Azimuthally oriented coil array for MWD resistivity logging
US5045795A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1990 |
| Grant date | Sep 3, 1991 |
| Priority date | — |
| Expiry date | Jul 10, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A coil array which is installed on a MWD drill collar for use in a resistivity logging system. The drill collar is provided with upper and lower coil support rings. These are toroids which support individual coil segments, and are connected by suitable magnetic shorting bars. The coil segments and shorting bars inscribe a specified solid angle or azimuthal extent. By connecting the outputs of the several coils through a combining circuit, the coils on a single coil form can be connected in series additive, or subtractive relationship. Through the use of two such coil forms with aligned coils on each, an azimuthally oriented window is thereby defined. By proper switching multiple azimuthally oriented windows can be made operative so that there is an azimuthal orientation to the current flow pattern relative to the MWD resistivity logging tool.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.