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:
Jun. 18, 1985
Filed:
Sep. 30, 1982
Robert A Moore, Houston, TX (US);
Edward P Karisch, Houston, TX (US);
Halliburton Company, Duncan, OK (US);
Abstract
In a dual guard type resistivity logging apparatus, the improvement having the preferred and illustrated form of a short guard electrode pair for making shallow resistivity measurements in a formation is disclosed; a long guard electrode pair is also incorporated for making deep resistivity measurements. The long and short guard pairs are driven by separate oscillators operating at the same frequency or at different frequencies. An electronic switch driven at a low frequency selectively connects the current emitting electrodes to a current return electrode for both long and short guard pair electrodes. The electronic switch empowers one measuring system to operate while the other is inoperative. The switching frequency at is typically of 20-40 Hertz. This enables both measuring systems to provide essentially continuous data in light of the dynamics of the use of such a log, and yet furnishes the two formation current signals wherein the operation of one resistivity measuring system does not interfere with the other resistivity system. A single electrode is used as the return current electrode, and a single voltage reference electrode on the tool is a reference electrode for voltage measurements by both measurement systems.