric dispersion of rocks. The dielectric constant is found to have a power law dependence on the frequency and a linear dependency between the rock's dielectric constant and the saturation is observed experimentally. Additionally, the dielectric constant increases with increasing salinity.