The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 15, 1995
Filed:
Apr. 16, 1993
Louis H Rorden, Incline Village, NV (US);
Baker Hughes Incorporated, Houston, TX (US);
Abstract
The present invention relates to a method and apparatus for measuring current resulting from a magnetic field source (i.e., a transmitter) positioned on a drill collar. A plurality of current detectors are carried on the surface of the drill collar in an insulated relationship thereto. Each of the detectors is positioned to detect the value of current being received by the same from the formation. In this connection, the detectors are positioned at differing longitudinally displaced positions relative to the axis of the drill collar and the transmitting antenna(s), whereby each detects a different value of current. These currents will respectively flow through successively deeper layers of the formation. The longitudinal displacement is directly proportional to the depth of investigation, whereby the depth of investigation is many times the longitudinal distance between the current detector and the corresponding transmitting antenna. This set of measurements then produces an estimate of the resistivity profile of the formation adjacent the borehole.