Permanent apparatus for monitoring a well by injecting current through the casing into the formations
US7151377B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2002 |
| Grant date | Dec 19, 2006 |
| Priority date | — |
| Expiry date | Oct 8, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/20
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Apparatus for monitoring an underground formation through which a borehole passes, comprises a conductive casing (6) located in the borehole (1) passing through the formation (4); a plurality of sensors (12-1) for measuring an electrical property of the formation (4) located in the borehole (1) outside the casing (6) and electrically insulated therefrom; and an electrical current source (11) positioned in the borehole (1) passing through the formation (4) and arranged to inject a current into the formation (4); the casing (6) having an electrically insulating coating (14) over the surface thereof, at least in the region of the sensors (12-1), and an electrically conductive portion (11) in electrical contact with the formation (4); and a current supply (10) being connected to the casing (6) such that current flows into the formation (4) from the electrically conductive portion (11) which acts as the current source, the sensors (12-1) measuring the electrical property of the formation (4) resulting from such current flow.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.