POWER-EFFICIENT TRANSIENT ELECTROMAGNETIC EVALUATION SYSTEM AND METHOD

摘要

A system for performing downhole logging operations includes a power supply for providing a current and a conductor coil electrically coupled to receive the current from the power supply. The system further includes a switch electrically coupled to the power supply for controlling current provided to the conductor coil and enabling a pulse of current to be supplied to the conductor coil for an “on” duration and turning off current provided to the conductor coil for an “off” duration after the “on” duration, in which the “off” duration lasts longer than the “on” duration. The system also includes a permanent magnet coupled to the conductor coil. The conductor coil receives the pulse of current from the power supply during the “on” duration and not receiving current during the “off” duration. The pulse of current causes the permanent magnet to reverse polarity and generate a transient magnetic field.