Abstract: A wall-engaging apparatus for microinductively investigating a characteristic of an earth formation traversed by a borehole comprises an antenna set mounted in an longitudinally elongated body adapted for a sliding engagement with the wall of the borehole. The antenna set includes a transmitter antenna mounted in the body for coupling electromagnetic energy into a formation; a receiver antenna for sensing a signal indicative of the characteristic; and at least one electroquasistatic shield element mounted coaxially with the magnetic dipole axis of the transmitter antenna.
Type:
Grant
Filed:
May 31, 1984
Date of Patent:
April 19, 1988
Assignee:
Schlumberger Technology Corporation
Inventors:
Douglas D. Griffin, Weng C. Chew, Brian Clark, Robert L. Kleinberg