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:
Nov. 20, 1979
Filed:
Apr. 20, 1978
Richard N Chandler, Danbury, CT (US);
Abstract
A nuclear magnetism logging system and method is disclosed in which a surface unit provides power to, control of, and signal reception from a downhole sonde. The surface unit comprises a source of alternating current power and switching circuit means for applying a sequence of alternating current waveforms from the alternating current power source to a surface transformer, each waveform in the sequence starting and stopping with substantially zero amplitude. The switching circuit means memorizes the starting and stopping polarity of the immediately preceding waveform in the sequence, and starts and stops the present waveform in the sequence of waveforms with polarities opposite that of the memorized starting and stopping polarities of the immediately preceding waveform in the sequence. The downhole sonde of the system has a transformer, the primary coil of which is electrically connected to the secondary coil of the surface transformer. A rectifier circuit is connected to a polarizing-receiving coil during the polarizing time of the polarizing-receive cycle. A receiving amplifier is connected to the polarizing-receiving coil during the receiving time of the polarizing-receive cycle. Receiver and recording circuits in the surface unit receive and record the downhole signals from the receiving amplifier. Timing circuitry controls a downhole switching circuit means for alternating the connection of the polarizing-receive coil to the rectifier and the receiving amplifier.