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:
Apr. 05, 1988
Filed:
Sep. 07, 1984
Wade M Johnson, Jr, Cypress, TX (US);
Western Atlas International, Inc., Houston, TX (US);
Abstract
In apparatus for investigating earth formations traversed by a borehole, improved methods and apparatus are provided for performing inductive type formation measurements. A transmitter coil of a well logging tool moving through a borehole emits an alternating field into the adjacent earth formation thus inducing eddy currents therein. A voltage in a receiver coil in the tool is sampled at discrete elevations as the tool traverses the borehole and amplified. This voltage is phase detected with respect to the transmitter coil voltage to insure that the measured receiver voltage corresponds to the currents induced in the formation. An average of these voltage measurements is formed. Variations in the magnitude of the average phase-detected voltage are used to discretely control the amplitude of the alternating current induced into the formation.