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, 1989
Filed:
Dec. 29, 1986
Dylan H Davies, Tokyo, JP;
Jiro Takeda, Yokohama, JP;
Schlumberger Technology Corporation, New York, NY (US);
Abstract
Apparatus and method for investigating a borehole casing. The preferred apparatus generally comprises: a housing which is connected to a cable; sets of electrodes, each set being axially spaced from another set, with the electrodes in each set being circumferentially spaced at an axial depth; a positioning device provided in the housing for bringing the electrodes into contact with the casing; a measuring circuit provided inside of the housing and electrically connected to the electrodes for measuring at least the potential difference of the casing between the electrode locations, wherein the potential difference information is amplified by the measuring circuit, and the amplified information is transmitted through the cable for processing; and a control circuit provided in the housing for controlling the operation of the positioning device and the measuring circuit. Preferably, a digitizing circuit is provided so that the amplified information is digitized before it is transmitted to the surface and processed.