Patent ID: 8664958

Claim:
An electromagnetic logging apparatus used in investigation of geological formations (GF) surrounding a borehole (WBH), comprising: a logging tool (TL) moveable through the borehole, an electromagnetic probe ( 1 ) comprising a pad ( 2 ) mounted on the logging tool (TL), adapted for engagement with the borehole wall (WBW) by a wall-engaging face of the pad, at least one antenna (Tu, Td) mounted in the wall-engaging face and used as a transmitting antenna, a plurality of spaced antennas (Ru, Rd) mounted in the wall-engaging face and used as receiving antennas positioned in spaced relation to the transmitting antenna (Tu, Td), a transmitter module ( 44 T) adapted for energizing the transmitting antenna to transmit electromagnetic energy into the formations at a determined frequency according to an electric dipole mode and according to a magnetic dipole mode, and a receiver module ( 44 R) adapted for receiving and processing an output signal at each of the receiving antennas representative of electromagnetic energy received from the formations.