Patent ID: 8035392

Claim:
An apparatus for use in a borehole in an earth formation, comprising: a conducting tubular; at least one transmitter on said conducting tubular for propagating an electromagnetic field in the earth formation; at least one receiver on said conducting tubular for receiving a transient signal resulting from interaction of said electromagnetic field with said earth formation; each of said at least one transmitter and said at least one receiver having a separate localized magnetostatic shielded region associated therewith; each of said at least one transmitter and said at least one receiver having a separate localized electromagnetic shielded region associated therewith; and processing circuitry for determining a bucking coefficient and for determining from said transient signal and said bucking coefficient a resistivity measurement of said earth formation, wherein said bucking coefficient K(t) is computed according to K ( t )= C 1 ( t )/ C 2 ( t ) where C 1 (t) and C 2 (t) comprise signals received at said at least one receiver in response to transmission of an electromagnetic pulse from said at least one transmitter while said apparatus is outside of said earth formation.