EP2315910B1 - Installation for the<i> in situ </i>extraction of a substance containing carbon - Google Patents

Description

The invention relates to a plant for the in-situ recovery of a carbonaceous substance from an underground deposit with reduction of its viscosity. Such a device is used in particular for the production of bitumen or heavy oil from a reservoir under an overburden, as is the case with oil shale and / or oil sand deposits, for example in Canada.

For the promotion of heavy oils or bitumen from the known oil sand or oil shale deposits their flowability must be significantly increased. This can be achieved by increasing the temperature of the reservoir. If an inductive heater is used for this purpose, the problem arises that the electrical supply and return conductors for supplying the inductors introduced into the reservoir unintentionally also heat the overburden. The heat output thus deposited in the overburden represents losses at the expense of the reservoir heater, which must be avoided.

The increase in fluidity can be done firstly by introducing solvents or diluents and / or on the other by heating or melting of the heavy oil or bitumen, for which by means of pipe systems, which are introduced through holes, heating takes place.

The most widely used and applied in-situ process for the extraction of bitumen or heavy oil is the SAGD (S team A ssisted G ravity D rainage) process. In this case, water vapor, which may be added to the solvent, is pressed under high pressure through a tube extending horizontally within the seam. The heated, molten and detached from the sand or rock bitumen or heavy oil seeps to a second about 5 m deeper located pipe through that the promotion of the liquefied bitumen or heavy oil takes place, wherein the distance from the injector and production pipe is dependent on reservoir geometry.

The steam has to fulfill several tasks at the same time, namely the introduction of heating energy for liquefaction, the detachment of the sand and the pressure build-up in the reservoir, on the one hand to make the reservoir geomechanically permeable for bitumen transport (permeability) and on the other hand, the promotion of bitumen without additional pumps to enable.

The SAGD process starts by steam being introduced through both pipes for typically three months in order first to liquefy the bitumen in the space between the pipes as quickly as possible. Thereafter, the steam is introduced only through the upper tube and the promotion through the lower tube can begin.

In the non-prepublished German patent application AZ. 10 2007 008 292.6 with older seniority is already stated that the commonly used SAGD method can be completed with an inductive heating device. Furthermore, in the non-prepublished German patent application AZ. 10 2007 036 832.3 with older seniority a device prescribed in the in Fig. 5 parallel inductor or electrode arrangements are provided, which are connected above ground to the oscillator or inverter.

In the older, not previously published German patent applications AZ. 10 2007 008 292.6 and AZ. 10 2007 036 832.3 So it is proposed to superimpose the steam input with an inductive heating of the deposit. Optionally, resistive heating between two electrodes may additionally be carried out.

In the above-described devices, the electrical energy must always be passed through an electrical forward conductor and an electrical return conductor. This requires a considerable effort.

Such facilities are in the US4,144,935 . DE2636530 and US4,116,273 described

In the earlier patent applications, individual inductor pairs of forward and return conductors or groups of inductor pairs in different geometric configurations are energized to inductively heat the reservoir. In this case, a constant distance of the inductors is assumed within the reservoir, resulting in a homogeneous electrical conductivity distribution to a constant heat output along the inductors. Described are the spatially close together outgoing and return conductors in the sections in which the overburden ("Overburden") is pierced in order to minimize losses there.

A variation of the heating power along the inductors can, as described in the older non-prepublished applications, especially by sectionwise injection of electrolytes, whereby the impedance is changed. This requires corresponding electrolyte injection devices that are expensive to integrate in the inductors or require additional costly drilling.

On this basis, it is an object of the invention to optimize the above-described device for inductive heating and to simplify in terms of energy input. In addition, the power consumption itself should be minimized.

The object is achieved by the totality of the features of claim 1. Further developments are specified in the subclaims.

The invention relates to an induction-heated system in which the outgoing and return conductors for the inductor lines are guided substantially vertically and have a small lateral distance of at most 10 m. Preferably, however, the distance is less than 5 m. For this purpose, parallel bores can be present in this distance in the cover structure, so that return conductors are guided individually for this purpose. Advantageously, it is possible to start from a single borehole in which the forward and return conductors are guided together. This has the advantage that virtually no electrical power is consumed in the vertically guided area, since the electromagnetics compensate for the closely merged conductors.

In the invention, therefore, the forward and return conductors of the induction conductors can be separate, laterally side-by-side guided lines. You can also form stranded cables and especially coaxial cables. In particular, such coaxial cables can be guided in a closely matched wellbore.

In particular, in the latter embodiment, a branch (so-called Y-junction) is present at the end of the merged lines. The outgoing, horizontally guided Induktorleitungen can run in the same, but also in opposite directions.

In an inventive development, the inductor lines running horizontally in the deposit can have different distances in regions. In particular, this can be avoided by losses in areas where no inductive heating is necessary and / or desired, the lines are again performed closely parallel, so that no unnecessary heating power is consumed.

1. 1. Die in einem Leitungspaar zusammengefassten senkrecht verlaufenden Hin- und Rückleiter lassen sich - wie bereits erwähnt - vorteilhafterweise in eine einzige Bohrung, die bis ins Reservoir hinabreicht, einbringen, um erst im Reservoir zu verzweigen ('Y-Junction'). Dabei kann das Hin-/Rückleiterpaar verseilt oder koaxial ausgeführt sein und einzeln oder zusammen - in einer zusammenhängenden Isolation - isoliert sein. Die Verwendung eines einzigen Bohrlochs, das ins Reservoir hinabreicht, ist auch für mehrer Hin-/Rückleiterpaare möglich.

In the invention, a wide variety of feature combinations or possibilities of an inventive development arise. The essential further developments are listed below in detail:

1. 1. The combined in a pair of lines vertically extending forward and return conductors can - as already mentioned - advantageously in a single hole, which reaches down to the reservoir, bring to first branch in the reservoir ('Y-junction'). In this case, the return / return pair can be made stranded or coaxial and individually or together - in a continuous isolation - be isolated. The use of a single borehole, which reaches down into the reservoir, is also possible for several pairs of return / return conductors.

In addition, with the invention, a specialized, optimized to the respective section embodiment of the conductor arrangement is possible. In this case, a first section - from the oscillator to the branch - be carried out particularly low loss, for example by RF stranded conductor, possibly with reduced requirement for temperature resistance. A second section is formed by the single-insulated conductor acting as an inductor. Increased mechanical requirements for installation and increased thermal requirements for operation must be taken into account, while low ohmic conductor losses are secondary. A third section is formed by the electrode, a non-insulated conductor end, which due to its length and z. B. by means of surrounding salt water has a low contact resistance to the reservoir. Such measures ("Saline injected regions at non-isolated tips") are known and thus represent a low-impedance grounding.

In order to prevent the accumulation of the inductive voltage drop along the entire conductor length, a compensated conductor with a resonant conductor system and a series resonant circuit - as described in the above-mentioned earlier patent applications - is also advantageously used here.

• 2. Bei der Erfindung werden Leistungsgeneratoren benötigt. Eine günstige Ausführungsform von Leistungsgeneratoren in dem betrachteten Frequenzbereich sind Stromrichter - wie in oben erwähnten deutschen Patentanmeldung AZ 10 2007 008 292.6 im Einzelnen beschrieben ist. Stromrichter liefern neben der Leistung bei der Grundfrequenz (Schaltfrequenz) erhebliche Anteile höhere Harmonischer, d.h. Leistung bei ganzzahligen Vielfachen der Grundfrequenz. Im Rahmen vorliegender Erfindung wird in einer spezifischen Weiterbildung vorgeschlagen, mehre benachbarte Hin-/Rückleiterpaare, die überwiegend bei der Grundfrequenz resonant sind, und einige, die bei Harmonischen resonant sind, parallel an einem oder einer Gruppe von Umrichtern zu betreiben, so dass die Leistung der Umrichter auch bei den höheren Harmonischen genutzt wird. Wegen der unmittelbaren Nähe der Einspeisepunkte sind dazu besonders die multi-lateralen Bohrungen geeignet.
• 3. Wesentlich sind bei der Erfindung die Zuordnung und Ausbildung der Induktorleitungen. Der einzelne kompensierte Induktor besteht aus abschnittsweise sich wiederholenden, kapazitiv verkoppelten Leitergruppen, deren Induktivitäts- und Kapazitätsbeläge sowie Länge die Resonanzfrequenz festlegt. Im vorliegenden Zusammenhang werden solche Leiterquerschnittskonfigurationen vorgeschlagen, deren Stromdichteverteilungen auf beiden Leitern rotationssymmetrisch oder annähernd rotationssymmetrisch zur Induktorachse sind. Dies ist bereits Gegenstand der älteren nicht vorveröffentlichten Patentanmeldung der Anmelderin AZ 10 2008 012895.4 .
• 4. Alternativ können die beiden endseitig geerdeten Induktoren in unterschiedliche, beispielsweise entgegen gesetzte Richtungen auseinanderstreben. Weiterhin wird vorgeschlagen, die Induktoranordnung periodisch in x-Richtung und/oder periodisch in y-Richtung fortzusetzen. In spezifischer Weiterbildung der Erfindung wird vorgeschlagen, die Stromamplituden und Phasenlage benachbarter Generatoren einstellbar zu machen, wozu ein Array aus Induktorleitungen und Generatoren geeignet ist.
• 5. Das Array von Induktoren entsprechend Pkt. 4 ist geeignet, das Reservoir großräumig zu beheizen. Erfindungsgemäß wird vorgeschlagen, mehrere Injektions- und Produktionsröhren senkrecht zur Orientierung (und unterhalb) der Induktoren anzuordnen. Demzufolge brauchen die Induktoren nicht wie bisher meist beschrieben parallel zu den Produktions- und Injektionsrohren verlaufen, sondern unter einem Winkel, im speziellen senkrecht zum Produktionsrohr orientiert - d.h. in Querrichtung. Dies erlaubt eine Variation de Heizleistung entlang der Produktionsrohre und insbesondere einen frühzeitigen Förderbeginn, da an den Kreuzungspunkten von Induktoren und Produktionsrohren der Abstand zwischen diesen sehr gering ist. Dabei ist die senkrechte Orientierung nur der Spezialfall. Dieselben Vorteile ergeben sich bereits auch unter kleineren Winkel zwischen Induktoren und Produktionsrohren.
• 6. Wenn eine Kühlung der Induktoren mittels z. B. Salzwasser nicht erforderlich ist, kann Salzwasser alternativ mittels senkrechter Bohrungen an die zu erdenden Induktorenden, d.h. Elektrodenabschnitte, eingebracht werden. Weiterhin können Kühlmedium und Elektrolyt (Salzwasser) unterschiedliche Flüssigkeiten sein. Das Kühlmedium kann im Induktor zirkulieren (z. B. koaxial verlaufende Hin- und Rückleitungen für das Kühlmedium) und in einem geschlossenen Kühlkreis mit Wärmetauscher umgewälzt werden. Hierzu wird nochmals auf die ältere Anmeldung AZ 10 2007 008 292.6 verwiesen.
• 7. Die Salzwasserinjektion zur besseren Erdung einer Zeile eines Induktor-Arrays entsprechend Pkt.6 kann alternativ mittels eines stellenweise geschlitzten Rohres, das durch eine Horizontalbohrung eingebracht wird und senkrecht zu den Induktoren orientiert ist, für mehrere Induktoren gemeinsam erfolgen.

The use of compensated conductors is mandatory in the section of the inductor lines routed in the reservoir due to its length and the usually large distance (> 5 m) between the inductors. In sections I and III u. U. be waived on compensated conductors, if the sections are short (<20 m) or the distance between the return and return conductors is very low (<0.5 m). Very small distance, and associated low inductance of the line section is particularly in stranded or coaxial forward and return conductors.

• 2. Power generators are needed in the invention. A favorable embodiment of power generators in the considered frequency range are converters - as in the above-mentioned German patent application AZ 10 2007 008 292.6 is described in detail. In addition to the power at the fundamental frequency (switching frequency), converters deliver considerable proportions of higher harmonics, ie power at integer multiples of the fundamental frequency. In the context of the present invention, it is proposed in a specific development, several adjacent pairs return / return, which are resonant predominantly at the fundamental frequency, and some that are resonant at harmonics to operate in parallel on one or a group of inverters, so that the performance the inverter is also used for the higher harmonics. Because of the immediate proximity of the entry points, the multi-lateral boreholes are particularly suitable for this purpose.
• 3. It is essential in the invention, the assignment and design of the inductor. The single compensated inductor consists of sectionally repeating, capacitively coupled conductor groups whose inductance and capacitance coverings and length determines the resonance frequency. In the present context, such conductor cross-section configurations are proposed whose current density distributions on both conductors are rotationally symmetric or approximately rotationally symmetrical to the inductor axis. This is already the subject of the earlier unpublished patent application of the applicant AZ 10 2008 012895.4 ,
• 4. Alternatively, the two end-grounded inductors can diverge in different, for example, opposite directions. Furthermore, it is proposed to continue the inductor arrangement periodically in the x-direction and / or periodically in the y-direction. In a specific embodiment of the invention, it is proposed to make the current amplitudes and phase position of adjacent generators adjustable, for which purpose an array of inductor lines and generators is suitable.
• 5. The array of inductors according to item 4 is suitable for heating the reservoir over a large area. According to the invention, it is proposed to arrange a plurality of injection and production tubes perpendicular to the orientation (and below) of the inductors. Consequently, the inductors do not need to run parallel to the production and injection pipes, as described so far, but at an angle, in particular oriented perpendicular to the production pipe - ie in the transverse direction. This allows a variation de heating power along the production pipes and in particular an early start of delivery, since at the intersections of inductors and production pipes, the distance between these is very low. The vertical orientation is only the special case. The same advantages already arise under smaller angles between inductors and production pipes.
• 6. If cooling of the inductors by means of z. Salt water is not required, salt water can alternatively be introduced by means of vertical bores to the inductor ends to be ground, ie electrode sections. Furthermore, cooling medium and electrolyte (salt water) may be different liquids. The cooling medium can circulate in the inductor (eg, coaxial outflow and return lines for the cooling medium) and be circulated in a closed cooling circuit with a heat exchanger. This is again on the older application AZ 10 2007 008 292.6 directed.
• 7. The Salzwasserinjektion for better grounding a row of an inductor array according to Pkt.6 can alternatively be done by means of a locally slotted tube, which is introduced through a horizontal bore and oriented perpendicular to the inductors, for several inductors together.

Alternatively, in the context of the invention, the electrode sections can also be led into water-bearing layers outside the reservoir (above or below) in order to realize a connection with good electrical conductivity to the surrounding soil, which is possible with less expenditure on equipment. In many cases water - bearing layers are contained in over - and / or underburden.

In an inventive development, it is further proposed to vary the distance between the forward and return conductors of a capacitively compensated inductor within the reservoir in sections. The change in distance causes sections of different inductance of the double line. It is proposed to compensate for the variation of the inductance lining by means of adapted resonance lengths and / or by adapted capacitance layers, for example by different dielectric thicknesses, at constant resonance lengths. It is also possible to compensate for the variation of the inductance coating by a combination of capacitance change and adaptation of the resonance lengths.

The laying of distance-optimized inductors in the reservoir can now be adapted to the geological conditions in the reservoir already at the beginning of the promotion. It may optionally be done as a retrofit for existing already promoting production and Dampfinjektionsrohrpaare.

The laying of a distance-optimized inductor can also be done in addition to existing inductors. In this case, an electrical connection can be made with outgoing or return conductors formerly laid inductors, the operation in the series resonance can be done by frequency adjustment on the generator / inverter. The distance variation can take place in the vertical and / or horizontal direction, whereby an adaptation of the heating power distribution to the reservoir geometry is possible.

With the latter inventive development advantageously results in a homogenization of the heating power along the inductors for sections different electrical conductivities by adjusting the distance. In this case, a Induktorverlegung done so that large-scale steam chambers horizontally and / or vertically dodged.

By the specified inventive development is an avoidance of penetration of the often formed at the beginning of the injection tube steam chamber by displaced forwardly and / or at a dull angle than 90 ° downwardly extending inductor possible. Optionally, the installation of the oscillator in the end region of the injection and production pipe pair can take place.

• Zu 1: Die Magnetfelder der in geringem Abstand geführten entgegensetzt bestromten Hin- und Rückleiter kompensieren sich nahezu vollständig, so dass bereits in unmittelbarer Umgebung im Deckgebirge (,Overburden') nur noch kleine Wirbelströme induziert werden und damit die Verlustleistung drastisch reduziert wird. Dabei ist die koaxiale Ausführung von Hin- und Rückleiter aus Verlustleistungssicht ideal, erfordert jedoch erhöhten Aufwand an der Verzweigung. Bei der koaxialen Anordnung ist die Umgebung vollständig feldfrei. Dies erlaubt insbesondere auch die Verwendung von elektrisch leitfähigen und magnetischen Werkstoffen (Stahl) für eine Umhüllung des Hin-/Rückleiterpaares bzw. einer Auskleidung der Bohrung mit Stahlrohren im Abschnitt des Leiterpaares. Weiterhin wird eine Bohrung eingespart. Weiterhin wird die Abstrahlung elektromagnetische Wellen erheblich reduziert und die Schirmung des Oszillators am Einspeisepunkt kompakter bzw. erleichtert, was den Expositionsbereich, in dem sich kein Betriebspersonal aufhalten darf, verkleinert.
• Zu 2: Es ergibt sich eine beachtliche Einsparung an Bohrungen unter Beibehaltung des unter Pkt. 1 angegebenen Vorteils. Die dazu benötigte Bohrtechnik ist zwischenzeitlich entwickelt und als ,multi-lateral drilling' bekannt. Weiterhin kann ein Oszillator aufgrund der räumlichen Nähe wechselweise an verschiedenen Induktoren betrieben werden, bzw. mehrere Oszillatoren zeitweise, z. B. in während der Vorheizphase, auf einen Induktor zusammengeschaltet werden. Wiederum verringert sich der Schirmungsaufwand, wenn mehrer Oszillatoren in einer Schirmkabine betreiben werden können.
• Zu 3: Die Erdung der Leiterenden führt zum elektrischen Schließen der Leiterschleife, ohne dass eine direkte elektrische Verbindung der Leiterenden notwendig wird. Damit erfordert die Leiterkonfiguration keine besonderen Bohrtechniken, sondern kommt mit den vorhandenen Standardbohrtechniken aus. Der isolierte Induktor-Abschnitt hält den Strom im Leiter und verhindert den vorzeitigen Kurzschluss über das Reservoir, was eine gleichmäßige Verlustverteilung entlang des Induktors ermöglicht. Man kann die Verlustverteilung, die mittels 3d-EM Simulation ermittelbar ist, in der Ebene auf Tiefe des Induktors darstellen. In einem konkreten Beispiel (10 kHz, 707 A rms) verteilen sich die ins Erdreich eingebrachten Verluste wie folgt: 0,3 % beim Hin-/Rückleiterpaar (Abschnitt A), 96,5 % beim Induktor (Abschnitt B) und 3,2 % um die Leiterenden (Abschnitt C).
• Zu 4: Damit werden Wellenlängeneffekte vermieden, die sonst zu Stromvariationen entlang der Leiter und damit zu entsprechender Variation der Verlustleistungsdichte führen würden.
• Zu 5: Die Leistung in den höheren Harmonischen der Umrichtergeneratoren kann zur Reservoirheizung genutzt werden, die anderenfalls als Verluste im Umrichter anfallen würden und diesen sogar zerstören könnten.
• Zu 6: Die rotationssymmetrische Stromverteilung liefert, für den Fall, dass in einem gewissen Radius um die Induktorachse kein Stromdichte vorliegt, ein feldfreies Induktorinneres, das zur Hindurchleitung des Salzwassers oder zur mechanischen Verstärkung des Induktors durch z. B. ein Stahlseil genutzt werden kann, ohne dass dabei im Salzwasser bzw. Stahlseil Wirbelstromverluste auftreten, d.h. ohne dass eine weitere Erwärmung des Induktors auftritt.
• Zu 7: Bei auseinander strebenden Induktoren wie auch bei Fortsetzung in x-Richtung und parallel verlaufenden Injektions- und Produktionsröhren braucht die Induktorlänge nur einen Bruchteil der Länge der Röhren zu haben, was bei Herstellung, Installation (max. Einbringlänge ist von Steifigkeit des Induktors abhängig und evtl. geringer als von Röhren) und Betrieb (Herabsetzung der Spannungsanforderungen an die Generatoren und Herabsetzung der Druckanforderungen zur Salzwasserinjektion) vorteilhaft ist. Die Einstellbarkeit der PhaSenlage der Generatoren relativ zueinander erlaubt die Beeinflussung der Rückströme durch das Reservoir und damit der Verlustleistungsdichteverteilung im Reservoir.
• Zu 8: Die von den Induktoren induzierten elektrischen Felder verlaufen parallel zu diesen und damit bei der vorgeschlagenen Orientierung senkrecht zu den Injektions- und Produktionsröhren. Damit kann eine weitgehende induktive Entkopplung von Induktoren und Röhren erreicht werden, womit Spannungen auf den Röhren, Wirbelstromheizung in der unmittelbaren Umgebung der Röhren sowie die Beeinflussung bzw. Störung von elektrischer Ausstattung (wie Sensoren) in/an den Röhren verhindert oder zumindest stark vermindert werden.
• Zu 9: Die Herstellung und die Betriebssicherheit der Induktoren werden vereinfacht, wenn keine Vorrichtung zur Salzwasserleitung vorgesehen werden muss. Andererseits verringert sich die Zahl der zusätzlichen (senkrechten) Bohrungen, die zur Injektion des Salzwassers benötigt wird, wenn die Elektrodenabschnitte dicht zusammengeführt werden.
• Zu 10: Die vorzugsweise erfolgende Zusammenfassung von elektrischem Hin- und Rückleiter und Einbringen in eine Bohrung spart in der Praxis erhebliche Bohrkosten.

The new system has considerable advantages over the systems and devices previously known from the prior art and also from those described in the prior, unpublished patent applications. These are in detail:

• To 1: The magnetic fields of the oppositely energized forward and return conductors are almost completely compensated so that only small eddy currents are induced in the immediate vicinity of the overburden ("overburdening") and thus the power loss is drastically reduced. The coaxial design of the forward and return conductors from the power loss view is ideal, but requires increased effort at the junction. In the coaxial arrangement, the environment is completely field-free. In particular, this also permits the use of electrically conductive and magnetic materials (steel) for enclosing the forward / return conductor pair or a lining of the bore with steel pipes in the section of the conductor pair. Furthermore, a hole is saved. Furthermore, the electromagnetic radiation emission is considerably reduced and the shielding of the oscillator at the entry point is made more compact or easier, which reduces the exposure area in which no operating personnel may be present.
• To 2: There is a considerable saving in drilling while maintaining the advantage specified in point 1. The required drilling technique has been developed in the meantime and is known as 'multi-lateral drilling'. Furthermore, an oscillator can be operated alternately on different inductors due to the spatial proximity, or several oscillators temporarily, for. B. in during the preheating, be connected to an inductor. Again, the shielding effort is reduced when multiple oscillators can be operated in a screen cabin.
• To 3: The grounding of the conductor ends leads to electrical closing of the conductor loop, without a direct electrical connection of the conductor ends is necessary. Thus, the ladder configuration requires no special drilling techniques, but comes with the existing standard drilling techniques. The isolated inductor section holds the current in the conductor and prevents premature shorting across the reservoir, which allows a uniform loss distribution along the inductor. One can represent the loss distribution, which can be determined by 3d-EM simulation, in the plane on the depth of the inductor. In a specific example (10 kHz, 707 A rms), the losses introduced into the ground are as follows: 0.3% for the return conductor pair (section A), 96.5% for the inductor (section B) and 3.2 % around the conductor ends (section C).
• Ad 4: This avoids wavelength effects that would otherwise lead to variations in the current along the conductors and thus to a corresponding variation in the power dissipation density.
• Re 5: The power in the higher harmonics of the inverter generators can be used for reservoir heating, which would otherwise be incurred as losses in the inverter and could even destroy it.
• To 6: The rotationally symmetric current distribution provides, in the event that there is no current density in a certain radius around the inductor axis, a field-free Induktorinneres that for passing the salt water or mechanical reinforcement of the inductor by z. B. a steel cable can be used without causing eddy current losses occur in salt water or steel cable, ie without further heating of the inductor occurs.
• 7: In the case of diverging inductors as well as continuation in the x-direction and parallel injection and production tubes, the inductor length only has to be a fraction of the length of the tubes, which depends on the rigidity of the inductor during manufacture, installation (maximum insertion length and possibly less than tubes) and operation (reduction of voltage requirements to the generators and reduction of pressure requirements for salt water injection) is advantageous. The adjustability of the phaSenlage the generators relative to each other allows the influence of the return currents through the reservoir and thus the power loss density distribution in the reservoir.
• To 8: The induced by the inductors electric fields parallel to these and thus in the proposed orientation perpendicular to the injection and production tubes. Thus, a substantial inductive decoupling of inductors and tubes can be achieved, which stresses on the tubes, eddy current heating in the immediate vicinity of the tubes and the influence or disturbance of electrical equipment (such as sensors) are prevented in / at the tubes or at least greatly reduced ,
• To 9: The manufacturing and the reliability of the inductors are simplified, if no device for salt water line must be provided. On the other hand, the number of additional (vertical) holes needed to inject saltwater is reduced as the electrode sections are tightly packed together.
• 10: The preferred combination of electrical return conductor and insertion into a bore saves considerable drilling costs in practice.

It can be produced in sections adapted Heizleistungsstärke. In the predominantly vertical sections, the return and the return conductors are close together. This allows very low inductive heating powers in the surrounding outer layer ('overburden') of, for example, only 2.5 W / m ( Fig. 5 Table 1, Distance 0.25 m), which is desirable because heating of the top coat is not intended. In Sections 2 to 7, the return and return conductors are routed at different distances, so that the heating power can be adapted to the respective section. The larger the distance, the higher the heating power per length. In table ( Fig. 5 ) are heating services for a typical reservoir is listed for different distances from the return conductor, which results when energized with 825 A (peak) @ 20 kHz. Today's drilling technology allows the distances to be reduced to 5m, whereby a variation of the heating power in the considered reservoir by a factor of 80 can be achieved (111 W / m with 5 m distance, 8874 W / m with 100 m distance) with the same current the sections, which is mandatory due to the series connection. This is possible on geological and conveyor technical conditions of the reservoir sections adapted heating power input.

In the table below, the inductance pads of a double line from the forward and return conductors of the inductor are specified. These vary depending on the distance. The influence of different reservoir conductivities is very low. The inductor as a whole constitutes a series circuit of series resonant circuits. A series circuit is formed by the line section having the resonant length. Ideally, all series circuits are resonant at the same frequency. Thus, the lowest voltages along the inductor are obtained. Sectionally varied distances lead in inductors constant resonant length to partially incomplete compensation, resulting in increased demands on the dielectric strength of the dielectric between filament groups, which in the worst case can lead to breakdowns and destruction of the inductor. Remedy is to be created by the resonance length and thus the capacity of this section are adapted to the existing inductance there.

In the invention, the capacitance coating can advantageously be easily adapted to the respective inductance coating, which in turn can be set in sections, the same resonant frequency without changing the resonance length. Even with a combination of the latter measure, the goal of minimum voltage requirement can be achieved in sections.

If the geological conditions in the reservoir are well known, the inductor laying can be carried out with intervals adjusted in sections to the heating power demand. This can be done practically simultaneously with the introduction of the steam injection and production pipes for SAGD, so that the inductive heating is already available for the preheating phase.

The following procedure can also be advantageous: The SAGD process is initially run for several months or years without EM support. The steam chambers are already formed. Vapor chamber expansion variations along the steam injection and production tubes are generally undesirable because they can result in showable vapor breakthrough in individual sections ("steam breakthrough region"). If such a steam breakthrough occurs can and circumstances, the bitumen still in the other sections of the reservoir no longer economical (S team to O il R atio (SOR) <3) are promoted, so heavy financial losses can be connected. Such losses can be avoided if long before a steam breakthrough, the inductive heating is used to regulate the Dampfkammerausdehnung. For this purpose, the spacer-optimized inductor laying can be carried out adapted to the inductive additional heating power required in sections. With this retrofit solution, the yield of existing SAGD fields can be achieved.

In the specific embodiments with the associated figures below, the inductors are shown within the reservoir at the same depth and the change in distance is accomplished only in the horizontal direction. Laying of the return conductor of an inductor can also take place at different depths if the resulting heat output distribution and / or the laying of the inductor lines are thus more favorable, for example due to lower drilling costs, which may result from softer rock formations or other geological boundary conditions.

If there are sections of different electrical conductivities in the reservoir, then the heating power density can be homogenized by adjusting the inductor distance. An example is given in the table. If 4 kW / m are to be introduced in a reservoir section with a specific resistance of 555 ohm * m, the inductor spacing must be 50 m in this example geometry. If the electrical conductivity in another section of the reservoir is only half, the inductor distance must be increased to 67 m in order to generate 4 kW / m heating power again.

In certain sections, return and return conductors can advantageously be guided close together, if only low heating power densities are required there. Thus, the return conductor may run through the steam chamber and be exposed to the high temperatures prevailing there (for example 200 ° C.), which may lead to premature aging of the inductor and thus to a reduction in the service life. This can be avoided if, as shown in Section VI, the area of the steam chamber is bypassed horizontally and / or vertically.

In many cases, in the SAGD process at the beginning of the horizontal section, the vapor chamber grows faster than in the more upstream sections, since the vapor temperature near the point of introduction is the hottest and the vapor pressure is highest. This often leads to the formation of a large steam chamber. Therefore, it may make sense to do without an additional inductive heating there, also to avoid premature steam breakthroughs. For this purpose, the oscillator can be moved forward, so that the inductor does not need to go through the steam chamber at the beginning.

The same can be achieved if the inductor is guided downwards at a more obtuse angle if the oscillator is to continue to be installed near the injection and production tubes. It is advantageous that inductor length and associated drilling costs can be saved. Furthermore, the premature aging of the inductor in the region of the first steam chamber is avoided.

In the invention inductor arrangements are possible in which the loop is closed underground, which can be done with advanced drilling techniques. The oscillator can be installed as shown in the end of the pipe pair or as in the previous figures in the vicinity of the beginning of the tube pairs (so-called Well-Heads). The underground closed conductor loop with recess of the steam chamber saves inductor length and therefore costs.

Further details and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings in conjunction with the claims.

Figur 1

eine Ölsand-Lagerstätte aus mehreren Elementarbereichen mit mehreren Leiteranordnungen zur induktiven Reservoir-Heizung und einem Förderrohr,

Figur 2

eine Leiteranordnung zur induktiven Reservoir-Heizung mit geerdeten Induktoren,

Figur 3

eine Anordnung entsprechend Figur 2 mit abschnittsweise verschiedenen Abständen der Induktorleitungen,

Figur 4

die Aufsicht einer Induktoranordnung gemäß Figur 3 mit acht Sektionen unterschiedlicher Leiterabstände,

Figur 5

den schematischen Aufbau eines kompensierten Induktors mit verteilten Kapazitäten,

Figur 6

den Querschnitt eines Multifilamentleiters mit zwei Filamentgruppen,

Figur 7

eine Aufsicht auf eine Anordnung mit einer groß ausgebildeten Dampfkammer am Anfangsabschnitt des Injektionsrohres und einer davon verlagerten Oszillatorposition,

Figur 8

eine von Figur 7 abgewandelte Aufsicht mit Oszillatorposition im Endbereich des Rohrpaares und unterirdisch geschlossener Leiterschleife,

Figur 9

eine Anordnung zur induktiven Reservoir-Heizung mit in entgegen gesetzten Richtungen verlaufenden und geerdeten Induktoren und

Figur 10

einen Ausschnitt aus einem zweidimensionalen Induktor-Oszillator-Array mit abschnittsweise zusammengeführten Elektrodenabschnitten zwecks Erdung.

Each shows in schematic and partial perspective view

FIG. 1

an oil sands deposit of several elementary areas with multiple conductor arrangements for inductive reservoir heating and a production pipe,

FIG. 2

a conductor arrangement for inductive reservoir heating with grounded inductors,

FIG. 3

an arrangement accordingly FIG. 2 with sectionally different distances of the inductor lines,

FIG. 4

the supervision of an inductor according to FIG. 3 with eight sections of different conductor distances,

FIG. 5

the schematic structure of a compensated inductor with distributed capacitances,

FIG. 6

the cross section of a multifilament conductor with two filament groups,

FIG. 7

a plan view of an arrangement with a large-scale steam chamber at the beginning portion of the injection tube and an oscillator position displaced therefrom,

FIG. 8

one of FIG. 7 modified plan view with oscillator position in the end area of the pipe pair and underground closed loop,

FIG. 9

an arrangement for inductive reservoir heating with running in opposite directions and grounded inductors and

FIG. 10

a section of a two-dimensional inductor-oscillator array with partially merged electrode sections for grounding.

In the individual figures, the same elements have the same or corresponding reference numerals. The figures are partly described together.

In the three-dimensional representations of a seam with oil reservoir according to the FIGS. 1 to 3 and 6, 9 and 10 each means 100 an elementary unit of the reservoir, which is considered in each case for the individual descriptions of the other figures. Such elementary unit is arbitrarily repeatable in both horizontal directions of the seam.

The latter goes for example from the FIG. 1 An underground oil sands deposit (seam) forms the reservoir, with elementary units 100 of length l, height h and thickness w being produced one behind the other or next to one another. Above the reservoir 100 is an overburden layer 105 ("overburden") of thickness s. Corresponding layers ("underburden") are under the reservoir 100, but are in FIG. 1 not marked in detail.

In the known SAGD method, at the bottom of the reservoir 100 are substantially one above the other an injection pipe for introducing steam, by which the viscosity of the bitumen or heavy oil is lowered, and a production pipe available. The production pipe is in FIG. 1 designated 102, while an injection tube is not shown here and possibly also unnecessary. It has already been proposed to provide 100 lines and / or electrodes for electrically heating the reservoir. Especially for inductive heating are in FIG. 1 the lines as inductor 10, 20 executed. The inductor lines 10, 20 are guided in the reservoir 100 at the predetermined distance a ₁ substantially parallel and horizontal.

It is essential in FIG. 1 that production tube 102 and inductor lines 10, 20 do not run in the same direction, but in particular form a right angle. There may also be other angles, ie orientations of inductor lines and production tubes. This allows for the geological boundary conditions.

Each of the repeating units 100 is assigned an oscillator unit 60, 60 ',... As an over-the-day RF power generator, from which the electrical power is generated and fed via the forward and return conductors into the inductors. For this purpose, the return and return conductors must be routed vertically through the overburden into the reservoir. If the distance a ₂ of the forward and return conductors in the vertical range is as low as possible and a1> a2, there is no heating and energy is saved.

In FIG. 1 are for two holes 12, 12 'available, which have a distance of less than 10 m. This is small in comparison to the dimensions of the reservoir and in particular the length of the inductor lines 10, 20. In one bore, the forward conductor and in the other bore of the return conductor is guided, wherein in the reservoir at the transition to the inductor lines widening to a multiple distance is made.

Instead of in separate parallel holes return conductor can also be performed in a single bore, which there is the possibility of an even smaller distance. In a single borehole, the forward and return conductors can be stranded together or form a coaxial cable, which is branched in the reservoir.

In the FIGS. 1 . 2 and FIGS. 6 to 8 each show a coordinate system with the coordinates x, y and z, which facilitates the mining orientation. The coordinate system can also have a different orientation.

Specially based FIG. 2 illustrates that below the ground first an area 105 with overburden, then a deposit with a reservoir 100 of bitumen and / or heavy oil and below an oil-impermeable area 106, the so-called basement, follow. Such soil or rock formations are typical for oil shale or oil sands deposits.

According to FIG. 2 is introduced into the deposit 100 by an oscillator 60 as a high-frequency generator, which stands for days, electrical energy. For this purpose, a single vertical bore 12 is present in this case, which extends into the region of the reservoir 100 and there passes into two horizontal holes, which are not marked in detail. From outside the overburden there are further provided means for introducing salt dissolved in water (so-called saline) which have suitable conductivity properties.

In the vertical bore 12, a pair of conductors with a common electrical return conductor 5 is introduced, wherein the end-side ends of the forward and return conductors are connected to the oscillator 60 as an energy converter. The other ends extend to the reservoir 100.

Upon reaching the reservoir 100, the forward / return pair 5 branches. For this purpose, a so-called Y-branch 25 is present. Starting from the Y-branch 25, the inductor lines 10 and 20 run horizontally in the reservoir 100 parallel in the reservoir 100 and into the region of the saline-injected region in which the conduits 10 and 20 are not insulated and act as electrical inducers. In particular in the area of the inductor lines 10, 20, therefore, the induction heating should be formed.

With such a device, the power loss is significantly reduced, since the magnetic fields of the guided at a small distance opposite energized forward and return conductors in the region A almost completely compensate. The combined return conductor pair may be formed, for example, as a coaxial line 5. In particular, in the coaxial arrangement, the environment of such a pair of conductors is completely field-free. This then allows the use of electrically conductive and magnetic materials for a sheathing of the forward / return pair or a border of the vertical bore 12 with steel pipes.

The formation of the Y-branch 25 is carried out in an electrotechnically known manner, which is not discussed in detail in the present context.

Since the radiation of electromagnetic waves in the region of the vertical borehole 12 is considerably reduced, the shielding of the oscillator 60 at the entry point can be made more compact. This proves to be advantageous for the so-called exposure area, in which no operating personnel may stay.

In the figures, the actual production pipe is indicated by 102. This is conventionally designed in accordance with the prior art such that the liquefied bitumen collects therein, whereafter it is sucked off in a known manner.

At the end of the two conductors 10 and 20 results according to FIG. 1 in each case an approximately cylindrical saline-influenced region 11/12, which is of particular importance for the electrical conductivity and thus the inductive heating effect. It will Thus, the effect of a low-impedance grounding of the inductors achieved without these need to be connected to each other via a separate conductor loop under or over days.

Total form in FIG. 2 So three areas: The lines 10/20 of the oscillator 60 to the branch 25 form a first section A, in the reservoir 100, a second section B and in the end a third section C. In the individual sections A, B and C may advantageously different Conductor arrangements are selected. For example, stranded conductors are used in the first section A. In the second section B, on the other hand, insulated conductor ("isolated single conductor") are used for the inductor lines, while in the third section C uninsulated conductor ends are present which form electrodes.

In FIG. 3 is shown that in an arrangement accordingly FIG. 1 lead in this case guided induction lines 10 and 20 need not be parallel. Rather, they have sections of different distances a _i , which can be adapted to the conditions of the deposit. Depending on the geological conditions, they can have sections for an inductive interaction with each other and be kept very narrow there, so that their fields compensate each other. In particular, in the event that in the deposit 100, a gas bubble 30 is present by the vapor input by SAGD method, which represents a so-called "deaf" area and / or which is already exploited, there can be the parallel arrangement of the lines 1/20 around this area of the vapor bubbles, and widen again behind the vapor bubble 30 to generate the inductive heating effect. In the end, in turn, results in a known manner, a conductor loop, which is particularly closed above ground, which is easy to achieve manufacturing technology.

A corresponding supervision of such an inductor arrangement results from FIG. 4 , There are here a total of eight sections I, II, ..., VIII entered with different distances a _{i of} the inductor 10/20. It should be noted that for the sections I, II,..., VIII separately individual compensation measures of the lines are carried out taking into account the changed resonance lengths.

The following table shows the inductance coverings of a double cable, ie the return conductor of the inductor. As mentioned, these vary between about 0.46 and 1.61 μH / m depending on the distance a _i . The influence of different reservoir conductivities is very low. The inductor as a whole represents a series connection of series resonant circuits.

A series circuit is formed by the line section having the resonance length L _R. Ideally, therefore, all series circuits would be resonant at the same frequency. This would give the lowest possible voltages along the inductor. Sectionally varying distances lead but in inductors constant resonant length to a partially incomplete compensation, which leads to increased demands on the dielectric strength of the dielectric between filament groups. Under certain circumstances, it may otherwise lead to breakdowns or even to the destruction of the inductor.

Remedy can be created by the resonant length and thus the capacity of this section are adapted to the present there inductance in the individual sections. Table: Removal of the ladder [m] Reservoir resistance [Ωm] Heating power rate [W / m] Inductance (analytic) [μH / m] Inductance (FEM) [μH / m] Resonance length @ 20kHz [m] 12:25 555 2.5 0456 0456 37.1 5 555 111 1055 1055 24.4 10 555 356 1194 1193 22.9 15 555 688 1275 1273 22.2 50 555 4059 1516 1490 20.5 100 555 8874 1564 1569 * 20.0 100 2 * 555 6859 1564 1608 * 19.8 67 2 * 555 4067 1574 1552 20.1

Column 1 of the table shows the distance of the induction lines in m, in column 2 the resistivity of the reservoir in m, in column 3 the applied electric power in W / m, n column 4 and the inductance in μH / m (analytically and by FEM calculated) and in column 6, the resonance length in the applied for an oscillator frequency of 20kHz.

It can be seen that with increasing distance of the inductor, the Heizleistungsrate increases as electrical power loss. Conversely, this results in that only a small power loss is obtained at comparatively small distance of the inductor, since the electromagnetic fields - as in the vertically guided return conductor pair 5 - compensate as far as possible and thus no inductive heating effect arises in nearby adjacent lines. This effect can be exploited if necessary. Similarly, the resonance length L _{R of} the line changes, which must be adjusted accordingly as described in detail in the earlier application AZ 10 2007 008 282.6 is shown.

In the table, therefore, the resonance lengths adapted for the respective distance of the return conductor are listed so as to obtain, in sections, the same resonant frequency, for example 20 kHz. The relative change in resonant length is proportional to 1 / sqrt (inductivity coating). This means that the resonance length in the vertical sections inductor distance of z. B. 0.25 m is about twice as large as a nominal inductor distance of 100 m. Corresponding changes result, for example, at a resonance frequency of 100 kHz. Specifically, resonant frequencies between 1 and 500 kHz are considered suitable, with 10 kHz on the one hand and 100 kHz on the other.

As already mentioned in the introduction, the compensation of the inductor lines is the subject of the earlier patent application AZ 10 2007 008 282.6 and there already described in detail, which is incorporated herein by reference. In particular, so-called multifilament conductors can be used accordingly FIG. 5 to be used, which in turn to the earlier patent application AZ 10 2008 036 832.3 is referenced.

In the latter context is on the Figures 5 and referenced: FIG. 5 shows the schematic structure of the compensated conductors for the inductor lines with distributed capacitances and FIG. 6 the cross section along the line VI - VI. The lines are formed of conductors 51 and 52, respectively FIG. 6 Multifilament lines within an insulation 53 form. The resonance length L _R can be adapted to the sectionally changing distance of the inductor lines.

Based FIG. 7 is clarified that in an arrangement accordingly FIG. 2 For example, a particularly large trained steam chamber 30 may be present at the beginning portion of the injection tube. In this case, it is recommended that the oscillator position, ie the generator 60, for days move or even in the end of the conductor pair 10/20 to arrange. The lines are closed in this case with an underground conductor loop 15, which may also be located directly behind the steam bubble.

In FIGS. 7 and 8 corresponding schemes are shown as a top view. From these two figures it is particularly clear that the inventive concept is also suitable for retrofitting existing bitumen or heavy oil conveyor systems. In practice, certain areas of oil sands deposits have already been exploited by the known SAGD method, with large vapor bubbles usually forming in the areas already exploited. By means of a device with "mobile" high frequency generator 60, it is possible to displace and redirect the inductor assembly from the initial section of the injection / delivery tube device. It is equally possible to provide the oscillator position in the end region of the tube pair. In this case, the inductor conductor loop is then advantageously always closed underground

In FIG. 9 an arrangement is shown in the corresponding FIG. 1 a vertical bore 12 is provided approximately in the center of the illustrated reservoir 100. At an oscillator 60 located there, a pair of conductors 5 is again introduced into the vertical bore 12. Upon reaching the deposit 100, such a branch 25 is now present, in which the horizontal conductors 110, 120 run diametrically in opposite directions-that is to say with an increasing distance-and are in each case earthed via electrodes 111 and 121 there.

The corresponding distribution of the heating power in this geometry was also calculated for this case by means of FEM (Finite Element Methods) and gave satisfactory boundary conditions.

It is also possible with such a routing of the inductor lines, the non-insulated conductor ends out of the reservoir out in areas of higher electrical conductivity. For example, water-bearing layers offer themselves outside the reservoir, for example in the overburden or underburden.

In the FIG. 10 is finally a modification of a system according to FIG. 1b with arrangements according to FIG FIG. 9 shown in which a two-dimensional 200 is formed of individual inductors. The inductors are shown with diverging lines one behind the other and in two rows next to each other. Two deposits of oscillators 60, 60 ', 60 ",... Are respectively present above the deposit 100, of which pairs of conductors 5, 5', 5",... Are perpendicular through the overburden to the deposit 100 run and branch off via corresponding rows of branches 25, 25 ', 25'', ... in opposite directions.

By counter-switching such arrangements, the power loss can be minimized and thus optimize the converted heat output.

Specific to the in FIG. 10 shown two-dimensional array is that it consists of a plurality of antennas, which in FIG. 10 Concrete by the individual inductor pairs 110 _ij / 120 _ij , are formed, which can be controlled individually by current amplitude and phase. For this purpose, each inductor pair is assigned its own generator from the group of the generators 60 _ij distributed in arrays in FIG.

Overall, it should be noted that now the forward and return conductors of the inductor in the overburden are guided substantially vertically to the depth of the deposit and in comparison to the longitudinal extension of the lines have a low lateral distance a of at most 10 m, but in particular less than 5 m. Preferably, the inductor lines are in led the deposit horizontally and regions have different distances, whereby the power distribution is changeable. If the vertical outward and return conductors running vertically in the overburden are combined to form a line pair, the line pair can be introduced in a single bore which reaches down into the reservoir and can only be branched in the reservoir. In the overburden then no power losses.

Claims (32)

1. Installation for the in-situ extraction of a substance containing hydrocarbons from an underground deposit via at least one production pipeline which leads out of the deposit, in particular for extracting bitumen or extra-heavy oil from a reservoir under a capping while reducing the viscosity thereof, wherein the production pipeline in the deposit is assigned means for induction heating of the production pipeline environment, said means comprising an electrical high-power generator outside of the capping and deposit, an electrical forward and return conductor, and inductor lines which are connected thereto and the forward and return conductors (5) of the inductor lines (10, 20; 110, 120) are guided essentially vertically in the capping (105) to the depth of the deposit (100) and, in comparison with the linear extent of the lines, have a small lateral distance (a) between them of maximally 10 m and characterised in that the inductor lines (10, 20; 110, 120) running horizontally in the reservoir (100) have regionally differing distances (a_i) between them.
2. Installation according to claim 1, characterised in that the forward and return conductors (5) for the two inductor lines (10, 20; 110, 120) are guided in parallel boreholes (12, 12') having a maximal distance between them of 10 m.
3. Installation according to claim 2, characterised in that the forward and return conductors (5) for the two inductor lines (10, 20; 110, 120) are guided as capacitively compensated lines in the parallel boreholes (12, 12').
4. Installation according to claim 1, characterised in that the forward and return conductors (5) for the two inductor lines (10, 20; 110, 120) have a maximal lateral distance between them of 0.25 m and are guided in a shared borehole (12).
5. Installation according to claim 4, characterised in that the shared borehole (12) has a diameter of < 0.5m, in which the forward and return conductors (5) for the two inductor lines are guided at a close distance to each other.
6. Installation according to claim 5, characterised in that the forward and return conductors (5) for the two inductor lines (10, 20; 110, 120) are insulated against each other and form a combined line.
7. Installation according to claim 5 or 6, characterised in that reverse lay stranding or same lay stranding applies for forward and return conductors (5) in the borehole (12).
8. Installation according to claim 5 or 6, characterised in that forward and return conductors (5) form a coaxial line in the borehole (12).
9. Installation according to one of the preceding claims, characterised in that a plurality of conductor pairs (5_i) comprising forward/return conductors for the inductor lines (10_i/20_i; 110_i/120_i) are guided in the single borehole (12).
10. Installation according to one of claims 6 to 8, characterised in that the combined line pair (5) comprising forward and return conductors for the inductor lines (10, 20) is split in the reservoir (100).
11. Installation according to claim 10, characterised in that a so-called Y junction (25) is formed for the branch point.
12. Installation according to one of the preceding claims, characterised in that a first section (A) is formed from the oscillator (60) to the reservoir (100), a second section (B) in the reservoir is formed in the reservoir, and a third section (C) including conductor loop (15) and/or saline (11, 21) is formed in the end region.
13. Installation according to claim 7 or 8, characterised in that a different structure of the conductor (5; 10, 20; 11, 21; 110, 120) is selected in each case in the individual sections (A, B, C).
14. Installation according to claim 14, characterised in that stranded conductors are used for the forward/return conductor pair (5) in the first section (A).
15. Installation according to claim 13, characterised in that active insulated conductors (insulated single conductors) are used for the inductor lines (10, 20; 110, 120) in the second section (B).
16. Installation according to claim 13, characterised in that capacitively compensated conductors are used for the inductor lines (10, 20; 110, 120) in the second section (B).
17. Installation according to claim 13, characterised in that non-insulated conductor ends are provided in the third section (C), forming electrodes (11, 21) in the saline region.
18. Installation according to claim 17, characterised in that the electrodes (11, 21) form an electrical loop in conjunction with salt enrichments.
19. Installation according to claim 17, characterised in that the non-insulated conductor ends (11, 21) are guided from the reservoir (100) into layers of greater electrical conductivity, e.g. to water bearing layers outside of the reservoir (100).
20. Installation according to claim 15, characterised in that the inductor lines (110, 120) run in the same direction at the end of section A.
21. Installation according to claim 15, characterised in that the inductor lines (110, 120) run in opposing directions at the end of section A.
22. Installation according to claim 21, characterised in that sections (I - VIII) having an adapted resonance length (L_R) in each case are formed along the inductor lines (10, 20; 110, 120) in the reservoir (100), such that all sections are resonant at the same frequency.
23. Installation according to claim 21, characterised in that "dead" or exploited regions of the deposit (100), e.g. regions containing a steam pocket (30), are bypassed by the inductor lines (10, 20; 110, 120) that run as a pair in each case.
24. Installation according to claim 23, characterised in that the two inductor lines (10, 20; 110, 120) in the bypassed region are guided closely together and their electromagnetic fields therefore compensate for each other and the heat output level is limited.
25. Installation according to one of the preceding claims, characterised in that an array (160) of conductor pairs (110_i, 120_i) and power generators (60_ij) is formed.
26. Installation according to claim 25, characterised in that each power generator (60_ij) is assigned a conductor pair (110_i, 120i).
27. Installation according to claim 25, characterised in that the array (160) with the orientation of the line pairs (110, 120) is arranged at a predefined angle, in particular transversely, relative to the direction of the extraction pipes (102_i).
28. Installation according to one of the preceding claims, characterised in that a power generator (60) can be used for a plurality of line pairs (110_i, 120_i).
29. Installation according to claim 25, characterised in that the power generators (60_ij) of the array (160) can be switched.
30. Installation according to one of the preceding claims, characterised in that the power generators are high-frequency oscillators (60_ij) which generate electrical power at frequencies between 1 and 500 kHz.
31. Installation according to claim 30, characterised in that the frequency is approximately 10 kHz.
32. Installation according to claim 30, characterised in that the frequency is approximately 100 kHz.

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