A high-power ultra-high temperature constant temperature heating cable and its application

Abstract

The present invention belongs to the field of cable technology, and specifically relates to a high-power ultra-high temperature constant temperature heating cable and its application in the exploitation of wax-forming wells and heavy oil wells. The heating cable includes a connecting wire, a heating wire connected to one end of the connecting wire, an inner metal protective layer and an outer alloy sheath layer coated outside the inner metal protective layer, the connecting wire and the heating wire are arranged in the inner metal protective layer, and an insulating part is filled between the connecting wire, the heating wire and the inner metal protective layer. The heating cable of the present invention has the advantages of constant temperature and constant power heating, waterproof, oil-proof and corrosion-resistant, high mechanical strength, large length and long service life, which can meet the heating needs of various types of wax-forming wells and heavy oil wells, and breaks through the bottleneck of high-temperature exploitation at the bottom of oil wells.

Description

Technical Field

[0001] The invention belongs to the technical field of cables, and in particular relates to a high-power ultra-high temperature constant temperature heating cable and its application in the exploitation of wax-forming wells and heavy oil wells, which plays the role of reducing viscosity and removing wax. Background Art

[0002] The quality of crude oil in most oil fields in my country is lower than that in the Middle East. The sulfur and wax contents are relatively high, and the oil viscosity is also relatively high. The self-flowing oil wells with high initial production often have reduced self-flowing capacity even before the mid-term of oil production. This is because the wax often condenses on the wall of the oil well pipe and causes blockage, which requires regular wax removal. Wax removal is very troublesome and greatly reduces the crude oil productivity. The most primitive wax removal method is to scrape the wax. There are also other heating methods to remove the wax. Although it is more economical, it is not very convenient to use. In the process of heavy oil and high-condensation oil production, due to the high viscosity of crude oil or wax deposition in the wellbore, coupled with the skin effect of heavy oil and high-condensation oil, the production of the oil well is seriously affected, and even the oil well is shut down.

[0003] Using heating cables is a simple method. Heating cables are selected to reduce crude oil viscosity and clean wax deposits, thereby improving oil recovery efficiency. In the prior art, since the power transmission and heating oil recovery equipment for high-condensation oil and high-viscosity oil is usually composed of heating conductors, rubber or fluoroplastics, the cables of this structure have low temperature resistance when in use, the surface is easily damaged, and maintenance is difficult; when used in some oil wells, the bottom temperature is too high, and the cable has poor temperature resistance, which will cause adhesion and scrapping.

[0004] Due to the particularity of the use environment, the heating cable for oil production is required to have special properties such as waterproof, high temperature resistance, corrosion resistance, and pressure resistance. In addition, the depth of most oil fields in my country is 1000m to 5000m. Traditional heating cables only meet the heating of the oil nozzles and cannot meet the heating needs in the well and at the bottom of the well. Therefore, the present invention improves a special constant temperature heating cable for high-power ultra-high temperature oil field development, which has more superior performance and can better meet the special use environment. Summary of the invention

[0005] In order to solve the defects of the heating cables in the prior art, such as poor temperature resistance, poor corrosion resistance, easy breakage and short life, the purpose of the present invention is to provide a high-power ultra-high temperature constant temperature heating cable and its application. The heating cable of the present invention has the advantages of constant temperature and constant power heating, waterproof and oil-proof corrosion resistance, high mechanical strength, large length and long life, and can meet the heating of various wax wells and heavy oil wells, breaking through the bottleneck of high-temperature exploitation at the bottom of oil wells.

[0006] The technical solution of the present invention is specifically achieved as follows:

[0007] A high-power ultra-high temperature constant temperature heating cable comprises a connecting wire, a heating wire connected to one end of the connecting wire, an inner metal protective layer and an outer alloy sheath layer covered outside the inner metal protective layer, the connecting wire and the heating wire are arranged in the inner metal protective layer, and an insulating part is filled between the connecting wire, the heating wire and the inner metal protective layer.

[0008] Preferably, the heating wires are connected in a Y-shaped three-phase manner in the longitudinal section (that is, there are three heating wires, and the three heating wires are finally gathered at one point for connection), and the heating wires are connected. The heating wires are connected in a Y-shaped three-phase manner so that the heating cable has a higher heating power (maximum power reaches 1.5kW / m), and the heating power is constant and the heating temperature is high, and the long-term operating temperature can reach a constant temperature of 800°C.

[0009] Preferably, the connecting wire and the heating wire are wires formed by extruding and stretching a solid bar, and are both wires made of PTC (positive temperature coefficient) material.

[0010] Preferably, the solid rod material used for the connecting wire is a high-purity copper rod with a copper content of ≥99.99%; the solid rod material used for the heating wire is a high-nickel alloy rod after solid solution strengthening treatment, and the chromium content of the high-nickel alloy rod is ≥80%.

[0011] Preferably, the insulating part is compacted inorganic mineral powder, the melting point of the inorganic mineral powder is ≥2800°C, and the compacted density is ≥2.7g / cm 3 , high temperature resistance level, which extends the service life of the heating cable.

[0012] Preferably, the inorganic mineral powder is metal oxide powder, more preferably magnesium oxide powder.

[0013] Preferably, the thickness of the inner metal protective layer is ≥0.94 mm, and the thickness of the outer alloy sheath layer is ≥2.0 mm.

[0014] Preferably, the material of the inner metal protective layer is deoxidized phosphorus copper with a copper content ≥ 99.9%, which is continuously prepared from non-magnetic metal material and has properties such as waterproof, oil-resistant, high temperature resistant, and anti-interference; the outer alloy sheath layer is a multi-phase alloy with a tensile strength of ≥ 550N / mm and an elongation of ≥ 30% after solid solution strengthening treatment.

[0015] The inner and outer double-layer high-strength metal protective layer structure adopted by the present invention effectively improves the overall strength of the heating cable, ensuring that the heating cable can reciprocate, be dragged, and stretched in oil wells of thousands of meters without being damaged.

[0016] The metal protective layer structure of the present invention, under the protection of rare gas, adopts the longitudinal wrap welding continuous production process, online rolling, annealing and non-destructive testing and other technologies to ensure the overall consistency of the cable, achieve a continuous long length of the cable (maximum length reaches 5000m), effectively clear the blockage in the well and at the bottom of the well, and meet the length requirements of conventional oil well exploitation.

[0017] Preferably, the connecting wire and the heating wire are connected by drilling, nesting or crimping.

[0018] The present invention also provides an application of the high-power ultra-high temperature constant temperature heating cable in the exploitation of wax-forming wells and heavy oil wells, which solves the defects of the traditional heating cable wellhead heating, realizes the heating in the well and the bottom of the well, and greatly improves the exploitation efficiency.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The heating wire of the present invention adopts a Y-type three-phase wiring method, has a high heating power (maximum power reaches 1.5kW / m), and has a constant heating power and a high heating temperature. The long-term operating temperature can reach a constant temperature of 800°C, which solves the defects of traditional heating cables such as low heating power, low heating temperature, poor heating effect, and large temperature control deviation.

[0021] (2) The present invention adopts a double-layer seamless metal protective layer (inner metal protective layer and outer alloy sheath layer) structure, which solves the defects of traditional heating cables such as easy damage, difficult maintenance and short life.

[0022] (3) The present invention adopts the selection and combination of materials for each layer, selects high-purity copper rods for connecting wires, selects high-nickel alloy rods after solid solution strengthening treatment for heating wires, and adopts high-melting point corrosion-resistant metal oxide powder as the insulating part. The combination makes the heating cable of the present invention have the advantages of high temperature resistance and long service life (lifespan can reach more than 30 years), solves the defect of low temperature resistance of traditional heating cables, and breaks through the bottleneck of high-temperature mining at the bottom of oil wells; through a long-length continuous production process, it solves the defect of wellhead heating of traditional heating cables, realizes heating in the well and at the bottom of the well, and greatly improves the mining efficiency.

[0023] (4) The high-power ultra-high temperature constant temperature heating cable of the present invention has the advantages of constant temperature and constant power heating, waterproof and oil-proof corrosion resistance, high strength and impact resistance, large length, long service life, etc. It is suitable for the development of various oil wells in China, especially for the exploitation of wax wells and heavy oil wells with a depth of 1000m to 5000m. The performance index of the cable fully meets the production and transportation requirements of high-condensation oil and high-viscosity oil, solves the problem of high-condensation oil and high-viscosity oil exploitation, and can also be used as a new heating cable to replace traditional heating cables and ordinary heating cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0025] Figure 1 This is a schematic diagram of the structure of a high-power ultra-high temperature constant temperature heating cable according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 The cross-section diagram of the structure along the AA direction;

[0027] Figure 3 for Figure 1 The cross-section diagram of the structure along the BB direction;

[0028] In the figure: 1-connecting wire; 2-heating wire; 3-insulating part; 4-inner metal protective layer; 5-outer alloy sheath layer. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0031] Example

[0032] like Figures 1 to 3As shown, a high-power ultra-high temperature constant temperature heating cable comprises a connecting wire 1, a heating wire 2 connected to one end of the connecting wire 1, an inner metal protective layer 4 and an outer alloy sheath layer 5 coated outside the inner metal protective layer 4, wherein the connecting wire 1 and the heating wire 2 are arranged in the inner metal protective layer 4, and an insulating part 3 is filled between the connecting wire 1, the heating wire 2 and the inner metal protective layer 4. The insulating part 3 is a compacted inorganic mineral powder, the melting point of the inorganic mineral powder is ≥2800°C, and the compacted density is ≥2.7g / cm 3 The inorganic mineral powder is a metal oxide powder, and in this embodiment it is magnesium oxide powder.

[0033] The connection wire 1 and the heating wire 2 are connected by drilling, nesting or crimping. The heating wire 2 is Y-shaped three-phase connected in the longitudinal section, and the heating wires 2 are conductive. The Y-shaped three-phase connection of the heating wire 2 makes the heating cable have a higher heating power (maximum power reaches 1.5kW / m), constant heating power and higher heating temperature, and the long-term operating temperature can reach a constant temperature of 800°C.

[0034] The connecting wire 1 and the heating wire 2 are wires formed by extrusion and stretching of solid rods; the solid rod used for the connecting wire 1 is a high-purity copper rod with a copper content of ≥99.99%; the solid rod used for the heating wire 2 is a high-nickel alloy rod after solid solution strengthening treatment, and the chromium content of the high-nickel alloy rod is ≥80%.

[0035] The thickness of the inner metal protective layer 4 described in this embodiment is ≥0.94mm, and the material is deoxidized phosphorus copper with a copper content of ≥99.9%. It is a non-magnetic metal material continuously prepared and has the properties of waterproof, oil-resistant, high temperature resistant, and anti-interference; the thickness of the outer alloy sheath layer 5 is ≥2.0mm, and it is a high-strength multi-phase alloy with a tensile strength of ≥550N / mm and an elongation of ≥30% after solid solution strengthening treatment. In this embodiment, it is a nickel-iron-chromium three-phase alloy.

[0036] The inner and outer double-layer high-strength metal protective layer structure adopted by the present invention effectively improves the overall strength of the heating cable, ensuring that the heating cable can reciprocate, be dragged, and stretched in oil wells of thousands of meters without being damaged.

[0037] The metal protective layer structure of the present invention, under the protection of rare gas, adopts the longitudinal wrap welding continuous production process, online rolling, annealing and non-destructive testing and other technologies to ensure the overall consistency of the cable, achieve a large continuous length of the cable (maximum length of 5000m), effectively clear blockages in the well and at the bottom of the well, and meet the length requirements of conventional oil well exploitation.

[0038] Corrosion resistance test:

[0039] The high-power ultra-high temperature constant temperature heating cable of the present invention is used for corrosion resistance test: acid solution (HCl, pH=2.0), salt solution (5% NaCl, pH=7.0), alkaline solution (NaOH, pH=11.1), and the results show that the corrosion rate of the heating cable is less than or equal to 0.05 mm / a, and can pass the salt spray corrosion and sulfur dioxide corrosion tests specified in TB / T 3479, and meet the standard of rating greater than or equal to 10 (highest level) specified in GB / T6461.

[0040] Waterproof performance test:

[0041] The high-power ultra-high temperature constant temperature heating cable of the present invention is used for waterproof performance test: the inner metal protective layer and the outer alloy sheath layer of the present invention are immersed in water for 1 hour respectively, and then withstand a voltage of 2500V, and the result is: the insulation is not broken down.

[0042] Mechanical strength test:

[0043] The high-power ultra-high temperature constant temperature heating cable of the present invention is used for mechanical strength performance test: it passes the bending test and flattening test specified in GB / T13033.1, and the result is: the sample does not break down during the test.

[0044] The above shows that the high-power ultra-high temperature constant temperature heating cable of the present invention has the advantages of constant temperature and constant power heating, waterproof and oil-proof corrosion resistance, high strength and impact resistance, large length, long life, etc., and is suitable for the development of various domestic oil wells, especially for the exploitation of wax wells and heavy oil wells with a depth of 1000m to 5000m. The performance index of the cable fully meets the production and transportation needs of high-condensation oil and high-viscosity oil, solves the problem of high-condensation oil and high-viscosity oil exploitation, and can also be used as a new heating cable to replace traditional heating cables and ordinary heating cables.

[0045] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high-power ultra-high temperature constant temperature heating cable, characterized in that: The invention comprises a connecting wire (1), a heating wire (2) connected to one end of the connecting wire (1), and an inner metal protective layer (4) and an outer alloy sheath layer (5) covering the inner metal protective layer (4); the connecting wire (1) and the heating wire (2) are arranged in the inner metal protective layer (4); and an insulating portion (3) is filled between the connecting wire (1), the heating wire (2) and the inner metal protective layer (4); The heating wires (2) are connected in a Y-shaped three-phase manner in a longitudinal section, and the heating wires (2) are conductively connected to each other; The connecting wire (1) and the heating wire (2) are wires formed by extruding and stretching solid rods, and are both wires made of PTC materials; the solid rod used for the connecting wire (1) is a high-purity copper rod with a copper content of ≥99.99%, and the solid rod used for the heating wire (2) is a high-nickel alloy rod that has been subjected to solid solution strengthening treatment, and the chromium content of the high-nickel alloy rod is ≥80%; The inner metal protective layer (4) and the outer alloy sheath layer (5) are obtained by a longitudinal welding continuous production process, online rolling, annealing and non-destructive testing process under the protection of rare gas; the insulating part (3) is a compacted inorganic mineral powder, the melting point of the inorganic mineral powder is ≥2800°C, and the compaction density is ≥2.7g / cm³; the inorganic mineral powder is a metal oxide powder.

2. A high-power ultra-high temperature constant temperature heating cable according to claim 1, characterized in that: The thickness of the inner metal protective layer (4) is ≥0.94 mm, and the thickness of the outer alloy sheath layer (5) is ≥2.0 mm.

3. A high-power ultra-high temperature constant temperature heating cable according to claim 1 or 2, characterized in that: The material of the inner metal protective layer (4) is deoxidized phosphorus copper with a copper content of ≥99.9%, and the outer alloy sheath layer (5) is a multi-phase alloy with a tensile strength of ≥550 N / mm and an elongation of ≥30% after solid solution strengthening treatment.

4. A high-power ultra-high temperature constant temperature heating cable according to claim 1, characterized in that: The connecting wire (1) and the heating wire (2) are connected by drilling, nesting or crimping.

5. Use of the high-power ultra-high temperature constant temperature heating cable according to any one of claims 1 to 4 in the exploitation of wax-forming wells and heavy oil wells.

Images