Continuous metal armored cable and preparation method thereof

Abstract

The invention discloses a preparation method of a continuous metal armored cable, and the method comprises the steps: enabling a wire to automatically penetrate into a magnesium oxide ring, and obtaining a wire coil with the magnesium oxide ring; simultaneously disassembling the obtained steel coil and the wire coil with the magnesium oxide ring, and placing the wire coil with the magnesium oxide ring at the center of the steel belt forming the steel coil; carrying out U forming and O forming treatment on the steel belt, and carrying out straight seam welding on the formed pipe to obtain an armored outer protection pipe; performing deformation drawing treatment and heat treatment on the armored outer protection pipe to obtain a continuous metal armored cable; the wire, the magnesium oxide ring and the steel belt are determined according to a heater connected with a cable and a heating target layer where the heater is located. The production process of the straight slit continuous pipe is wide in application, suitable corrosion-resistant alloy can be selected according to environmental requirements, the high-temperature endurance strength and the corrosion resistance of the armored outer protection pipe are guaranteed, meanwhile, the wires and the insulating magnesium oxide rings are continuously filled while the continuous pipe is formed, and the production efficiency can be greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas production, and in particular to a continuous metal armored cable and a preparation method thereof. Background Art

[0002] The exploitation of heavy oil resources in Liaohe Oilfield and Xinjiang Oilfield in my country mostly adopts steam injection, steam drive, and steam-assisted gravity drainage (SAGD) to increase the internal pressure and temperature of heavy oil formations, reduce the viscosity of heavy oil, and improve the fluidity of heavy oil. The heat generated by heating can gasify the light components inside the heavy oil, making it easier for the heavy oil to separate from the oil sand, significantly increasing the production of heavy oil. The general temperature of steam injection is about 300℃~350℃, but due to heat loss in the process of high-temperature and high-pressure steam being transported to the reservoir, the steam drops and affects the production. In order to compensate the temperature of underground water vapor or directly generate high-temperature steam in situ underground, and ensure the temperature and dryness conditions of the steam, and maximize the production capacity of on-site heavy oil development, the oil field has developed an underground high-power heater.

[0003] In order to place the heater at the target layer, a cable of 1000 to 1500 meters long must be connected from the ground to bear the weight of the heater and transmit electrical characteristics. However, since the cable is in a high-temperature steam environment of 300°C for a long time, the strength of the outer armor metal tube of the commonly used cable drops sharply, the outer wall corrodes at high temperature, and the circumferential weld is prone to cracking. Summary of the invention

[0004] The object of the present invention is to provide a continuous metal armored cable and a preparation method thereof, so as to solve the above-mentioned technical problems.

[0005] To achieve the above object, the present invention provides a method for preparing a continuous metal armored cable, the method comprising:

[0006] Automatically threading the wire into the magnesium oxide ring to obtain a wire coil with the magnesium oxide ring;

[0007] The obtained steel coil and the wire coil with the magnesium oxide ring are simultaneously unpacked, and the wire coil with the magnesium oxide ring is placed at the center of the steel strip forming the steel coil;

[0008] The steel strip is subjected to U-forming and O-forming treatments, and the formed pipe is subjected to straight seam welding to obtain an armored outer protective pipe;

[0009] The armored outer sheath is subjected to deformation drawing and heat treatment to obtain a continuous metal armored cable;

[0010] The conductive wire, the magnesium oxide ring and the steel belt are determined according to the heater connected to the cable and the heating target layer where the heater is located.

[0011] The present invention also provides a continuous metal armored cable, which comprises, from outside to inside, an armored outer protective tube obtained by straight seam welding of steel strips, a magnesium oxide ring, and a conductor;

[0012] Wherein, the conductive wire is arranged inside the magnesium oxide ring; the conductive wire, the magnesium oxide ring and the steel belt are determined according to the heater connected to the cable and the heating target layer where the heater is located.

[0013] Technical effects and advantages of the present invention:

[0014] The prior art is to fill a single seamless tube of 10 to 20 meters in length with a conductor and an insulating material, and then connect it to a coiled cable of the required length by means of a ring weld. This method is prone to weld cracking due to repeated bending of the weld during coiling and use, and the preparation method is lengthy, the process is unreasonable, and the production efficiency is low. The present invention combines the straight seam welding process for obtaining the armored outer protective tube with the drawing and compacting process of the internal insulating magnesium oxide ring, which not only achieves the high-strength and corrosion-resistant characteristics of the armored outer protective tube, but also ensures the electrical properties of the copper wire and its insulation requirements.

[0015] The present invention has the following advantages: 1. The straight seam continuous pipe production process is widely used, and suitable corrosion-resistant alloys can be selected according to environmental requirements to ensure the high-temperature long-lasting strength and corrosion resistance of the armored outer protective pipe; 2. While the continuous pipe is being formed, the conductors and insulating magnesium oxide rings are continuously filled, which can greatly improve the production efficiency; 3. The multi-pass small deformation drawing and online heat treatment process take into account the performance of the armored outer protective pipe and also ensure the electrical characteristics and insulation requirements of the internal conductors; 4. The length of the coiled cable can be flexibly adjusted according to the depth of the underground heating target layer; 5. The coiled cable can choose high-temperature resistant stainless steel as the outer armor metal pipe, or a composite of high-strength carbon steel and stainless steel sheathing.

[0016] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a method for preparing a continuous metal armored cable;

[0018] Figure 2 is a schematic diagram of the interface of the magnesium oxide ring structure;

[0019] Figure 3 is the overall schematic diagram of the magnesium oxide ring;

[0020] Figure 4 is a cross-sectional view of a continuous metal armored cable;

[0021] Figure 5 This is the U-molding and O-molding structure diagram. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings provided by the present invention, and the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0024] The present invention discloses a method for preparing a continuous metal armored cable. Figure 1 A detailed explanation of the method is given below:

[0025] S1: Automatically insert the wire into the magnesium oxide ring to obtain a wire roll with the magnesium oxide ring.

[0026] Specifically, use an automatic threading machine to simultaneously and continuously thread one or three copper wires (of course, other numbers of wires can also be used, and the wires can also be other wires) into single-hole or three-hole magnesium oxide rings of equal length (similarly, the number of holes in the magnesium oxide ring can also be changed according to needs), such as Figure 2 As shown. The assembled copper wire with magnesium oxide ring is wound on a reel to obtain a wire coil with magnesium oxide ring. The magnesium oxide ring is composed of many short sections, such as Figure 3 As shown,

[0027] Before step 1, it is also necessary to calculate the specifications of the conductor, magnesium oxide ring and steel strip. Specifically, the required electrical characteristics of the cable are calculated according to the power of the heater, and the minimum cross-sectional area of ​​a single or multiple conductors, as well as the outer diameter, hole layout position, hole diameter and other structural dimensions of the magnesium oxide ring are calculated according to the electrical characteristics requirements; the total length and hanging weight of the cable are obtained according to the depth of the heating target layer, and the outer diameter and wall thickness of the armored outer protective tube are designed in combination with the annular space size of the cable and the oil pipe, and then the steel strip with appropriate wall thickness and width is selected.

[0028] S2-S3: The obtained steel coil and the wire coil with the magnesium oxide ring are simultaneously unpacked, and the wire coil with the magnesium oxide ring is placed at the center of the steel strip forming the steel coil.

[0029] Specifically: disassemble the steel belt, grind both sides and make the grooves, and at the same time disassemble the wire coil with the magnesium oxide ring and place it in the center of the steel belt.

[0030] S4-S5: The steel strip is subjected to U-forming and O-forming treatments, and the formed tube is subjected to straight seam welding to obtain an armored outer protective tube, such as Figure 5 shown.

[0031] Specifically, the steel strip is subjected to U-forming and O-forming in sequence by using rollers of different angles (of course, O-forming can also be performed directly) to obtain a tube. The inner diameter of the O-shaped steel strip is equal to the outer diameter of the magnesium oxide ring, and the gap at the root of the groove on both sides is 2mm±0.5mm.

[0032] The steel strip is welded into a tube, which is called an armored outer protective tube. Preferably, the present invention obtains the armored outer protective tube by online straight seam TIG welding. Specifically, the weld can be welded in one pass or three passes (i.e., root weld, filler weld and cap weld) according to the thickness of the armored outer protective tube. Generally, the outer protective tube of a high-power cable is thicker, and three passes of welding are used to ensure that the temperature difference of each weld is less than 100°C.

[0033] S6-S7: The armored outer protective tube is subjected to deformation, drawing and heat treatment to obtain a continuous metal armored cable.

[0034] Specifically, in order to ensure the compactness of the insulating magnesium oxide material, the armored outer sheath is drawn. That is, according to the cold workability of the outer sheath material, multiple small deformation drawing is adopted until the designed outer diameter size is met. An annealing and softening process can also be added in the middle of the drawing process to reduce the difficulty of drawing and avoid cracking.

[0035] The continuous cable is heat treated online using an induction heating furnace of a certain length (i.e. the length of the magnesium oxide ring), taking into account the high temperature strength and corrosion resistance of the outer sheath and the electrical properties of the inner conductor, and undergoing solution treatment, tempering treatment or annealing treatment to remove residual stress at a specific temperature, insulation time and cooling method.

[0036] S8: Wrapping tape. If the armored outer protective tube is made of high-strength corrosion-resistant material, this step can be omitted. If the corrosion resistance of the outer protective tube needs to be enhanced, multiple 825 or other corrosion-resistant alloy strips with good flexibility can be used to protect the armored outer protective tube in a woven wrapping manner.

[0037] S9: Reeling. Reel the processed outer armored metal continuous tube cable onto a reel with a larger diameter, inspect, package and store.

[0038] The present invention also provides a continuous metal armored cable, such as Figure 4 As shown, it includes, from outside to inside, an armored outer protective tube 4 provided with a straight weld 3, a magnesium oxide ring 2, and a conductor 1;

[0039] The conductor 1 is arranged inside the magnesium oxide ring 2; the conductor 1, the magnesium oxide ring 2 and the steel belt are determined according to the heater connected to the cable and the heating target layer where the heater is located.

[0040] If the armored outer protective tube 4 is made of high-strength corrosion-resistant material, this step can be omitted. If the corrosion resistance of the armored outer protective tube 4 needs to be enhanced, multiple 825 or other corrosion-resistant alloy strips 5 with good flexibility can be used to protect the armored outer protective tube in a woven and wrapped manner.

[0041] Among them, the magnesium oxide ring 2 is a single-hole or three-hole magnesium oxide ring 6 (the number of holes of the magnesium oxide ring can be changed according to needs), preferably a three-hole magnesium oxide ring, such as Figure 2 shown.

[0042] In order to better understand the present invention, examples are provided below.

[0043] Example 1

[0044] S1: Sintering magnesium oxide powder ring with an outer diameter of 35 mm and a length of 50 mm, and the core is prefabricated with through holes with a diameter of 6 mm distributed at an angle of 60°;

[0045] S2: Threading. Thread three nickel-chromium alloy wires with an outer diameter of 5.8 mm into the magnesium oxide ring at the same time. After the magnesium oxide ring covers the entire length of the wire, coil it up. The length of the wire is 1.3 times the length of the outer armor steel belt;

[0046] S3: Synchronous unwinding. Select the outer armor 825 steel strip coil with a thickness of 3.5-4mm and a width of 145mm, unwind it, grind both sides, open a 60° groove, unwind the copper wire coil at the same time, and lay the wire continuously in the center of the steel strip;

[0047] S4: Steel strip forming, U forming, the inner diameter of the lower semicircle is 35mm, just wrapping the magnesium oxide ring, further O forming, ensuring that the distance from the root of the groove is about 2mm;

[0048] S5: Online automatic TIG welding, three welds, ensuring that the temperature difference of each weld is not less than 100℃;

[0049] S6: The first drawing process, after which the outer armor continuous tube diameter is reduced from 43mm to 41mm;

[0050] S7: Soft annealing, 450℃~550℃ insulation, furnace length 50m, outer armor continuous tube speed 2~3m / min;

[0051] S8: The second drawing process reduces the diameter from 41 mm to 38.1 mm;

[0052] S9: Online heat treatment, furnace length 50m, temperature 850℃~950℃, outer armor cable speed 1~2m / min;

[0053] S10: Spray water to cool to below 400°C.

[0054] S11: Roll up, inspect and store in warehouse.

[0055] Example 2

[0056] S1: Sintering a magnesium oxide powder ring with an outer diameter of 25 mm and a length of 50 mm, with the core prefabricated with through holes with a diameter of 6 mm distributed at an angle of 60°;

[0057] S2: Threading: insert three copper wires with an outer diameter of 4 mm into the magnesium oxide ring at the same time. After the magnesium oxide ring covers the entire length of the copper wire, coil it. The length of the copper wire is 1.3 times the length of the outer armor steel tape.

[0058] S3: Synchronous unwinding: select the outer armor T91 steel strip with a thickness of 2.5-3mm and a width of 110mm, unwind it, grind both sides, open a 60° groove, unwind the copper wire coil at the same time, and lay the wire continuously at the center of the steel strip;

[0059] S4: Steel strip forming, U forming, the inner diameter of the lower semicircle is 25mm, just wrapping the magnesium oxide ring, further O forming, ensuring that the distance from the root of the groove is about 2mm;

[0060] S5: Online submerged arc welding, three welds, ensuring that the temperature difference of each weld is not less than 100℃;

[0061] S6: The first drawing process, after which the outer armor continuous tube diameter is reduced from 30 mm to 28 mm;

[0062] S7: Soft annealing, 700℃~750℃ insulation, furnace length 50m, outer armor continuous tube speed 2~3m / min;

[0063] S8: The second drawing process reduces the diameter from 28 mm to 25.4 mm;

[0064] S9: Online heat treatment, furnace length 50m, temperature 700℃~800℃, outer armor cable speed 1~2m / min;

[0065] S10: Spray water to cool to below 300°C.

[0066] S11: Select three 1mm thick 825 steel strips and wrap them tightly and cross-wrap them around the outer surface of the T91 steel pipe to protect the internal cables from high temperature oxidation.

[0067] S12: Roll up, inspect and store in warehouse.

[0068] Comparative Example 1

[0069] The product in this example is a low-power cable with 15CrMo carbon steel as the outer armor material.

[0070] The cables in the above-mentioned embodiments and comparative examples were subjected to a lasting strength evaluation test and a corrosion resistance evaluation test. The experimental results are shown in Table 1.

[0071] The specific test of endurance strength evaluation is as follows: at a temperature of 350°C, a constant stress is applied to the sample for 5000 hours. The maximum stress at which the sample does not break is σ3 5 5 0 0 00 ℃.

[0072] The corrosion resistance evaluation test is specifically as follows: a high-temperature and high-pressure autoclave is used to simulate the working conditions of a steam injection well. The test temperature is 300°C, the pressure is 8.4MPa, the liquid medium is on-site boiler water, the sample is placed in a saturated wet steam environment, the test speed is 2m / s, and the test time is 720h.

[0073] Table 1 Experimental data table

[0074]

[0075] It can be seen from Table 1 that the endurance strength value in the embodiment is greater than that in the comparative example, indicating that the present invention improves the endurance strength of the cable; the oxidation weight gain rate in the embodiment is less than 0.01 g / m 2 ·h, belonging to the first level of oxidation resistance, the pitting rate is less than 0.025mm / a, belonging to the category of mild corrosion, which shows that the corrosion resistance of the cable is improved in the present invention.

[0076] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a continuous metal armored cable, It is characterized in that The method comprises: Automatically threading the wire into the magnesium oxide ring to obtain a wire coil with the magnesium oxide ring; The obtained steel coil and the wire coil with the magnesium oxide ring are simultaneously unpacked, and the wire coil with the magnesium oxide ring is placed at the center of the steel strip forming the steel coil; The steel strip is subjected to U-forming and O-forming treatments, and the formed pipe is subjected to straight seam welding to obtain an armored outer protective pipe; The armored outer sheath is subjected to deformation drawing and heat treatment to obtain a continuous metal armored cable; The conductive wire, the magnesium oxide ring and the steel belt are determined according to the heater connected to the cable and the heating target layer where the heater is located.

2. The method according to claim 1, It is characterized in that The invention relates to a method for automatically inserting a conductor into a magnesium oxide ring to obtain a conductor roll with the magnesium oxide ring, comprising: automatically inserting the conductor into the magnesium oxide ring for assembly, and winding the assembled copper wire with the magnesium oxide ring on a reel to obtain a conductor roll with the magnesium oxide ring.

3. The method according to claim 1, It is characterized in that The magnesium oxide ring is composed of a plurality of short sections.

4. The method according to claim 1, It is characterized in that The conductor, the magnesium oxide ring and the steel belt are determined according to the heater connected to the cable and the heating target layer where the heater is located, including: Determine the number of wires and the minimum cross-sectional area according to the power of the heater; According to the number of wires and the minimum cross-sectional area, determine the outer diameter, hole layout position, and hole diameter of the magnesium oxide ring; Determine the total length and hanging weight of the cable according to the depth of the target layer to be heated and the weight of the heater; Determine the outer diameter and wall thickness of the cable armored outer sheath according to the total length and hanging weight of the cable and the annular dimensions of the cable and oil pipe; Determine the steel strip based on the outer diameter and wall thickness of the cable's armored outer protective tube.

5. The method according to claim 4, It is characterized in that The formed pipe is straight-seam welded, including: one pass or three passes of welding are performed on the formed pipe according to the wall thickness of the cable armor outer protective pipe; Among them, the three welding processes include: root welding, filling welding and cap welding.

6. The method according to claim 4, It is characterized in that The armored outer sheath is subjected to deformation and drawing treatment, including: according to the cold workability of the armored outer sheath material, multiple small deformation and drawing processes are performed until the outer diameter of the armored outer sheath of the cable is met.

7. The method according to claim 1, It is characterized in that The armored outer protective tube is heat treated, including: using an induction heating furnace to perform online heat treatment on the armored outer protective tube.

8. The method according to claim 1, It is characterized in that After the deformation, drawing and heat treatment of the armored outer protective tube, the following steps are also included: After the armored outer protective tube is subjected to deformation drawing treatment and heat treatment, a treated armored outer protective tube is obtained; Determine the material of the treated armored outer sheath tube. If the material of the armored outer sheath tube is a high-strength corrosion-resistant material, the treated cable is a continuous metal armored cable. If the material of the armored outer protective tube is not a high-strength corrosion-resistant material, the armored outer protective tube is protected by using corrosion-resistant alloy strips in a woven and wrapped manner.

9. The method according to claim 1, It is characterized in that The magnesium oxide ring is a magnesium oxide ring with three holes, and the three holes form an angle of 60 degrees; the wires are three copper wires.

10. A continuous metal armored cable prepared according to any one of claims 1 to 9, It is characterized in that From outside to inside, it includes: an armored outer protective tube obtained by straight seam welding of steel strips, a magnesium oxide ring, and a conductor; Wherein, the conductive wire is arranged inside the magnesium oxide ring; the conductive wire, the magnesium oxide ring and the steel belt are determined according to the heater connected to the cable and the heating target layer where the heater is located.

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