Method and apparatus for measuring azimuthal as well as longitudinal waves in a formation traversed by a borehole
US5168234A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 1990 |
| Grant date | Dec 1, 1992 |
| Priority date | — |
| Expiry date | Sep 7, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A new type of microwave azimuthal wave propagation, never before known to exist, provides the basis for a new formation evaluation measurement for Electromagnetic Wave Propagation Tools (EPT). Although prior art tools measure longitudinally propagated waves which propagate in the formation along the direction of the longitudinal axis in the borehole, the newly discovered azimuthal waves propagate in the formation around the borehole. The new azimuthal waves propagate around the borehole like planewaves except for a spreading loss which is independent of the properties of the media. Measurements of phase shifts and attenuation between azimuthally spaced receivers determine formation azimuthal microwave dielectric properties. A new antenna configuration and a new method for determining azimuthal microwave dielectric properties is disclosed in this specification, the antenna configuration alternatingly measuring both longitudinal and azimuthl waves propagation thereby providing a new measurement with extremely high vertical resolution as compared to the resolution obtained by measuring longitudinal waves using prior art EPT tools.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.