Method and apparatus for making induction measurements through casing
US5038107A · kind A · utility
56Cited by
13References
27Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1989 |
| Grant date | Aug 6, 1991 |
| Priority date | — |
| Expiry date | Dec 21, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
High resolution induction logs (28) are obtained through borehole casing (15) by magnetically saturating the casing (15), logging with a tool (10) having different transmitter (35a, 35b)-to-receiver (40) coil spacings, and determining the formation (30) conductivities as a function of the coil spacings, coil frequency, and phase difference between the signals at these spacings. The logging is preferably done at an intermediate frequency which gives good resolution but is little affected by the saturated casing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.