Method of compensating laterlog measurements for perturbation of survey voltage by cable armor voltage
US6211679A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 1998 |
| Grant date | Apr 3, 2001 |
| Priority date | — |
| Expiry date | Aug 11, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus are disclosed for correcting erroneous downhole resistivity measurements. In particular, capacitive coupling downhole leads to erroneous resistivity readings. The invention compensates for such coupling by measuring a survey voltage between the resistivity tool voltage and a reference voltage on the wireline cable. A correction voltage is measured between a point on the armor around the wireline cable and the reference voltage. The characteristics of a transmission wireline used at a specific site are measured and are combined with the measured downhole correction voltage and survey voltage to determine more accurately formation resistivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.