Systems and methods having pot core antennas for electromagnetic resistivity logging
First Claim
1. An electromagnetic resistivity logging tool having a tool axis, wherein the tool comprises:
- a rotational position sensor;
at least one transmitter antenna and at least one receiver antenna wherein at least one of the transmitter and receiver antennas is a ferrite half-torus antenna; and
a processor to receive at least one of a phase and amplitude measurement for at least one rotational position to determine a formation property.
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0 Petitions
Accused Products
Abstract
Disclosed herein are electromagnetic resistivity logging systems and methods that employ magnetic dipole antennas embedded in wall-contacting surfaces. In some embodiments, the antennas are pot-core or ferrite-rod antennas. Prototypes of electromagnetic resistivity logging tools having such antennas exhibit good resistivity logging performance in both water-based and oil-based borehole fluids, indicating that this architecture may yield a logging tool that is suitable for use with borehole fluids of all types. Moreover, the tool offers good spatial resolution, enabling the creation of formation resistivity images for the borehole walls.
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Citations
18 Claims
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1. An electromagnetic resistivity logging tool having a tool axis, wherein the tool comprises:
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a rotational position sensor; at least one transmitter antenna and at least one receiver antenna wherein at least one of the transmitter and receiver antennas is a ferrite half-torus antenna; and a processor to receive at least one of a phase and amplitude measurement for at least one rotational position to determine a formation property. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An electromagnetic resistivity logging method comprising:
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moving a logging while drilling (LWD) tool in a borehole in a formation; sending an electromagnetic signal from at least one transmitter antenna into the formation; receiving an electromagnetic signal from the formation with at least one receiver antenna, wherein at least one of the transmitter and receiver antennas is a ferrite half-torus antenna; determining a formation property log based at least in part on the received electromagnetic signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification