Method and apparatus for measuring mud resistivity in a wellbore including a probe having a bottom electrode for propagating a current from and to the bottom electrode in a direction approximately parallel to a longitudinal axis of the probe
US5574371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1996 |
| Grant date | Nov 12, 1996 |
| Priority date | — |
| Expiry date | Jan 31, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A logging apparatus is adapted to be disposed in a mud filled wellbore, and a measurement probe is connected to a bottom of a tool string of the logging apparatus. The measurement probe is adapted for measuring a resistivity of a mud in the mud filled wellbore. The measurement probe includes a bottom electrode disposed on a bottom of the probe when the logging apparatus is disposed in the wellbore, a second electrode, and at least one measurement electrode disposed adjacent the bottom electrode for measuring a voltage potential drop in a region of the mud which is disposed directly below the bottom electrode of the measurement probe when the probe is disposed in the wellbore. When the measurement probe is energized, a current flows in the mud between the bottom electrode and the second electrode. When the current is initially emitted into the mud from the bottom electrode, and when the current is received from the mud in the bottom electrode, the current flows in a direction which is approximately parallel to a longitudinal axis of the logging apparatus tool string. Since the measurement electrode is disposed adjacent the bottom electrode, the measurement electrode measures the vol…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.