0648342-A1 is referenced by 2 patents and cites 6 patents.

A calibration fixture for an MWD logging tool consists of a plurality of concentric co-planar conductive calibration loops (22, 24), mounted on a carrier disk of insulate material (16). The disk positions the calibration loops around the logging tool mandrel coaxially. The logging tool supports conventional transmitter(s) and receiver(s). The calibration loops are terminated with a multiple-tap impedance quantizer (34) for discretely varying the impedance of the calibration loops. When a transmitter is activated to emit an electromagnetic signal, the calibration loops are excited to re-radiate a portion of that signal into the receivers with an intensity that is a function of the loop impedance thereby to simulate the effects of formations having known resistivities.

Method and apparatus for calibrating an mwd electromagnetic logger.
Application Number
EP19930916960 19930702
Publication Number
0648342 (A1)
Application Date
July 2, 1993
Publication Date
April 19, 1995
Zhou Qiang
Western Atlas Int
G01V 13/00
G01V 13/00
G01V 03/18
G01V 13/00
G01V 03/28
View Original Source Download PDF