System for measuring earth formation resistivity through and electrically conductive wellbore casing
US6975121B2 · kind B2 · utility
13Cited by
25References
50Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 22, 2004 |
| Grant date | Dec 13, 2005 |
| Priority date | — |
| Expiry date | Jun 3, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus is disclosed for measuring formation resistivity through a conductive pipe in a wellbore. The apparatus includes a sonde adapted to be moved through the wellbore, and a plurality of voltage measurement electrodes are disposed on the sonde at spaced apart locations. At least one current source electrode is disposed on the sonde. All the electrodes are adapted to make electrical contact with the pipe. The apparatus includes a digital voltage measuring circuit controllably coupled to selected ones of the voltage measurement electrodes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.