Apparatus and method for determination of subsurface permittivity and conductivity
US4185238A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 21, 1977 |
| Grant date | Jan 22, 1980 |
| Priority date | — |
| Expiry date | Sep 21, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The disclosure is directed to an apparatus and method for determining dielectric constant and/or conductivity of earth formations surrounding a borehole. Electromagnetic energy is generated at a first location in the borehole. The relative attenuation of the electromagnetic energy is detected at a second location in the borehole. The detection is preferably performed using a first or "close" differential receiver arrangement. The relative phase of the electromagnetic energy is detected at a third location in the borehole, the third location being spaced farther from the first location than is the second location; in other words, the second location is between the first and third locations. The relative phase shift of the electromagnetic energy is measured by a second or "far" differential receiver arrangement located at the third location in the borehole. Means are provided for determining the dielectric constant and/or the conductivity of the formations as a function of the detected relative attenuation and relative phase. The dielectric constant and/or conductivity are determined with improved accuracy as compared to prior art techniques, since the attenuation and relative phase …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.