Patent ID: 6809521
Filing Date: 2004-10-26
Classification: G01V

Abstract:
An apparatus for use in a borehole for obtaining a resistivity parameter of an earth formation penetrated by the borehole, the borehole having a substantially nonconducting fluid having a dielectric constant therein, the apparatus comprising:(a) a downhole tool including at least one measure electrode coupled to the earth formation through said nonconducting fluid, said at least one measure electrode conveying a measure current from a source thereof into the formation, said measure current having a frequency selected to make an impedance caused by said dielectric constant to be substantially less than a resistivity of said nonconductive fluid, said frequency being further selected to make an impedance caused by a dielectric constant of said formation to be substantially less than a resistivity of said formation; (b) a device responsive to least one of (I) the current in the at least one measure electrode, and, (ii) a voltage of the at least one measure electrode for producing a measure signal representative of the resistivity parameter.