EP2947261A1 - Inductor and method for heating a geological formation - Google Patents

Abstract

The invention relates to an inductor (1) for heating a geological formation, in particular a deposit (100) of a hydrocarbonaceous substance, for example an oil sands, oil shale or heavy oil deposit, by means of electromagnetic induction, in particular for recovering the hydrocarbonaceous substance from the deposit (100). , The inductor (1) comprising at least one conductor (2), wherein the conductor (2) has at least one interruption point (4), wherein at least at one end region (6) of the conductor (2) at the point of interruption (4) a rounded conductive body (40) is applied. In particular, a single wire can be interrupted and connected to the rounded conductive body (40). Preferably, a sleeve may be used which comprises the rounded conductive body. The invention further relates to an operating method and a manufacturing method for the inductor.

Description

For in-situ production of hydrocarbons from an underground reservoir, for example for the production of heavy oils, heavy oils or bitumen from oil sands or oil shale deposits, it is necessary to achieve the greatest possible flowability of the hydrocarbons to be pumped. One way to improve the fluidity of hydrocarbons in their production is to increase the temperature prevailing in the reservoir.

One method used to increase the temperature of the deposit is to inductive heating by means of an inductor which is introduced into the deposit (i.e., into the soil). By means of the inductor eddy currents are induced in electrically conductive deposits (also called reservoir) by forming electromagnetic fields, which heat the deposit, so that there is thus an improvement in the fluidity of the hydrocarbons present in the deposit. In this case, eddy currents are induced in particular in the pore water of the deposit, which has an electrical conductivity due to salts dissolved therein. The heat transfer from the water to the hydrocarbon takes place by heat conduction.

In order to achieve a sufficient heat to the required temperature increase in the vicinity of the inductor, typically large AC amperages of some 100 A are necessary because the reservoir surrounding the inductor is usually only slightly electrically conductive. Operating the inductor at a high AC current results in a high inductive voltage drop across the inductor, with the inductive voltage drop being on the order of a few hundred kV. Such high voltages can only be achieved difficult to handle practically, so that it is expedient to compensate for them.

A compensation of the inductive voltage drop is, as in the patent DE 10 2007 040 605 described, for example, by capacitors connected in series allows (reactive power compensation). In the solution presented there, the current-carrying conductors of the inductor are interrupted to form the capacitors and thus have a plurality of interruption points.

In the series connection of capacitors may be disadvantageous that the interruption point can form weak points of the inductor. At the points of interruption, for example, partial discharges could occur in the event of a fault. Due to the inaccessibility of a deeply introduced into the deposit inductor are particularly high demands on the reliability of the inductor to make. In particular, a continuous and maintenance-free operation over ten to twenty years is desired. In case of failure of a capacitor of the inductor due to the series connection of the capacitors, the entire inductor would be inoperative and would have to be replaced.

The present invention is therefore an object of the invention to improve the reliability of an inductor.

The object is achieved by an inductor having the features of independent claim 1 and by an operating method having the features of independent claim 12, and by a manufacturing method having the features of independent claims 13 and 14, respectively. In the dependent patent claims advantageous refinements and developments of the invention are given.

The invention relates to an inductor for heating a geological formation, in particular a deposit of a hydrocarbonaceous substance, for example a Oil sand, oil shale or heavy oil deposit, by means of electromagnetic induction, in particular for recovering the hydrocarbonaceous substance from the deposit, comprising at least one conductor, wherein the conductor has at least one point of interruption, characterized in that at least at one end portion of the conductor at the point of interruption a rounded conductive body is applied.

Preferably, both end portions of a broken conductor are formed at the point of interruption as described above.

The application of a rounded conductive body according to the invention is understood in particular as the contacting of the rounded conductive body with the end region of the conductor. In this case, the rounded conductive body is a separate element. It is not merely a deformation of the end portion of the conductor.

The inductor is a conductor. The conductor is preferably made cable-like from a plurality of electrically insulated individual wires. It can be obtained with repeated attachment of interruption points on the inductor according to the invention, an electrical series resonant circuit, wherein the design is preferably such that a resonance frequency in the range of about 10 kHz to 200 kHz is obtained, which also represents the preferred operating frequency of the inductor. The inductor is preferably driven by a generator which is operated at least with the aforementioned frequency range.

The interruption point according to the invention is used to form capacitively acting conductor sections (in the sense of capacitors). This is done by the capacitive coupling of adjacent conductor groups over a defined conductor length - for example 10 to 50m - for reactive power compensation. The capacitances are preferably in series arranged. In the case of a series connection, if one capacitor fails, the complete inductor would become inoperative depending on the fault. This problem is inventively reduced in that a partial discharge strength of isolated individual wire ends is increased against adjacent continuous wires and the opposite end of the wire.

A further advantage according to the invention is that sharp edges, which would otherwise lead to a field strength increase (increase in the electric field strength) at the point of interruption, are avoided by means of the embodiment according to the invention. Advantageously, by avoiding field strength spikes that can lead to destruction of the insulating layer at the point of interruption over the duration of the continuous operation of the inductor and consequently failure of the inductor, the reliability of the inductor is further improved.

An embodiment of the invention is directed to providing each individual wire - a wire - which is preferably individually insulated, with such an interruption point. Each wire preferably has such break points at repeating intervals. This embodiment is advantageous if a wire for an inductor is prepared in a first step and only then, together with a sequence of interruption points, is stranded with further wires.

Another embodiment of the invention is directed to providing a bundle of wires, the wires preferably being individually insulated, with such an interruption point. At a position in the inductor, all the wires in a bundle are broken, not just a wire. The break points are made over the length of the inductor at repeated intervals. This embodiment is advantageous if already completely stranded cable is present without interruption points and to achieve an inductor in a subsequent step, in which a bundle of wires on the cable is repeatedly severed at certain points.

In one embodiment of the invention, the rounded conductive body may comprise a hemispherical surface or a continuously curved collar-shaped surface.

In a further embodiment, the conductor can be made up of a plurality, preferably individually - i. individually insulated wires. Wire ends of the end portion of the conductor may be connected to the rounded conductive body by means of compression and / or crimping and / or soldering and / or welding and / or electrically conductive bonding.

Furthermore, the conductor may consist of a single wire. A variety of conductors can form the inductor.

Furthermore, the rounded conductive body may be formed at one end as a sleeve. The end portion of the conductor may be inserted into the sleeve.

In particular, the sleeve may have a blind bore or through bore into which the end region of the conductor is inserted into the sleeve.

Preferably, a mechanical connection between the sleeve and the end region of the conductor by means of pressing and / or crimping and / or soldering and / or welding and / or electrically conductive adhesion can take place.

In one embodiment, a further rounded conductive body can be applied to a further end region of the conductor at the point of interruption. An insulating spacer may be positioned between the rounded conductive body and the further rounded conductive body.

Furthermore, the insulating spacer may have a surface portion configured such that the surface portion of the insulating spacer is mechanically and preferably positively connected to a surface portion of the rounded conductive body.

Further, the insulating spacer may be configured and surface shapes of the insulating spacer may be engaged in surface shapes of the rounded conductive body and surface shapes of the further rounded conductive body such that the rounded conductive body and in the other rounded conductive body to each other without offset and at a predetermined distance be fixed.

Preferably, a mechanical connection between the rounded conductive body and the insulating spacer by means of pressing and / or crimping and / or soldering and / or welding and / or gluing done.

Furthermore, the rounded conductive body and the further rounded conductive body and the insulating spacer may be inserted into a hollow cylindrical further sleeve, wherein the further sleeve is formed as an insulator or as a conductive sleeve.

Wires of another conductor can be guided by the material of the formed as an insulator further sleeve.

Preferably, wires of another conductor may be conductively connected to the material of the conductive sleeve.

The inductor may further comprise at least two conductor bundles, wherein a first of the two conductor bundles may comprise at least the first conductor and a second conductor and a second of the two conductor bundles may comprise at least a third conductor and a fourth conductor, wherein a first hollow cylindrical sleeve with a second hollow cylindrical Sleeve is integrally formed such that a jacket body of the first hollow cylindrical sleeve and a jacket body of the second hollow cylindrical sleeve are united together for a section. It thus creates a sleeve which corresponds in cross section to the shape of the number 8.

• ein Mantelkörper der ersten hohlzylindrischen Hülse und ein Mantelkörper der zweiten hohlzylindrischen Hülse für einen ersten Abschnitt miteinander vereint sind, und
• der Mantelkörper der ersten hohlzylindrischen Hülse und ein Mantelkörper der dritten hohlzylindrischen Hülse für einen zweiten Abschnitt miteinander vereint sind, und
• der Mantelkörper der zweiten hohlzylindrischen Hülse und der Mantelkörper der dritten hohlzylindrischen Hülse für einen dritten Abschnitt miteinander vereint sind.

Es entsteht auf diese Weise eine besonders kompaktes Hülsenelement aus drei hohlen Zylindern.In addition, the inductor may comprise at least three conductor bundles. A first of the three conductor bundles may comprise at least the first conductor and a second conductor. A second of the three conductor bundles may comprise at least a third conductor and a fourth conductor. A third of the three conductor bundles may comprise at least a fifth conductor and a sixth conductor. A first hollow cylindrical sleeve may be formed in one piece with a second hollow cylindrical sleeve and with a third hollow cylindrical sleeve such that:

• a sheath body of the first hollow cylindrical sleeve and a sheath body of the second hollow cylindrical sleeve are united together for a first portion, and
• the sheath body of the first hollow cylindrical sleeve and a sheath body of the third hollow cylindrical sheath for a second portion are united together, and
• the sheath body of the second hollow cylindrical sleeve and the sheath body of the third hollow cylindrical sheath are united together for a third section.

This results in a particularly compact sleeve member of three hollow cylinders.

In a development of the invention, the point of interruption of the conductor and conductor sections adjoining the point of interruption and components provided at the point of interruption may be enclosed by a sleeve.

Preferably, the inductor can be formed as a multifilament conductor. In particular, the conductor may form a conductor or a wire of the multifilament conductor.

With a plurality of conductors each having an interruption point, the respective interruption points of the conductors may have a mutual offset along a longitudinal extent of the inductor.

Preferably, the conductors may form an interlaced and / or stranded structure extending along the length of the inductor.

The invention further relates to an operating method for heating a geological formation, in particular a deposit of a hydrocarbonaceous substance, for example an oil sands, oil shale or heavy oil deposit, by means of electromagnetic induction, in particular for recovering the hydrocarbonaceous substance from the deposit, in which one in the geological formation arranged inductor with at least one conductor is driven such that an electromagnetic field is formed in the geological formation, to which the conductor has at least one point of interruption, wherein at least at one end portion of the conductor at the point of interruption, a rounded conductive body is applied.

Preferably, the conductor can be energized with alternating current, preferably with a frequency in the range of 10 kHz to 200 kHz.

The hemispherical design of the ends advantageously sharp edges or corners that may arise in the manufacture of the point of interruption, for example, by the separation of the conductor with a cutting tool compensated. The partial discharge strength at the point of interruption of the conductor is further improved. This is because the hemispherical flat and / or smooth configuration of the end prevents field strength peaks, such as occur with edged shapes. Preferably, both ends of the interruption point are configured hemispherical.

An embodiment of the end region in which the radii of curvature are greater than or equal to a radius of the cross section (cross-sectional radius) of the conductor is preferred.

As a result, field strength peaks are further reduced, so that the partial discharge resistance of the conductor at the point of interruption is additionally increased.

According to an advantageous embodiment of the invention, the conductor forms a conductor of a multifilament conductor.

In this case, it is provided that, in particular, all conductors of the multifilament conductor have an interruption point whose end regions are designed according to the invention. By designing a multifilament conductor comprising a plurality of conductors with end regions according to the invention, a particularly advantageous inductor for inductive heating is made possible. Here, the filaments of the multifilament conductor are formed by the plurality of conductors. Preferably, a multifilament conductor comprises a plurality of at least 10 and at most 5000 conductors. As a result, the heating power of the inductor is advantageously increased.

According to an advantageous embodiment of the invention, the point of interruption of the conductor is enclosed by an electrically insulating sleeve.

The sleeve serves for the mechanical, frictional connection of the two ends of the conductor, which ends are formed by the point of interruption of the conductor. Here, the sleeve is expediently designed to avoid a short circuit at the point of interruption electrically insulating. Preferably, a molded from insulating and / or insulating plastic sleeve which encloses both ends of the point of interruption. Here, a sleeve is provided, the outer diameter is substantially larger than the diameter of the cross section of the conductor.

Sleeve in the sense of the invention is an electrically insulating sealing element. It can be a molded sleeve, which results when a mold is ejected. It has an insulating effect and gives mechanical stability.

A sleeve is in the present case a connecting element and in particular also an insulation and / or protective elements. The sleeve is preferably fixed to the inserted cable. It encloses an interruption point. Conceivable are designs as Gießharzmuffen, Gelmuffen, shrink sleeves - heat shrink or Kaltschrumpfmuffen.

An inductor having a plurality of conductors is preferred, wherein the interruption points of the conductors of a conductor group have a mutual offset along a longitudinal axis of the inductor. The offset is preferably small compared to the distance to the adjacent break points of the second conductor group.

As a result, an inductor is advantageously formed whose individual conductors are capacitively coupled to each other. Due to the series connection of the capacitors, which is formed by the capacitively coupled conductors, the reactive power of the inductor is advantageously reduced and / or approximately compensated in the case of resonance.

Particularly preferred is in inductor of a plurality of conductors, wherein the conductors extend in parallel along the longitudinal axis of the inductor.

Advantageously, an approximately constant capacitance between the conductors is made possible by the parallel course of the conductors, so that there is a uniform and equally distributed load on the conductors of the inductor.

According to an advantageous embodiment of the invention, the conductors form an interlaced and / or stranded structure which extends along the longitudinal axis of the inductor.

As a result, a cable arrangement of the conductors of the inductor is advantageously made possible, which is mechanically stabilized by an entanglement and / or stranding on the one hand and on the other hand is particularly suitable for the formation of capacitances between the individual conductors.

According to an advantageous embodiment of the invention, the conductor is energized with an alternating current. If the conductor corresponds to a conductor group, the conductor group is supplied with an alternating current.

Advantageously, all conductor groups of the inductor are supplied with alternating current.

As a result, advantageously formed by the inductance of the conductor and the capacitances, which is formed by the point of interruption and by means of adjacent conductors, an electrical resonant circuit having a resonant frequency specific to the resonant circuit. Advantageously, the formation of a resonant circuit, in particular in the resonance of the resonant circuit, reduces the reactive power which must be made available for the operation of the inductor. Here, the offset of the break points, which offset periodically continues along the conductor or inductor, corresponds to the resonant length of the inductor.

It is expedient to energize with an alternating current whose frequency is in the range of 10 kHz to 200 kHz.

• Bereitstellen des Kabels mit mindestens zwei miteinander verdrillte Leiterbündeln;
• Aufspreizen eines ersten der zwei Leiterbündeln an der longitudinalen Position des Kabels;
• Trennen aller Drähte eines zweiten der zwei Leiterbündel an der longitudinalen Position des Kabels;
• Entisolieren von Kabelenden der durchtrennten Drähte;
• Verbinden von abgerundeten leitender Körpern jeweils auf ein jeweiliges entisoliertes Kabelende;
• Einfügen eines jeweiligen Abstandshalters zwischen Paaren von abgerundeten leitender Körpern;
• optional das Einbringen einer hohlzylinderförmigen Hülse, wobei Drähte des ersten Leiterbündels in einer Mantelfläche der Hülse geführt werden;
• optional das Anbringen einer Muffenform, Ausspritzen der Muffenform zu einer Muffe, wobei die Muffe die Hülse und die abgerundeten leitenden Körpern und einen Abschnitt der zwei Leiterbündel umschließt, und das Entfernen der Muffenform.

Here, advantageously, the resonant frequency of the resonant circuit is in the range of 10 kHz to 200 kHz. Moreover, the invention relates to a method for producing an inductor for heating a geological formation, in particular a storage of a hydrocarbonaceous substance, for example an oil sand, oil shale or heavy oil deposit, by means of electromagnetic induction, comprising the following manufacturing steps for at least one longitudinal position of a cable:

• Providing the cable with at least two interconnected conductor bundles;
• Spreading a first of the two conductor bundles at the longitudinal position of the cable;
• Separating all the wires of a second of the two conductor bundles at the longitudinal position of the cable;
• De-insulation of cable ends of the severed wires;
• Connecting rounded conductive bodies respectively to a respective uninsulated cable end;
• Inserting a respective spacer between pairs of rounded conductive bodies;
• Optionally, the introduction of a hollow cylindrical sleeve, wherein wires of the first conductor bundle are guided in a lateral surface of the sleeve;
• optionally, attaching a socket mold, ejecting the socket form into a sleeve, the socket enclosing the sleeve and the rounded conductive bodies and a portion of the two conductor bundles, and removing the socket form.

1. a) Durchführen der nachfolgenden Bearbeitungsschritte für mindestens eine longitudinale Position eines Drahts:
   • Bereitstellen des, vorzugsweise isolierten, Drahts;
   • Trennen des Drahts an der longitudinalen Position des Drahts;
   • Entisolieren von beiden Kabelenden des durchtrennten Drahts;
   • Verbinden von abgerundeten leitenden Körpern jeweils auf ein jeweiliges entisoliertes Kabelende;
   • Einfügen eines jeweiligen Abstandshalters zwischen Paaren von abgerundeten leitender Körpern ;
   • optional das Anbringen einer Muffenform, Ausspritzen der Muffenform zu einer Muffe, wobei die Muffe die abgerundeten leitenden Körper und zwei Endbereiche des aufgetrennten Drahts umschließt, und das Entfernen der Muffenform;
2. b) Aufwickeln des bearbeiteten Drahts und/oder Verseilen einer Vielzahl derartig bearbeiteter Drähte zu einem Induktor.

Alternatively, the invention relates to a further production method for an inductor for heating a geological formation, in particular a deposit of a hydrocarbonaceous substance, for example an oil sand, oil shale or heavy oil deposit, by means of electromagnetic induction, comprising the following production steps:

1. a) performing the following processing steps for at least one longitudinal position of a wire:
   • Providing the, preferably insulated, wire;
   • Separating the wire at the longitudinal position of the wire;
   • Stripping from both cable ends of the severed wire;
   • Connecting rounded conductive bodies respectively to a respective uninsulated cable end;
   • Inserting a respective spacer between pairs of rounded conductive bodies;
   • optionally attaching a socket mold, ejecting the socket form into a socket, the socket enclosing the rounded conductive bodies and two end portions of the severed wire, and removing the socket form;
2. b) winding the processed wire and / or stranding a plurality of such processed wires to an inductor.

In the above method, preferably, the rounded conductive bodies are first connected to the respective uninsulated cable ends. Subsequently, the respective spacers are inserted between pairs of rounded conductive bodies.

Alternatively, these last-mentioned steps may be reversed so as to provide first an already connected unit consisting of a spacer and a pair of rounded conductive bodies connected thereto. This unit is preferably already positively connected to each other. Subsequently, this unit can be connected to the two stripped cable ends. b) winding the processed wire and / or stranding a plurality of such processed wires to an inductor.

• Aufschieben von Hülsen an die jeweiligen Kabelenden, wobei die Hülsen jeweils die abgerundeten leitenden Körper umfassen;
• Kraftschlüssiges Verbinden, insbesondere Crimpen, der jeweiligen Hülse mit dem jeweiligen entisolierten Kabelende.

The manufacturing method may be preferably implemented so that the connection of rounded conductive bodies is carried out in each case on a respective entisoliertes cable end with the following steps:

• Pushing sleeves onto the respective cable ends, the sleeves each comprising the rounded conductive bodies;
• Non-positive connection, in particular crimping, the respective sleeve with the respective entisolierten cable end.

• Anordnen mehrerer bearbeiteter Drähte so zueinander, dass mindestens zwei Bündel von Drähten gebildet werden, wobei die Drähte eines ersten der zwei Bündel in longitudinaler Ausrichtung so zueinander ausgerichtet werden, dass Trennstellen der durchtrennten Drähte des ersten Bündels weitgehend nebenander zu liegen kommen und die Drähte eines zweiten der zwei Bündel in longitudinaler Ausrichtung so zueinander ausgerichtet werden, dass Trennstellen der durchtrennten Drähte des zweiten Bündels weitgehend nebenander zu liegen kommen, wobei die Trennstellen des ersten Bündels zu den Trennstellen des zweiten Bündels zueinander versetzt angeordnet werden;
• Verseilen der derart angeordneten Drähte derart, dass die Drähte des erste Bündels und des zweiten Bündels abwechselnd zueinander verseilt werden.

In addition, the above-mentioned stranding of a plurality of such processed wires to an inductor can be carried out by the following steps:

• Arranging a plurality of processed wires to each other such that at least two bundles of wires are formed, wherein the wires of a first of the two bundles are aligned in longitudinal alignment with each other so that separation points of the severed wires of the first bundle are substantially juxtaposed and the wires of a second the two bundles are aligned in longitudinal alignment with each other so that separation points of the severed wires of the second bundle are largely adjacent to each other, wherein the separation points of the first bundle to the separation points of the second bundle are offset from each other;
• Stranding the wires thus arranged so that the wires of the first bundle and the second bundle are alternately stranded with each other.

Figur 1

eines Induktor-Abschnitts, der einen Leiter mit kugelförmigen Abschlüssen einer Unterbrechungsstelle aufweist, nach einem ersten Herstellungsschritt;

Figur 2

eine Schnittzeichnung der Figur 1 mit einem Abstandshalter, nach einem zweiten Herstellungsschritt;

Figur 3

eine Schnittzeichnung der Figur 2 mit einem zusätzlichen hohlzylindrischen umgebenden Isolationskörper, nach einem dritten Herstellungsschritt;

Figur 4

eine dreidimensionale Darstellung der Figur 3;

Figur 5

eine dreidimensionale Darstellung der Figur 2 mit einem zusätzlichen hohlzylindrischen umgebenden Isolationskörper, nach einem alternativen dritten Herstellungsschritt;

Figur 6

eine Darstellung von drei Leiterabschnitten mit jeweilig angebrachten zusätzlichen hohlzylindrischen umgebenden Isolationskörpern, die Teil des gemeinsamen Induktors sind;

Figur 7

eine Darstellung einer alternativen Ausgestaltung von drei Leiterabschnitten mit jeweilig angebrachten zusätzlichen hohlzylindrischen umgebenden Isolationskörpern, die Teil des gemeinsamen Induktors sind;

Figur 8

schematische Darstellung eines Induktor-Abschnitts, der zwei Multifilamentleiter umfasst;

Figur 9

eine Schnittzeichnung eines alternativen Induktor-Abschnitts, bei dem eine Unterbrechungsstelle über zwei Hülsen, einen Abstandshalter und einer Muffe mechanisch verbunden wird;

Figur 10

eine Schnittzeichnung eines weiteren alternativen Induktor-Abschnitts, bei dem eine Unterbrechungsstelle über zwei alternativ gestaltete Hülsen, einen daran angepassten Abstandshalter und einer Muffe mechanisch verbunden wird;

Figur 11

eine schematische Darstellung einer perspektivischen Ansicht eines Induktor in einer Lagerstätte.

Further advantages, features and details of the invention will become apparent from the embodiments described below and with reference to the drawings. This show in a schematic representation:

FIG. 1

an inductor portion having a conductor with spherical terminations of an interruption point after a first manufacturing step;

FIG. 2

a sectional drawing of FIG. 1 with a spacer, after a second manufacturing step;

FIG. 3

a sectional drawing of FIG. 2 with an additional hollow cylindrical surrounding insulating body, after a third manufacturing step;

FIG. 4

a three-dimensional representation of the FIG. 3 ;

FIG. 5

a three-dimensional representation of the FIG. 2 with an additional hollow cylindrical surrounding insulating body, according to an alternative third manufacturing step;

FIG. 6

a representation of three conductor sections with each attached additional hollow cylindrical surrounding insulating bodies, which are part of the common inductor;

FIG. 7

a representation of an alternative embodiment of three conductor sections with each attached additional hollow cylindrical surrounding insulating bodies, which are part of the common inductor;

FIG. 8

schematic representation of an inductor portion comprising two multifilament conductors;

FIG. 9

a sectional view of an alternative inductor section, in which a point of interruption is mechanically connected via two sleeves, a spacer and a sleeve;

FIG. 10

a cross-sectional view of another alternative inductor section, in which a point of interruption on two alternatively shaped sleeves, a matched spacer and a sleeve is mechanically connected;

FIG. 11

a schematic representation of a perspective view of an inductor in a deposit.

Similar elements may be provided in the figures with the same reference numerals.

The figures relate to an inductor 1 for the exploitation of oil sand and heavy oil deposits, which is intended to effect a heating of a deposit in order to improve the flowability of the hydrocarbons to be delivered in situ. The proposed electromagnetic heating method is also called inductive heating, in which one or more conductor loops are introduced into the deposit, which are energized with alternating current. Thereafter, eddy currents will induce in the electrically conductive deposit, which will then heat the deposit. The conductors are cable-like according to the present invention, preferably made of a plurality of electrically insulated individual wires.

Half of the individual wires are interrupted alternately and at defined intervals. Thus, the electric current is forced to penetrate the single core insulation as a displacement current. The cable inductor - inductor 1 - thus acts in sections as a capacitance whereby the unavoidable inductance of the conductor arrangement can be specifically compensated for a frequency. The conductor loop with the intermittent interrupts electrically acts as a series resonant circuit which, at its resonant frequency, has no reactance, i. without reactive power, can be operated.

The embodiment of interruption points in the cable inductor discussed below has the advantage that sharp-edged wire ends can be avoided. Since particularly high electric field strengths can occur at sharp-edged wire ends, it is advantageous to avoid such embodiments.

The FIGS. 1 to 7 relate to an embodiment in which a conductor according to the invention of a plurality of individual wires consists. All of these individual wires belonging to a conductor are separated at an interruption point.

FIG. 1 shows a section of an inductor 1, wherein the inductor 1 includes a conductor 2 with a point of interruption 4. In the embodiment shown, the inductor 1 is thus formed by means of the conductor 2 and other conductors, not shown, with a plurality of identically designed conductors for the inductor 1, for example, for adjusting the resonance frequency, is preferred. To form a suitable capacitance, a second conductor, which runs largely parallel to the conductor 2 (not shown in FIG FIG. 1 , however, clarifies in FIG. 4 ) intended. Here, the second conductor (in FIGS. 3 and 4 marked with reference numeral 3) have a comparison with the conductor 2 staggered interruption point 4, wherein the offset continues periodically and corresponds to the resonance length.

At the point of interruption 4, the conductor 2 has two end regions 6, on each of which a rounded conductive body 40 and 40 'is applied. The rounded conductive bodies 40 form ends of the conductive cable-shaped structure.

The rounded conductive bodies 40, 40 'are according to FIG FIG. 1 formed hemispherical or three-quarters spherical, with the curves of the two rounded conductive body 40, 40 'are opposite to each other and have a distance and thus are not in contact. Due to the hemispherical configuration or design of the ends, field strength peaks at the ends and consequently at the point of interruption 4 are avoided, so that the partial discharge strength at the point of interruption 4 is thereby increased.

According to FIG. 1 Several twisted wires form the conductor 2.

The extending along a longitudinal axis A conductor 2 is preferably surrounded by an insulating layer (not shown), which surrounds the conductor 2. Individual wires are also preferably provided with an individual insulating layer.

The rounded conductive bodies 40, 40 'are each solid bodies which are conductive. Metals or metallic alloys are particularly suitable as material.

The rounded conductive bodies 40, 40 'may be referred to as electrodes. They are preferably massive bodies and / or solids. The rounding takes place in the same direction that would otherwise show the severed cable end.

Ends of the individual wires are connected to the respective rounded conductive body 40 or 40 ', in particular to a back side of the rounded conductive bodies 40 and 40', which in turn can form a flat surface. The mechanical and conductive connection of the wires to a respective rounded conductive body 40, 40 'may be by soldering, welding, crimping or other bonding technique. A penetration of a wire end into the back of a rounded conductive body 40, 40 'to achieve a solid and conductive connection is, for example, in FIG. 2 indicated.

The rounded conductive body 40, 40 'in operation have the same electrical potential as the conductor. 2

The rounded conductive body 40 (or also 40 ') can also be considered as an electrode of a capacitance. According to FIG. 1 are paired spherical electrodes in all or at least several wire ends brought together and electrically connected. This avoids sharp-edged wire ends and the resulting high electric field strengths at these sharp-edged wire ends to the partial discharges would ignite preferred.

A positive and positive pairwise fixation of the rounded conductive body 40, 40 'may be provided. This is in FIG. 2 illustrated in a sectional drawing. There, an insulating body is shown as insulating spacer 32. This is preferably made of ceramic and / or mineral and / or plastic-based material. It includes a pair of rounded conductive bodies 40, 40 'at least partially. The surface shape of a portion of the insulating spacer 32 is adapted to the surface shape of one of the rounded conductive bodies 40, 40 '. Preferably - as in FIG. 2 1, the insulating spacer 32 comprises two mutually opposite recesses, into each of which a rounded conductive body 40, 40 'can at least partially be inserted.

In this case, the insulating spacer 32 may be a solid that has been prepared in advance and that is only connected to the rounded conductive bodies 40, 40 '. Alternatively, the insulating spacer 32 can also be applied by means of spraying and / or filling in liquid form, wherein the material then hardens. An application of the insulating spacer 32 (also called insulating layer) on the surface of the conductor 2 can be effected by means of extrusion.

The insulating spacer 32, which may be preferably ceramic or mineral or plastic based, comprises the electrodes, maintaining them at a defined distance, centering them relative to the continuous conductor pattern (in FIG FIGS. 1 and 2 not shown, but in FIG. 3 ) and thus ensures a defined E field distribution without large field peaks (ie low relative peak values).

The rounded conductive body 40, 40 'together with the insulating spacer 32 at the same time enable a mechanical and electrical strength of the insulation at the point of interruption 4 of the conductor 2.

The rounded conductive body 40 or 40 'according to the invention prior to assembly, a separate element or a separate body which / which only by joining to the conductor 2 forms a unit. The rounded conductive body 40 or 40 'is in particular not just the cable end of a severed conductor.

FIG. 1, 2 , and 3 may be understood as illustrating the inductor 1 in various sequential manufacturing steps.

FIG. 3 illustrates in a sectional drawing how two conductors 2 and 3 are advantageously arranged at an interruption point 4 of the ladder 2. An inner conductor corresponds to the conductor 2, which has an interruption point 4 with a pair of rounded conductive bodies 40, 40 'and an insulating spacer 32 disposed therebetween. Another conductor 3 - also formed by a plurality of twisted wires - becomes external at the point of interruption 4 - largely annular - passed. For this purpose, a surrounding hollow cylindrical insulating body 34 may be provided at the point of interruption 4, wherein the wires of the further conductor 3 are guided by a lateral surface of the hollow cylindrical insulating body 34. For this purpose, the hollow cylindrical insulating body 34 may have grooves into which the wires of the conductor 3 can be inserted.

The conductor 2 is an inner conductor for the illustrated drawing section, the other conductor 3 an outer conductor. However, for another section, the conductor 2 may represent the outer conductor and conductor 3 the inner conductor.

FIG. 4 shows the same arrangement as FIG. 3 in a three-dimensional representation from the outside.

The overall structure of the break according to FIGS. 3 and 4 is achieved by diverging the two conductor groups (2 and 3) into an inner group and an outer group. The inner wires (ie the conductor 2) are interrupted and merged on both sides in spherical electrodes, while the outer continuous wires (ie the other conductor 3) defined in an insulator are performed. The overall arrangement can additionally be cast with an insulating compound and / or enclosed with shrink tubing.

FIGS. 3 and 4 illustrate how a twisted cable consisting of two groups of wires can be machined by widening and / or spreading a first group of wires to interrupt a second group of wires. In the axial course, the two groups are brought together again, so that at the two edges of image FIG. 4 a largely normal twisted cable can be seen. Would you FIG. 4 now extend, which is not shown, however, the second group of wires would be widened and / or spread apart at the distance of the resonance length in order to make an interruption there for the first group of wires.

The hollow cylindrical insulating body 34, through the outer surface of which the wires of the further conductor 3 are guided, ensure a defined spacing of the wires of the further conductor 3 to the rounded conductive bodies 40, 40 '. In this way, dangers of electrical flashovers are prevented. The wires of the further conductor 3 are not interrupted by the hollow cylindrical insulating body 34 but extend through the insulating body 34 therethrough.

In its outer configuration largely identical to FIGS. 3 and 4 , The hollow cylindrical insulating body 34 can also be replaced by a hollow cylindrical conductor piece 33. This will be on hand FIG. 5 explained.

FIG. 5 provides an alternative FIGS. 3 and 4 shows that the continuous outer wires of the other conductor 3 (for the illustrated drawing section thus the outer conductor) are mechanically and electrically combined in a hollow cylindrical conductor 33. The still existing inner insulating body - the spacer 32 - holds the ball electrodes relative to each other and relative to the outer conductor (3) and the hollow cylindrical conductor 33 in position. Again, defined E field distributions are achieved with low field peaks, for which preferably also the edges of the hollow cylindrical conductor 33 is rounded.

Similar to the hollow cylindrical insulating body 34, the wires of the other conductor 3 can be easily passed through the hollow cylindrical conductor 33, so that the hollow cylindrical conductor 33 and the wires of the conductor 3 have the same potential.

Alternatively, the wires of the further conductor 3 can be severed at the point of interruption. Subsequently, the separated ends can be mechanically and electrically connected to the hollow cylindrical conductor 33. This approach has the advantage that the complete inductor can be severed in place, then for the conductor 2, the rounded conductive body 40, 40 'and the spacer 32 can be inserted, and finally the wires of the conductor 3 via the hollow cylindrical conductor 33rd can be reconnected. The processing is thus simplified.

The cable inductor (inductor 1) can be constructed from a plurality of conductor bundles. FIG. 6 shows the inductor 1 with three conductor bundles, each having an outer insulator (34) according to FIGS. 3 and 4 exhibit. In the FIG. 6a is a conductor bundle in three-dimensional view largely obscured by another conductor bundle. FIG. 6b shows the view of the three conductor bundles from the axial direction. All conductor bundles each have an interruption point 4, wherein the interruption points 4 at different longitudinal position along of the inductor 1 done. The positioning of the interruption points 4 is based on FIG. 8 explained.

The cable inductor according to FIG. 6 is composed of several conductor bundles, which are all interrupted within a short axial distance to each other (eg within 1m). The inner conductors of the bundles can be interrupted individually, whereby the interruptions take place with a small axial offset. The breaks (ie, the break points 4) could then be potted together in a cable sleeve (not shown).

Alternatively - not shown - now all the wires of each outer conductor (corresponding to the other conductor 3, as shown in the figures) can be formed from different bundles to a common outer conductor. Also without illustration, the common outer conductor could be passed through a common outer insulating body.

The FIG. 6 shows a representation with a plurality of hollow cylindrical insulating bodies 34. Similarly, a configuration with a metallic cylinder (from FIG. 5 ) according to FIG. 6 be formed. That is, in this case, it is not hollow cylindrical insulating body 34, but hollow cylindrical metallic body 33. Otherwise, the embodiment according to FIG. 6 corresponding.

The FIG. 6b shows a section through the inductor at an inductor portion in which the wires are not spread. The cut is thus made by a section in which the wires are compactly twisted. The cutting plane would be outside the in FIG. 6a illustrated area. FIG. 6b Incidentally, therefore, also illustrates that the wires of the conductor 2 and the wires of the other conductor 3 in the inductor portions in which they are not spread, are twisted such that the wires of the conductor 2 and the wires of the other conductor 3 alternately - Alternating - are arranged.

FIG. 7 shows analogously to FIG. 6 the inductor 1 with three conductor bundles, each having an outer insulator (34) according to Figures 3 and 4. In the Figure 7a is a conductor bundle in three-dimensional view largely obscured by another conductor bundle. FIG. 7b shows the view of the three conductor bundles from the axial direction. All conductor bundles each have an interruption point 4, wherein the interruption points 4 can take place at different longitudinal position along the inductor 1 or at the same longitudinal position. The representation in FIG. 7 is to be understood that in the insulation body 34 shown only one conductor is interrupted. Alternatively, several conductors may be interrupted in the insulation body 34 shown.

The cable inductor according to FIG. 7 is made up of several conductor bundles. The inner conductors of the bundles can be interrupted individually. The breaks could then be potted together in a cable sleeve (not shown).

The three separately configured hollow cylindrical insulating body 34 from FIG. 6 are now after FIG. 7 as a common body 34 'is formed, in which three hollow cylinders are interconnected via their lateral surface. FIG. 7b illustrates that central axes of the three hollow cylinders are arranged offset by 120 ° to each other, with respect to a central axis of the insulating body (34 '). This type of arrangement leads to no lateral offset and thus a very compact design.

The FIG. 7 shows a representation with several united hollow cylindrical insulating bodies 34 '. Similarly, an embodiment with a common metallic cylinder (assembled from the individual metallic cylinders FIG. 5 ) according to FIG. 7 be formed. That is, in this case, it is not a body of a plurality of hollow cylindrical insulating bodies, but a plurality of hollow cylindrical metallic bodies. Otherwise, the embodiment according to FIG. 7 corresponding.

Out FIG. 4 . 5 . 6 and 7 It can be seen that the inductor 1 per se is a twisted cable of a plurality of individually insulated wires, with the twist for the interruption points possibly being widened. In the cited figures, two conductor bundles - denoted by 2 and 3 - are shown, wherein all the wires of a conductor bundle is at the same potential. The wires of the conductor bundles are twisted so that wires of the first conductor bundle are adjacent to wires of a second conductor bundle, and then in turn connect wires of the first conductor bundle. By virtue of this neighborhood of different phases of the wires, the capacitive effect between the wires can be improved.

Also conceivable are inductors with more than two conductor bundles. Then, with N conductor bundles, one wire each of the different conductor bundles are arranged adjacent to one another, followed by the next N wires of one wire each of the different conductor bundles.

All these wires extend in the extension of the inductor 1, but twisted together.

It is also conceivable to form different groups of wires and to twist each group individually, the inductor 1 comprising all twisted groups.

FIG. 8 shows an inductor 1 comprising at least two multifilament conductors 21, 22, wherein the multifilament conductors 21, 22 are each formed of a plurality of conductors 2.

Each conductor 2 of the multifilament conductors 21, 22 thus has interruption points 4, wherein the end portions 6, not shown, of the conductors 2 are formed according to the invention at the points of interruption 4. Put in other words the multifilament conductors 21, 22 of a plurality of conductors 2 according to FIG. 1 together.

The conductors 2 of the multifilament conductors 21, 22 are substantially parallel to each other. Due to the interruption points 4 and an offset 14 of the interruption points 4 of the first multifilament conductor 21 with respect to the interruption points 4 of the second multifilament conductor 22, the conductors 2 of the first multifilament conductor 21 are advantageously capacitively coupled to the conductors 2 of the second multifilament conductor 22. In this case, the offset 14 essentially corresponds to a resonance length, wherein the offset 14 continues periodically along the conductor 2. In this case, each conductor 2 has a plurality of interruption points 4, wherein the interruption points 4 of each conductor 2 have a constant distance from each other.

Advantageously, the conductor 12 of the multifilament conductors 21, 22 improves the partial discharge resistance of the inductor 1 by means of the end regions 6 (not illustrated in more detail and according to the invention). In addition, the mechanical strength at the points of interruption 4 is increased.

FIG. 9 shows a schematic sectional view in which the rounded conductive body 40, 40 'is placed as a sleeve 31 on a cable end of a respective wire of the inductor.

The FIGS. 9 and 10 In this case relate to an embodiment in which a conductor according to the invention consists of a single wire - a single wire. Each individual wire is separated at a point of interruption and the two resulting ends are individually provided with a sleeve 31 each.

According to FIG. 9 an interruption point 4 is shown as an alternative embodiment Figure 1 to 5 , An end portion 6 of the conductor 2 - this may be a plurality of twisted wires - is stripped. Otherwise is the Head 2 surrounded by an insulation 55. A largely cylindrical and largely rotationally symmetrical sleeve 31 includes a recess for receiving the end portion 6 of the conductor 2. The other end of the sleeve 31 forms the rounded conductive body 40, 40 '. By receiving the end portion 6 of the conductor 2 in the recess of the sleeve 31 and making a firm connection, thus the rounded conductive body 40, 40 'is applied to the conductor 2. The firm connection - conductive and non-positive - preferably takes place by means of pressing and / or crimping and / or soldering and / or welding and / or electrically conductive bonding.

The other end of the broken conductor also receives a corresponding sleeve 31.

The sleeve 31 - hereinafter also referred to as the shielding sleeve - is a molded part, preferably on copper or another electrically conductive material.

The sleeve 31 corresponds to a cable lug, which can be pushed in the manufacture of the inductor via a wire end - the end portion 6 -.

The sleeve 31 thus has in operation the same electrical potential as the conductor. 2

According to the superficial shape of the rounded conductive body 40, 40 ', there is provided an insulating spacer 32 having two opposite recesses, each corresponding to the superficial shape of the rounded conductive body 40, 40'.

In this way, the insulating spacer 32 can be positively and / or non-positively connected to the rounded conductive body 40, 40 '.

The insulating spacer 32 yields FIG. 9 a recess into which the rounded conductive body 40, 40 'can penetrate. The insulating spacer 32 also preferably surrounds the sleeve 31 transversely to the axial extent of the sleeve 31, so that the sleeve 31 is arranged coaxially with the conductor 2 and / or the insulating spacer 32.

According to FIG. 9 the entire arrangement of the interruption point 4 is enclosed by an electrically insulating sleeve 30. The sleeve 30 is in particular a spray sleeve. An injection molded sleeve has the advantage that cavities and air pockets can be avoided. The sleeve 30 has an insulating effect and at the same time gives mechanical stability.

The sleeve 30 encloses in particular the two end portions 6 of the conductor 2, the two sleeves 31 and the spacer 32. Preferably, the sleeve 30 encloses already insulated portions of the conductor 2, but also in particular the stripped portions of the conductor 2 in the end regions 6. Die Sleeve 30 is in particular a rotationally symmetrical body.

To explain the manufacturing process, will continue on FIG. 9 Referenced. The two ends of the wire, which are formed when a wire is broken, are inserted into the insulating element in order to connect and electrically isolate them mechanically, in a defined position. The insulating element consists of two conductive shielding sleeves (31) (for example a copper molding), an electrically insulating spacers 32 mechanically connecting the shielding sleeves (31) and an outwardly acting insulating sheath, which is designed in particular as a sprayed sleeve (30). Each shielding sleeve (31), which consists of highly electrically conductive material - such as copper, aluminum, other metals or alloys, graphite, possibly electrically conductive plastics such as CF PEEK (carbon fiber reinforced polyetheretherketone) - has a bore into which the previously order a few millimeters from the wire insulation freed single wire end is introduced. The mechanical and electrical connection of single wire end and shielding sleeve (31) can by deformation of the collar of the shielding sleeve (31) by means of a suitable pressing / crimping tool, wherein the tool is designed such that no burrs or edges on the shielding sleeve (31) arise. Alternatively, the connection can be made by soldering, welding or electrically conductive bonding. The spacer 32 is made of a high-temperature-resistant and electrically insulating material, for example, a plastic such as PFA (perfluoroalkoxylalkane), PTFE (polytetrafluoroethylene) or PEEK (polyetheretherketone) or a ceramic. The shielding sleeves (31) are mechanically fixed, preferably inserted in a form-fitting manner in the spacer 32. The spacer provides a defined axial distance between the screen sleeves (31), coaxially orientes the screen sleeves (31) and centers them. The production of the insulation element is completed by a gas-free sheath (in the form of said spray sleeve) of shielding sleeve pair (31) and spacer 32 by a high temperature resistant insulating material, which already touches the single core insulation. Insulating plastics (for example those mentioned above) may preferably be used for this purpose. In particular, those which can be applied by a spray, (vacuum) potting or extrusion process are suitable. In particular, the same thermoplastic material can be used, which already form the outer layer of the single core insulation and / or the spacer 32, for example PFA.

FIG. 10 shows an alternative embodiment FIG. 9 in which the arrangement is analogous to the shape of the sleeves 31 and the spacer 32 FIG. 9 is trained. However, the transition between the sleeve 31 and the spacer 32 is largely inverse to FIG. 9 ie concave surfaces are now convex and vice versa.

The rounded conductive body 40, 40 'points in FIG. 9 a hemispherical convex surface on. According to FIG. 10 it now has a continuously curved collar-shaped surface (40B). The surface of the sleeve 31 is partially concave. Since the sleeve 31 is preferably rotationally symmetrical, one can also designate the shape of the axial end face directed toward the spacer 32 as a torus-shaped, more precisely as a half-torus-shaped.

The spacer 32 is again adapted to the surface of the sleeve 31. As a result, the insulating spacer 32 has a rounded pin. The pin can be inserted into the recess of the central collar-shaped surface (40B) of the sleeve 31, so that a stable connection between sleeve 31 and spacer 32 is formed.

Preferably, the spacer 32 is in FIGS. 9 and 10 formed axisymmetric and rotationally symmetrical. However, it is also possible to provide individual shapes, so that the spacer 32 and the sleeve 31 engage with each other so that only a certain position is possible. It should be noted, however, that the surfaces of the conductive elements are as uniform as possible and the conductive body is rounded, so that a rollover of a current arc can be avoided.

The spacer 32 provides a defined axial distance between the mutually facing surfaces (40A) of the shield sleeves (31). It orients the screen sleeves (31) coaxially with one another. He centers them on each other.

The design of the FIG. 10 is different FIG. 9 in that the spacer 32 is introduced analogously to the wire ends into a screen sleeve (31) which is in turn modified on both sides with blind bores. Alternatively - not shown - can also be a through hole with possibly different radii on both sides of a shielding sleeve (31) are used. The connection of shield sleeves (31) and electrically insulating spacer 32 can bwz by pressing bwz. Crimping (possibly in one operation together with the wire ends) or gluing done. The final injection molded sleeve - so the sleeve 30 - again turns the Isolation radially outward, in particular to the adjacent continuous wires, safe.

The FIGS. 1 to 7 relate to an embodiment in which the conductor 2 in the context of the invention consists of a plurality of individual wires. All of these individual wires belonging to a conductor are separated at an interruption point. This is advantageous if a twisted cable already exists and subsequently interruption points are to be inserted.

The FIGS. 9 and 10 On the other hand, an embodiment in which the conductor 2 in the sense of the invention consists of a single individual wire. This single wire may for example have a cross-section of about 1 mm ² . Each individual wire is separated at a point of interruption and the two resulting ends are individually provided with a sleeve 31 each. This embodiment is advantageous if individual wires are provided in advance with interruption points and only then a twisting or stranding or winding to a common cable comprising a plurality of these individual wires is produced. The stranding causes a strain relief for the inductor. 1

• Die Anordnung ermöglicht die Vermeidung von lokalen Überhöhungen der elektrischen Feldstärke an sonst vorliegenden Leiterkanten und -spitzen, die zu Teilentladungen und damit zum Ausfall des Induktors 1 führen können. Weiterhin vorteilhaft ist, dass die Zahl der kritischen Leiter-Enden drastisch reduziert wird, was ebenfalls der Erhöhung der Zuverlässigkeit dient.

The use of rounded surfaces (see 40, 40 ') at the point of interruption 4 has the following advantages:

• The arrangement allows the avoidance of local elevations of the electric field strength at otherwise existing conductor edges and tips, which can lead to partial discharges and thus to failure of the inductor 1. It is also advantageous that the number of critical conductor ends is drastically reduced, which also serves to increase the reliability.

A positive side effect is that the inductor cable (in a first step but without interruptions) can be made continuously like a common cable, and the Interruptions are made later. This makes it possible, in particular, to subject the uninterruptible cable in advance to a partial discharge test in order to identify any weak points of the individual conductor insulation in advance.

Furthermore, the determination of the resonant frequency, which depends on the distance of the interruptions in addition to the inductor loop geometry, after the cable production tuned to the respective reservoir done and need not be known before the cable production. That The cable can be produced within limits independently of the individual deposit and the adaptation to it takes place only by the subsequent introduction of the interruption points in individually defined distance (resonance length).

• Die Schirmhülsen (31) umhüllen die Einzeldrahtenden, die aufgrund der Auftrennung/Zerschneidung ohne weitere Maßnahmen in der Regel scharfe Kanten und Grate aufweisen, und vermeiden Überhöhungen des elektrischen Feldes an den Einzeldrahtenden, aufgrund der Schirmwirkung bedingt durch gleiches Potential von Drahtende und Schirmhülse (31).

The advantages of the isolation element are still as follows:

• The shield sleeves (31) envelop the individual wire ends, which generally have sharp edges and ridges due to the separation / cutting without further measures, and avoid overshoots of the electric field at the individual wire ends due to the shielding effect due to the same potential of the wire end and shielding sleeve (31 ).

On the outer surfaces of the shield sleeves (31) occur no field elevations of the electric field, since the shield sleeves (31) according to the invention have no edges but only curves.

The spacers 32 ensure that the electric field strength between a pair of screen sleeves (each reference numeral 31) does not exceed critical values.

Critical field strengths at the end of the single wire insulation of the wire end are avoided or reduced by the intended overhang of the shielding sleeve (31). This job is critical, because it may not be ensured that they can be encapsulated gas-free.

The insulation element provides a tension-proof connection of one wire end via first shielding sleeve (31), spacer 32, second shielding sleeve (31) to the other end of the wire. This is needed for subsequent stranding steps.

The spacer after FIG. 9 guarantees a minimum layer thickness of the insulation thickness in the radial direction, even if the injection sleeve - that is, the sleeve 30 - is applied axially offset, since the spacer can lie during the injection process maximum on the inner wall of the mold.

With the spacer 32 after FIG. 10 can possibly achieve a more rational production by the wire ends can be pressed simultaneously with the spacer 32 with the shielding sleeve (31).

FIG. 11 shows a perspective section of an oil sands reservoir as a deposit with a largely horizontally extending in the reservoir inductor 1, which can also be referred to as electrical conductor loop. It is shown as a reservoir oil sands deposit, with the specific considerations always a cuboid unit 100 with the length 1, the width w and the height h is taken out. The length 1 may for example be up to some 500 m, the width w 60 to 100 m and the height h about 20 to 100 m. It has to be taken into account that starting from the earth's surface E there can be an overburden of thickness s up to 500 m.

Next, an arrangement for inductive heating of the reservoir cutout 100 is shown. This can be formed by a long, ie some 100 m to 1.5 km, laid in the ground conductor loop 120 to 121, wherein the forward conductor 120 and return conductor 121 side by side, ie at the same depth, are guided and at the end via an element 15 within or outside the reservoir. Initially, the conductors 120 and 121 are led down vertically or at a shallow angle and are powered by a high frequency generator 60 which may be housed in an external housing. The high-frequency generator 60 or medium-frequency generator preferably covers a range of 10 kHz to 200 kHz or a sub-range and can preferably be set to any frequencies in this frequency range. Also conceivable is an operating range of 1khz to 500kHz.

In FIG. 11 the conductors 120 and 121 run side by side at the same depth. But they can also be performed on top of each other. Below the conductor loop (ie, the conductors 120 and 121), ie, on the bottom of the reservoir unit 100, a conveying pipe 102 is indicated, can be collected and / or removed via the liquefied bitumen or heavy oil.

Typical distances between the return and return conductors 120, 121 are 5 to 60 m with an outer diameter of the conductors of 10 to 50 cm (0.1 to 0.5 m).

The forward conductor 120 and the return conductor 121 FIG. 11 are at least in the region of their largely horizontal extent preferably with interruptions according to the FIGS. 1 to 10 educated.

Exemplary operating parameters are, for example, an inductively introduced heating power of 1 kW per meter of double cable. A current amplitude can be provided, for example, 300 A to 1000 A. For example, a single wire may be 0.5 to 1 mm in diameter. In sum, all the wires in the inductor can have a cross section of 1000 to 1500 mm ² . For example, the inductor may consist of 2500 to 3500 individual solid wires. As material for the wires copper may be provided. As insulation for each wire, for example Teflon can be provided. Wall thickness of the insulation can be, for example 0.2 to 0.3 mm. The double resonance length for an exemplary inductor may be, for example, 35 to 50 m. The arrangement of the wires in the longitudinal direction is carried out with an offset of the interruption points to the resonance length.

The invention according to the figures relates to an arrangement and a method for introducing heat into a geological formation, in particular into a deposit located in a geological formation, in particular for obtaining a hydrocarbon-containing substance - in particular crude oil - from the deposit. An inductor is proposed which is designed for "in situ" extraction of underground deposits, for example from a depth of about 75 m. This means that with this technique, the oil sands - the sand and the rock with the contained oil - remain in place. The oil or the bitumen is separated from the grain of sand by means of electromagnetic waves and possibly further different processes and made more flowable so that it can be conveyed. The presented "in situ" -method has the principle to increase the temperature in the ground and thus to reduce the viscosity of the bound oil or bitumen and make it more fluid, in order to pump it afterwards. The effect of heat in particular causes long-chain hydrocarbons of the high-viscosity bitumen to split. The inductor - ie an electrical conductor which is designed as an induction line - can be operated as a resonance circuit with little loss. Since both ends of the inductor are preferably connected to the frequency generator, the induction line forms an induction loop. The technical realization of the electrical line is performed as a resonant circuit. The frequency generator may preferably be formed as a frequency converter, which converts a voltage having a frequency of 50Hz or 60Hz from the mains to a voltage having a frequency in the range of 1kHz to 500kHz. The frequency converter can be installed on a day-to-day basis. Furthermore, at least one of the deposit zones heated by the induction loop can preferably be used Drilling hole to be drilled. In addition, optionally between two continuous quasi-parallel bores in which the induction loop is arranged, be provided at least one injection hole for the injection of hot steam.

After installation of the inductor as an induction loop in at least two holes and the connection of the induction loop to the frequency generator starts in the operation of the energizing the conductor, and thus the inductive heating substrate with devoted formation of a heating zone, which is characterized by an elevated temperature. The conductor loop or induction loop acts as an induction heater in operation to introduce additional heat into the deposit. The active area of the conductor may describe a nearly closed loop (ie, an oval) in the substantial horizontal direction within the deposit. The active area may be adjoined by an end area, possibly located above ground. The above-ground parts of the beginning and end of the conductor can be electrically connected to a power source - the frequency generator. It is preferably provided to partially compensate the line inductance of the conductor by series capacitances. It can be provided for the line with integrated compensation that the frequency of the frequency generator is tuned to the resonance frequency of the current loop. The capacitance in the conductor can be formed between cable sections. An existing dielectric is chosen so that it meets a high withstand voltage and high temperature resistance.

Insulating the inductor against the surrounding soil is advantageous for preventing resistive currents through the earth between the adjacent cable sections, particularly in the region of the capacitors. The insulation furthermore prevents a resistive current flow between the forward and return conductors.

The compensation of the longitudinal inductance can be done in operation by means of transverse capacitances. The capacitance - which is a two-wire line such. B. provides a coaxial line or multi-wire cables anyway over their entire length - can be used to compensate for the Längsinduktivitäten. For this purpose, the inner and outer conductors are alternately interrupted at equal intervals, thus forcing the flow of current through the distributed transverse capacitances.

The temperature in operation in the heating zone depends on the electromagnetic power introduced, which consists of the geological and physical (eg electrical conductivity) parameters of the deposit, as well as the technical parameters of the electrical arrangement, in particular consisting of the inductor and the high frequency generator , results. This temperature can reach up to 300 ° C and is adjustable by changing the current through the loop of the inductor. The regulation takes place via the frequency generator. The electrical conductivity of the reservoir may be increased by injecting additional water or another fluid, e.g. As an electrolyte can be increased.

The temperature development is initially due to the induction of eddy currents in the electrically conductive areas of the substrate. In the course of heating, temperature gradients, that is, places of higher temperature than the original reservoir temperature, are produced. The places of higher temperature arise where eddy currents are induced. The starting point of the heat is therefore not the induction loop or the electrical conductor, but it is the eddy currents induced by the electromagnetic field in the electrically conductive layer. Due to the temperature gradient that occurs over time, heat conduction also occurs depending on the thermal parameters such as thermal conductivity, which compensates for the temperature profile. With a greater distance from the conductor, the strength of the alternating field decreases, so that only a lower heating is possible there.

If, on the other hand, a removal of the fluids or of the fluids made of electrically conductive fluids takes place immediately as soon as they have been made fluid, then the less heated by electrical eddy currents, the more the soil with its electrical conductivity has been carried away at the vacancies. Although the electromagnetic field is still there, eddy currents can only form where there will still be conductivity. However, draining a liquid can cause other liquid to flow.

The input power is preferably set between 100kW to several megawatts.

The invention relates only to an inductor. In a deposit, however, depending on the size of several inductors can be moved side by side and at a distance from each other.

Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, or other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims (16)

An inductor (1) for heating a geological formation, in particular a deposit (100) of a hydrocarbonaceous substance, for example an oil sand, oil shale or heavy oil deposit, by means of electromagnetic induction, in particular for recovering the hydrocarbonaceous substance from the deposit (100), comprising at least one conductor (100). 2), the conductor (2) having at least one point of interruption (4), characterized in that at least at one end region (6) of the conductor (2) at the point of interruption (4) a rounded conductive body (40) is applied. The inductor (1) according to claim 1, characterized in that the rounded conductive body (40) comprises a hemispherical surface (40A) or a continuously curved collar-shaped surface (40B). An inductor (1) according to claim 1 or 2, characterized in that the conductor (2) consists of a single wire and a plurality of conductors (2) form the inductor (1). Inductor (1) according to one of claims 1 to 3, characterized in that the rounded conductive body (40) is formed at one end as a sleeve (31) and the end portion (6) of the conductor (2) in the sleeve (31). is introduced. An inductor (1) according to claim 4, characterized in that the sleeve (31) has a blind bore or through-hole into which the end region (6) of the conductor (2) is inserted into the sleeve (31). Inductor (1) according to claim 4 or 5, characterized in that a mechanical connection between the sleeve (31) and the end portion (6) of the conductor (2) by means of pressing and / or crimping and / or soldering and / or welding and / or electrically conductive adhesion takes place. Inductor (1) according to one of the preceding claims, characterized in that at a further end region (6) of the conductor (2) at the point of interruption (4) a further rounded conductive body (40 ') is applied and that between the rounded conductive body (40) and the further rounded conductive body (40 ') an insulating spacer (32) is positioned. An inductor (1) according to claim 7, characterized in that the insulating spacer (32) has a surface portion, wherein the surface portion of the insulating spacer (32) is mechanically and preferably positively connected to a surface portion of the rounded conductive body (40). An inductor (1) according to claim 7 or 8, characterized in that the insulating spacer (32) is configured to have surface shapes of the insulating spacer (32) in surface shapes of the rounded conductive body (40) and surface shapes of the further rounded conductive body (32). 40 ') engage the rounded conductive body (40) and in the further rounded conductive body (40') are fixed to each other without offset and at a predetermined distance. An inductor (1) according to any one of claims 7 to 9, characterized in that a mechanical connection between the rounded conductive body (40) and the insulating spacer (32) by means of pressing and / or crimping and / or soldering and / or welding and / or or gluing done. Inductor (1) according to one of the preceding claims, characterized in that the interruption point (4) of the conductor (2) and the interruption point (4) adjoining conductor sections and the interruption point (4) provided components by a sleeve (30) is enclosed , Operating method for heating a geological formation, in particular a storage of a hydrocarbonaceous substance, for example, an oil sands, oil shale or heavy oil deposit, by means of electromagnetic induction, in particular for recovering the hydrocarbonaceous substance from the deposit, in which an arranged in the geological formation inductor (1) with at least a conductor (2) is controlled such that an electromagnetic field is formed in the geological formation, for which purpose the conductor (2) has at least one point of interruption (4), wherein at least at one end region (6) of the conductor (2) on the Breakpoint (4) a rounded conductive body (40) is applied. Manufacturing method for an inductor for heating a geological formation, in particular a deposit of a hydrocarbon-containing substance, for example an oil sand, oil shale or heavy oil deposit, by means of electromagnetic induction, comprising the following production steps: a) performing the following processing steps for at least one longitudinal position of a wire: - providing the, preferably insulated, wire; - separating the wire at the longitudinal position of the wire; - stripping of both cable ends of the severed wire; - connecting rounded conductive bodies (40) each on a respective entisoliertes cable end; - inserting a respective spacer (32) between pairs of rounded conductive bodies (40); optionally mounting a socket mold, ejecting the socket form into a sleeve, the socket enclosing the rounded conductive bodies (40) and two end portions of the severed wire, and removing the socket form; b) winding the processed wire and / or stranding a plurality of such processed wires to an inductor (1). Manufacturing method for an inductor for heating a geological formation, in particular a deposit of a hydrocarbon-containing substance, for example an oil sand, oil shale or heavy oil deposit, by means of electromagnetic induction, comprising the following production steps: a) performing the following processing steps for at least one longitudinal position of a wire: - providing the, preferably insulated, wire; - separating the wire at the longitudinal position of the wire; - stripping of both cable ends of the severed wire; - providing an already connected unit comprising a spacer (32) and a pair of rounded conductive bodies (40) connected thereto; - Connecting the unit with the two stripped cable ends; optionally mounting a socket mold, ejecting the socket form into a sleeve, the socket enclosing the rounded conductive bodies (40) and two end portions of the severed wire, and removing the socket form; b) winding the processed wire and / or stranding a plurality of such processed wires to an inductor (1). A manufacturing method according to claim 13 or 14, characterized in that the joining of rounded conductive bodies (40) is carried out in each case on a respective entisoliertes cable end with the following steps: - Sliding sleeves on the respective cable ends, wherein the sleeves each comprise the rounded conductive body (40); - Frictional connection, in particular crimping, the respective sleeve with the respective entisolierten cable end. A manufacturing method according to any one of claims 13 to 15, characterized in that the stranding of a plurality of such processed wires to an inductor (1) is carried out by the following steps: Arranging a plurality of processed wires to each other such that at least two bundles of wires are formed, wherein the wires of a first of the two bundles are aligned in longitudinal alignment with each other so that separation points of the severed wires of the first bundle are substantially juxtaposed and the wires of one second of the two bundles are aligned in longitudinal alignment with each other so that separation points of the severed wires of the second bundle come to lie substantially next to each other, wherein the separation points of the first bundle to the separation points of the second bundle are offset from each other; Stranding the wires arranged in such a way that the wires of the first bundle and of the second bundle are stranded alternately with each other.

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