Apparatus for locating an elongated conductive body by electromagnetic measurement while drilling
US4933640A · kind A · utility
246Cited by
26References
28Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 30, 1988 |
| Grant date | Jun 12, 1990 |
| Priority date | — |
| Expiry date | Dec 30, 2008 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/0228
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for determining the distance and direction of a well from a borehole. A toroidal inductor surrounds a drill stem within a borehole. The inductor acts as a primary for a transformer, with the drill stem, the earth surrounding the borehole, and electrically conductive material at the target well forming a single loop transformer secondary. An oscillator is connected to the primary to produce an induced AC current in the secondary. Secondary current flowing in the target well produces an AC secondary magnetic field which is detected at the borehole.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.