Well logging method and apparatus for determining downhole Borehole fluid resistivity, borehole diameter, and borehole corrected formation resistivity
US5900733A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1997 |
| Grant date | May 4, 1999 |
| Priority date | — |
| Expiry date | Jan 29, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A well logging method and apparatus are disclosed for determining borehole corrected formation resistivity, borehole diameter, and downhole borehole fluid (mud) resistivity with improved accuracy. A logging device in the borehole transmits electromagnetic energy from a transmitter, which energy is received at receivers on the logging device. The phase and amplitude of the received energy are measured at the receivers and a phase shift, phase average, and attenuation are associated with the transmitter-to-receivers spacing. The process is then repeated for a plurality of further transmitters having different spacings from the receivers. A formation and borehole model having model values of borehole corrected formation resistivity, borehole diameter, and borehole fluid resistivity is generated. Values of borehole corrected formation resistivity, borehole diameter, and borehole fluid resistivity that would produce a model phase shift, phase average and attenuation corresponding to the measured values of these parameters are then determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.