Logging Tool Ferrites and Methods of Manufacture
AssigneeHalliburton Energy Services, Inc.
InventorMatthew Chase Griffing
Life of this patent
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Abstract
A method of fabricating a ferrite for use in a resistivity logging tool includes mixing a ferrite powder with a binder to provide a mixture, and pressing the mixture into a mold to form the ferrite. The mold exhibits a specific geometry corresponding to a channel defined on an inner surface of a bobbin associated with the resistivity logging tool, and the channel is arcuate and extends at an angle offset from a central axis of the bobbin. At least one of a length, a width, and a thickness of the ferrite is then adjusted to manipulate a magnetic permeability of the ferrite in a direction of a magnetic field passing through the ferrite.
Claims21
-10. (canceled)
A resistivity logging tool, comprising:
- a tool mandrel;
- a bobbin positioned about the tool mandrel and having a cylindrical body that provides an inner surface and an outer surface, wherein a plurality of channels are defined on the inner surface and laterally adjacent channels are separated by a divider extending radially inward from the inner surface;
- a coil winding wrapped about the outer surface of the body at an angle offset from a central axis of the body;
- and
- a plurality of ferrites received within the plurality of channels and interposing the coil winding and the tool mandrel, wherein the dividers prevent physical contact between laterally adjacent ferrites and each ferrite conforms to a geometry of a corresponding one of the plurality of channels, and
- wherein at least one of a length, a width, and a thickness of each ferrite is adjusted to manipulate a magnetic permeability of each ferrite in a direction of a magnetic field passing through the ferrite.
A method of fabricating a ferrite for use in a resistivity logging tool, comprising:
- providing a block of magnetic material that exhibits an isotropic magnetic permeability;
- and
- excising the ferrite from the block of magnetic material such that the ferrite exhibits a geometry corresponding to a channel defined on an inner surface of a bobbin associated with the resistivity logging tool, and wherein the channel is arcuate and extends at an angle offset from a central axis of the bobbin.
A resistivity logging tool, comprising:
- a tool mandrel;
- a bobbin positioned about the tool mandrel and having a cylindrical body that provides an inner surface and an outer surface, wherein a plurality of grooves are formed in the outer surface, wherein a plurality of channels are defined on the inner surface and laterally adjacent channels are separated by a divider extending radially inward from the inner surface;
- a coil winding wrapped about the outer surface of the body, wherein the coil winding is received in the plurality of grooves in the outer surface of the body;
- a plurality of ferrites received within the plurality of channels and interposing the coil winding and the tool mandrel, wherein the dividers prevent physical contact between laterally adjacent ferrites and each ferrite is received in a corresponding one of the plurality of channels, wherein each ferrite comprises a ferrite powder and a binder to provide a mixture that is pressed into a mold that exhibits the geometry of the corresponding one of the plurality of channels;
- wherein at least one of a length, a width, and a thickness of each ferrite is selected to enhance a magnetic permeability of each ferrite in a direction of a magnetic field passing through the ferrite.
Dependencies are inferred from the claim text.