Induction logging sensor
First Claim
1. An apparatus, comprising:
- an electromagnetic sensor comprising a plurality of sectors,wherein the plurality of sectors comprises a plurality of circumferentially extended sectors collectively configured in a substantially cylindrical shape with a separating gap between adjacent ones of the plurality of sectors, the separating gap separating the adjacent ones of the plurality of sectors in a circumferential direction,wherein each of the plurality of sectors comprises a magnetic core formed of a material having a high initial magnetic permeability, the material comprising at least one of a nano-magnetic material, a nano-magnetic ribbon material, a nano-crystalline material, an amorphous ribbon, or a non-ferrite material, andwherein at least one of the plurality of sectors comprises (a) two coils disposed on respective portions of the magnetic core thereof, and (b) a shield disposed between respective portions of the two coils, the respective portions of the two coils both facing a region radially exterior of the respective sector.
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Accused Products
Abstract
Apparatuses and methods are provided herein that may improve sensitivity to transient signals. For example, an electromagnetic sensor for downhole measurements that includes a plurality of sectors (e.g., four quadrants) is provided herein. Each quadrant may include a magnetic core formed of a material with a high initial magnetic permeability to improve sensitivity to transient signals. A sensor for continuous wave induction tools is also provided, and may include a magnetic core formed of a material with a high initial magnetic permeability. Forming each sector magnetic core of a material with a high mechanical reliability may allow the magnetic core of the corresponding sensor to be pliable and flexible and not brittle and prone to breaking. Furthermore, the corresponding sensor may have enhanced sensitivity, greater stability of sensitivity relative to temperature changes, and high mechanical reliability.
25 Citations
18 Claims
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1. An apparatus, comprising:
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an electromagnetic sensor comprising a plurality of sectors, wherein the plurality of sectors comprises a plurality of circumferentially extended sectors collectively configured in a substantially cylindrical shape with a separating gap between adjacent ones of the plurality of sectors, the separating gap separating the adjacent ones of the plurality of sectors in a circumferential direction, wherein each of the plurality of sectors comprises a magnetic core formed of a material having a high initial magnetic permeability, the material comprising at least one of a nano-magnetic material, a nano-magnetic ribbon material, a nano-crystalline material, an amorphous ribbon, or a non-ferrite material, and wherein at least one of the plurality of sectors comprises (a) two coils disposed on respective portions of the magnetic core thereof, and (b) a shield disposed between respective portions of the two coils, the respective portions of the two coils both facing a region radially exterior of the respective sector. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of manufacturing an electromagnetic sensor, comprising:
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creating a plurality of sectors, (i) wherein the plurality of sectors comprises a plurality of circumferentially extended sectors collectively configured in a substantially cylindrical shape with a separating gap between adjacent ones of the plurality of sectors, the separating gap separating the adjacent ones of the plurality of sectors in a circumferential direction, and (ii) wherein each of the plurality of sectors comprises a magnetic core formed from at least one layer of a material having a high initial magnetic permeability, the material comprising at least one of a nano-magnetic material, a nano-magnetic ribbon material, a nano-crystalline material, an amorphous ribbon, or a non-ferrite material; and disposing (a) two coils on respective portions of the magnetic core of at least one of the plurality of sectors, and (b) a shield between respective portions of the two coils, the respective portions of the two coils both facing a region radially exterior of the respective sector. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method, comprising:
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providing a logging tool comprising a sensor, the sensor comprising a plurality of sectors, (i) wherein the plurality of sectors comprises a plurality of circumferentially extended sectors collectively configured in a substantially cylindrical shape with a separating gap between adjacent ones of the plurality of sectors, the separating gap separating the adjacent ones of the plurality of sectors in a circumferential direction, (ii) wherein each of the plurality of sectors comprises a magnetic core formed of a material having a high initial magnetic permeability, the material comprising at least one of a nano-magnetic material, a nano-magnetic ribbon material, a nano-crystalline material, an amorphous ribbon, or a non-ferrite material, and (iii) wherein at least one of the plurality of sectors comprises (a) two coils disposed on respective portions of the magnetic core thereof, and (b) a shield disposed between respective portions of the two coils, the respective portions of the two coils both facing a region radially exterior of the respective sector; disposing the logging tool within a wellbore; and performing a transient induction measurement using the logging tool. - View Dependent Claims (15, 16, 17, 18)
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Specification