Borehole casing diagnostic apparatus and method
US4857831A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1986 |
| Grant date | Aug 15, 1989 |
| Priority date | — |
| Expiry date | Dec 29, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/261
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.