JPS60133196A - Electrode apparatus for electrically heating hydrocarbon underground resources and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electrode device for electrically heating hydrocarbon-based underground sources and a method for manufacturing the same. When extracting hydrocarbons with high viscosity and low fluidity from wells, electricity is applied to the hydrocarbon-containing layer that exists underground in order to increase the fluidity of the hydrocarbons.
The present invention relates to an electric heating electrode device used for heating and a manufacturing method thereof.

[Prior art]

Typical hydrocarbons with high viscosity and low fluidity that exist underground include bitumen contained in what is generally called oil sand or tar sand, and kerogen contained in what is called oil shale.

Traditionally, oil sands have been the focus of research in consideration of economic effects. The two methods currently being researched to heat underground oil reservoirs are burying a steel casing underground that reaches the underground oil reservoir and injecting hot water or high-temperature, high-pressure steam into the reservoir. In this method, moss lightning poles are buried at appropriate intervals in the moss, and electricity is passed between the electrodes to heat them using Joule heat. The former method has the advantage of being easy in terms of equipment, but has the disadvantage of being inefficient. The latter method has been theoretically or experimentally recognized to be very efficient, but it has the disadvantage that it is extremely difficult to use equipment.

This invention relates to an electrode device used in the latter electric heating method. With the well-known electric heating method, it is impossible to extract underground oil sands using only electric heating, and the oil sands are buried underground! A method in which a tubular electrode is supported at the lower end of each pair of casings, the viscosity of the oil is reduced by applying electricity, and then high temperature and high pressure steam is injected into one casing, and oil is collected through the other casing. is taken.

Here, to make it easier to understand, we will explain the characteristics required of the electrode device, including the state of existence of oil sands and the method of collection. 6"o oil sands have been confirmed to exist in reserves in Canada, the United States, Venezuela, etc. Oil in oil sands exists on the surface of the sand and in the interstices between the sands along with salt water, but it has an extremely high viscosity and is often exposed in naturally occurring canyons, riverbanks, etc. Most of the oil exists in a layer several/θm thick at a depth of 200 to 200 rooms underground.It is economical and environmentally friendly to excavate the oil sand and separate the oil above ground. Due to restrictions, it is necessary to extract only oil from underground.Furthermore, there is a risk that the ground will collapse if oil is extracted from a shallow layer underground, so it is preferable to extract oil from a layer less than 300 meters underground. has been done.

In the electrode device that heats the oil sand layer by applying electricity as described above, the biggest problem 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. Although it is difficult to uniformly display the values because they differ depending on the conditions of each location, the average values are 10θQm for the oil sand layer and ioΩm for the upper stratum. Therefore, l made of steel pipes
When electrodes connected to the pair of casings are buried in the oil sand layer and energized, most of the current is 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. Although this invention relates to the latter device,
A conventional device of this type will be described below.

Cables f and /F for sending current are connected to the electrodes 3 and 13, respectively, which are connected to the electrodes 3 and 13, respectively, and a device having such a configuration is called an electrode device. Further, S is a power supply device, 6 is an oil sand layer, 7 is an electrode 3. /3, g is the ground surface, RI is the upper layer of oil sands, and IO is the lower layer of oil sands. With such a configuration, when a voltage is applied from the ground power supply S to the electrode 3.13 buried in the oil sand layer B through the cables p and /F, the current 7 increases depending on the electrical resistance in the oil sand layer 6. flows, Joule heat is generated, and the oil sand layer 6 is heated. At this time, is the 7th part of the current 7 the upper layer of the oil sand? The electric current 7 also flows to the lower oil sand layer 10, but the leakage of the current 7 is suppressed to a small level because the insulating parts /2 are interposed between the casing /, // and the electrodes 3, 73. When the oil sand layer 6 is heated to a predetermined temperature, electricity is turned off, and hot water or high-temperature, high-pressure steam is injected into the oil sand layer 6 from the top of one casing of the electrode device. / Outflows with oil. In order to improve the outflow of hot water or high-temperature, high-pressure steam, 3. i3 usually has pores.

In order to reduce 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 nozzle (not shown), and the salt water and the casing i
, it, there is a partition plate φ above the electrodes 3 and 13.
(shown in FIG. 6), and the upper part of the partition plate vp is filled with an insulating liquid.

Such electrode devices do not break when buried, and have sufficient strength to withstand earth pressure when initially buried, but when energized, the temperature rises, which is particularly noticeable near the electrodes due to the high current density. In addition, it is required that it does not deform or break, that it can withstand the static pressure of the liquid that fills the inside, and that it does not break or leak when hot water or high-temperature, high-pressure steam is injected. By the way, if it is buried 5ooa underground, if the specific gravity of the liquid filled inside is /, then the pressure of 5Q will be applied, and the temperature of the water vapor with the pressure of So will reach 265°C.

Note that this insulating part, 2. The upper part of /2 is the casing/,/
Since the upper and lower parts of / are connected to the electrode 3.73, a suspension load is always applied to the insulation parts λ and 1, and the conditions are 2: high temperature conditions of 0 to 300°C. Since it is below, characteristics that satisfy this are required. Since this insulating part 2, 7.2 is installed next, it is practically impossible to avoid contacting or colliding with the hole wall during the installation process. Therefore, since the overall weight is heavy, even a slight contact causes a large mechanical impact on the insulating parts 12, and the insulation parts 12 are required to have characteristics that can withstand this impact and not be damaged.

The present inventors, in order to obtain a useful electric heating electrode device,
First, we conducted research on useful insulated pipe joints.

The following items were listed as characteristic goals. In other words, since the electrodes are held suspended, the mechanical strength is high.

Since a voltage of qoooo to 5ooov is applied between both electrodes, high withstand voltage characteristics must be maintained to withstand this voltage.

Although the temperature rises due to the current flowing between the electrodes and reaches a temperature of about 300° C., the mechanical and electrical properties should be maintained even under this temperature condition. Must have excellent cold and thermal shock resistance. Since contact with the hole wall inevitably occurs during burial, the mechanical impact strength must be high.

A casing with a central through hole at the top /, // and an electrode 3,
The flow resistance should be low, as is the inner diameter of No. 13.

Furthermore, it must maintain a high degree of water (oil) tightness under the above conditions. and have long-term reliability without deterioration over time. and upper and lower casings /, // and electrodes 3, 1
Can be easily connected to 3. etc.

We succeeded in obtaining an insulated pipe joint with the above-mentioned target characteristics and proposed it earlier (Japanese Patent Application No. 2,79/f).

The structure of this insulated pipe joint will be explained with reference to FIG.

That is, it is composed of an inner metal fitting 2 and an outer metal fitting 2 each made of steel and having a through hole in the center, and an insulator 2 interposed in the gap between them. Internal metal fittings
An outer circumferential ring 2/-/ is formed at the lower end. The external metal fitting 22 consists of an upper metal fitting JJ-/ and a lower metal fitting Cococo.
The outer ring 2 of the internal fitting 21 is attached to the upper end of the upper fitting Coco-7.
An inner circumferential ring 22-3 facing /-/ is formed. After this inner ring 2-3 penetrates the outer periphery of the wall 2/- of the internal fitting 21, its lower end is screwed or welded to the outer periphery of the wall 22-11 of the lower fitting 22-. Junction λS
do. Note that the inner peripheral diameter of the wall portion 2 corder is larger than the through-hole diameter of the internal fitting 2/.

The insulating material 2 fills the gap between the internal fitting 21 and the external fitting 2, and continuously fills the outer peripheral surface of the wall 2/- of the internal fitting 2 and the wall of the external fitting 2. It is formed on the inner peripheral surface of Hiro.

Next, regarding the material of the insulator, a glass-mica plastic body is used. This glass-mica plastic body is made from a mixture of vitreous powder and mica powder, heated to a temperature where the vitreous material softens and can flow under pressure, and then pressure-molded in the heated state. It is an insulator made by

In the conventional insulated pipe joint with the above configuration, the inner fitting 27 has an outer ring 21-7, and the outer fitting 22 has an inner ring 21-7.
Both have metal fittings on the inner and outer circumferential surfaces of the insulator core, so there is no phenomenon of loosening even when the temperature rises or falls. Therefore, from room temperature to 300℃
In this temperature range, not only the water (oil) tightness but also the mechanical strength does not deteriorate. In addition, the outer circumferential ring λ/-/ of the internal fitting 21 and the inner circumferential ring Coco of the external fitting 2.2
3 facing each other, it maintains extremely high strength against suspension loads. Finally, casing /, /// and electrode 3. /3 can be connected by screws or by welding. In the case of screw connection, as shown in Fig. 2, each screw 23- /, and J-2 are screwed.

As is clear from the above description, such a conventional insulated pipe joint has almost all the characteristics necessary as an insulated pipe joint for an electrode device. However, there was an unavoidable flaw in creepage insulation properties.

In the first place, saline water is fed into this electrode device through a pipe in order to lower the contact resistance between the electrode and the oil sand layer as described above. For this reason, the saline solution also exists on the outer periphery of the insulated pipe joint, so it is necessary to form a long creeping insulation part on the outer periphery to ensure high creeping insulation properties.

Regarding the inner peripheral surface, a partition plate 914+ shown in FIG. 6 is provided above the electrodes 3 and 13 to separate the saline solution from the casings i and ii, and an insulating liquid is provided above the partition plate pp. Since it is filled, there are no defects on the inner surface that would pose a problem regarding creepage insulation properties.

Now, the creeping insulation properties of the outer circumference of this insulated pipe joint are determined by the length of the insulator formed on the outer circumferential surface of the wall of the internal fitting col, 2/2, but there is naturally a limit to the length that can be formed. The limit is about % of the inner diameter. The reason is mainly due to the problem of moldability. Breaking through this barrier requires a huge amount of molding equipment, and when considering the cost as well, the result is as described above. was not obtained.

[Summary of the invention]

The present inventors utilized the above-mentioned conventional insulating pipe joint, which has extremely excellent properties in terms of various properties, and secured the insulation properties of the outer bath surface by other means, thereby realizing an electrode device that has all the required properties. I ended up doing it.

Generally, the structure is such that the internal metal fittings of the insulated pipe fittings are faced to each other, and an insulated pipe with an insulating layer formed on the outer peripheral surface of the metal pipe is joined and interposed between them, and the insulating layer and the insulated pipe fitting are interposed between them. Electrode device for electric heating, which is formed by forming another connecting insulating layer between the insulating layers on the outer circumferential surface of an internal metal fitting t, thereby ensuring creeping insulation properties of the outer circumferential surface, and its manufacture. It provides a method.

[Embodiments of the invention]

An embodiment of the present invention will be described below, but prior to that, the material of the insulating layer formed on the outer peripheral surface of the metal tube will be discussed.

The first problem in implementing the above-mentioned device is to obtain an insulating tube having an insulating layer firmly adhered to its outer circumferential surface. If the usage conditions are in the temperature range from room temperature to about 100'C, the desired product can be easily obtained by forming an organic insulating layer that has corrosion resistance, etc., but the usage conditions such as this electrode device When the temperature reaches about 30θ℃, the situation changes dramatically. First, it is necessary to select a material that maintains heat resistance at 700°C. Examples of materials having the above-mentioned characteristics among organic materials include polyfluorinated ethylene (Teflon), poly, needle, ether, and ketone (Peak). The coefficient of thermal expansion of these materials is extremely large, differing by an order of magnitude from the steel pipe material that is the base material, so when the temperature rises, flexible materials such as polyfluoroethylene deform significantly, and non-flexible poly and ether , ether, ketone, etc., the absolute amount of the difference in the amount of expansion and contraction becomes large due to the breakage phenomenon. This is an inevitable physical phenomenon, and it is essentially impossible to avoid it. In the case of this electrode device, it is necessary to have a diameter of 200 to 230 meters and a length of about 1 to λm, so it is completely unthinkable to construct an insulating layer using an organic material.

In the temperature range of room temperature to 300 degrees Celsius, an insulating tube with an insulating layer that does not cause phenomena such as peeling or damage on the outer peripheral surface of the steel pipe has a thermal expansion coefficient of the insulator in the temperature range of room temperature to 300 degrees Celsius. The essential condition is that it approximates that of a steel pipe.In addition to satisfying this essential condition regarding the coefficient of thermal expansion, it maintains electrical and mechanical properties in the temperature range from room temperature to Jl! When it comes to insulating materials that are rich in properties, have excellent corrosion resistance properties, and have long-term reliability, the selection range is extremely limited.

The present inventors considered using an insulating tube in which a glassy insulating coating layer was formed on the surface of the steel tube.

In this case, the problem is the characteristics of the glass forming the insulating coating layer. After many experiments focusing on corrosion resistance, coefficient of thermal expansion, and adhesion to steel pipes, we finally succeeded in obtaining an insulated pipe that satisfies the above properties.

The next important thing is to insulate the vitreous insulating coating layer formed on the surface of the steel pipe of the insulated pipe and the insulating layer made of glass-mica plastic formed on the outer peripheral surface of the metal pipe of the insulated pipe joint. The problem is how to configure the connecting insulators to hold and connect them. Taking this into consideration, we investigated the structure of the insulating tube.

It was decided that the insulating tube and the internal metal fitting 21 of the insulating pipe joint would be connected by four welding joints, and the structure thereof was determined.

FIG. 3 shows an example of an insulated pipe, and the inner diameter of the steel pipe 6 has a pressure equivalent to the through-hole diameter of the insulated pipe joint shown in FIG. 2, that is, the inner diameter of the wall 21-2 of the internal fitting 21. , and the outer diameter of both end portions 2A-/ is equal to the outer diameter of the wall portion 2/-2. The outer diameter of the other portions has dimensions equivalent to the outer diameter of the outer circumferential insulating body of the insulated pipe joint when the coated insulating core is applied. The covering insulator λ is connected to the outer circumferential surface and end of steel pipe 7, and the side surface of 26-/.

obtain.

Next, insulated pipe joints are joined to both ends of the insulated pipe, and a connecting insulator is formed between the covering insulator 27 of the insulated pipe and the outer circumferential insulator ρ-/ of the insulated pipe joint, and a series of creeping insulation layers are formed. We will explain how to do this.

As shown in Fig. 2 (a), the inner diameter of the wall 2/-2 of the internal fitting 21 of the insulated pipe joint lθ/ is finished to the same size as the through hole, and the outer peripheral insulator 2'l-2 at the tip is finished. Delete part of /2g
and expose the wall portion, 2/-, 2.

Next, the above wall portions 2/-2 are brought into contact with both ends of the insulating tube ioo, and the contact surfaces 29 are joined by welding.

Note that electron beam welding is ideal for this welding because it causes less temperature rise in the peripheral area.

In this way, as shown in FIG. 4(a), the insulation tube io
An integrated structure 10 in which insulating pipe joints 10/ are connected to both ends of o.
get ko. As shown in Fig. 3(b) K, connecting insulators 3o are bonded to the insulators 3o at both ends so as to maintain insulation by closely contacting the insulators 1 and 2 at the joints 29. 'l-/, the connecting insulator 30 and the covering insulator 27 are a series of outer peripheries The above connecting insulator 3o must meet the following conditions. In order to maintain perfect insulating properties with the adjacent insulator 2'l-/, it is essential that the wall 2/ and the metal tube roller, which have a gap at the contact surface, match well, and the temperature rises and falls. No phenomena such as gaps may occur even when repeated. In addition, it is necessary to have corrosion resistance and also maintain necessary mechanical strength.

The glass-mica plastic body used as the insulator of insulated pipe joints is an extremely suitable material, but the problem is how to form it.

As a result of much research and experimentation, the present inventors succeeded in forming the connecting insulator 3θ appropriately.

The method for forming it will be explained below. First, a special molding die is used for its formation. FIG. 5(a) shows an embodiment of a molding die and a molding method, in which the molding die has a molding part composed of a lower metal 31 and a lower metal 32 whose upper and lower surfaces are in contact with each other,
In the center of the contact surface part, there is a horizontal through hole 33 into which the joined body 102 of the insulating pipe joint 10/ and the insulating tube 100 can be fitted and loaded, and the center part has a lateral through hole 33 in which the connecting body 3Q can be constructed. An annular space 3da is provided to facilitate the flow of the fluid.

Shimokin again? At the top of / there is a filling hole 3 that leads to the space 3 Hiro.
S is provided, and the three lower molds are provided with a reservoir 36 at the bottom, and this reservoir 36 and the space, ? There are 3 communication holes between the two to communicate with each other. The lower surface of the raw material filling metal 3t is in contact with the upper surface of the lower metal 31, has a raw material filling chamber J9 in the center, and has an outflow hole V communicating with the filling hole 3S of the lower metal 37 at the bottom thereof.
0 is the default.

Pressurized metal F/ is raw material filling chamber 3? Fits into the inner wall of the

The upper surfaces of the base metals F and 2 are in contact with the lower surface of the lower metal J to support the molding die. Note that the bottom metal 31, the bottom metal 32, and the raw material filling metal 3g are divided vertically into pieces in consideration of ease of disassembly after completion of forming and shaping. However, it goes without saying that measures must be taken to prevent relative displacement of each part of the mold during pressure molding.

Next, the raw material of the connecting insulator 30 will be explained.

The glass and mica used are the same as those used for manufacturing the insulated pipe joint 10/. The mixing ratio will be detailed later, but
The insulated pipe joint/θl contains more glass powder than the one with 2 da insulators, and uses a mixture of glass powder SOV% and mica powder SOv%.

Approximately jw% of water is added to the above mixed powder to make it wet and the water is removed, and the pre-acid is used as Form DA 3.

For forming, assemble the base metal ψ and the lower metal 32, place the assembled lower metal 31 and 3g of raw material filler metal on top of it, and place the joined body in aSO℃ without assembling the pressure metal F/. For 10 pieces, use a circular furnace to J! around the joint 29. r0'G3 and preform Hiroshi 3 are heated to 750°C. After heating is completed, the 10 joined bodies are loaded into the through hole 33 and held so that the joined part 29 is located directly below the filling hole 35. Next, the preformed body 3 is loaded into the raw material filling chamber 3.

The state at this time is shown in FIG. S (a). Next, pressurized metal F/
The preform uJ is placed on top of the pressurized metal plate l using a pressurized molding plate (not shown). The pressurized preform Hiroshi 3 flows and passes through the outflow hole ρQ and the filling hole 33, and the space 3. It reaches the upper part of the tube and branches to the left and right of the joint IOA to form a space 3, that is, an outer circumferential insulator 2 of the insulating pipe joint 10/ and a covering insulator J? of the insulating tube 10θ. flows through the space constituted by the glass, the leading parts join together at the lowest part, and then pass through the flow holes 3 and rise up to form a connected insulator 3O made of a glass-ika plastic body. The state at this time is shown in Figure 5(b).
This is shown below. What is the temperature of the formed connecting insulator 3o?
When the temperature reaches 00°C, the mold is disassembled and the molded product is taken out. At this time, the portions of the filling hole 35 and the flow hole 37 may break, but there is almost no damage caused by breakage of the connecting insulator or yoK.

Connecting insulators 3θ are also formed for the remaining joint portions by the above process.

The thus formed connecting insulator 3θ has no voids at the contact surface with the adjacent insulator 2hiro-i and the covering insulation 27, and maintains perfect insulation. The features of the method for forming the connecting insulator 3O that maintains perfect insulation as described above will be explained below.

First, the connecting insulator? Glass powder with raw material mixing ratio of 0!
(The mica powder SOV% is 7%, and the glass powder content is higher than the powder 35% in the mixing ratio of the insulator uf for insulated pipe joints.In the case of this raw material, the glass powder mixing ratio increases. The smaller the coefficient of thermal expansion (in this case, the coefficient of thermal contraction) becomes.

Connecting insulator 3 at the moment when connecting insulator 3θ is formed
Since the temperature of θ is high, a raw material with a low thermal shrinkage rate is used to reduce the total amount of shrinkage, and the adjacent insulators 2'l-/, 2?
Care has been taken to ensure that no voids occur between the two.

This creates a series of insulating layers that maintain perfect contact.

Next, regarding the relationship between the heating temperatures of the preformed body 3, the joined body 10.2, and the molding mold during molding, first of all, heating the molding mold to 456°C is because the glass is too high and will not penetrate. When the bonded body 102 is loaded into the hole 33, the insulator 2-/
This is not desirable because the temperature of 27 and 27 rises too much. Also, the heating temperature of the bonded body/θλ is
It is closely related to the glass transition temperature of the raw material glass of the mica plastic body and the vitreous insulator 27. If the temperature exceeds the transposition temperature, there is a risk of deformation as the viscosity of the glass decreases. On the other hand, if the temperature is too low, cracks will occur when it comes into contact with the flowing preform 3 at a high temperature. When heated to a temperature slightly lower than the transposition temperature, the above-mentioned phenomenon is not observed at all, and even if the preform 3 is brought into contact with the high temperature and subjected to pressure, no cracks will occur at all. Therefore, it is desirable to set the temperature lower than the transition temperature, and in the above example, the temperature was set at 3° C., which is lower than the transition temperature of glass. Furthermore, the heating temperature of the preform v3 is
It is an essential condition to heat the preform to a temperature at which it has a viscosity that allows the preform to flow under pressure and to form a connecting insulator 3o with high density in each part.
and heat-formed to 27.

Finally, regarding the structure of the mold, a major feature is that a reservoir J6 having a flow hole 37 is provided at the bottom. During molding, the preformed body ψJ pressurized by the pressurizing metal tI/ passes through the outflow hole VO and the filling hole 3s, and passes through the lower metal 31 and the lower metal 3.
2 reaches the upper part of the space 3 formed between the joined body/θ Yu, where it branches left and right upper and flows, collides and coalesces at the bottom of the joined body 102, and the combined part becomes a single body. Flow hole 3
7 and fills the reservoir 36, and the flow is stopped. Thereafter, the density of the preformed body 13 whose flow has been stopped is increased by further pressurization by the pressurized metal, and a connected insulator 3o made of a glass-mica plastic body is formed. The preform v3 that has passed through the filling hole 35 as described above branches left and right and flows into the 7-joined body 10. ! They collide and coalesce at the bottom of the
The temperature of the leading end of the fluid is decreasing because it is flowing in contact with the mold wall and the surface of the joined body l/)2. Therefore, the joint surfaces formed by the collision cannot maintain a completely fused state. If the molding die does not have the reservoir 36, a joint surface that does not maintain the above-mentioned completely fused state will appear at the bottom of the joined body ios, causing cracks and deteriorating mechanical and electrical properties. The mold used in the present invention includes a reservoir section 76 and a communication hole communicating therewith. ? Since 7 is a provision, the joint that does not maintain the above-mentioned completely fused state passes through the communication hole 7 and is pushed out to the reservoir j61c,
A bonding surface that maintains a completely fused state is formed at the lower bonding portion of the bonded body 102.

The electrical heating electrode device equipped with the above-mentioned insulating tubes is used individually, and the casing l and the electric head 3 are connected to each external fitting 22 by screws 3-2, and the opposing insulating tube joints io
The metal tube roller of the insulating tube 100 is joined to the internal fitting 21 of t by welding. This configuration ensures complete insulation between the casing l and the electrode 3. Next, the creeping insulation properties on the outer peripheral surface required for this electrode device are:
Outer circumferential insulation 2'l-/ of insulated pipe joint 10/ and insulated pipe 10
A connecting insulator 3Q is bonded and formed in the gap of the covering insulator 27 of No. 0, and the integral insulating layer covers the internal fitting 21 of the insulating pipe joint 10/ and the metal tube roller of the insulating tube 100 to ensure insulation. So you can get exactly the desired characteristics.

In the embodiment shown in FIG.
However, if necessary, the number of connections can be increased to further improve creeping insulation characteristics. Also,
In this embodiment, a screw connection is used to connect the insulating pipe joint 10 to the casing l and the electrode 3, but the connection method is not limited to these, and other methods may be used based on ease of assembly and economical effects. You can select .

In addition, the bonded body/
A space 3q is provided for winding the joint part of θ, but this is to facilitate the flow of the preform φ3, especially when the flow is easy due to the structure of the joint. There is no need to provide a space.

〔Effect of the invention〕

As described above, in this invention, the electrical insulation properties 2, mechanical impact strength and suspension load strength, which are necessary properties other than the creeping insulation properties of the outer circumferential surface, are ensured by the insulated pipe joints, and the creepage insulation properties are ensured by the insulated pipes and the connections. It is secured by an insulator,
It is possible to completely eliminate the fatal defect of conventional electrode devices, which was poor creepage insulation properties, and has a remarkable effect in recovering underground resources.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view schematically showing the state of use of a conventional insulated pipe joint, Fig. 1 is a partial vertical sectional view of a conventional insulated pipe joint, and Figs. 3 to 6 show an embodiment of the present invention. , Fig. 3 is a longitudinal cross-sectional view of the insulated pipe, and Fig. 7 is a longitudinal cross-sectional view of the insulated pipe joint and the insulated pipe that are joined to each other.
b) shows the state after forming the connecting insulator, and Fig. S is a longitudinal cross-sectional view showing the method of forming the connecting insulator. FIG. 6 is a vertical sectional view showing the main parts of the apparatus, showing the state after the press forming is completed. In the figure, / +' / / is the casing, /2 is the insulating part, 3 and 13 are the electrodes, 21 is the internal fitting 1.2/-/ is the outer ring, 22 is the external fitting, and 2 -/ is the upper part. Metal fittings, Ko2-2
2-13 is the lower metal fitting, 2-13 is the inner ring, 23 is the screw, 2φ is the insulator, 2. 'l-'/ is the outer insulator, 2S is the joint, 2
6 is a gold layer tube, the core is a covering insulator, 2t is a deleted part, 2q is a joint part, 30 is a connecting insulator, 31 is a stopper, 32 is a bottom metal,
33 is the through hole 1. ? 4t is a space, 3S is a filling hole, J6
is the reservoir, 3゛7 is the flow hole, 3g is the raw material filling metal, 39 is the raw material filling chamber, ILlo is the outflow hole, ψl is the pressurized metal, Hiroko is the alloy, Hiro3 is the preformed body, Hiro≠ is the partition In the plate, 100 is an insulated pipe, 10/ is an insulated pipe joint, and /'02 is a joined body. In each figure, the same reference numerals indicate the same or corresponding parts. Almost 1 figure, 2 figures, 3 figures, 5 figures ((1), 5 figures, (b) 1 Procedural amendment (spontaneous), No. 6, 1983, 7th, Mr. Commissioner of the Patent Office, 1, Indication of the case, 1989 patent Application No. Koda ot-oo and its manufacturing method 3, and its relationship to the amended case Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name
(601) To Mitsubishi Electric Co., Ltd. Representative: Katayuni Department 4, Agent address: 66, 4th floor, Marunouchi Building, 2-4-1 Marunouchi, Chiyoda-ku, Tokyo The detailed statement of amendments has been amended as follows.

Claims (2)

[Claims] (1) A cylindrical internal fitting made of a metal tube on which an outer ring is formed, an upper fitting on which an inner ring facing the outer ring is formed, and a lower fitting connected to the upper fitting. an outer metal fitting made of a metal tube having an inner diameter larger than an outer diameter of the glass-mica L pairs of cylindrical insulating pipe joints each having an insulating material made of a plastic body, and a vitreous insulating coating coated on the outer circumferential surface except for both ends, the joints being welded between the L pairs of insulating pipe joints. a rim tube made of a metal tube, a connecting insulator made of a glass-mica plastic body formed over the outer periphery of the welded joint, and an electrode and a casing each coupled to the outer end of the l pair of insulated pipe joints. An electrode device for electrically heating hydrocarbon-based underground resources, comprising: and. (2) A cylindrical internal fitting made of a metal tube on which an outer ring is formed, an upper fitting on which an inner ring facing the outer ring is formed, and a lower fitting connected to the upper fitting. an outer metal fitting made of a metal tube having an inner diameter larger than an outer diameter of the glass-mica A first step of creating a cylindrical insulated pipe joint with an insulator made of plastic, and an insulated pipe made of a metal pipe with a glassy ridge insulator coated on the outer peripheral surface except for both ends. a second step of welding and joining the end of the joint to the end of the internal metal fitting to create a joined body; and an annular space surrounding a horizontal through-hole into which the joined body is loaded and a welding part of the joined body. A molding tool comprising a separable lower metal having a filling hole and a reservoir connected to the bottom metal, and a stopper and a pressurizing metal having a raw material filling chamber communicating with the filling hole and directly connected to the upper surface of the lower metal. A third step of preparing a mold, and a V step of creating a preform made of a glass-mica plastic body.
an Sth step of heating the molding die, the joined body, and the preformed body to respective predetermined temperatures; and a step S of heating the molded body, the joined body, and the preformed body to respective predetermined temperatures, and placing the preformed body in the through hole in the heated state. a sixth step of loading each raw material into a filling chamber and pressurizing and fluidizing the preformed body using the pressurizing metal to form an annular connected IP edge around the outer periphery of the welded and joined portion; and after cooling; , a seventh step of disassembling the molding die to take out the joined body;