JPH0135159B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode device for electric heating of hydrocarbon-based underground resources. More specifically, when producing hydrocarbons with high viscosity and low fluidity that exist underground from a well, an electrode device is used to heat and conduct electricity underground in order to increase the fluidity of the hydrocarbons. It is related to.

Note that "hydrocarbons" here refer to petroleum or oil, bitumen contained in oil sands (also called tar sands), and kerogen contained in oil shells. , these hydrocarbons are called oils. Also,
"Production" refers to the removal of fluid oil from an oil well, including artesian injection, pumping, and fluid transfer.

Normally, if the oil that exists underground has fluidity, a well is dug to reach the oil layer on the surface, and the oil is pumped up by the pressure of the gas coexisting in the oil layer, pumped up, or liquid such as salt water is pumped out from one well. It is possible to produce oil by injecting oil into one well and letting it flow out from the other well. However, if the fluidity of underground oil is low, production cannot be achieved unless measures are taken to make the oil fluid. A common method for fluidizing oil is to reduce the viscosity of the oil by heating.The optimal temperature for fluidizing varies depending on the individual properties of the oil, but it becomes necessary to heat the underground oil layer. .

Possible methods for heating oil layers include injection of hot water, injection of high-temperature, high-pressure steam, underground electrification, underground combustion (igniting the underground oil layer and blowing air to burn it), and the use of explosives. , the latter two are difficult to control and lack generality.

In addition, hot water or high-temperature and high-pressure steam injection methods are
It is possible to heat the oil layer to increase the fluidity of the oil and at the same time allow the fluidized oil to flow to the surface, but if there are places in the oil layer with low passage resistance, such as fissures, the oil will pass through only those places and spread to the entire surface. On the other hand, if the oil layer is hard and dense, hot water or steam will not diffuse and the temperature will be difficult to rise.

On the other hand, in the electrical heating method, multiple wells are dug in the oil layer, electrodes are installed in these wells, and a potential difference is applied between each electrode to heat the oil layer using the conductivity of the oil layer. Or, even if it is hard and dense, it has the advantage of being easy to heat as a whole.
However, other means are required to extract the fluidized oil.

Therefore, as a method to increase the efficiency of oil production, a method has been considered that first heats the oil layer by applying electricity, and when the oil layer softens, hot water or high-temperature, high-pressure steam is injected to continue heating and extract the fluidized oil. There is. In order to efficiently heat the oil layer, the electrode device used in this method must be electrically insulated to avoid leakage of current outside the oil layer as much as possible, and electric current leakage due to underground earth pressure or heating must be provided. It is necessary that the container not be destroyed by the pressure of the steam, injected hot water, or high-temperature, high-pressure steam, and furthermore, it is necessary that the hot water or high-temperature, high-pressure steam does not leak.

In order to explain this electrode device in more detail, the case where oil is produced from oil sand will be described below as an example.

Oil sands are also called tar sands, and reserves have been confirmed in Canada, Venezuela, and the United States. Oil in oil sand coexists with salt water on the surface of the sand and in the gaps between the sand, but it has extremely high viscosity and does not have fluidity in its natural state. The oil sand layer is partially exposed in canyons, riverbanks, etc., but most of it exists at a depth of 200 to 500 meters underground and several tens of meters thick.The oil sand layer is excavated and separated on the ground. Due to economic and environmental protection constraints, it is necessary to extract only the oil from underground. Also, the production of oil from a thick layer underground
Due to the risk of ground subsidence after oil production,
It is said that it is desirable to collect from layers below 300m underground.

The biggest problem with this electrode device that heats the oil sand layer by applying electricity is that the electrical resistance of the oil sand layer is higher than that of the stratum above the oil sand layer, that is, the upper layer of the oil sand layer. It is difficult to express it uniformly because it varies depending on the location and conditions, but the average value is 100 Ωm for the oil sand layer and 10 Ωm for the upper stratum.
It is. For this reason, if two electrode devices are installed in which electrodes are connected to a casing made of steel pipes and the electrodes are buried in the oil sand layer and then energized, most of the current will be consumed in the upper stratum. In order to avoid this phenomenon, it is necessary to provide an insulating coating layer on the surface of the casing in the strata, or to insulate the electrode from the casing.

The present invention relates to the latter device, and this device will be described below.

If this device is schematically shown, the electrode devices are arranged as shown in FIG. 1 of the accompanying drawings. In Fig. 1, numerals 1 and 11 are casings made of steel pipes,
2 and 12 are insulating parts joined to the casings 1 and 11, 3 and 13 are electrodes joined to the insulating parts 2 and 12, and 4 and 14 are cables that send current to the electrodes 3 and 13, and these together constitute an electrode device. It's called. Also, code 5
is a power supply device, 6 is an oil sand layer, 7 is an electrode 3,
13 is the current at the ground surface, 9 is the upper oil sand layer, and 10 is the lower oil sand layer. When a voltage is applied to the electrodes 3, 13 buried in the oil sand layer 6 through the cables 4, 14 from the power supply device 5 on the ground, a current 7 flows according to the electrical resistance in the oil sand layer 6, generating Joule heat. Then, the oil sand layer 6 is heated. At this time, a part of the current 7 also flows to the upper oil sand layer 9 and the lower oil sand layer 10, but since the insulating parts 2 and 12 are interposed between the casings 1 and 11 and the electrodes 3 and 13, the leakage of the current 7 is small. It can be suppressed. When the oil sand layer 6 warms up, the current is turned off and one casing 1 of the electrode device is closed.
If hot water or high-temperature, high-pressure steam is injected from above, it passes through the oil sand layer 6 and flows out of the casing 11 of the local electrode device together with oil.
In order to improve the outflow of hot water or high-temperature, high-pressure steam, the electrodes 3 and 13 are usually provided with pores.

In order to improve the contact resistance between the electrodes 3 and 13 and the oil sand layer 6, salt water is normally fed into the electrode device through a pipe (not shown), and to separate the salt water and the casings 1 and 11. A partition plate (not shown) is provided above the electrodes 3 and 13, and the upper part of the partition plate is filled with an insulating liquid.

Note that these matters regarding electric heating are described in, for example, US Pat. No. 3,946,809 and Canadian Patent No. 1,022,062.

This type of electrode device does not break when buried, and has sufficient strength to withstand earth pressure when it is first buried, but when energized, the temperature rises, which is especially noticeable near the electrodes due to the high current density. In addition, it can withstand the static pressure of the liquid filled inside without deforming or breaking.
In addition, it is required to not break or leak when hot water or high-temperature, high-pressure steam is injected. By the way, if a burial site is buried 500m underground, if the specific gravity of the liquid filled inside is 1, then a pressure of 50Kg/cm ² will be applied, and the temperature of water vapor with a pressure of 50Kg/cm ² will be
Reaching 265℃.

Incidentally, since the upper parts of the insulating parts 2 and 12 are connected to the casings 1 and 11, and the lower parts thereof are connected to the electrodes 3 and 13, a suspended load is always applied to the insulating parts 2 and 12. is under high temperature conditions of 250 to 300°C, so properties that satisfy this are required. Next, the insulating parts 2 and 12 are installed several hundred meters underground with the electrodes 3 and 13 suspended from the lower ends and the upper ends connected to the casings 2 and 12, so the hole wall is removed during the installation process. In reality, contact with or collision with other vehicles is an unavoidable condition. Therefore, since the overall weight is heavy, even a slight contact causes a large mechanical impact on the insulating parts 2 and 12, and the insulation parts 2 and 12 are required to have characteristics that can withstand this impact and not be damaged.

The inventors of the present invention have conducted extensive research in order to obtain insulating parts 2 and 12 that satisfy the above-mentioned required characteristics and have practical value. The first method we investigated was to connect the entire surface of a flanged tubular product made of metal with an organic resin coating with excellent heat resistance, such as Teflon. According to this, it is possible to obtain a product that maintains perfect characteristics in terms of suspension load strength and mechanical impact strength, but it is extremely difficult to establish a connection method that maintains the coating structure and insulation of the flange part, and it is difficult to achieve a connection method that maintains insulation under normal temperature conditions. Although it is possible to obtain a product that maintains the required insulation properties, when exposed to repeated temperatures from room temperature to 250°C, which is the actual usage condition, due to the inherent difference in thermal expansion and contraction rates, peeling occurs, especially at the flange part. This caused an unavoidable fatal defect in that the insulation would break down, making it unusable.

The next material to be considered was porcelain. In the first place, these insulating parts 2 and 12 contain water (oil) as described above.
Since dense characteristics are required, it is necessary to consider the connection method between the casings 1 and 11, the electrodes 3 and 13, and the insulating parts. A common idea is to shrink-fit a metal tube onto the outer periphery of a porcelain tube and connect the metal tube by a conventional method such as welding or screwing. In this method, water (oil) at room temperature
Although tight properties can be ensured, as the temperature rises, the shrink fit strength decreases, leading to a decrease in suspension strength.
In addition, defects such as breakage appear due to the stress generated at the tip of the shrink fit. In order to eliminate this defect, there is a method of providing flanges at both ends of the porcelain tube, interposing packing material on the contact surface, and tightening the flanges with metal, but in this case, sufficient characteristics cannot be secured at room temperature. However, as the temperature rises, an unavoidable defect appears in that water (oil) tightness deteriorates due to the difference in thermal expansion coefficient with porcelain. Other porcelain materials inherently have poor mechanical impact strength, so as mentioned above, there is an inherent condition that there is an extremely high possibility that they will be damaged by mechanical impact that occurs under unexpected conditions during the installation work process. However, there is also the unavoidable drawback that there is a large risk element when actually used.

The present inventors have conducted as much research as possible to obtain a useful electrical heating electrode device that eliminates the above-mentioned defects, and has found a device that has the required suspension load strength in the temperature range from room temperature to 300°C, and is mechanically resistant. We have obtained an insulated pipe joint that maintains complete strength even in the target impact strength.
At both ends, casings 1, 11 and electrodes 3, 1
We previously proposed an electrode device for electrical heating consisting of 3 connected by screws (Japanese Patent Application No. 175226/1983, Electrode Device for Electrical Heating of Underground Hydrocarbon Resources).

As mentioned above, the insulated pipe joint used in this electric heating electrode device not only maintains the necessary mechanical strength but also completely maintains water (oil) tightness, but has poor electrical insulation properties. There is a serious problem of low creeping insulation properties, and this is an extremely serious and fatal defect that cannot be improved due to unavoidable mechanical structural reasons. It was necessary to connect a large number of insulated pipe joints in series to obtain the necessary creepage insulation length and to ensure the characteristics. This is an unavoidable drawback, as it not only complicates assembly but also directly leads to a rise in price.

The present invention completely eliminates the drawbacks of conventional products as described above, and has improved characteristics such as suspension load strength, water (oil) tightness, cold and mechanical impact strength, aging resistance, and long-term reliability. In particular, it is an object of the present invention to provide a useful electrical heating electrode device having an insulating portion with excellent creeping insulation properties.

In order to achieve this object, the present invention includes a metal tubular casing that is buried underground, an electrode that is buried in a hydrocarbon-based underground resource layer to flow an electric current into the underground resource layer, and the casing and an insulating part that is interposed between the electrodes and connects and electrically insulates the casing and the electrodes, and includes one or more interconnected insulating pipe joints; the casing and the insulating part; and a cable that passes through the inside of the tube to supply current to the electrode, and the insulated pipe joint has a connection portion continuous to one end of the cylinder and protrudes toward the outer diameter side at an intermediate portion of the cylinder. A first tubular member having a flange formed therein and a groove portion formed on the inner diameter side corresponding to the flange, the first tubular member being in close contact with the first tubular member via an electrical insulator, and having a length thereof. is extended to a desired length on the one end side beyond the one end side of the electrical insulating material sandwiching the flange portion, and on the other end side is flush with the other end side of the electrical insulating material sandwiching the flange portion. The second tubular member formed as shown in FIG. an electrical insulator that is continuous to the other end; and a through hole at the tip of the second tubular member that is airtightly attached to the other end of the second tubular member at a distance from the electrical insulator. It is characterized in that it is comprised of a connecting tool having a.

Next, before explaining the present invention in detail, in order to facilitate understanding of the present invention, an insulated pipe joint used in a conventional electric heating electrode device is shown in the attached drawing 2.
This will be explained using figures. Incidentally, FIG. 2X is a longitudinal sectional view showing the structure of the product, which is manufactured by performing machining on the molded product shown in FIG. 2Y.

In the figure, a conventional insulated pipe joint 21 is composed of an inner peripheral fitting 22, an outer peripheral fitting 23, and an electrical insulator 24 filled in a gap 25 formed between these two fittings.

In this way, a female thread 23-1 is provided on a part of the inner periphery of the outer circumferential fitting 23 of the insulated pipe joint, and a female thread 23-1 is provided on a part of the outer periphery of the inner circumferential fitting 22. A screw 22-1 is provided. The inner circumferential fitting 22 is placed in the outer circumferential fitting 23 by passing the male thread 22-1 through the female thread 23-1 while holding each gap 25, and this gap 25
Electrical insulator 24 made of glass/mica plastic material
is filled, and the inner and outer circumferential metal fittings 22 and 23 are hermetically fixed to form a molded body 31 before machining.

The glass-mica plastic body constituting the above-mentioned insulator 24 is a mixture of vitreous powder and mica powder, for example, a mixture of 35 to 40 to 65 to 60 in volume ratio. This raw material powder is heated to a temperature at which the glassy material becomes soft and can flow under pressure, and in this heated state, the gap 25 is heated.
It is an electrical insulator formed by filling and press-molding.

Such a molded product 31 is produced by using a special mold (not shown) and forming an inner circumferential metal fitting 32 and an outer circumferential metal fitting 33.
is assembled as shown in Figure 2 Y, and
The raw material powder is molded by cold pressure using another mold (not shown) into a cylindrical shape that can be inserted into a space formed by the inner peripheral metal fitting 32 and a mold located on the outer periphery thereof. The constructed preformed body is inserted into the space and filled under pressure to be molded.

The mold, the metal fitting, and the preform are each heated to a predetermined temperature, and the metal fitting and the preform of raw materials are inserted into the mold in the heated state, and the preform is pressurized to form both metal fittings. The electrical insulator 34 is formed by press-fitting the gap 25 and filling it.

The thus formed molded article 31 is machined to form an outer insulator 24 as shown in FIG.
-1 and the inner surface insulator 24-2 are exposed and formed to constitute a creeping insulation part, and the inner peripheral metal fitting 32
and the connecting screw 22- for connecting the metal pipe to the outer peripheral fitting 33.
2, 23-2 are formed and finished into an insulating pipe joint 21 used in an electric heating electrode device.

The reason why this insulating pipe joint 21 cannot obtain sufficient creeping insulation properties, especially the creeping insulation resistance of the inner surface, and specifically, the reason why it is impossible to obtain a long inner peripheral insulator 24-2 This will be explained next.

The metal fitting material of this insulated pipe joint 21 is approximately
It is heated to a temperature of about 600℃, and in this state it is 1.5~
Receives a pressing force of 3.0ton/cm ² . It is necessary to maintain a predetermined mechanical strength under these conditions, and therefore the materials that can be used are naturally limited to iron and its alloys, stainless steel, etc. However, the coefficient of thermal expansion of iron is
11.5×10 ^-6 , and that of stainless steel is about 18×10 ^-6 . On the other hand, the coefficient of thermal expansion of glass-mica plastic bodies, which are electrical insulators, is 8 to 9×10 ⁻⁶ . The preformed body that becomes this glass-mica plastic body is generally
It is heated to 750 to 800°C, which is a necessary condition to improve fluidity during pressure molding. Furthermore, since natural mica decomposes when heated to this temperature, synthetic mica that does not thermally decompose is inevitably used.In reality, synthetic fluorine-containing gold mica is used, and the coefficient of thermal expansion of this mica is 8× 10 ^-6 .
On the other hand, glass with a coefficient of thermal expansion of 8 to 10 x 10 ^-6 is used due to constraints from the viewpoint of essential properties such as softening and melting temperature, electrical insulation properties, and corrosion resistance, and those with a coefficient of thermal expansion larger than this are used. It's impossible.
Therefore, the above-mentioned coefficient of thermal expansion is inevitably achieved.

In addition, due to the above-mentioned difference in coefficient of thermal expansion, the inner surface insulator 24-2, which controls the creeping insulation properties of the inner circumference of the product, can move the molded product in the axial direction as shown by arrows 35-1 and 35-2 at room temperature. Further, the center portion in the circumferential direction indicated by the arrow 36 is inevitably subjected to a compressive force. The compressive force per unit that this inner surface insulator 24-2 receives increases in the axial direction as the length increases, and in the circumferential direction as the diameter increases. However, in the state of the molded product, depending on the metal fittings,
Since this inner insulator 24-2 is surrounded,
Although no abnormality is observed in the phenomenon, the metal fittings on the inner periphery are removed to make the product, and this compressive force may be greater than the compressive strength maintained as a glass/mica plastic body. , a phenomenon in which the nails break and scatter, the so-called nail-flying phenomenon, occurs. This phenomenon is significantly accelerated when the temperature increases or decreases.

For these reasons, the length of the inner insulator 24-2 is necessarily restricted, and the length is limited to about 1/2 of the diameter of the inner insulator 24-2.

The present invention uses an insulated pipe joint that maintains the required creepage insulation properties, i.e., long creepage insulation, and overcomes the fatal flaw of conventional electric heating electrode devices, namely, by connecting a large number of insulated pipe joints in series. The object of the present invention is to provide a useful and practical electrode device for electric heating that completely eliminates the complexity of assembly due to connections and the resulting increase in price.

Prior to explaining the present invention, an example of an insulated pipe joint to be used will be explained based on FIGS. 3 and 4 of the accompanying drawings. In addition, Fig. 3 X shows the structure of the finished product, Fig. 3 Y shows the structure of the finished product after machining and installing the necessary parts, and Fig. 4 X shows the structure of the finished product. FIG. 4Y is a vertical cross-sectional view showing the state before pressurization, and FIG. 4Y shows the state after pressurization is completed.

In FIG. 3, reference numeral 41 indicates one end, e.g.
In the figure, the connection part 41-1 is connected to the cylindrical body 41-1 at the upper end.
2, a flange 41-3 is provided in the middle of the cylindrical body 41-2 and protrudes toward the outer diameter side, and a support base 41-4 is provided at the lower part of the flange 41-3. 1 tubular member, reference numeral 42, surrounds the flange 41-3 of the first tubular member 41 or surrounds the flange 41-3 with the lower part open. 41 and 42 to insulate both the tubular members 41 and 42. The length of the gap 44-1 is such that the upper end side in the figure is the same as the above-mentioned flange. Part 4
It is extended to the required length beyond the upper end of the electrical insulator 43-2 that sandwiches the flange 41-3, and its lower end is flush with the lower end surface of the electrical insulator 43-3 that also sandwiches the flange 41-3. Alternatively, it is a second tubular member formed to extend slightly downward, and the electrical insulator 43 is a second tubular member formed to extend slightly downward from the electrical insulator 43-2, 43-2.
-3, the upper part extends to the vicinity of the boundary between the cylinder body 41-2 of the first tubular member 41 and the connecting part 41-1,
Electric insulators 43-4 and 43-5 extend downward to the lower end of the first tubular member 41, respectively, and of course, the connection between the collar portion 41-3 and the second tubular member 42 is An electrical insulator 43-1 is also continuously interposed between them. In addition, the second tubular member 42
A connecting tool 46 is attached to the lower end of the outer periphery of the electrical insulating material 43-5 and is airtightly attached thereto by, for example, at least one of screwing with a screw 45-1 and welding 45-2. A hole 46 - 1 having an inner diameter the same as the inner diameter of the first tubular member 41 is formed at the lower end of the connector 46 .

Note that the first and second tubular members 41 and 42 described above
As with conventional products, any material may be used as long as it maintains a predetermined mechanical strength under heating conditions of about 600°C, and iron, stainless steel, etc. are preferably used.

The product of the present invention is constructed as described above, and its molding will now be explained with reference to FIG. In addition, in the molding, the connector 46 is molded in a state where it is not attached, and the first and second tubular members 41 and 42 are
The other parts can be used as they are, except that a machining allowance is added to the inner diameter of the first tubular member as necessary.

Further, the mold has the same outer diameter as the outer diameter of the second tubular member 42, and the cylindrical body 4 of the first tubular member 41.
1-2, a predetermined gap 4 necessary to form an electrical insulator 43-4 interposed therebetween.
4-4, and a circumferentially divisible auxiliary having a length necessary to form an electrical insulator 43-4 whose upper end has an inwardly inclined surface 47-1. The wall portion 47 and the gap portion 44 necessary to support the lower end surface of the second tubular member 42 on the upper surface and to form the electrical insulator 43-3.
-3 between the flange 41-3 and the first
The step portion 48-1 that supports the lower end surface of the tubular member 41 is formed, and the gap is necessary to form an electrical insulator 43-5 between the first tubular member 41 and the lower support base 41-4. A split-structure support metal 48 having a portion 44-5, a wall portion 49, a frame 50, and a pressure metal 51 similar to those used in molding conventional products.
It is composed of.

Further, as the raw material, a preformed body 52 formed into a cylindrical body from a mixed powder of vitreous powder and mica powder is used, as in the conventional case.

In order to mold this insulated pipe joint using each member configured in this way, the wall portion 49, frame 50, and support metal 48 must be assembled in the mold, and the auxiliary wall portion 47 and the pressure metal 51 must be assembled. The first and second tubular members 41 and 42 and the preform 52 are also heated to a predetermined temperature separately without assembly.

Next, when heating is completed, the first tubular member 41 is first inserted onto the support metal 48 of the assembled mold, and then the second tubular member 42 is inserted into the support metal 48 as well.
Insert it on top. Next, the auxiliary wall portion 47 is placed on the second tubular member 42 , and subsequently the preform 52 is placed on the auxiliary wall portion 47 . The state in this case is shown in Figure 4
It is shown in

Next, a pressurized metal 51 is placed on the preformed body 52,
Pressurization metal 51 is pressurized by a pressure molding machine (not shown). The preformed body 52 flows due to this pressurization, and forms gaps 44-1 to 44-5 formed by the first tubular member 41, the second tubular member 42, the auxiliary wall portion 47, and the support metal 48. is filled, a part of which remains on the upper inclined surface 47-1 of the auxiliary wall portion 47,
Electrical insulators 43, i.e. 43-1 to 43-5
Configure. The situation in this case is shown in FIG. 4Y.

When the molding is completed in this way, the molded product is cooled to a predetermined temperature, and then the mold is disassembled to take out the molded product. Because of this, it can be easily disassembled and removed. Such a molded article is shown in FIG. 3X. Moreover, the gap 44- between the first and second tubular members 41 and 42
Electrical insulators 43-1~ filled in 1~44-3
43-3 is compressed by the second tubular member 42 and securely fixes the first tubular member 41.

Further, insulators 43 - 4 and 43 formed on the outer peripheral surface of the first tubular member 41 at both ends of the second tubular member 42
-5 has an auxiliary wall part 47 and a support plate 48 on the outer circumferential surface that are split structure and freely movable molds during molding, so that the molding can be performed without any compressive force being applied in both the axial and circumferential directions. The inner peripheral surface is also the first
Since the coefficient of thermal expansion of the tubular member 41 is large, no abnormal pressure remains and the tubular member 41 is in an extremely stable state.

For the above reasons, there are no restrictions on the length, so a molded product with a length necessary to maintain creeping insulation properties can be obtained.

As described above, in the electric heating electrode device according to the present invention, as shown in FIG. A connecting tool 46 having a through hole 46-1 equal to the inner diameter of the tubular member 41 is screwed into the screw 4.
5-1 or welding 45-2, an insulating pipe joint 61 that is water-tightly (oil-tightly) connected is used.

Next, an embodiment of an electric heating electrode device according to the present invention using this insulated pipe joint 61 will be described with reference to FIG. 5 of the accompanying drawings.

In the figure, the casing 1, electrode 3, and cable 4 are the same as those in FIG.
and connection screws 62-1, 62- that connect the insulated pipe joint 61 and are engaged with the connection screws formed in the connection portion 41-1 of the insulated pipe joint 61 and the through hole 46-1 of the connector 46. Connecting pipe 6 in which 2 is formed
2. Both ends of the insulating section 2 configured and connected in this way are connected to the casing 1.
and a connection screw formed on the electrode 3, and an insulated pipe joint 61.
The connection screws 41-5 and 46-2 are connected to the connecting portion 41-1 and the hole 46-1.

As described above, in the electric heating electrode device of the present invention, the connection screws used to connect the casing 1 can be used as they are to connect each part, so the connection work can be standardized. , it becomes possible to assemble without requiring complicated labor. Moreover, since it is possible to provide communication holes with the same inner diameter in each component, necessary components such as the above-mentioned partition plates can be easily attached. In addition, in this basic configuration diagram, two insulating pipe joints 61 are provided to connect the insulating part 2.
However, as mentioned above, when the concentration of saline water existing in the outer periphery of the insulating section 2 is high and higher creeping insulation characteristics are required, the insulated pipe joint 61 is used.
By increasing the number of connections, this characteristic can be easily secured.

The electric heating electrode device according to the present invention has an insulating portion 2
The construction is made up of insulating pipe joints 61 with good creeping insulation properties that allow the desired number of connections to be made easily through connecting pipes 62, and the inner diameters are made to be the same. The fatal defect of low creepage insulation properties can be eliminated, and as a result, the necessary properties can be completely ensured. The facing part is set, and the suspension load strength can be maintained by mechanical calculation, and the water (oil) tightness, cold heat and mechanical impact strength also completely maintain the necessary properties. Because it does not change over time and has long-term reliability, it is extremely useful as an electric heating electrode device for underground resource recovery, and its practical and technical effects are extremely significant. have.

Furthermore, since the metal fitting structure constituting the insulated pipe joint is extremely simple and easy to mold, it can be manufactured at low cost, and one of the major effects is that it can be manufactured at low cost.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view schematically showing the state in which an oil sand layer is heated by an electric heating electrode device, and Fig. 2 is a longitudinal cross-sectional view of an insulated pipe joint used in a conventional electric heating electrode device. Fig. 2 X shows the structure of the product, Fig. 2 Y shows the structure of the molded product, and Fig. 3 shows the insulated pipe joint used in the electric heating electrode device of the present invention. FIG. 3 is a longitudinal sectional view showing one embodiment, and FIG. 3 is a vertical sectional view showing the structure of a molded product, FIG. FIG. 4 is a vertical cross-sectional view showing an example of a method for forming an insulated pipe joint used in a heating electrode device, in which FIG. 4 X shows the state immediately before pressure forming, and FIG. FIG. 5 is a vertical cross-sectional view showing the structure of an embodiment of the electric heating electrode device according to the present invention. In the figure, 1, 11...casing, 2, 12...
Insulating section, 3, 13... Electrode, 4, 14... Cable, 5... Power supply device, 6... Oil sand layer, 7
... Current, 8 ... Ground surface, 9 ... Oil sand upper layer, 10 ... Oil sand lower layer, 41 ... First tubular member, 41-1 ... Connection section, 41-3 ... Cylindrical body, 41-2 ...Trim section, 41-4...Support stand, 4
1-5... Connection screw, 42... Second tubular member, 4
2-1... Groove, 43, 43-1 to 43-5...
Electrical insulator, 44, 44-1 to 44-5... Gap, 45-1... Screw, 45-2... Welding, 46
...Connection tool, 46-1...Through hole, 46-2...
Connection screw, 47... Auxiliary wall part, 48... Support metal,
49...Wall part, 50...Frame, 51...Pressure metal, 6
1...Insulation pipe joint, 62...Connecting pipe, 62-1,
62-2... Connection screw. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A metal tubular casing buried underground, an electrode buried in a hydrocarbon-based underground resource layer underground to flow a current into the underground resource layer, and between the casing and the electrode. an insulating part consisting of one or more interconnected insulating pipe joints interposed to connect and electrically insulate the casing and the electrode; and an insulating part that penetrates the inside of the casing and the insulating part. and a casing for supplying current to the electrode, and the insulating pipe joint has a connecting portion continuous to one end of the cylindrical body, and a flange protruding toward the outer diameter side is formed in the middle part of the cylindrical body. being the first
A groove is formed between the tubular member and the first tubular member, the inner diameter side of which corresponds to the flange, and the length of the tubular member is in close contact with the flange on the one end side. a second tubular member extending to a desired length beyond the one end of the electrical insulating material to be sandwiched, and formed so that the other end thereof is flush with the other end of the electrical insulating material to sandwich the flange; , continuous from the vicinity of the connection part of the first tubular member and the boundary between the cylinders to the other end of the first tubular member via the part sandwiched between the first and second tubular members. and a connector having a through hole at its tip, which is airtightly attached to the outer diameter portion of the other end of the second tubular member, separated from the electrical insulator. An electrode device for electrically heating hydrocarbon underground resources, characterized by: 2. The above-mentioned connection of the insulating part that connects the casing and the electrode and is composed of one or more mutually connected insulating pipe joints is connected to the inner diameter part of the tip of the connecting part of the first tubular member and the tip of the connecting tool. When two or more insulated pipe joints are provided, the two or more insulated pipe joints can be connected by interlocking with the screws formed in the casing and electrode formed in the through holes, respectively, and the two or more insulated pipe joints. An electrode device for electrically heating hydrocarbon-based underground resources according to claim 1, which is connected by a connecting pipe. 3. The electrical insulator of the insulating pipe joint is a glass-mica plastic body made of glass and mica powders, heated under pressure to a temperature at which it can flow, and heated and press-fitted into the desired position. An electrode device for electrically heating hydrocarbon-based underground resources according to claim 1 or 2.