Method and apparatus for borehole wall resistivity imaging with full circumferential coverage
US9709692B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 2008 |
| Grant date | Jul 18, 2017 |
| Priority date | — |
| Expiry date | Dec 1, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A logging tool for performing resistivity measurements on the sidewall of a borehole in an earth formation is provided with a circumferential series of evenly-spaced measurement electrodes providing complete circumferential coverage of resistivity measurements. In one embodiment, the measurement electrodes are carried on a conductive pad circumferentially surrounding an elongate mandrel or tubular. The conductive pad is held at a voltage adapted to focus measurement current into the sidewall of the borehole. Preferably, the pad has dimensions relative to the measurement electrodes and a standoff distance between the measurement electrodes and said borehole wall to effectively focus the measurement current into the borehole wall. In accordance with one aspect of the invention, the measurement electrodes are spaced apart by a distance that is less than the width of each measurement electrode, thereby ensuring full circumferential resolution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.