Apparatus and method for determining the resistivity of earth formations
US5339037A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 9, 1992 |
| Grant date | Aug 16, 1994 |
| Priority date | — |
| Expiry date | Oct 9, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for determining the resistivity of formations surrounding an earth borehole. An elongated electrically conductive body is movable through the borehole. A first transmitter establishes a first current in the body from a first transmitter position on the body, the first current traveling in a path that includes the body and the formations. An electrode is mounted on the body and has a surface that is electrically isolated from the surface of the body. A first electrical signal, resulting from the first current, is measured at the electrode. A second transmitter establishes a second current in the body from a second transmitter position on the body that is spaced from the first transmitter position, the second current traveling in a path that includes the body and the formations. A second electrical signal, resulting from the second current, is measured at the electrode. A current monitor measures the axial current passing a monitor position on the body to obtain a monitor current value. An indication of formation resistivity is derived as a function of the first electrical signal, the second electrical signal, and the monitor current value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.