Our goal is 2-fold. Firstly, we re-assess the benefits of the extra information that dielectric measurements bring about, using different methodologies in different contexts which include Water Based Mud as well as Oil Based Mud drilling environments. Secondly, we propose a practical method for Shaly Sands. Several methods have blossomed for interpreting the Electromagnetic Propagation Tool (EPT*) measurements. Some of them have been extensively and routinely applied in the field under different labels. Yet they stem from the same propagation model of the 1.1 GHz signal transmitted by the EPT antenna through the formation. Some confusion has arisen which we are trying to alleviate. In this paper, all the interpretation methods implemented in the various examples, make full use of the Attenuation measurement along with the Phase Shift measurement. Up-to-date characterisation of the dielectric properties of a brine, in terms of its salinity and temperature, permits the simultaneous computation of the water-filled porosity and of the effective resistivity of this water from the two EPT measurements only. The DC micro-resistivity (Rxo) measurement can then be used to derive an estimate of the cementation exponent, a vital parameter to interpret the virgin zone resistivity in terms of water saturation. The natural relaxation frequency of bound water is much closer to 1.1 GHz than that of free water. Thus in shaly formation the contribution to Attenuation from dipolar losses is not negligible and in very fresh water environment, it may even be the main effect. In order to obtain a more direct measurement of shaliness and CEC, the attenuation due to conductivity must be corrected. This is done, in a semi-empirical way, by a cross-plot of the two EPT measurements. The method has been tried successfully in very thinly laminated shaly sands.

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