Microdevice for measuring the electromagnetic characteristics of a medium including a shield
First Claim
1. A microdevice for logging a medium in a bore hole comprising a transmitting coil and two receiving coils, an E-shaped, electrically insulating, soft magnetic material circuit adjacent the medium and having a median portion and three lateral branches perpendicular to said median portion and parallel to one another, the coils being wound onto said lateral branches in such a way that the receiving coils are located on adjacent lateral branches, said microdevice also comprising means for forming a shield between the transmitting coil and an area lacking interest in the medium.
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Accused Products
Abstract
A microdevice is provided for measuring the electromagnetic characteristics of a medium in a borehole. The microdevice includes at least one emitting or transmitting coil (31), and at least one receiving coil (41,51). The microdevice generates an A.C. voltage at the terminals of the transmitting coil and measures a signal at the terminals of the receiving coil. The microdevice also includes an E-shaped electrically insulating, soft magnetic material circuit serving as a support for each of the coils and which is positioned adjacent to the medium in the borehole.
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Citations
33 Claims
- 1. A microdevice for logging a medium in a bore hole comprising a transmitting coil and two receiving coils, an E-shaped, electrically insulating, soft magnetic material circuit adjacent the medium and having a median portion and three lateral branches perpendicular to said median portion and parallel to one another, the coils being wound onto said lateral branches in such a way that the receiving coils are located on adjacent lateral branches, said microdevice also comprising means for forming a shield between the transmitting coil and an area lacking interest in the medium.
- 12. A microdevice for logging a medium in a borehole comprising a transmitting coil and two receiving coils, a second transmitting coil, an electrically insulating, soft magnetic material circuit serving as a support for each of the coils and which is adjacent the medium and which has a median portion and four lateral, parallel branches perpendicular to the median portion, said microdevice also comprising means for forming a shield between at least one transmitting coil and an area without interest in the medium.
- 21. A device comprising a central support for carrying a plurality of microdevices for logging a medium in a borehole, each of said microdevices including a transmitting coil and two receiving coils, an E-shaped, electrically insulating soft magnetic material circuit adjacent the medium and having a median portion and three lateral branches perpendicular to said median portion and parallel to one another, the coils being wound onto said lateral branches in such a way that the receiving coils are located on adjacent lateral branches, each of said microdevices also including means for forming a shield between the transmitting coil and an area lacking interest in the medium.
- 24. A device comprising a central support for carrying a plurality of microdevices for logging a medium in a borehole, each of said microdevices including a transmitting coil and two receiving coils, a second transmitting coil, an electrically insulating, soft magnetic-material circuit serving as a support for each of the coils and which is adjacent the medium and which has a median portion and four lateral, parallel branches perpendicular to the median portion, each of said microdevices also including means for forming a shield between at least one transmitting coil and an area without interest in the medium.
Specification