MODELING OF THE DIELECTRIC LOGGING TOOL AT HIGH FREQUENCIES: APPLICATIONS AND RESULTS.

Abstract

The high-frequency dielectric logging tool is useful in electromagnetic well logging, because, by measuring the dielectric constants of rock formations at high frequencies (1 GHz), the water saturation of rocks can be inferred without knowing the water salinity in the rocks. The results of a theoretical model presented in a previous paper by the author are reported. Use is made of the theoretical model to study the behavior of such a tool across geological sedimentary beds. The effect of using different polarizations on the measurement is considered, along with the standoff and mudcake effects that reflect on the depth of investigation of such a tool. The use of borehole compensation modes in the measurements is also considered. It has been found that the TE polarization is more robust than the TM polarization in terms of mudcake and standoff effects. Also, the standoff effect affects the measurement more severely than the mudcake effect. Shorter receiver spacings give rise to higher resolution in the measurement. Borehole compensation results in a slight loss of resolution, and horns in the logs are removed.