WO2012049007A1 - Device and method for using the device for "in situ" extraction of bitumen or heavy oil from oil sand deposits - Google Patents

Abstract

The present invention relates to a device and a method for using the device for "in situ" extraction of bitumen or heavy oil from oil sand deposits (1). The device has at least one electrical conductor loop (2) comprising a feed conductor (10), a return conductor (20) and an inductor (15) connected therebetween, wherein at least the inductor (15) is at least partially or completely disposed in the oil sand deposit (1). The device further has an alternating current generator (30) that is electrically connected to the at least one conductor loop (2) by means of at least two electrical contact points (40, 40'). The alternating current generator (30) has a transformer (50) comprising at least one primary (PR) and at least one secondary winding (SE). The at least one secondary winding (SE) comprises a center tap (70) to which a ground potential U_E is electrically connected.

Description

description

Apparatus and method for using the apparatus for "in situ" production of bitumen or heavy oil from oil sands deposits

The present invention relates to an apparatus and a method of using the device for "in situ" production of bitumen or heavy oil from oil sands deposits.The device comprises at least one electrical conductor loop comprising a forward conductor and a return conductor, and has an interposed inductor, wherein at least the inductor is at least partially or completely disposed within the oil sands deposit. Furthermore, the apparatus comprises an alternating current generator, comprising a conductor loop via at least two electrical ^¬ specific contact points is electrically connected to the at least. the alternator includes a Transformer with at least one primary and at least one secondary winding.

Bitumen or heavy oil may be mined from open-pit or "in situ" production from oil sands or oil shale deposits, which are hereinafter referred to simply as "oil sands" or "reservoirs" for simplicity the introduction of solvents or diluents and / or the heating of the soil of the oil sands deposit in order to make the heavy oil or bitumen flowable and pumpable. A widely used method for the "in situ" -promoting based on the SAGD (Steam Assisted Gravity Drainage) process. Water vapor is introduced ^¬ introduced under high pressure into the ground through a horizontally extending inside the reservoir tube The heated, flowable heavy oil. or bitumen si ^¬ ckert to a second, for example about 5m deeper pipe through which it is pumped or conveyed.

From DE 102007040605 B3 a method is known in which the heating of the soil of an oil sands deposit inductively via an electrical / electromagnetic Heizver ^¬ drive takes place. The process allows the heating of unconventional heavy oil with viscosities of, for example, 5 ° API to 15 ° API of temperatures from about 10 ° C ambient to up to 280 ° C. Thereby, the oil can flow in a gravitativen by the improvement of the fluidity process to the lower non-permeable boundary layer of the reservoir and from there by known drainage production pipes abflie ^¬ Shen, pumped either by lifting pumps to the surface or by the in the reservoir by heating and / or Steam introduced pressure to be conveyed gravity overcoming to the surface.

The electromagnetic heating process may in particular be combined with a steam process, which provides for a verbes ^¬ serte permeability and / or conductivity. It is also possible to let the steam stimulation through the production pipe at the beginning of the heating phase or later cyclically.

The electrical / electromagnetic heating method is Runaway ^¬ leads with the aid of at least one electric conductor loop which / is powered by an alternating current generator with electric power or alternating current voltage. This enables "in situ" underground mining at depths of up to several hundred meters The conductor loop in conjunction with the alternator forms a resonant oscillating circuit in the current-carrying state, which results in an alternating magnetic field in the vicinity of the conductor loop in the reservoir. The eddy currents lead to egg ^¬ ner heating of the reservoir and thus to a liquefaction of the heavy oil or bitumen.

In order to achieve a good heat output in the MW range, the conductor loop must be supplied with an electrical voltage of up to 10 kV or even greater from the alternator. This means that the voltage of up to to 10kV or greater is applied to terminals that electrically connect the conductor loop to the alternator, and that the voltage can drift freely to ground potential. In order to reliably prevent electrical breakdowns or arcing from a connection of the conductor loop to the surrounding earth ^¬ rich, a dielectric strength by a factor of X, which may be 2 to 10, for example, interpret higher than the maximum clamping voltage. This leads to ei ^¬ nem high insulation costs and high costs.

The object of the present invention is therefore to provide a device and a method for using the device for "in situ" production of bitumen or heavy oil from oil sands deposits, which reduce the insulation effort and there ^¬ possibly with associated costs high electrical heating power be given a reliable insulation of the terminals from the environment.

The stated object is with respect to the device for "in situ" production of bitumen or heavy oil from oil sands deposits with the features of claim 1, and with respect to the method of using the device for "in situ" - promotion of bitumen or heavy oil from oil sands -Lagerstätten solved with the features of claim 11.

Advantageous embodiments of the device according to the invention and of the method for using the device for "in situ" production of bitumen or heavy oil from oil sands deposits emerge from the respectively associated dependent subclaims be combined with each other.

An inventive device for "in situ" extraction of bitumen or heavy oil from oil sands deposits comprises at least one electric conductor loop, which has a Hin ^¬ conductor and a return conductor and an inductor connected therebetween or comprises. The inductor is infrequent partially or wholly located in the oil sands deposit. The forward and return conductors can also act as an inductor or give it identically, the conductor loop in the latter case being formed from a continuous conductor. In the following, a Hinlei ^¬ ter and a return conductor and an intermediate inductor is described for the sake of simplicity, even if return and return conductors act as an inductor or identical result. Under a forward conductor and a return conductor and an inductor connected in between is thus mutatis mutandis to understand a forward and a return conductor, which act as an inductor or give identical. Furthermore, the device ^{according to} the invention Vor ^¬ direction comprises an alternator, which is electrically connected to the at least one conductor loop via at least two electrical contact points. The alternator comprises a transformer with at least ei ^¬ ner primary and at least one secondary winding. The at least one secondary winding has a center tap, to which a ground potential U _{E is} electrically applied.

By applying the ground potential U _E and a ground of the center tap is the maximum electrical output clamping ^¬ voltage which is applied between the contact points on the conductor loop, half the maximum output voltage is limited to, for example. As a result, a considerably smaller insulation requirement for the contact points with respect to the soil in the environment is necessary in order to effectively and reliably prevent flashovers or arcs. With the lower insulation requirements are also associated with lower costs. Free drift of the voltage across the contact cells to the environment or soil is effectively prevented.

The ground potential U _E may be electrically applied to the center tap electrically via a galvanic connection, resulting in a simple and inexpensive solution to the problem. Alternatively, the ground potential U _E may be stinging circuit ^¬ cally applied via an electrical circuit to the active center tap. This will be a circuit engineering Control or regulation according to the method requirements ^¬ ments possible.

Alternatively or in addition to the center tap on the at least one secondary winding, to which a ground potential U _{E is} electrically applied, a Vorrich ^¬ device according to the invention for "in situ" promotion of bitumen or heavy oil from oil sands deposits with the features described above with or without Center tap, on the conductor loop at a location spatially away from the alternator electrically applied a ground potential U _E. The advantages are analogous to the advantages associated with a ground potential U _E at a ^¬ telabgriff on the at least one secondary winding, as described above.

The earth potential U _E can be spatially applied in a region at the conductor loop, in particular at the inductor wel ^¬ cher is furthest away from the alternator. As a rule, the farthest point is in the region of half the length of the conductor loop. A grounding at this point gives a maximum possible limitation of the maximum electrical output voltage which is applied between the contact points on the conductor loop. The insulation requirement of the contact points can be reduced.

Via the inductor, a voltage U _H in the range of greater than 10 kV can be applied for inductive heating of the oil sands deposit. This can result in a heat output in the range of MW and thus sufficient to heat the soil such that bitumen or heavy oil is flowable. The transformers ^¬ tor can be designed as a matching transformer for transforming an output voltage U _A at a voltage in the range of the voltage U _H.

The inductor may have a length of greater than 1km, in particular greater than 5km. So enough soil from the inductor can be heated to ensure a conventional oil production from oil sands deposits. With the exception of a point on the alternator and / or a point of the conductor loop spatially away from the Wech ^¬ selstromgenerator, to each of which the ground potential U _{E can be applied} to ^¬ , the electrical conductor loop fully ^¬ constantly be electrically isolated from the oil sands deposit. In particular, the ground potential U _E can be designed so that heating of the oil sand deposit via the electrical conductor loop is pure or at least substantially purely inductive. The at least one primary winding may be gal ^¬ vanisch separated from the at least one secondary winding. The primary winding may be electrically connected to power converters. The alternator can be designed as an HF generator, with an electrical power in the range of one to several MW at 5 to 200 kHz, in particular 50 kHz. This arrangement and values allow optimum heating of the oil sands deposit to produce bitumen or heavy oil.

An inventive method, in particular using Verwen ^¬ tion of the device described above, comprises applying the ground potential U _E at a location of the secondary winding and / or at a location of the conductor loop spatially away from the alternator, wherein the voltage between the contact points is reduced to a value which corresponds to the value of an output voltage without an applied ground potential U is _e klei ^¬ ner. The voltage between the pads can be reduced to a value which is substantially half the value of an output voltage without applied ground potential U _E.

The advantages associated with the method of using a previously described apparatus for "in situ" production of bitumen or heavy oil from oil sands deposits are analogous to the advantages previously described with respect to the apparatus. Preferred embodiments of the invention with advantageous developments according to the features of the dependent claims are explained in more detail below with reference to the figures, but without being limited thereto.

It is shown in the figures:

1 is a perspective section of an oil sand reservoir 1 with a running in the reservoir 1 electrical conductor loop 2, and

2 shows a circuit diagram of an embodiment of a device according to the invention for "in situ" production of bitumen or heavy oil from oil sands deposits 1 according to FIG. 1.

FIG. 1 shows an oil sand deposit designated as a reservoir, a cuboid unit 1 with the length 1, the width w and the height h always being described for the further considerations. The length 1 may be, for example, up to some 500 m, the width w 60 to 100 m and the height h about 20 to 100 m. It should be noted that starting from the surface E can be up to 500 m present a "overburden" the Staer ^¬ ke s.

When the SAGD method is implemented, in known manner, and for the sake of simplicity not shown, there is an injection pipe for steam or water / steam mixture in the oil sand reservoir 1 of the deposit, and a conveyor pipe for the liquefied bitumen or oil, such as from the prior art, for example DE 102007040605 B3 is known.

The arrangement shown in Fig. 1, or apparatus that comprises, inter alia, a partially or completely arranged in the reservoir 1 conductor loop 2, is provided for the inductive Hei ^¬ wetting of the reservoir 1. This can be done additionally or alternatively to a known heating with eg water vapor. The laid in the ground conductor loop 2, which For example, may have a length of several hundred meters to several ^¬ ren kilometers, comprises a forward conductor 10 and a return conductor 20 and an inductor 15. The forward conductor 10 and the return conductor 20 are side by side, in particular into the ground out or out and the Inductor 15 is electrically connected between the forward and return conductors 10, 20. In general, the inductor 15 is constructed of a substantially U-shaped conductor which is guided horizontally in the ground, wherein both parts of the U-shape are guided in the same depth or are superimposed.

The inductor 15 may be formed continuously from a conductor or be constructed of two conductors, which are connected to each other at the U-shaped end via an element inside or outside of the reservoir 1. In this context, the term "conductor" is understood to mean always electrical conductors. The ladder 10 and 20 are led at the beginning vertically or at a shallow angle down into the ground. Typical distances between the return and return conductors 10, 20 and / or the two parts of the inductor 15 are 5 to 60 m with an outer diameter of the conductors of 10 to 50 cm. The conductors 10, 15 and 20 may also be formed of a continuous conductor or ladder parts. Instead of outgoing and return conductors 10, 20, the inductor 15 can also fulfill its task or, according to its course, be led into the ground and replace it.

An RF generator 30, which may be housed in an external housing, is e.g. electrically connected to the conductor loop 2 via terminals and supplies them with electrical power. In Fig. 1, the terminals are not shown, since they are in the housing with the RF generator 30. A double electric cable, e.g. from the

DE 102007040605 B3 is known as the conductor 10, 20 and 15 be used. A double line, with the above-ge ^¬ called typical dimensions, has a series inductance from 1.0 to 2.7 μΗ / m. The transverse capacitance is only 10 to 100 pF / m with the dimensions mentioned, so that the capacitive cross currents can initially be neglected. At the same time wave effects should be avoided. A shaft speed of an electrical wave is gege ^¬ ben by the capacitance and inductance of the conductor arrangement.

The characteristic frequency of the arrangement is due to the loop length and the wave propagation speed along the arrangement of the double line 10, 15, 20. The loop length is therefore to be chosen so short that no disturbing wave effects result here. The loss Leis ^¬ tung density distribution in a plane perpendicular to the conductors - as it forms at anti-phase energization of the upper and lower conductor - decreases radially. A inductively heating capacity of 1 kW per meter double line at 50 kHz a current amplitude of et ^¬ wa 350 A for low reservoir with specific resistance is ^¬ supernatants of 30 Ω-m and about 950 A for high impedance reservoirs having specific resistances of 500 Ω- m needed. The required current amplitude for 1 kW / m falls quadratically with the excitation frequency, ie at 100 kHz the current amplitudes fall to 1/4 of the above values. With an average current amplitude of 500 A at 50 kHz and a typical inductivity of 2 μΗ / m, the inductive voltage drop is about 300 V / m.

With the above-mentioned total lengths of the double conductors 10, 15, 20, the total inductive voltage drop would add up to values> 100 kV. Such high voltages must be avoided in order to reduce the risk of flashover, in particular between the terminals, and to avoid the need for large insulation layer thicknesses. The terminals must be insulated against the reservoir 1 high voltage resistant to prevent a resistive current flow. Thick insulation layers lead to high material costs and costs.

A solution to the problem can be achieved according to the invention in the grounding of a position of the conductor loop 2 in a region 15 or by grounding a center tap 70 of a secondary winding SE of a transformer 50 of the power generator 30. The latter is possible by the circuit shown schematically in Fig. 2. The conductor loop 2 comprises the forward and return conductors 10, 20 and the inductor 15. The forward and return conductors 10, 20 can also act as an inductor 15 or give it identical, the conductor loop 2 is formed in the latter case of a continuous conductor. The conductor loop 2 is electrically connected via terminals 40, 40 ^' to a transformer 50. The transformer 50 may adjust an output voltage U _A to a voltage U _H at a frequency which is optimal for inductive heating with the conductor loop 2. As described ^above , this is dependent on, for example, dimensions such as length, cross section or construction of the lines or double lines 10, 15, 20 and frequency.

The transformer 50 is constructed, for example, from a primary coil PR and a secondary coil SE. The primary coil PR is supplied by a current / voltage supply 60 with electrical power, with an output voltage U _A. The output voltage U _A is transformed by the transformer 50 to a voltage U _H for heating the inductor 15, wherein in this Be ^¬ consideration voltage losses at the out and return line 10, 20 are neglected for simplicity. The latter Wür ^¬ the additive which result to be obtained or to the secondary coil SE with the voltage U _H to be transformed voltage. The device according to the invention comprises a center tap 70 on the secondary coil SE. At the center tap 70, a ground potential U _{E is} electrically applied, ie it is grounded. Oh ^¬ ne the center tap 70 and with a complete insulation of the conductors 10, 20, 30, would be at the terminals 40, 40 ^'to the full voltage U _H , which may be greater than 10 kV in the maximum in relation to the ground potential U _E and would drift freely. By a grounded center tap 70, the potential difference between the inductor 15 and 10. Hin- 10 and return conductor 20 and surrounding soil safely to half the voltage U _H between the terminals 40, 40 ^' limited. Without a determination of the potential at the center tap 70 or at the opposite end of it conductor loop 2, the potential of the conductor loop could freely drift and so take on a branch on the outgoing or return side higher voltages than half the voltage U _H to the surrounding soil, resulting in flashovers or Arcs could cause. Depending on the arrangement of the center tap 70 on the secondary coil SE, other than half voltage values at the connection terminals 40, 40 ^' can be achieved. This depends on the breakdown of

Secondary coil SE in two parts through the center tap 70 from. However, a maximum possible reduction of the voltage applied to the connection terminals 40, 40 ^' is half the value of the voltage U _H , which is obtained by dividing the secondary coil SE into two equal parts by the center tap 70.

An alternative possibility for reducing the maximum voltage applied to the connection terminals 40, 40 ^' with respect to the environment is not shown in the figures for the sake of simplicity. Instead of or in addition to a center tap 70, as shown in FIG. 2, the inductor 15 and / or the forward or return line 10, 20 may have a location at which a ground potential U _{E is} applied or which is grounded , This can be done by putting the insulation on a otherwise completely opposite the ground electrically insulated conductor 10, 15, 20 is interrupted at the point. Egg ne Maximum reduction of 40 ^'abutting a maximum at the connection terminals 40 voltage U _H is analogous to the execution ^¬ example of the center tap 70 upon application of the Erdpo ^¬ tentials or the voltage U _E at a position which cavities ^¬ Lich maximum of the terminals 40, 40 ^' away. In an inductor 15 with a U-shape, as shown for example in Fig., The two equal parts are connected together by a U-shaped end, results in a grounding of the point 15 with the U-shaped end, the maximum reduction of the maximum at the terminals 40, 40 ^' applied potential. A grounding is usually meaningful way only one of two possible locations in the conductor loop 2, the center tap 70 of the secondary winding or at the gege nüberliegenden body in the conductor loop 2 itself. Be other places, such as places in the Hin- 10 or return conductor 20 pulled to ground potential, so can not the maximum possible reduction of the voltage between the inductor 15 and ground to half the value of the maximum voltage applied to the terminals 40, 40 ^' voltage U _H can be achieved.

Both in the embodiment shown in Fig. 2 with grounded center tap 70, as well as in the last-described embodiment with a grounded point on In ^¬ ductor 15 and / or the forward and return conductors 10, 20, a ground can be passive or active , Passive in this context means that a grounding takes place via an electrical line or a direct electrical contact with the environment. Active, that a grounding or applying the potential U _E via a Gere applies ^¬ or controlled electric circuit is carried out in this context.

The invention is not limited to the Ausführungsbei ^¬ games described ^above . Including combi ^¬ nations of the embodiments may include each other and / or with Embodiments of the prior art done. Also, instead of a ground at one point earthing at more than one site be low, depending on the structure and Ver ^¬ application of the device according to the invention, in particular with active ground. A grounding of one of the two contact points 40, 40 ^' can also take place. Characterized ^'the full potential U to _H, however, a reduction of the insulation expenditure possible by Iso lation ^¬ only the second contact point 40 or ^40', although located on the second contact point 40 or 40th

Claims

claims 1. Device for "in situ" production of bitumen or Heavy oil from oil sands deposits (1), - With at least one electrical conductor loop (2) which comprises a forward conductor (10) and a return conductor (20) and an intermediate inductor (15), wherein at least the inductor (15) at least partially or completely in the oil sands deposit (1) is arranged, and with an alternating current generator (30) which is electrically connected to the at least one conductor loop (2) via at least two electrical contact points (40, 40 ^' ), the alternating current generator (30) having a transformer (50) with at least one primary (PR). and at least one secondary winding (SE), characterized in that the at least one secondary winding ^¬ (SE) having a center (70) to which a ground potential U _E is electrically applied. 2. The device according to claim 1, characterized in that the ground potential U _{E is} electrically connected via a galvanic connec ^¬ tion to the center tap (70) is applied or that the ground potential U _E circuitarily applied via an electrical circuit to the center tap (70) is. 3. Device for "in situ" production of bitumen or Heavy oil from oil sands deposits (1), in particular according ei ^¬ nem of the preceding claims, comprising at least one electrical conductor loop (2) comprising a forward conductor (10) and a return conductor (20) and an inductor (15) connected therebetween, wherein at least the inductor (15) is at least partly or completely immersed in the oil sand deposit (1 ), and with an alternating current generator (30) which is electrically connected to the at least one conductor loop (2) via at least two electrical contact points (40, 40 ^' ). is, wherein the alternator (30) comprises a transformer (50) having at least one primary (PR) and at least one secondary winding (SE), characterized in that on the conductor loop (2), a ground potential U _E at a location spatially away from the alternating current generator ^¬ (30) is electrically applied. 4. Apparatus according to claim 3, characterized in that the ground potential U _E spatially in a region on the conductor loop (2), in particular on the inductor (15) is applied, which is farthest from the alternator (30). 5. Device according to one of the preceding claims, character- ized in that on the inductor (15) is applied a voltage U _H in the range of greater lOkV for inductive heating of the oil sands deposit (1). 6. Apparatus according to claim 5, characterized in that the transformer (50) is designed as a matching transformer for transforming an output voltage U _A to a voltage in the range of voltage U _H. 7. Device according to one of the preceding claims, character- ized in that the inductor (15) has a length of greater than 1km, in particular greater than 5km. 8. Device according to one of the preceding claims, characterized in that with the exception of a point on the alternator (30) and / or a point of the conductor loop (2) spatially away from the alternator (30) to which the ground potential U _{E is} applied that elekt ^¬ generic conductor loop (2) is completely opposite to the oil sands deposit (1) is electrically insulated, and in particular the earth potential U _e is set so that a heating of the oil sand reservoir (1) via the electrical conductor loop (2) pure inductively. 9. Device according to one of the preceding claims, characterized in that the at least one primary winding (PR) is electrically isolated from the at least one secondary winding (SE), and in particular the primary winding (PR) is electrically connected to power converters. 10. Device according to one of the preceding claims, characterized in that the AC generator (30) is designed as an RF generator with an electric power in the range of one to several MW at 5 to 200 kHz, in particular 50 kHz. 11. A method for using a device according to one of claims 1 to 10, characterized in that by applying the ground potential U _E at a location of the secondary winding ^¬ (SE) and / or at a point of the conductor loop (2) spatially away from Alternating current generator (30), the voltage between the contact points (40, 40 ^' ) is reduced to a value which is smaller than the value of an output voltage without an applied ground potential U _E. 12. The method according to claim 11, characterized in that the voltage between the contact points (40, 40 ^' ) is reduced to a value which is substantially half as large as the value of an output voltage without applied earth ^¬ potential U _E.