Dielektriztätsmessungen in oil-based mud with imaging scanning tool

A downhole Sensing method comprising the steps of: Generating an oscillating electric field in the wall of a borehole in a formation, wherein at least two current electrodes of a sensor array can be used, wherein the well is filled with a non-conductive fluid; Measuring the phase and magnitude of a voltage difference with at least two voltage electrodes which are arranged between the at least two current electrodes; and Using the measured phase and magnitude of the voltage difference and the magnitude of the current to determine a value for the dielectric constant, which is linked to the position in the wall of the borehole, and Generating an image of the borehole wall from a plurality of such values ​​for the permittivity.