Logging apparatus for measurement of earth formation resistivity
US5191290A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1990 |
| Grant date | Mar 2, 1993 |
| Priority date | — |
| Expiry date | Oct 29, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A logging apparatus for measurement of earth formation resistivity is disclosed. The apparatus includes an elongated sonde having an insulated section and an electrically isolated conductive pad mounted for lateral extension into contact with a borehole wall. The electrically isolated conductive pad includes a plurality of current electrodes disposed longitudinally along the pad and a return electrode disposed on the reverse face thereof. A focussing section is utilized to provide varying depths of investigation by electrode current to preferably permit measurement of earth formation resistivity in the mudcake, flush zone, and uninvaded formation. In a preferred embodiment of the present invention, the conductive pad includes a pair of hingeably mounted sections which permit the apparatus to accommodate varying radii of curvature of boreholes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.