RU2426868C1 - Device for extraction of hydrocarbon containing substance in places of natural bedding - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: device for extraction of hydrocarbon containing substance in places of natural bedding consists of at least one operation pipeline outgoing from deposit. The device also consists of at least two electrodes of inductive or resistive operation relative to at least separated parts of the deposit. ^ EFFECT: reduced phase of heating on considerable area of deposit for short time before commencement of productive phase. ^ 15 cl, 5 dwg

Description

The invention relates to a device for the extraction of hydrocarbon-containing substances in places of natural occurrence. A hydrocarbon-containing substance is extracted under conditions of a decrease in its viscosity from an underground deposit. The device comprises at least one production pipeline withdrawn from the field. Such devices for the extraction of hydrocarbon-containing substances are known, for example, from the Steam-Injection Strategy and Energetics of Steam-Assisted Gravity Drainage von IDGates, 2005, SPE International Thermal Operations and Heavy Oil Symposium, Calgary, Canada, November 1-3 2005.

Large volumes of world oil reserves exist in the form of oil sands. Oil sand is a mixture of rock, clay, sand, water and bitumen or other heavy oil fractions. Further, referring to heavy oil fractions, especially heavy oil fractions or generally long-chain hydrocarbons, bitumen should be meant, which, depending on the field, usually has a viscosity of 5 ° to 15 ° API. Bitumen in the subsequent stages of the process can be converted into synthetic crude oil. Deposits of oil sand are partially located in earthen formations of small depth, which are available for open-pit mining. However, there are also large oil sand deposits that are not available for open pit mining. Usually, mining in places of natural occurrence is carried out at a depth of 60 m and deeper, since reducing the overlying rock will not otherwise be cost-effective.

The usual method used to develop such a field is the Steam Assisted Gravity Drainage (SAGD) method. In the implementation of the SAGD method, the bitumen present in the deposit is heated by superheated steam, and the deposit becomes more permeable due to the vapor pressure. Thus, the viscosity of bitumen is reduced, so that it is in liquid form, and can also be quickly delivered out of the field. The change in the viscosity of bitumen occurs due to an increase in temperature. To this end, superheated steam is piped into the underground field through pipelines, so that the field warms up and excess pressure is simultaneously generated in the field. Liquid bitumen, due to the overpressure prevailing in the field, is fed through the next pipe to the surface (cf. also the main workshop on the set of topics “Unconventional hydrocarbons” with the topic “Heavy oils and especially heavy oils” J. Seim, Freiberg, Germany, January 2001).

To improve the flowability of bitumen, a solvent may be added to the superheated steam. Pipelines for injecting superheated steam or a mixture of superheated steam and solvent are laid mainly parallel to each other and horizontally inside the field. The discharge pipeline and the production pipeline usually have a gap of 5 m to 10 m in the vertical direction relative to each other. The gap between the discharge pipe and the production pipe, however, depends on the capacity of the field. In the horizontal direction, the pipes are located inside the field in length from several hundred meters to several kilometers.

Before the actual extraction of bitumen from the field begins, this field must first be warmed up in order to lower the viscosity of the bitumen present in the sand or rock. During the warm-up phase, for quick heating of the field, superheated steam is supplied both to the injection pipeline and to the production pipeline for a period of approximately 3 months. At the end of the warm-up phase, the bitumen in the field has such a viscosity that with further supply of superheated steam to the discharge pipe and with the resulting overpressure in the field, liquid bitumen can be supplied to the surface from the production pipe. With a sufficient increase in pressure, you can refuse to install lifting oil pumps, which give out a bituminous-water emulsion.

The currently practiced SAGD method, outlined in general terms, has various technical problems. Firstly, through channels or porous rock layers in the deposit, superheated steam can be removed from the deposit, and this leakage reduces the thermal energy transferred to the deposit. Due to excessive pressure in the field, blow-outs may occur, in particular if the overlying rocks have a small layer thickness. The next problem is the so-called “formation of steam tongues” inside the store, in which, for the most part, steam breaks out (steam short circuit) at the beginning or at the end of the horizontal section of the parallel discharge pipe for steam and the production pipe, and steam is looking for an exit the preferred interconnecting path between the two pipes and the pressure is undesirably reduced, the introduced steam condenses and is discharged through the production pipe in the form of water, moreover, in the field A small amount of steam is supplied, and thereby thermal energy, and the efficiency of the process is markedly reduced. The pressure and temperature inside the field for its quick heating can increase, thus, depending on the conditions inside the field, not in any way. To implement the SAGD method, a large amount of fresh water is required. The amount of water needed is measured based on the “Steam to oil ratio” (SOR). Strict environmental standards in mining areas require a reduction in the “Steam to oil ratio” to conserve above-ground or underground water supplies.

An object of the present invention is to provide a device for the extraction of a hydrocarbon-containing substance in places of natural occurrence, in particular, a device for the extraction of heavy oil fractions or bitumen from a field of oil sand, which, at least in relation to the prior art, is improved in such a way that it can be a shortened warm-up phase was obtained before the start of the production phase.

The problem is solved by means of a device of the previously indicated type characterized by the features of paragraph 1 of the claims. Other preferred embodiments of the invention are presented in the dependent claims.

The basis of the invention is the idea of using an electric heating device, which both inductively and resistively acts in relation to at least individual parts of the field, for their quick heating. The deposit itself acts as a resistive (ohmic) resistance with respect to at least two electrodes of the heating device. At the same time, the field is inductively heated by an electric heating device.

The present invention relates to a device for the extraction of a hydrocarbon-containing substance in places of natural occurrence in the face of a decrease in its viscosity from an underground deposit, which contains at least one production pipeline withdrawn from the deposit. The device further has at least two electrodes acting inductively or resistively as an electric heating device with respect to at least individual parts of the field. In a preferred embodiment, by means of the present invention, the warm-up time of the storage containing a hydrocarbon-containing substance can be reduced. Compared to devices known in the art, the “Steam to oil ratio” can be reduced.

Preferred embodiments of the device in accordance with the invention for the extraction of a hydrocarbon-containing substance in places of natural occurrence follow from the claims that are dependent on paragraph 1. Moreover, the embodiment in accordance with paragraph 1 of the claims may be combined with the characteristics of one, preferably several dependent claims. In accordance with this device for the extraction of hydrocarbon-containing substances in accordance with the invention may additionally have the following characteristics:

- Two electrodes of an electric heating device can be formed by at least partially located in the field, mainly vertically oriented electrical conductors. A vertical well requires low drilling costs. Thus, electrical conductors inductively and resistively acting on at least individual parts of the field can be easily and efficiently placed in the field. This device is preferred, in particular, when it is necessary to proceed from the fact that the permeability decreases with increasing depth, or that the permeability in the horizontal direction is inhomogeneous, that is, that there is heterogeneous and, under certain conditions, anisotropic with respect to permeability and / or porosity deposit.

- At least two electrodes of an electric heating device can be formed by at least partially located in the field, mainly horizontally oriented electrical conductors. Using electrical conductors that are horizontally located inside the field, most of the field can be heated electrically resistively, as well as inductively.

- Under the electrodes can be understood as rod-shaped metal conductors. Rod-shaped metal conductors are particularly simple and economical.

- At least the individual parts of the electrodes may have a spatial gap relative to each other, which decreases with increasing length of the electrodes in the direction from the current source. Reducing the gap can occur, in particular, continuously. In particular, the spatial gap between the individual parts of the electrodes may decrease linearly. Due to the changing gap between the electrodes, the circumstance that the voltage drop along the length of the electrodes remains constant can be achieved. This voltage drop is determined by the electrical resistance of the electrodes themselves and is summed with the electrical resistance of the soil respectively located between the electrodes. Thus, in a preferred embodiment, the circumstance that the total heating power of the electrodes in the soil zone close to the current source is reduced can be prevented.

- The electrodes can be located coaxially in the guide tube, and the guide tube for the targeted supply of fluid to separate parts of the field in the corresponding separate areas located in the field is permeable to liquid. Water can be supplied to certain zones through the guide pipe to the field, as a result of which the electric conductivity of the field may be affected. Thus, it is possible to ensure the electrical conductivity of the field, so that there is the possibility of uninterrupted operation of the electric heating device.

- The device may have an injection pipeline entering the field. Due to the fact that the device has both a discharge pipe and a production pipe, the field can be heated, firstly, by means of an electric heating device, and secondly, for example, by means of a steam heating method. Both methods can interact with each other.

- The electrodes at their end zones remote from the current source can be electrically connected to each other via a conductor bridge. By such an electrical connection, the operational reliability of the electric heating device can be improved.

- The discharge pipeline and the production pipeline can have in the field, mainly parallel to each other, mainly horizontally oriented pipe sections. In a section perpendicular to the discharge and production pipe, the electrodes of the electric heating device are located on both sides of the injection and production pipe. Due to the arrangement of the electrodes of the electric heating device on both sides of the discharge and production pipelines, in particular, the volume of the field that is located between the discharge and production pipelines in the horizontal direction can be heated by an electric heating device. Thus, in a particularly preferred manner, a large volume of field can be generated. By using SAGD methods known in the art, a yield of 40 to 60% of the bitumen present in the field can be achieved. In accordance with the previously described embodiment of the invention, it is possible to generate more than 70%.

- At least two electrodes of the electric heating device may be formed by at least separate parts of the discharge pipe or production pipe. Due to the fact that the electric heating device is formed by at least separate parts of the injection or production pipe, additional material for the electric heating device can be saved; further drilling is therefore not necessary. Such an embodiment of an electric heating device is therefore particularly preferred.

- Superheated steam may be supplied to the discharge pipe and to the production pipe. If an underground field is produced by the SAGD method or by a similar method, or by a method related to it, then usually superheated steam is supplied to the pipelines in the field. The combination of such a method based on the use of superheated steam with an electric heating method is particularly preferable, since by means of superheated steam additional water is introduced into the field, which increases the electrical conductivity of the field. To implement the method of inductive and resistive electrical heating requires a certain electrical conductivity. Due to the synergistic combination of the method using superheated steam and the electric heating method, the efficiency of the method combined from these two separate methods can be increased.

- Superheated steam may be enriched in an electrolyte, preferably a salt. The electrical conductivity of the steam is thus increased. The effectiveness of the inductive and resistive electric heating device with respect to at least individual parts of the field substantially depends on the electrical conductivity of the field. Due to the fact that superheated steam introduced into the field through the injection and / or production pipelines is additionally supplied with minerals, preferably salt, the electrical conductivity of the field can be purposefully adjusted and, if necessary, increased.

- An electric heating device refers to an AC heating device. Heating with alternating current prevents the migration of ions inside the field. In a preferred embodiment, carbonization or salt formation in the discharge and / or production pipelines can thus be avoided.

Other preferred embodiments of the device in accordance with the invention follow from the claims.

Preferred embodiments of the present invention are illustrated by drawings, which represent the following:

figure 1 - sketch of a device for the extraction of hydrocarbon-containing substances in places of natural occurrence from an underground field;

figure 2 is a cross section of the development zone of such a field;

figure 3 and 4 - a device for the extraction of hydrocarbon-containing substances in places of natural occurrence using an electric heating device;

5 is another preferred embodiment of the device.

The details shown in the figures are denoted by the same reference numerals. Elements not presented in more detail are by and large the state of the art.

Figure 1 shows in a schematic illustration a device for the extraction of hydrocarbon-containing substances in places of natural occurrence from underground deposits 100 in conditions of decreasing its viscosity. Under such a device can be understood, for example, a device for the extraction of bitumen from oil sand deposits. The injection pipeline 101 leads from the earth's surface to the thickness of the field 100. The production pipeline 102 leads from the thickness of the field 100 to the surface of the earth. Devices are possible in which several injection pipelines 101 and several production pipelines 102 are used to extract a hydrocarbon-containing substance from underground deposits 100. The deposit 100 may mean, in particular, an oil sand deposit or a tar shale deposit from which bitumen or other heavy oil can be extracted fractions.

In order to be able to extract a hydrocarbon-containing substance from the field 100, the viscosity of the hydrocarbon-containing substance in the field 100 must be reduced. For this purpose, at least some parts of the deposit 100 must be warmed up. To heat the deposit 100, superheated steam is supplied to the injection pipe and to the production pipe 102. After a warm-up period of usually 3 months, the viscosity of a hydrocarbon-containing substance present in the field, due to high temperatures, is reduced so much that the substance becomes fluid. If superheated steam is supplied to the discharge pipe 101 and further, then due to the presence of excessive pressure in the field or, at least in some parts of the field, the hydrocarbon-containing substance can be supplied to the surface via production pipeline 102. To maintain the temperature necessary for fluidity of the hydrocarbon-containing substance, superheated steam is supplied to the discharge pipe 101 and then. Upon reaching the surface, the produced hydrocarbon-containing substance can be transferred to subsequent processing steps, as a result of which synthetic crude oil can be obtained.

Figure 2 shows a cross section of a field 100 in which two injection pipelines 101, 101 'and two production pipelines 102, 102' are located. The superheated steam exiting the discharge lines 101, 101 ′ is schematically represented by arrows. Superheated steam forms steam chambers 201, 201 ′ within the field 100, from which the hydrocarbon-containing substance that has become fluid can be discharged upstream. In the horizontal direction between the steam chambers 201, 201 ′, there is a dead zone 202 in which the viscosity of the hydrocarbon-containing substance present in the field 100 is too high for this hydrocarbon-containing substance to be expelled. Dead zone 202 of deposit 100 cannot be depleted.

FIG. 3 shows a device for producing a hydrocarbon-containing substance at a natural occurrence site from a field 100, which, along with two injection pipelines 101, 101 'having pipe sections horizontally located in the field 100, has two production pipelines 102, 102'. The device for producing a hydrocarbon-containing substance in a natural occurrence site further has two electrodes 301, 301 ', which are located in vertical wells inside the field 100. The electrodes 301, 301' in relation to at least some parts of the field 100 act as inductive and resistive electric heating devices. Due to the electrical conductivity of at least some parts of the field 100, in particular the dead zone 202, it can be resistively heated by the current flowing between the two electrodes 301, 301 ′. Resistive heat is indicated by arrows or lines inside the deposit 100. At the same time, the electrodes 301, 301 'act in volumes 303, 303' as inductive heating devices. The electrodes 301, 301 'in those areas where they extend outside the field 100 itself can be insulated with respect to the ground by means of electrical insulators 304, 304'. Thus, the resistive heat load can be transferred to certain zones of the deposit 100. Under the electrodes 301, 301 'can be understood, in particular, rod-shaped conductors made of metal, in particular of metal with high electrical conductivity.

The device for producing a hydrocarbon-containing substance shown in FIG. 3 in places of natural occurrence can be exploited, in particular, in such a way that the field 100 is heated both by superheated steam and by means of an electric heating device. During the warm-up phase of the deposit 100, superheated steam can thus be supplied both to the injection pipelines 101, 101 'and to the production pipelines 102, 102', an additionally determined amount of hydrocarbon-containing substance can be discharged uphill, and in particular, dead zone 202 can be heated by electric heating with electrodes 301, 301 '. Thus, it is possible to achieve a shorter warm-up time compared to heating the deposit 100 only by electric heating or by supplying steam. The electric heating device can be, in particular, an alternating current heating device, as a result of which no ion migration occurs inside the deposit 100.

By heating the deposit 100 or at least some parts of the deposit 100, a decrease in the liquid content in the deposit 100 can occur, thereby reducing the electrical conductivity of the deposit 100. The decreasing electrical conductivity of the deposit 100 results in electric heating, in particular a resistive principle, loses its effectiveness. In order to counteract these electrical conductivity losses, superheated steam introduced into the field 100 can be enriched with minerals, in particular salts. Further, by adjusting the degree of enrichment of the superheated steam with minerals, in particular salts, the electrical conductivity of the deposit 100 can be adjusted in a targeted manner. Minerals or salts are added to the superheated steam after it exits the steam generator. On the other hand, if bitumen is produced in a certain place, then there is no need for electrical conductivity in this place. In particular, the mechanism of inductive action then leads to the fact that there are losses only where there is electrical conductivity, that is, the penetration depth increases correspondingly, and the bitumen, which is immobilized during natural electrical conductivity, is heated and due to the mutual gravity force with the naturally occurring electrolyte in the storage, smoothly flows down. It should be noted that at first the mechanism of losses on the electrode, due to the resistive or inductive principle of action, will be the most effective; that is, with the start of bitumen production there will be given greater fluidity. If the conductivity of the electrode is small, then there will be no contact between the electrode and the storage; then the inductive mechanism starts to work, which is independent of the electrical contact between the electrode and the storage.

FIG. 4 shows a device for producing a hydrocarbon-containing substance in a natural occurrence from a field 100. According to the embodiment of FIG. 4, at least parts of the discharge pipes 101, 101 ′ are used as electrodes of an electric heating device. In particular, these same parts of the discharge pipes 101, 101 'can be used as electrodes 301, 301' of an electric heating device, which are located mainly horizontally inside the deposit 100. Working as electrodes 301, 301 'of the parts of the discharge pipes 101, 101' at least some parts of the deposit 100 are heated not only resistively, but also inductively. In particular, the electrodes 301, 301 'heat up the zones 303, 303', which are arranged around the discharge pipelines 101, 101 'in the shape of a cylinder. Along with these inductively heated zones 303, 303 ', in particular, the dead zone 202 is heated in a resistive way. For electrical heating, the discharge pipes 101, 101' are connected to an AC power source 302.

Fig. 5 shows a device for producing a hydrocarbon-containing substance in places of natural occurrence from a field 100. The embodiment shown in Fig. 5 comprises two production pipelines 102, 102 'that exit from a field 100. Two electrodes 301, 301 extend into the thickness of the field 100. ', which are located, respectively, in the guide tube 501, 501'. The guide tubes 501, 501 'are accessible from the surface and additionally in 100 parts located outside the field or in the areas of the field intended for heating by electrical insulating materials 304, 304', and are electrically isolated from the ground. Guide pipes 501, 501 'are accessible for liquid to enter from the surface of the soil and have liquid permeable sections in certain areas within the field 100. Such areas can be, for example, porous structures of the walls of pipes or, respectively, cuts or holes.

Due to the fact that in a targeted manner, a liquid, preferably a liquid enriched in an electrolyte to improve electrical conductivity, is introduced into the field 100 or in separate parts of the field 100, the electrical conductivity of the field 100 can be controlled in a targeted manner. Thus, the operation of the electric heating device can be guaranteed. As a further measure to ensure the functioning of the electric heating device, the ends of the electrodes 301, 301 ', which are facing from the current source 302, can be shorted by means of an electric bridge 502.

By means of the embodiment of FIG. 5, it is possible to develop a bitumen deposit without using superheated steam. The field can only be heated by means of electric heating in an inductive and resistive way; Liquid bitumen available in production pipelines 102, 102 ′ can be raised by means of a lifting pump or transported to the surface due to the presence of natural geological overpressure. Optionally, superheated steam may be supplied to the field 100 at intervals through production pipelines 102, 102 ′, so that the pressure inside the field 100 increases. The excess pressure thus obtained can also be used to extract bitumen from deposit 100.

The electrodes 301, 301 'can further be located inside the field 100 so that the distance between them, in the direction from the current source 302, decreases with an increase in the length of the electrodes 301, 301'. In particular, a linear decrease in the distance between the electrodes 301, 301 ′ may occur. Thus, the circumstance that the electric heat load, in particular the resistive electric heat load, in the direction from the current source 302, can be transferred to the beginning of the electrodes 301, 301 ′ into the deposit 100 or into this zone can be prevented. The distance between the electrodes 301, 301 'can be selected, in particular, in such a way that a continuous thermal load can be obtained along the length of the electrodes 301, 301', in particular along the length of the fragments of the electrodes 301, 301 ', which are located inside the deposit 100, s taking into account the electrical conductivity of the field 100.

The distance between the boreholes can be adjusted in this way by well-known measures, for example, a transmitting device can be introduced into the first borehole, and the drill head of the second well can determine the distance to the first well based on the signal from this transmitting device.

Claims (15)

1. A device for the extraction of hydrocarbon-containing substance in places of natural occurrence, in the conditions of decreasing its viscosity, from an underground field (100), containing at least one production pipeline (102, 102 ') leading out of the field (100) and at least at least two electrodes (301, 301 ') inductively and resistively acting on at least portions of the deposit (100) of the electric heating device. 2. The device according to claim 1, in which at least two electrodes (301, 301 ') of the electric heating device are formed by at least partially located in the field (100), mainly vertically oriented electrodes (301, 301 '). 3. The device according to claim 1, in which at least two electrodes (301, 301 ') of the electric heating device are formed by at least partially located in the field (100), mainly horizontally oriented electrodes (301, 301 '). 4. The device according to any one of claims 1 to 3, in which individual sections of the electrodes (301, 301 ') have a spatial gap relative to each other, which with increasing length of the electrodes (301, 301') in the direction from the current source (302), preferably with a constant decrease. 5. The device according to claim 4, in which the spatial gap between the individual sections of the electrodes (301, 301 ') is reduced linearly. 6. The device according to any one of claims 1 to 3, in which the electrodes are made in the form of rod-shaped, metal, electrical conductors. 7. The device according to any one of claims 1 to 3, in which the electrodes are coaxially located in the guide tube (501, 501 '), and the guide tube (501, 501') for the targeted supply of fluid in the part of the field (100) on the corresponding, located in the field (100), individual sections are permeable to liquid. 8. The device according to any one of claims 1 to 3, in which the electrodes (301, 301 ') in their end regions remote from the current source (302) are electrically connected to each other by means of a conductor bridge (502). 9. The device according to any one of claims 1 to 3, containing at least one discharge pipe (101, 101 ') entering the field (100). 10. The device according to claim 9, in which the discharge pipe (101, 101 ') and the production pipe (102, 102') are in the field (100), mainly parallel to each other, horizontally oriented pipe sections, and in section perpendicular to the discharge and production pipelines (101, 101 ', 102, 102'), the electrodes (301, 301 ') are located on both sides of the injection and production pipelines (101, 101', 102, 102 '). 11. The device according to claim 9, in which one of the at least two electrodes (301, 301 ') of the electric heating device is formed by at least parts of the discharge pipe (101, 101'), and the other electrode by at least parts of the production pipeline (102, 102 '). 12. The device according to any one of claims 1 to 3, in which the discharge pipe (101, 101 ') and the production pipe (102, 102') are configured to supply superheated steam to them. 13. The device according to item 12, in which an electrolyte, preferably salt, is added to the superheated steam to increase its electrical conductivity. 14. The device according to any one of claims 1 to 3, in which the electric heating device is made in the form of an alternating current heating device. 15. The device according to any one of claims 1 to 3, in which a frequency in the range from 1 Hz to 200 kHz and a voltage in the range from 100 V to 10 kV are provided for the electric heating device.

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