Transient electromagnetic tool mounted on reduced conductivity tubular
US9482777B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 2014 |
| Grant date | Nov 1, 2016 |
| Priority date | — |
| Expiry date | May 25, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Systems, devices, and methods for evaluating an earth formation. Apparatus may include a carrier configured for conveyance in a borehole including a conducting tubular comprising a reduced conductivity portion made of reduced conductivity material adjacent at least one of (i) at least one transmitter antenna, and (ii) at least one receiver antenna on the carrier. The material may be a composite and may have a resistivity of between 10−4 and 102 ohm-meters. Methods and apparatus may be configured for producing time-dependent transient electromagnetic (TEM) signals using the transmitter(s) and receiver(s) and estimating a value of a resistivity property using the signals. The apparatus may be used in drilling and may include a bottom hole assembly with a drill bit, and the value may be indicative of a portion of the earth formation ahead of the bit. The value may be used to conduct further operations in a borehole, including geosteering.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.