US4808929A — Shielded induction sensor for well logging

Claim 1

Independent Claim 136 words

An induction sensor adapted for use in a well logging system, comprising: a support member; a sensor conductor coiled coaxially around said support member; a plurality of shielding conductors coiled essentially orthogonally around the support member and the sensor conductor, each of said shielding conductors having ends and being angularly spaced from each other, said shielding conductors collectively defining at their ends a nonconducting gap, said gap being disposed coaxially around said support member and orthogonally to each of said shielding conductors thereby creating in each shielding conductor less than a complete three hundred sixty degree loop about the support member; means disposed within said gap for firmly holding the ends of each of said shielding conductors; and a ground wire disposed coaxially about said support member and electrically connected to each of said shielding conductors.

Claim 2

Dependent Claim 136 words

An induction sensor adapted for use in a well logging system, comprising: a support member; a sensor conductor coiled coaxially around said support member; a plurality of shielding conductors coiled essentially orthogonally around the support member and the sensor conductor, each of said shielding conductors having ends and being angularly spaced from each other, said shielding conductors collectively defining at their ends a nonconducting gap, said gap being disposed coaxially around said support member and orthogonally to each of said shielding conductors thereby creating in each shielding conductor less than a complete three hundred sixty degree loop about the support member; means disposed within said gap for firmly holding the ends of each of said shielding conductors; and a ground wire disposed coaxially about said support member and electrically connected to each of said shielding conductors.

Claim 3

Dependent Claim 34 words

The induction sensor of claim 1 wherein said support member has a cross-section shape, said cross-section shape being an outwardly facing "U" shape, said sensor conductor being coiled in the bight of the "U".

Claim 4

Dependent Claim 35 words

The induction sensor of claim 1 wherein said support member has a cross-section shape, said cross-section shape being generally rectangular and having a central opening therein, said sensor conductor being coiled within said central opening.

Claim 5

Dependent Claim 45 words

The induction sensor of claim 1 wherein said gap defined by the shielding conductors comprises a circular cut, the means for holding comprising a ring of elastomeric material disposed in said cut, the elastomeric material firmly holding the ends of each of said shielding conductors.

Claim 6

Dependent Claim 35 words

The induction sensor of claim 1 wherein the ends of said ground wire defines a gap thereby creating in said ground wire less than a three hundred sixty degree loop coaxially about said support member.

Claim 7

Dependent Claim 30 words

The induction sensor of claim 1 wherein the diameter of said shielding conductors is smaller than a skin depth at a frequency of operation selected for said well logging system.

Claim 8

Dependent Claim 126 words

A shielded coil adapted for use in a well logging apparatus, comprising: a support member disposed coaxially about an axis, said member having a cross sectional shape which defines a hollow space at the interior of the cross-section; a conductor coil disposed in said hollow space and wound coaxially around said support member; a shield wrapped essentially orthogonally around said support member and said conductor coil thereby enveloping said support member and said conductor coil, said shield being cut at its ends thereby defining a groove disposed substantially coaxially about said axis; means disposed in said groove for firmly holding the ends of said shield thereby preventing said shield from un-wrapping about said support member; and grounding means connected to said shield for grounding said shield.

Claim 9

Dependent Claim 126 words

A shielded coil adapted for use in a well logging apparatus, comprising: a support member disposed coaxially about an axis, said member having a cross sectional shape which defines a hollow space at the interior of the cross-section; a conductor coil disposed in said hollow space and wound coaxially around said support member; a shield wrapped essentially orthogonally around said support member and said conductor coil thereby enveloping said support member and said conductor coil, said shield being cut at its ends thereby defining a groove disposed substantially coaxially about said axis; means disposed in said groove for firmly holding the ends of said shield thereby preventing said shield from un-wrapping about said support member; and grounding means connected to said shield for grounding said shield.

Claim 10

Dependent Claim 48 words

The coil of claim 7 wherein the grounding means comprises a ground wire disposed coaxially about said support member, the wire having ends, the ends defining an electrical gap thereby creating in said ground wire less than a three hundred sixty degree loop coaxially about said support member.

Claim 11

Dependent Claim 28 words

The coil of claim 8 wherein the diameter of the shield is smaller than a skin depth at a frequency of operation selected for said well logging apparatus.

Claim 12

Dependent Claim 28 words

The coil of claim 7 wherein the shield is separated from the conductor coil by a wall of said support member thereby minimizing shield to conductor coil capacitance.

Claim 13

Dependent Claim 100 words

A shielded coil adapted for use in a well logging system, comprising: a conductor coil having outside, bottom, top and interior surfaces; a plurality of grounded shielding conductors disposed essentially orthogonally to said conductor coil about said outside, bottom, top and interior surfaces thereof, each of said plurality of shielding conductors being interrupted at its ends thereby defining a gap between said ends; and means disposed in said gap and connected to the ends of said shielding conductors from firmly holding the ends of each of said shielding conductors, whereby said shielding conductors cannot unwrap from about said conductor coil.

Claim 14

Dependent Claim 100 words

A shielded coil adapted for use in a well logging system, comprising: a conductor coil having outside, bottom, top and interior surfaces; a plurality of grounded shielding conductors disposed essentially orthogonally to said conductor coil about said outside, bottom, top and interior surfaces thereof, each of said plurality of shielding conductors being interrupted at its ends thereby defining a gap between said ends; and means disposed in said gap and connected to the ends of said shielding conductors from firmly holding the ends of each of said shielding conductors, whereby said shielding conductors cannot unwrap from about said conductor coil.

Claim 15

Dependent Claim 24 words

A shielded coil of claim 11 wherein said shielding conductors extend essentially as a three hundred and sixty degree loop about the conductor coil.

Claim 16

Dependent Claim 24 words

A shielded coil of claim 11 wherein said shielding conductors are angularly spaced from each other about the respective surfaces of said conductor coil.

Claim 17

Dependent Claim 35 words

A shielded coil of claim 11 wherein said conductors have a diameter that is smaller than a skin depth defined by a frequency of operation selected for the alternating current flowing in said conductor coil.

Claim 18

Dependent Claim 90 words

An induction sensor adapted for use in a well logging system, comprising, a conductor coil having outside, bottom, top and interior surfaces; a shield disposed about said outside, bottom, top and interior surfaces of said conductor coil, the disposition of said shield about said conductor coil defining a groove which is coincident with said conductor coil, said shield having ends; and means disposed in said groove for firmly holding in place the ends of said shield, whereby said shield cannot easily be removed from the surfaces of said conductor coil.

Claim 19

Dependent Claim 90 words

An induction sensor adapted for use in a well logging system, comprising, a conductor coil having outside, bottom, top and interior surfaces; a shield disposed about said outside, bottom, top and interior surfaces of said conductor coil, the disposition of said shield about said conductor coil defining a groove which is coincident with said conductor coil, said shield having ends; and means disposed in said groove for firmly holding in place the ends of said shield, whereby said shield cannot easily be removed from the surfaces of said conductor coil.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-02-28	1992-08-29	1993-02-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-02-28	1996-08-29	1997-02-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-02-28	2000-08-29	2001-02-28	$7700.00	Window Closed / Lapsed

Shielded induction sensor for well logging

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