Method, system, and tool for investigating borehole casings
US4794322A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1986 |
| Grant date | Dec 27, 1988 |
| Priority date | — |
| Expiry date | Oct 30, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N17/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Systems, for investigating casings which are fitted into boreholes that traverse earth formations and which are suitable for use in evaluating and/or optimizing the cathodic protection of casings and for finding the location and rate of casing corrosion, generally includes a downhole tool capable of investigating the casing along a measurement control unit located around the surface of the earth formation, and a cable having one end connected to the downhole tool and the other connected to the measurement control unit, with the cable including at least a plurality of first connection lines. The tool invention generally includes at least a first pair of longitudinally spaced electrodes, at least a pair of second connection lines, each of the second connection lines having one end connected to a corresponding one of the electrodes, and relays interposed between the first connection lines and the second connection lines. The relays are arranged such that in a first position, the first connection lines of the cable are short-circuited, and in a second position, the first connection lines are connected to their corresponding second connection lines thereby establishing an electrical con…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.