Determining formation anisotropy based in part on lateral current flow measurements
US7227363B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Oct 1, 2004 |
| Grant date | Jun 5, 2007 |
| Priority date | — |
| Expiry date | Jun 30, 2025 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B49/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed herein are methods and apparatus using one or more toroids to measure formation anisotropy and/or vertical conductivity. In one embodiment, a disclosed method comprises: inducing a current to flow through a conductive surface of a tool body into a surrounding formation; measuring a lateral portion of the current flow; and calculating an anisotropy coefficient from the apparent conductivity so measured. The lateral current flow may be that portion of the current flowing through the tool body surface between two predetermined, axially spaced, circumferences of the tool. In an alternative embodiment, a disclosed logging tool comprises: a substantially cylindrical and conductive tool body, a toroidal transmitter, and a current measuring means. The current measuring means is configured to measure that portion of an induced current that radiates through a predetermined surface of the tool into the formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.