Method and apparatus for determining the conductivity of subsurface earth formations by filtering and summing in-phase and quadrature conductivity signals with correction values
US5146167A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 1991 |
| Grant date | Sep 8, 1992 |
| Priority date | — |
| Expiry date | May 30, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved induction well logging processing technique for determining conductivity measurements of subsurface earth strata. An in-phase conductivity signal and a quadrature conductivity signal are obtained from a downhole induction logging tool. The in-phase conductivity signal and the cubed square root of the in-phase conductivity signal are filtered by a first filter and a second filter, respectively. The outputs of the filters may be summed to provide a first conductivity signal having reduced environmental effects and indicating the conductivity of the earth formation under test. Additionally, the in-phase conductivity signal and the quadrature signal may be filtered and summed to provide a second conductivity signal. A weighted average of the first and second conductivity signals may be used as an indication of the earth formation conductivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.