Patent ID: 8901933

Claim:
An apparatus for imaging a formation through a substantially non-conductive medium interposed between the apparatus and the formation; the apparatus comprising: a first electrode spaced at a first distance from the formation and configured to inject a first current into the formation; a second electrode recessed from the formation with respect to the first electrode, wherein the second electrode is configured to inject a second current into the formation; processing circuitry for determining a first impedance from said first current and a second impedance from said second current, and taking a difference between the first and the second impedance to determine the complex conductivity of the non-conductive medium, wherein the processing circuitry is suitable for determining conductivity and permittivity of the non-conductive medium based on real and imaginary components of the complex conductivity, using the below relationship: σ=Real(σ*) ∈=Imag(σ*)/ω where σ is the conductivity, ∈ the permittivity.