Structure for electromagnetic induction well logging apparatus
First Claim
1. An electromagnetic induction logging instrument, comprising:
- an electrically conductive support;
at least one magnetic dipole transmitter antenna disposed at a selected position on the support;
at least one magnetic dipole receiver antenna disposed at a selected position on the support axially spaced apart from the position of the transmitter antenna; and
a magnetically permeable shield disposed between the support and the transmitter and receiver antennas, the shield extending substantially the entire distance between the transmitter and receiver antennas.
1 Assignment
0 Petitions
Accused Products
Abstract
An electromagnetic induction logging instrument is disclosed, which includes an electrically conductive support. At least one magnetic dipole transmitter antenna is disposed on the support. At least one magnetic dipole receiver antenna is disposed on the support and is axially spaced apart from the position of the transmitter antenna. The instrument includes a magnetically permeable shield disposed between the support and the transmitter and receiver. The shield extends substantially the distance between the transmitter and receiver. A measurement while drilling instrument is also disclosed, including an electrically conductive collar, at least one transmitter antenna disposed at a selected position on the collar and at least one receiver antenna disposed on the collar axially spaced apart from the transmitter antenna. A magnetically permeable shield is disposed between the collar, and the transmitter and receiver, and extends substantially the distance between the transmitter and receiver.
110 Citations
47 Claims
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1. An electromagnetic induction logging instrument, comprising:
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an electrically conductive support;
at least one magnetic dipole transmitter antenna disposed at a selected position on the support;
at least one magnetic dipole receiver antenna disposed at a selected position on the support axially spaced apart from the position of the transmitter antenna; and
a magnetically permeable shield disposed between the support and the transmitter and receiver antennas, the shield extending substantially the entire distance between the transmitter and receiver antennas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A measurement while drilling instrument, comprising:
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an electrically conductive drill collar adapted to be coupled within a drill string;
at least one magnetic dipole transmitter antenna disposed at a selected position on the drill collar;
at least one magnetic dipole receiver antenna disposed at a selected position on the drill collar axially spaced apart from the position of the transmitter antenna;
a magnetically permeable shield disposed between the drill collar and the transmitter and receiver antennas, the shield extending substantially the entire distance between the transmitter and receiver antennas;
circuits operatively coupled to the at least one transmitter antenna for passing an alternating current having a selected waveform through the at least one transmitter antenna; and
circuits operatively coupled to the at least one receiver antenna for detecting voltages induced in the at least one receiver antenna. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. An electromagnetic induction logging instrument, comprising:
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a plurality of coupled, spaced apart electrically conductive supports;
at least one magnetic dipole transmitter antenna disposed at a selected position on one of the supports;
at least one magnetic dipole receiver antenna disposed at a selected position on one of the supports and axially spaced apart from the position of the transmitter antenna; and
a magnetically permeable shield disposed on an exterior surface of each of the supports, one of the shields disposed between the transmitter antenna and the one of the supports on which the transmitter is disposed, one of the shields disposed between the receiver antenna and the one of the supports on which the receiver antenna is disposed, the shields extending over substantially the entire exterior of each of the supports. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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Specification