JPH0433958B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrode supporting conduit for electric heating of underground hydrocarbon resources, and in particular to an electrode supporting conduit for electrical heating coated with an electrical insulator and used when extracting underground hydrocarbon resources by an electric heating method. It is related to the manufacturing method. In this specification, hydrocarbon underground resources are
Refers to bitumen contained in oil sands or tar sands, and is referred to as oil sands below unless otherwise specified. In recent years, with the rise in the price of petroleum resources, extraction of oil from underground oil sand layers in countries such as Canada and Venezuela is being carried out in earnest. This oil sand layer is usually underground
It exists in a layer approximately 50m thick 100m deep underground, but due to its high viscosity, it cannot be pumped up and collected at room temperature. The method used was to raise the temperature of the oil by injecting it, lower its viscosity, and then pump it out. However, this method is inefficient and expensive, so a more productive method is to use a steel tube or stainless steel tube with an electrode section supported at the lower end.
A pair of conduits is buried underground at a distance of approximately 30 to 200 meters, with the electrodes located in the oil sand layer, and a voltage of several hundred to several thousand volts is applied between the two electrodes, and the Joule heat is applied. proposed a method for extracting oil by increasing the temperature of the oil sand layer and lowering the viscosity of the oil sand layer. In this latter oil extraction method, the resistivity of the oil sand layer is several times higher than that of the upper stratum, so the part of the conduit buried in the stratum is coated with an electrical insulator to prevent current from flowing through the upper stratum. You must do so. If it is not coated with an electrical insulator, current will flow through the strata and no current will flow between the electrodes buried in the oil sand layer. Accordingly, there is a rapidly increasing need to develop electrode support conduits coated with electrical insulators that can withstand use under these special conditions. The characteristics that such an electrical insulator must have are (a) voltage resistance of several hundred to several thousand volts not only at room temperature but also at temperatures of approximately 300°C, which can reduce the viscosity of oil in the oil sand layer; and 10 ⁶ Ω-cm
(b) In order to heat the water contained in the oil sand layer to a temperature of approximately 300℃ that can reduce the viscosity of the oil sand layer, (c) Mechanical strength to allow the electrode to be suspended, and mechanical strength to the extent that it will not contact the hole wall and cause damage when the electrode is supported and suspended at the lower end of the conduit and is buried in the oil sand layer through the buried hole. Must have impact strength. etc. are required. The present invention was made in response to the above requirements, and an object of the present invention is to provide an electrode support conduit for electrically heating hydrocarbon underground resources that has excellent voltage resistance, heat resistance, and mechanical strength. This invention will be described in detail below. The present inventors have conducted extensive research to develop an electrode supporting conduit coated with an electrical insulator that has all of the characteristics (a) to (c) above, and as a result, the outer circumferential surface of the metal conduit is coated with polyether. Etherketone resin film and polyethersulfone resin (hereinafter referred to as PES) or polysulfone resin (hereinafter referred to as
Glass fibers impregnated with PSU (abbreviated as PSU) are wound alternately, and the outer periphery is pressed using a mold at a temperature of 350 to 450℃ and a pressure of 10 to 200 kg/cm ² to form polyetheretherketone resin and PES. Alternatively, the inventors discovered that an electrode supporting conduit coated with an electrical insulator having all of the characteristics (a) to (c) above can be obtained by melting and molding PSU under heating and pressure, and completed this invention. I arrived. This invention provides an electrical insulator on the outer circumferential surface of a metal conduit, consisting of a plurality of alternating layers of polyetheretherketone resin film layers molded under heat and pressure and glass fiber layers impregnated with polyethersulfone resin or polysulfone resin. An electrode support conduit for electric heating of hydrocarbon underground resources, characterized by: The present invention also provides a method in which polyetheretherketone resin film and glass fiber impregnated with polyethersulfone resin or polysulfone resin are alternately wound multiple times around the outer peripheral surface of the metal conduit.
The temperature of the outer circumference is 350 to 450℃, the pressure is 10 to 200Kg/cm ²
The present invention also relates to a method for producing an electrode supporting conduit for electric heating of underground hydrocarbon resources, characterized in that the conduit is provided with an electric insulator formed under heat and pressure. The polyetheretherketone resin used in the present invention is represented by the following chemical structural formula and includes, for example, aromatic polyetheretherketones developed by British Imperial Chemical Industries. Polyetheretherketone resin has a thickness of
A film of 0.01 to 0.40 mm, preferably 0.02 to 0.30 mm is used. If the film is less than 0.01 mm thick, the tension applied to avoid gaps between the layers of the film or between the layers of the glass fiber may cause the film to break, causing the film to be cut between the metal conductors. I can't wrap it around. If the film is thicker than 0.40mm, the elastic repulsive force of the film is large and it is not possible to wrap the film layers tightly, resulting in gaps between the film layers and between the film and glass fiber layers. During heating and pressure molding, air bubbles are incorporated into the insulator, making it impossible to obtain an insulator with excellent hot water resistance and electrical properties. As the glass fiber, those having a shape that can be wound around a metal conduit, such as cloth, tape, roving, and mat, are used. Impregnating glass fiber
PES is represented by the following chemical structural formula, (Product name: Victorex PES, ICI Ltd., UK) In addition, PSU is represented by the following chemical structural formula. (Product name: Udel P1700, UCC Company, USA) (Product name: Astel 360, 3M Company, USA) To impregnate glass fiber with these PES or PSU, they are dissolved in a solvent and used as a varnish. As the solvent for the varnish, methylene chloride, dimethylformamide, N-methyl-
2-pyrrolidone, cyclohexanone, trichlorethylene, 1,2-dichloroethane, toluene,
Xylene, methyl ethyl ketone, dioxane, etc. are appropriately selected and used. As the metal conduit, a steel pipe or a stainless steel pipe having excellent corrosion resistance and good electrical conductivity is suitable. The length of the conduit is determined depending on the depth of the underground oil sand layer, but it is usually about 200 to 600 meters. Next, the manufacturing process of the electrode support conduit will be described. First, a metal conduit is impregnated with a polyetheretherketone resin film and a PES or PSU varnish to reduce the PES or PSU content to 20%.
After winding glass fibers of ~50% by weight alternately, the outer peripheral surface is pressurized with a pressure of 10~200Kg/ ^cm2 using a mold and heated to a temperature of 350~450℃ to form polyether ether. Ketone resin and above
Insulators can be formed by melting PES or PSU and integrating it with glass fibers. If the heating melting temperature is lower than 350°C, the melt viscosity of the polyetheretherketone resin is high, and the bubbles inside the insulator cannot be removed, making it impossible to obtain an insulator with excellent hot water resistance and electrical properties. If the heating melting temperature is higher than 450°C, thermal deterioration of PES or PSU impregnated with polyetheretherketone resin and glass fiber will occur, and an insulator with excellent hot water resistance, mechanical properties, and electrical properties cannot be obtained. Instead of this invention, polyetheretherketone resin films and glass fibers are alternately wrapped around the outer circumferential surface of a metal conduit, and the outer circumferential surface is pressed with a mold at a temperature of 350 to 450°C and a weight of 10 to 200 kg/cm. When an insulator made of a composite material of polyetheretherketone resin and glass fiber is formed by heating and pressurizing melting at a pressure ^of Bubbles are formed inside, making it impossible to obtain an insulator with excellent hot water resistance and electrical properties. Additionally, when polyamide, polycarbonate, polybutylene terephthalate, ABS, AS, or polystyrene resin is used as the thermoplastic resin impregnated into glass fibers, the insulator deteriorates due to hot water at 300°C, resulting in poor mechanical and electrical properties. It is not possible to obtain a good insulator. However, polyetheretherketone resin films and glass fibers impregnated with hot water-resistant thermoplastic resin PES or PSU are alternately wrapped around the outer circumferential surface of the metal conduit, and the outer circumferential surface is held in a mold at a predetermined temperature and pressure. The insulator according to the present invention, which is molded under heat and pressure, has no air bubbles inside the insulator and can withstand a hot water test at 300°C, making it suitable as an electrical insulator for electrode support conduits for electrical heating of oil sand layers. Become something. Next, embodiments of the electrode support conduit coated with the electrical insulator of the present invention will be described with reference to the drawings. FIG. 1 shows the lower end of an electrode support conduit covered with an electrical insulator, in which an insulator 3 formed by the method described above is provided on the outer peripheral surface of a metal conduit 2 to which an electrode 1 is coupled and supported. . In addition, the length of the metal conduit 2 is generally about 200 to 600 m.
However, since the length of each ordinary steel pipe or stainless steel pipe is 5 to 50 m, the individual pipes are inserted while being joined one after another. FIG. 2 shows a joint of metal conduits covered with an electrical insulator. When joining a metal conduit 2a coated with an insulator 3a and a metal conduit 2b coated with an insulator 3b, each of the metal conduits 2a and 2b A taper screw 5 is cut at the end, and a coupling ring 4 is used to join the parts. In that case, to prevent electrical leakage from the joint,
That is, an insulator 3c is further provided over the surface of the coupling ring 4 and the end of the metal conduit to cover it. Next, electrical insulator 3, 3a, 3b or 3c
The coating method and its properties will be explained in more detail by citing data from Examples and Comparative Examples, but the present invention is not limited to these Examples. Example 1 A tape made of polyether ether ketone resin film with a thickness of 0.10 mm and a width of 30 mm was wound in a half overlap.
2 times, wrapped around the outer circumferential surface of the metal conduit, and then
A glass fiber tape having a size of 0.20 mm and a width of 30 mm and containing 30% by weight of polyether sulfone resin (PES) was wound once in a half-overlap manner. The process of winding this polyetheretherketone resin film tape and glass fiber tape containing 30% by weight polyethersulfone resin (PES) was repeated 4 more times, for a total of 5 times. mm,
A polyetheretherketone resin film with a width of 30mm is wound once in a half-overlap manner, and a composite layer of glass fiber impregnated with polyetheretherketone resin and polyethersulfone resin (PES) with a thickness of 3.2mm is applied to the outer peripheral surface of the metal conduit. was formed. Next, the metal conduit wrapped with this composite layer was placed in a quarter mold and pressed, heated to 380°C, and a pressure of 100 kg/cm ² was applied to form polyether ether ketone resin and polyether on the conduit. A composite insulation coating of glass fiber impregnated with sulfone resin (PES) was formed. The adhesion strength (Kg/cm ² ) and withstand voltage value (KV/mm) at 25℃ of the insulator obtained in this way, and the insulator was placed in water and heated to 300℃, and then kept in hot water at 300℃ for 50 hours. The adhesion strength and withstand voltage values measured at 25° C. after the hot water test are shown in the Example 1 column of the table. Examples 2 to 12 Experiments were conducted in the same manner as in Example 1 except that the composition and molding conditions of the composite insulating layer were changed to those shown in the table, and an electrical insulator was formed on the outer peripheral surface of the metal conduit. The properties of the insulators are shown in the table as Examples 2 to 12. Example 13 Instead of half-wrapping the glass fiber tape in Example 1, the polyether sulfone resin (PES) content was
An experiment was conducted in the same manner as in Example 1, except that a glass roving containing 30% by weight and a thickness of 0.40 mm was wound in parallel on a polyetheretherketone resin film to form an electrical insulator on the outer circumferential surface of the conduit. let me,
The properties of the obtained insulator are shown in the table as Example 13. Comparative Examples 1 to 9 Experiments were conducted in the same manner as in Example 1 except that the composition or molding conditions of the composite insulating layer were changed, and an electrical insulator was formed on the outer circumferential surface of a metal conduit under conditions outside the scope of the present invention. Comparative Examples 1 to 9 show the properties of the insulators obtained.
Shown as

【table】

[Table] As is clear from the results listed in the table, the electrode supporting conduit formed with an electrical insulator according to the present invention has excellent electrical properties, mechanical properties, and hot water resistance, and The heating method has the effect of obtaining a suitable electrode support conduit used for extracting hydrocarbon underground resources.

[Brief explanation of drawings]

FIG. 1 is a partial vertical cross-sectional view of the lower end of an electrode support conduit according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view showing a connection structure of the electrode support conduit shown in FIG. 1... Electrode, 2, 2a, 2b... Metal conduit,
3, 3a, 3b, 3c...electric insulator, 4...coupling, 5...tapered screw. In addition, in each figure,
The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. An electric insulator consisting of a plurality of alternating layers of polyetheretherketone resin film layers molded under heat and pressure and glass fiber layers impregnated with polyethersulfone resin or polysulfone resin is applied to the outer peripheral surface of a metal conduit. An electrode supporting conduit for electric heating of hydrocarbon underground resources, characterized in that it is provided with. 2. The electrode supporting conduit for electric heating of hydrocarbon underground resources according to claim 1, wherein the polyetheretherketone resin film layer has a thickness in the range of 0.01 to 0.40 mm. 3. Wrap polyetheretherketone resin film and glass fiber impregnated with polyethersulfone resin or polysulfone resin multiple times alternately around the outer circumferential surface of the metal conduit, and then
A method for producing an electrode supporting conduit for electrically heating hydrocarbon underground resources, comprising an electrical insulator that is heated and pressed at 350 to 450°C and a pressure of 10 to 200 Kg/cm ² .