ELECTROMAGNETIC FORMATION EVALUATION TOOL APPARATUS AND METHOD

摘要

Apparatus and methods are described, such as for obtaining information indicative of a formation resistivity using an electromagnetic formation evaluation tool apparatus. For example, the electromagnetic formation evaluation tool apparatus includes exciter electrodes configured to transmit and receive a formation current. A first exciter electrode may be insulated from a conductive apparatus housing and a second exciter electrode may be coupled to the conductive apparatus housing. Monitor electrodes may be insulated from the conductive apparatus housing. A receiver circuit may be coupled to the monitor electrodes and configured to measure a voltage differential between the monitor electrodes. A power amplifier circuit may be coupled to the first exciter electrode and the conductive apparatus housing and configured to generate the formation current wherein the conductive apparatus housing provides a return path to the power amplifier circuit for the formation current.

主权项

1. An electromagnetic formation evaluation tool apparatus comprising:
a plurality of exciter electrodes configured to transmit and receive formation currents, the plurality of exciter electrodes comprising:
a first exciter electrode insulated from a conductive apparatus housing that is insulated from a borehole environment; anda second exciter electrode coupled to the conductive apparatus housing; a plurality of monitor electrodes insulated from the conductive apparatus housing; a receiver circuit coupled to the plurality of monitor electrodes and configured to measure a voltage differential between the plurality of monitor electrodes; and a power amplifier circuit coupled to the first exciter electrode and the conductive apparatus housing and configured to generate the formation current, wherein the conductive apparatus housing provides a return path to the power amplifier circuit for the formation current.