Azimuthally segmented resistivity measuring apparatus and method
US6025722A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1997 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | Mar 7, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An instrument for measuring resistivity of earth formations within azimuthal segments. The instrument includes azimuthally separated measure electrodes placed in contact with the wall of a wellbore penetrating the earth formations. The electrodes are placed in contact with the wall by springs, hydraulics or similar mechanisms. A guard electrode surrounds each measure electrode. The instrument includes a booster current electrode axially spaced apart from the guard electrodes. An insulator axially separates the guard electrodes from the booster electrode. Monitor electrodes are disposed on the exterior of the insulator. A first bucking current circuit is connected to the guard electrodes. The first bucking current constrains the flow of measuring currents from each measure electrode to a path substantially perpendicular to the axis of the instrument. A booster current circuit is connected to the booster electrode. The booster current circuit is controllably operated to maintain substantially zero voltage drop across the monitor electrodes. The instrument includes first measuring current sources each connected to one of the measure electrodes, and circuits for measuring voltage and c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.