EP2321496A1

EP2321496A1 - Method and device for the "in-situ" conveying of bitumen or very heavy oil

Info

Publication number: EP2321496A1
Application number: EP09780765A
Authority: EP
Inventors: Dirk Diehl
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2008-08-29
Filing date: 2009-07-17
Publication date: 2011-05-18
Also published as: CA2735357A1; MX2011002135A; RU2505669C2; CN102197191A; US8813835B2; DE102008044955A1; UA105366C2; AU2009286936A1; CN102197191B; RU2011111733A; CA2735357C; AU2009286936B2; BRPI0917926A2; WO2010023035A1; US20110146981A1

Abstract

Providing an electric/electromagnetic heater to reduce the viscosity of bitumen or very heavy oil, wherein at least two linearly expanded conductors are configured in a horizontal alignment at a predetermined depth of the reservoir, has already been described. The conductors are connected to each other in an electrically conducting manner inside or outside of the reservoir, and together form a conductor loop, and are connected to an external alternating current generator outside of the reservoir for electric power. According to the invention, the heating of the reservoir is predetermined in a chronologically and/or locally variable manner in accordance with the electric parameters, and may be changed outside of the reservoir for optimizing the feed volume during the conveying of the bitumen. At least one generator (60; 60', 60", 60'", 60'''') is present in the related device, however multiple generators are preferred, wherein the parameters (I, fi f) thereof are variable for the electric power.

Description

description

Method and apparatus for "in situ" production of bitumen or heavy oil

The invention relates to a method for "in situ" - promotion of bitumen or heavy oil from oil sands deposits as a reservoir according to the preamble of claim 1. In addition, the invention also relates to the associated apparatus for performing the method.

For conveying heavy oils or bitumen from oil sands or oil shale deposits by means of pipe systems which are introduced through boreholes, the flowability of the starting materials in solid consistency must be considerably increased. This can be achieved by increasing the temperature of the reservoir.

If inductive heating is used exclusively or in support of the usual SAGD (Steam Assisted Gravity Drainage) process, the problem arises that adjacent simultaneously energized inductors can negatively affect each other. Thus, adjacent oppositely energized inductors weaken with respect to the heat output deposited in the reservoir.

In the older German, unpublished patent applications AZ 10 2007 008 292.6, AZ 10 2007 036 832.3 and AZ 10 2007 040 605.5 individual inductor pairs, ie return conductor, energized in a predetermined geometric configuration to heat the reservoir inductively. The current is used to set the desired heating power, while the phase angle is fixed at 180 ° between adjacent inductors. This anti-phase current supply inevitably results from the operation of an inductor pair with forward and return conductors to a generator. In a parallel patent application of the applicant entitled "In situ recovery plant for a carbon Among other things, the control of the heating power distribution in an array of inductors is described, whereby this is achieved by the adjustability of the current amplitudes and phase angle of adjacent inductor pairs

Exposure for longer periods of days to months experiences only minor adjustments and there is a fixed assignment of a generator to an inductor pair.

On this basis, it is an object of the invention to propose suitable methods and to provide associated devices which serve to improve the efficiency of the promotion of oil sands or oil shale reservoirs.

The object is achieved by a method of the type mentioned by the measures of claim 1. An associated device is specified in claim 13. Further developments of the method and the associated device are the subject of the respective dependent claims.

The object of the invention is to make the relevant parameters of the necessary electric power generators temporally and / or locally variable in the electric heating of the reservoir and to provide the possibility of these parameters from outside the reservoir for optimizing the delivery volume during the conveyance of the bitumen or heavy oil to change. Thus, the widest possible control options for the energization of the inductors are created, in particular, locally detected temperatures can be used as control variables. For this purpose, the temperatures in the reservoir can be distributed locally, for example at the individual inductors, but possibly also outside the reservoir, in the so-called overburden, ie in the mountain region above the reservoir, or in the underburden, ie in the mountain region below the reservoir become. In detail, the invention includes various possible combinations of individually energizable inductors and these assignable generators. In particular, the following measures are possible:

1. According to the invention it is proposed to perform the energization of adjacent inductors temporally sequential and preferably to use spatially widely spaced forward and return conductors. Below, by way of example, the temporally sequential wiring of four inductor pairs is shown. The inductors, which serve as forward and return conductors, can be selected by means of individual switches.

2. The energization of the Induktorpaare can be done, for example, at equal time proportions. Due to the high heat capacities of the reservoir, large time intervals in the range of hours or days can be selected, provided that the thermal load capacity of the inductors is not exceeded.

3. The time shares of the energization can be chosen differently for the individual inductor pairs and changed during different phases of the exploitation of the reservoir.

4. The combination of return conductor to form an inductor pair can be changed during different stages of exploitation of the reservoir.

5. To control the time intervals and to assemble the inductors to return pairs, the

Temperature of the inductors or the surrounding of the reservoir are used. Thus, thermally low-loaded inductors can preferably be energized or reservoir areas low temperature preferably heated. 6. An inductor pair formation can be used to influence the heating power components in the overburden, reservoir and underburden. During different temporal exploitation phases of the reservoir, it is possible to switch between the two kinds of energization - temporally sequential or simultaneous energization with several generators.

7. Wiring in close proximity to one another in space can be carried out by over-wiring on the generator and / or connection side in order to avoid or reduce the unwanted heating of the overburden.

8. Instead of the switch on the return conductor, several permanently connected generators can be used, which can be operated on a timely basis sequentially or simultaneously with the same or different frequencies.

9. When energizing adjacent inductors with different frequencies no erasure effects occur and the total heat output (and their distribution) resulting from the sum of the heat outputs (or their distributions) of the individual inductors.

10. The effective resistance, which represents the reservoir as secondary winding, is much higher for far-distant forward and return conductors than for closely adjacent conductors, whereby high heat outputs can be introduced into the reservoir with comparatively low currents in the inductor (primary winding).

11. When operating the generators with different frequencies, an inductive coupling of the generators with fundamental and harmonic waves is preferably avoided, which could otherwise lead to malfunction or high loads of the generators. 12. The capacitively compensated inductors are basically tuned to the respective operating frequency to manufacture. If the generators can deliver a small part of the total reactive power to be applied, or their compensation can be effected by capacitive or inductive circuits directly at the generator, uniform inductor designs tuned to a mean operating frequency can be used. Otherwise, using these external compensation circuits, inductors can be operated at slightly different frequencies, which is sufficient to avoid cancellation effects.

The invention is based on the insight gained in detailed investigations that significant advantages over the prior art are realized with the measures indicated above. These are in particular:

Re 1: The effective resistance of the inductive reservoir heater is significantly increased, for example by a factor of 4. This means that with the same current amplitude in the inductor, the heating power in the reservoir can have a four times higher value relative to a simultaneous energization.

Model calculations were carried out in the context of the invention. The finite element method (FEM) was based on such a model which currently contains an inductor pair, four such sections being arranged next to one another and one section each without inductors for the left and form right edge area.

Together, advantageously results in a 2d FEM model with eight individual inductors, for example, form four separate Induktorpaare (1/5), (2/6), (3/7) and (4/8), and associated edge regions. This 2d FEM model can be used to investigate the heat output distribution for different types of current. By calculation then results in a suitable heating power distribution, when a first inductor as a forward conductor and an inductor as far as possible serves as a return conductor. The total heating power is Pl in W / m with continuous energization of the inductors with a current of predetermined Il

Amplitude at a given frequency f1. Preferably, it is assumed that a frequency of 10 kHz, in principle, frequencies between 1 and 500 kHz are suitable.

With simultaneous energization of all inductors with the same current amplitude Il at the same frequency fl results in a different heating power distribution. The currents of adjacent inductors each have a phase shift of 180 °. However, the total heating power is in this case again approximately Pl in W / m.

Re 2: In the example given under point 1, for example, four individual pairs of inductors (1/5), (2/6), (3/7) and (4/8) are each energized to a quarter (25%) of the time, This requires only one generator (inverter), which can supply the required current of the specified current amplitude (1350 A) with four times the active power, but without increasing the reactive power requirement. Thus, the same heating power would be introduced into the reservoir in the time average as with simultaneous energization according to point 1. This means that instead of four generators, each provide 1/4 of the desired heating power as active power and in addition a dependent on the inductor reactive power need only a generator with 4 times the active power needed without the reactive power demand increases.

3: It is now possible to achieve a control of the heating power distribution in accordance with the respective requirements. For example, inhomogeneities in the temperature distribution due to uneven heating by steam injection can be compensated within limits. To 4: As under point 3, it is possible to control the heating power distribution.

To 5: The temporal variation of the current in combination with the free choice of return conductor can be used advantageously to protect the inductors from too high a temperature due to their ohmic losses in addition to external heating by the reservoir.

To 6: The heating power in Overburden, reservoir and underburden can be influenced by a current to the inductors within limits, which will be discussed below.

To 7: With the latter measures the losses in the overburden are minimized. The merging of all lines by the Overburden allows a free combination of return conductor with the advantages according to the points 3.-6.

To 8: Advantageously, now a simple change of the types of power is possible.

Ad 9: Alternatively, it is proposed to simultaneously feed adjacent inductors with different frequencies. For example, the wiring of four inductor pairs possible with four generators of different frequency.

To 10: Each generator feeds a pair of return conductors of the inductors, the individual conductors being spatially as far apart as possible.

11: The frequencies of the participating generators should not be integer multiples of each other in the latter approach.

To 12: The frequencies of the generators involved can be nearly equal, e.g. B. differ less than 5%. Further details and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing in conjunction with the claims.

Show it

FIG. 1 shows a section of an oil sand deposit with a repeating unit as a reservoir and an electrical conductor structure running horizontally in the reservoir,

FIG. 2 shows the diagram of the wiring of four inductor pairs with temporally sequential energization,

Figure 3 shows the scheme of the wiring of four inductor pairs with simultaneous energization with separate generators, which may have different frequencies, the associated return conductors are spatially far apart and

Figure 4 shows the scheme of the wiring of four inductor pairs with separate generators of different frequencies, the associated forward and return conductors are adjacent.

While Figure 1 shows a perspective view as a linear repeating array, Figures 2 to 4 are respectively plan views, i. Horizontal sections in the Induktorbene seen from above, with the overlying mountains ("Overburden") is on both sides opposite.Equal elements in the figures have the same reference numerals .The figures are described below partially together.

For conveying heavy oils or bitumen from oil sands or oil shale deposits by means of pipe systems, which are introduced through bores in the oil reservoir, the flowability of the solid-like bitumen or the tough must

Heavy oils are significantly improved. This can be achieved by increasing the temperature of the reservoir (reservoir), which causes a decrease in the viscosity of the bitumen or heavy oil.

Applicant's earlier patent applications were primarily directed to using inductive heating to support the conventional SAGD process. In this case, the return conductor of the inductor lines, which together form the induction loop, are arranged at a comparatively great distance of, for example, 50-150 m. The mutual weakening of the oppositely energized forward and return conductors is low and can be tolerated.

Increasingly, so-called EMGD methods are considered in which the inductive heating is to be used as the sole heating method of the reservoir without the introduction of superheated steam. a. brings the advantage of reduced or virtually no water consumption.

With inductive heating alone, the inductors must be placed closer to the bitumen production pipe in order to allow an early start of production with simultaneous reduced pressure in the reservoir. As a result, return and return conductors also move closer together. This entails the problem that the mutual field weakening of the oppositely energized forward and return conductors is considerable and leads to reduced heating power. Although this can be compensated in principle by higher Induktorströme, but with which the demands on the current carrying capacity of the conductors and thus their production costs would increase significantly.

It is possible to energize spatially closely adjacent conductors temporally sequential, ie not simultaneously, so that the problem of field weakening does not occur. The advantage here is that a generator (inverter) can be used for several conductor loops. However, it is disadvantageous that the inductors are energized only a fraction of the time and only contribute to the reservoir heater. This will be clarified below with reference to FIGS. 2 to 4. FIG. 1 shows an arrangement for inductive heating. This can be formed by a long, ie some 100 m to 1.5 km, laid in a reservoir 100 conductor loop 10 to 20, wherein the forward conductor 10 and return conductor 20 side by side, ie at the same depth, are guided at a predetermined distance and at the end are connected together via an element 15 as a conductor loop inside or outside of the reservoir 100. Initially, the conductors 10 and 20 are routed vertically or at a predetermined angle into holes through the overburden ("overburden") and are powered by an RF generator 60 which may be housed in an external housing.

In particular, the conductors 10 and 20 extend at the same depth either side by side or one above the other. It may be useful to offset the ladder. Typical distances between the return and return conductors 10, 20 are 10 to 60 m with an outer diameter of the conductors of 10 to 50 cm (0.1 to 0.5 m).

An electrical double line 10, 20 in Figure 1 with the aforementioned typical dimensions has a Längsinduktivitätsbelag of 1.0 to 2.7 uH / m. The cross-capacitance coating 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. The shaft speed is given by the capacitance and inductance of the conductor arrangement.

The characteristic frequency of an inductor arrangement

FIG. 1 is due to the loop length and the wave propagation speed along the arrangement of the double line 10, 20. The loop length is therefore to be chosen so short that no disturbing wave effects result here.

FIG. 2 shows how four inductor pairs can be switched with temporally sequential energization. 60 is again the high frequency power generator. whose outputs are applied to switching units 61, 61 '. The switching units 61, 61 'each have four different contacts, the switching unit 61 being connected to four inductors 1, 2, 3, 4 as a forward conductor and the switching unit 61' to four inductors 5, 6, 7, 8 as a return conductor. A switching clock 62 provides for switching or switching on the generator voltage to the individual lines 1 to 8.

The individual inductors 1 to 8 are arranged according to FIG. 1 in the reservoir 100. There are areas 105 on both sides of the reservoir 100 which are not to be heated and phenomenologically represent the "overburden." Furthermore, a connection 15 is connected to the ends of the inductors which connect the forward and return conductors

Connection 15 can be arranged above or below ground.

With the latter arrangement, it is possible, controlled each to heat individual adjacent areas of the reservoir. This can be done in particular chronologically one after the other, ie sequentially. The switching clock 62 can be controlled by a separate control unit 63, which takes into account in particular the temperature T in the reservoir 100. For example, temperature sensors, not shown in FIG. 2, can be placed on the individual inductors or inductor lines in order to locally measure temperatures T ₁ there and to conduct them to the control unit 63 for evaluation. In particular, it is thus possible to take into account excess temperatures at the inductors.

However, it is also possible to measure the temperatures locally at other locations in the reservoir 100 or else in the overburden and / or unbalance and to take these into account when controlling the generators. It is essential that the power output of the generators changes and can be adapted to the respective requirements, which changes in the temporal exploitation phases of the deposit. This applies in especially because the time periods in the exploitation are long, for example, years and more.

In FIG. 3, the arrangement according to FIG. 2 is modified such that four high-frequency power generators 60 ',

60 '', 60 '' 'and 60' '' 'are present, which drive in pairs two of the inductors 1 to 8. Again, there is an overground or underground connection 15. With this arrangement, it is possible, in particular, to supply four inductor pairs with different current intensities at different frequencies at the same time.

An arrangement according to FIG. 3 can be modified such that different frequencies are also used. This is illustrated in FIG. 4, in which in turn eight inductors 1 to 8 are arranged in the reservoir parallel to one another. In each case two of the inductors 1 to 8 are driven by a separate generator 60 'to 60''''. In this case, those generators are selected which generate different predefinable frequencies. For example, generator 60 'has frequency fi, generator 60''frequency f ₂ , generator 60''' frequency f _3, and generator 60 '''' frequency f ₄ . By supplying currents of different frequencies, the individual areas are now selectively heated differently.

Using the examples, it was shown that the heating power components in Overburden (OB), Reservoir 100 and Underburden (UB) can be influenced within specified limits by differentiated current supply to the inductors. These proportions are given conclusively for an example examined in detail:

a: When energizing, for example, the inductors 1 to 5, for example, a percentage loss distribution of:

OB 31.3%, reservoir 45.5% and UB 23.2%. b: With simultaneous energization of all inductors, on the other hand:

OB 24.2%, reservoir 62.8% and UB 13.0%.

The latter means that most of the heating power in the reservoir is then deposited when a simultaneous energization of the inductors takes place, with a phase shift of φ = 180 between adjacent inductors. Therefore, a switchover between the types of energization may be advantageous depending on the timing of the exploitation of the deposit, in particular as a function of the desired heating power distribution of the generators or of the number of generators used in the process.

Finally, it should be noted that when the power generator is placed outside the reservoir, underground installation of the generator is also possible, which may be advantageous in some circumstances. In that case, the low frequency electrical power, i. 50-60Hz or possibly also as direct current, led down and could be a conversion into the kHz range underground, so that no losses occur in the overburden.

Overall, it can be stated that the electrical parameters decisive for the heating of the reservoir can be preset variably in terms of time and / or location and can be changed from outside the reservoir to optimize the delivery volume during the conveyance of the bitumen. In the associated device, at least one generator is present, but preferably a plurality of generators, wherein its electrical parameters (I, f _lr φ) are variable.

Claims

claims

1. A method for "in situ" promotion of bitumen or heavy oil from oil sand deposits as a reservoir, wherein the reservoir with thermal energy to reduce the viscosity of the bitumen or heavy oil is applied, including at least one electrical / electromagnetic heating is provided and a delivery pipe for Routing the liquefied bitumen or heavy oil is provided and at least two linearly extending conductors are guided at least partially parallel in a horizontal orientation at predetermined depths of the reservoir, wherein the ends of the conductors are electrically conductively connected inside or outside the reservoir and together form a conductor loop and are connected outside the reservoir to an external AC generator for electrical power, characterized in that the relevant parameters for the electrical / electromagnetic heating of the reservoir are temporally and / or locally variable and from outside outside the reservoir to optimize the volume of the feed during production of the bitumen or heavy oil.

2. The method according to claim 1, characterized in that an inductive heating of the reservoir by introducing electrical power of at least one power generator via lines and inductors, wherein the electrical power of the at least one power generator is variable and changed during the promotion of bitumen or heavy oil and adapted to the respective needs.

3. The method according to claim 2, characterized in that the energization of the inductors is changed in different temporal exploitation phases of the oil sand deposit.

4. The method according to claim 2, characterized in that the at least one power generator for the inductive heating with different, optionally variable frequencies, is operated.

5. The method according to claim 1, characterized in that the output currents of the at least one power generator are variable and changed during the promotion of the bitumen or heavy oil and adapted to the respective needs.

6. The method according to claim 1, characterized in that when using multiple power generators, each energizing an induction loop, the phase position of the electrical currents are variable relative to each other and adapted to the respective needs.

7. The method according to any one of the present claims, characterized in that the temperatures are detected locally within the reservoir and used to control the time sequential energization of the inductors and / or current amplitude control of the power generators.

8. The method according to claim 7, characterized in that the temperature of the reservoir is detected locally at the inductors.

9. The method according to claim 8, characterized in that upper temperature limits of the inductors and line connections are used for controlling the temporally sequential energization.

10. The method according to claim 8, characterized in that the temperature at the inductors for amplitude control of the currents flowing through the inductors is used.

11. The method according to, characterized in that the temperatures outside the reservoir, in particular locally in the over- and / or underburden of the reservoir, are detected and used for control purposes.

12. The method according to any one of the preceding claims, characterized in that not subsequently exploited areas of the oil sands deposit are developed by subsequently introduced into the reservoir inductors.

13. A device for carrying out the method according to claim 1 or one of claims 2 to 12, with in the reservoir guided lines as separate inductors and outside of the reservoir associated with at least one power generator, characterized in that the at least one generator (60; 60 ', 60 ", 60 '", 60 "") is variable for the electric power in terms of its output power determining parameter (I, fi, φ).

14. The device according to claim 13, characterized in that means for the sequential connection of the individual outputs of the at least one generator (60; 60 ', 60' ', 60' '', 60 '' '') to the inductors (1-8 ) available.

15. The apparatus according to claim 13, characterized in that the at least one generator (60; 60 ', 60' ', 60' '', 60 '' '') has individual outputs for different frequencies (fj has.

16. The apparatus according to claim 13, characterized in that a plurality of generators (60; 60 ', 60 ", 60'", 60 '"') for different frequencies (f _x ) are present.

17. The apparatus according to claim 13, characterized in that the conductors for the electromagnetic heating in the reservoir (100) are guided horizontally and individual inductors (1-8) form.

18. Device according to one of claims 13 to 17, characterized in that the conductors (1-8) for the electromagnetic heating have a conductor loop (15).

19. Device according to one of claims 13 to 18, characterized in that the conductor loops of inductors (1-8) and connection (15) are equipped with sensors for detecting temperatures (T ₁ ).

20. Device according to one of claims 13 to 19, characterized in that external switching means (62, 63) are present, each connecting different inductor lines (1-8) to an inductor loop.

21. Device according to one of claims 13 to 20, characterized in that by switching over by means of the external switching means (62, 63), the distance of the inductor lines

(1 - 8) and thus the introduced heating power is selected.

22. The device according to claim 11, characterized in that the temperature sensors, the temperatures (T ₁ ) within and / or outside of the reservoir (100) are arranged and for temporally sequential control and / or current amplitude control of the generators (60; 60 ', 60 ", 60 '", 60 "").