Patent ID: 8237444
Filing Date: 2012-08-07
Classification: G01V

Abstract:
1. An apparatus for investigating a geological formation surrounding a borehole, comprising: a logging tool moveable through the borehole, an electromagnetic probe comprising a pad mounted on the logging tool for engagement with the borehole by a wall-engaging face of the pad, at least one pair of transmitting antennas, each pair of the at least one pair of transmitting antennas comprises a first antenna and a second antenna mounted in the wall-engaging face, a plurality of spaced receiving antennas mounted in the wall-engaging face spaced in relation to the at least one pair of transmitting antennas, and wherein each of the antennas is an open-ended antenna forming a substantially pure electric dipole normal to the pad face, and wherein the first transmitting antenna of the at least one pair of transmitting antennas is positioned above the plurality of spaced receiving antennas and the second transmitting antenna of the at least one pair of transmitting antennas is positioned below the plurality of spaced receiving antennas.