ELECTROMAGNETIC RESISTIVITY INSTRUMENT HAVING LOOK AHEAD CAPABILITY

摘要

An electromagnetic well logging instrument is disclosed which includes at least one transmitter antenna oriented to have at least some magnetic dipole moment component transverse to an axis of the instrument. The instrument includes at least two receiver antennas oriented to have at least some magnetic dipole moment component transverse to the axis and parallel to the magnetic dipole moment component of the at least one transmitter antenna. The at leas t two receiver antennas are axially spaced apart from the transmitter antenna s~o that a response of the instrument to the transverse magnetic dipole moment component is axially substantially on one side of a more distant spaced one of the at least two receiver antennas.