A special cable for oilfield deep well high pressure resistant submersible pump

Abstract

The invention discloses a special cable for oilfield deep well high-pressure submersible pumps, belonging to the technical field of electric wires and cables. The special cable for submersible pumps is composed of a conductor core, an insulating layer, a shielding layer, a filler, an explosion-proof layer, an armor layer and a sheath layer from the inside to the outside, and the raw materials of the sheath layer include: 90-100 parts of polyethylene resin, 24-32 parts of modified fillers, 15-30 parts of nitrile rubber, 5-15 parts of plasticizers, 2-5 parts of pigments, 1-3 parts of lubricants, 0.5-1 parts of ultraviolet absorbers, 0.5-1 parts of antioxidants, and 0.5-1 parts of cross-linking agents. The modified filler contains nitrogen and phosphorus, and also contains magnesium hydroxide, gas-phase silica, nano titanium dioxide and talcum powder, and the modified filler can be highly dispersed and stably present in the sheath layer, giving full play to the role, giving the sheath layer excellent and stable flame retardant and smoke suppression, wear resistance and ultraviolet resistance, etc., plus the joint effect of the explosion-proof layer, armor layer, etc., the cable of the present invention has excellent comprehensive performance.

Description

Technical Field

[0001] The invention belongs to the technical field of electric wires and cables, and in particular relates to a special cable for a deep well high-pressure resistant submersible pump in an oil field. Background Art

[0002] In the deep well working environment of oil fields, cables play an important role. The components of cables from inside to outside generally include: conductor, insulation, inner sheath, filler, outer sheath. High-voltage submersible pump cables are mainly used to power submersible electric pump units in oilfield mechanical oil production equipment. High-voltage submersible pump special cables are mainly composed of conductors, insulation layers, sheath layers and armor layers.

[0003] The wear resistance of the special cable for submersible pumps in the prior art is poor, and the wear of the cable can easily cause electrical accidents. In addition, due to the complex environment of the oil field, fires are prone to occur, and the flame retardant performance of the special cable for submersible pumps in the prior art is poor and unstable, and it cannot play a lasting and efficient flame retardant effect. Therefore, when a fire occurs, the cable cannot effectively slow down the spread of the fire, buy time for emergency treatment, and reduce losses. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a special cable for a deep well high-pressure resistant submersible pump in an oil field.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A special cable for oilfield deep well high-pressure resistant submersible pumps comprises, from inside to outside, a conductor core, an insulating layer, a shielding layer, a filling material, an explosion-proof layer, an armor layer and a sheath layer.

[0007] Furthermore, the conductor core is formed by twisting copper wires together.

[0008] Furthermore, the insulating layer is one or more of a polytetrafluoroethylene insulating layer, a polyperfluoroethylene propylene insulating layer, a cross-linked polyethylene insulating layer, and an EPDM rubber insulating layer.

[0009] Furthermore, the shielding layer is composed of polyethylene as a base material and carbon black.

[0010] Furthermore, the filler is one or more of aramid yarn, cotton thread, hemp rope, polypropylene rope and glass fiber yarn.

[0011] Furthermore, the explosion-proof layer is one or more of a polyvinyl chloride explosion-proof layer, a polyethylene explosion-proof layer, and a cross-linked polyethylene explosion-proof layer.

[0012] Furthermore, the armor layer is composed of steel strip or steel wire armor.

[0013] The mixture of liquid and gaseous hydrocarbons in deep wells of oil fields is flammable. Therefore, special cables for high-pressure submersible pumps must pay special attention to fire prevention and explosion prevention to prevent destructive damage. Adding an explosion-proof layer to the cable can slowly release the energy after the shock wave generated by the explosion, reduce the damage to the insulation caused by the shock wave overpressure, and protect the cable; adding an armor layer to the cable is to prevent the storm impact caused by the explosion from damaging the cable, and to prevent electromagnetic interference between the line and surrounding equipment. At the same time, the addition of the armor layer also improves the high-voltage and heat resistance of the cable, and extends the service life of the cable.

[0014] Furthermore, the sheath layer comprises the following raw materials in parts by weight: 90-100 parts of polyethylene resin, 24-32 parts of modified filler, 15-30 parts of nitrile rubber, 5-15 parts of plasticizer, 2-5 parts of pigment, 1-3 parts of lubricant, 0.5-1 parts of ultraviolet absorber, 0.5-1 parts of antioxidant, and 0.5-1 parts of cross-linking agent.

[0015] Furthermore, the modified filler is prepared by the following steps:

[0016] S1. Add 2-amino-4,6-dichloro-S-triazine, diallyl chlorophosphate and dimethyl sulfoxide into a dry three-necked flask, stir until completely dissolved, then slowly add 20wt% sodium hydroxide solution, react for 8h in an ice water bath (0°C), then add deionized water, shake and let stand for stratification, measure the pH of the aqueous phase to be neutral, take the organic phase and dry it with anhydrous sodium sulfate, filter it, and distill the filtrate under reduced pressure to obtain intermediate 1; the molar ratio of 2-amino-4,6-dichloro-S-triazine to diallyl chlorophosphate is 0.1mol:0.22mol;

[0017] The -NH2 of 2-amino-4,6-dichloro-S-triazine and the -Cl of diallyl chlorophosphate undergo a nucleophilic substitution reaction under alkaline conditions. The reaction process is as follows:

[0018]

[0019] S2, add intermediate 1, 10wt% sodium carbonate solution and dimethyl sulfoxide into a dry three-necked flask, stir and dissolve, heat to 60°C, slowly add a mixed solution of stearyl alcohol and dimethyl sulfoxide, and keep warm for 5 hours. After the reaction is completed, cool to room temperature and then add deionized water. After shaking, stand and separate. After the pH of the aqueous phase is measured to be neutral, take the organic phase and dry it with anhydrous magnesium sulfate, filter it, and distill the filtrate under reduced pressure to obtain intermediate 2; the amount ratio of intermediate 1 to stearyl alcohol is 45.3g:27g;

[0020] Under heating conditions, the molar ratio of intermediate 1 to stearyl alcohol is controlled to be 1:1.05-1.1, then -Cl of intermediate 1 and -OH of stearyl alcohol undergo substitution reaction, and the reaction process is as follows:

[0021]

[0022] S3, add intermediate 2, 10wt% sodium carbonate solution and dimethyl sulfoxide into a dry three-necked flask, stir and dissolve, then heat to 60°C, slowly add 1,4-butanediol, keep warm and react for 3h, cool to room temperature after the reaction, add deionized water, shake and let stand to separate, measure the pH of the aqueous phase to be neutral, take the organic phase and dry it with anhydrous magnesium sulfate, filter it, and distill the filtrate under reduced pressure to obtain intermediate 3; the usage ratio of intermediate 2 and 1,4-butanediol is 61g:8.1mL;

[0023] Under heating conditions, the molar ratio of intermediate 2 and 1,4-butanediol is controlled to be 1:1.05-1.1, then -Cl of intermediate 2 and -OH of 1,4-butanediol undergo substitution reaction, and the reaction process is as follows:

[0024]

[0025] S4. Add intermediate 3, DMAP (4-dimethylaminopyridine) and DMF (N,N-dimethylformamide) to a dry three-necked flask, stir and heat to 60°C, then slowly add maleic anhydride and keep warm for 12 hours. After the reaction is completed, filter out the precipitate, wash the filtrate with saturated brine, quickly dry with anhydrous magnesium sulfate, and distill under reduced pressure to obtain intermediate 4; the usage ratio of intermediate 3, maleic anhydride, DMAP and DMF is 38.5g:5.7g:0.16g:180mL;

[0026] Under the catalytic action of DMAP, the molar ratio of intermediate 3 to maleic anhydride is controlled to be 1:1.1-1.2, and then intermediate 3 and maleic anhydride undergo esterification reaction. The reaction process is as follows:

[0027]

[0028] S5. Add inorganic filler, intermediate 4 and DMF into a dry three-necked flask, stir thoroughly until mixed, then slowly add concentrated sulfuric acid, stir and heat to 110°C for 6 hours after adding, cool to room temperature after the reaction, filter, wash with deionized water until the filtrate is neutral, and then dry the filter residue at 110°C for 12 hours to obtain a modified filler; the amount ratio of inorganic filler, intermediate 4, concentrated sulfuric acid and DMF is 80g:10g:0.7mL:200mL.

[0029] Furthermore, the inorganic filler in step S5 is a mixture of magnesium hydroxide, fumed silica, nano-titanium dioxide and talc in a mass ratio of 6:3:3:4.

[0030] The surfaces of magnesium hydroxide, fumed silica, nano-titanium dioxide and talc all contain abundant hydroxyl groups, which can undergo esterification reaction with the carboxyl group of the intermediate 4 under the catalytic action of concentrated sulfuric acid, thereby preparing a modified filler.

[0031] The surface of the modified filler is rich in halogen-free flame retardant elements nitrogen and phosphorus, which work synergistically to give the sheath layer an efficient and safe flame retardant effect.

[0032] The modified filler also contains magnesium hydroxide, fumed silica, nano titanium dioxide and talc.

[0033] When magnesium hydroxide is decomposed by heat, it absorbs heat and releases water. This property enables it to effectively dilute the oxygen on the surface of the burning object during the flame retardant process, thereby inhibiting the generation of smoke. In addition, the active magnesium oxide generated by the decomposition of magnesium hydroxide will adhere to the surface of the burning object, further preventing the combustion from proceeding, and will not release harmful substances during the entire flame retardant process. Therefore, adding modified fillers containing magnesium hydroxide into the cable sheath layer can make the sheath layer have flame retardant and smoke suppression properties.

[0034] Fumed silica has the characteristics of small particle size, large specific surface area and high surface activity, which enables it to play a thickening and thixotropic role in the cable sheath layer, thereby enhancing the wear resistance of the cable.

[0035] Adding nano titanium dioxide into the cable sheath can give it good UV resistance.

[0036] Talc powder has many functions such as lubrication, isolation, insulation, cost reduction and weather resistance. In addition, talcum powder has strong adsorption capacity and can absorb impurities and moisture generated in the cable production process to keep the cable clean and dry.

[0037] The modified filler is prepared by grafting the intermediate 4 onto the surface of the inorganic filler through an esterification reaction. The surface of the modified filler contains lipophilic ester groups, ether bonds and long carbon chains, which greatly promote the compatibility between the modified filler and the other raw materials of the sheath layer. In addition, the surface of the modified filler also contains abundant carbon-carbon double bonds, which can react chemically with the unsaturated double bonds at the end of the polyethylene resin under the action of the cross-linking agent, and then cross-link with the polyethylene resin to form a stable network structure, thereby improving the corrosion resistance of the sheath layer. The network structure also enables the modified filler to not only be further dispersed in the sheath layer, but also to exist more stably in the sheath layer, giving full play to its role, thereby improving the flame retardancy, smoke suppression, wear resistance, UV resistance, corrosion resistance and insulation properties of the sheath layer.

[0038] Furthermore, the plasticizer is one or more of diethylene glycol dibenzoate, 2,2,4-trimethylpentanediol isobutyl ester, and dioctyl phthalate.

[0039] Furthermore, the pigment is one or more of Pigment Red 254, Phthalocyanine Red, Azo Orange, Azo Yellow, Phthalocyanine Blue, Phthalocyanine Green, and Carbon Black.

[0040] Furthermore, the lubricant is one or more of paraffin, polyethylene wax, stearic acid, sodium stearate, magnesium stearate, zinc stearate, butyl stearate, and ethylene bisstearamide.

[0041] Furthermore, the ultraviolet absorber is one or more of ultraviolet absorber UV-531, ultraviolet absorber UV-9, light stabilizer AM-101, light stabilizer GW-540, and light stabilizer 744.

[0042] Furthermore, the antioxidant is one or more of antioxidant 2246, antioxidant 1010, antioxidant 1076, antioxidant DLTDP, and antioxidant 168.

[0043] Furthermore, the cross-linking agent is one or both of benzoyl peroxide and triallyl isocyanurate.

[0044] Beneficial effects of the present invention: the modified filler of the present invention contains halogen-free flame retardant elements of nitrogen and phosphorus, and also contains flame retardant and smoke suppressing magnesium hydroxide, wear-resistant gas-phase silica, UV-resistant nano titanium dioxide and talcum powder with good insulation performance and good corrosion resistance. In addition, the modified filler has good compatibility with other raw materials of the sheath layer and forms a mutually cross-linked network structure with the polyethylene resin. The modified filler can be highly dispersed and stably present in the sheath layer, and play its role to the maximum extent, giving the sheath layer excellent and stable flame retardant and smoke suppressing properties, wear resistance and UV resistance and other properties. In addition, due to the combined effects of explosion-proof layer, armor layer, etc., the special cable for submersible pumps of the present invention has excellent comprehensive performance. DETAILED DESCRIPTION

[0045] The following will be combined with 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, not all of the embodiments. 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.

[0046] Example 1

[0047] The specific steps for preparing the modified filler are as follows:

[0048] 16.5 g of 2-amino-4,6-dichloro-S-triazine, 43.2 g of diallyl chlorophosphate and 200 mL of dimethyl sulfoxide were added to a 500 mL dry three-necked flask, stirred until completely dissolved, and then 36 mL of 20 wt% sodium hydroxide solution was slowly added. After the addition was completed, the mixture was reacted in an ice-water bath (0°C) for 8 h, and then deionized water was added. After shaking, the mixture was allowed to stand for stratification. After the pH of the aqueous phase was measured to be neutral, the organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure to obtain intermediate 1;

[0049] S2, add 45.3g of intermediate 1, 40mL of 10wt% sodium carbonate solution, and 170mL of dimethyl sulfoxide into a 500mL dry three-necked flask, stir and dissolve, then heat to 60°C, slowly add a mixed solution of 27g of stearyl alcohol and 50mL of dimethyl sulfoxide, and keep warm for 5h. After the reaction is completed, cool to room temperature and then add deionized water. After shaking, stand and separate. After the pH of the aqueous phase is measured to be neutral, take the organic phase and dry it with anhydrous magnesium sulfate, then filter, and distill the filtrate under reduced pressure to obtain intermediate 2;

[0050] S3, add 61g of intermediate 2, 42mL of 10wt% sodium carbonate solution, and 220mL of dimethyl sulfoxide into a 500mL dry three-necked flask, stir to dissolve, then heat to 60°C, slowly add 8.1mL of 1,4-butanediol, and keep warm for 3h. After the reaction is completed, cool to room temperature and then add deionized water. After shaking, stand and separate. After the pH of the aqueous phase is measured to be neutral, take the organic phase and dry it with anhydrous magnesium sulfate, filter it, and distill the filtrate under reduced pressure to obtain intermediate 3;

[0051] S4, add 38.5g of intermediate 3, 0.16g of DMAP and 180mL of DMF to a 500mL dry three-necked flask, stir and heat to 60°C, then slowly add 5.7g of maleic anhydride, keep warm and react for 12h, after the reaction is completed, filter and remove the precipitate, wash the filtrate with saturated brine, quickly dry with anhydrous magnesium sulfate, and distill under reduced pressure to obtain intermediate 4;

[0052] S5. Add 30g of magnesium hydroxide, 15g of fumed silica, a mixture of 15g of nano-titanium dioxide and 20g of talc, 10g of intermediate 4 and 200mL of DMF into a 500mL dry three-necked flask, stir thoroughly until mixed, then slowly add 0.7mL of concentrated sulfuric acid, stir after adding, heat to 110℃ and react for 6h, cool to room temperature after the reaction, filter, wash with deionized water until the filtrate is neutral, and then dry the filter residue at 110℃ for 12h to obtain a modified filler.

[0053] Example 2

[0054] The specific steps for preparing the modified filler are as follows:

[0055] 30 g of magnesium hydroxide, 15 g of fumed silicon dioxide, 15 g of nano titanium dioxide and 20 g of talc were fully mixed to obtain a modified filler.

[0056] Example 3

[0057] Prepare the sheath layer, the specific steps are as follows:

[0058] 90 parts of polyethylene resin, 15 parts of nitrile rubber, 24 parts of the modified filler prepared in Example 1, 5 parts of dioctyl phthalate, 2 parts of Pigment Red 254, 1 part of polyethylene wax, 0.5 parts of ultraviolet absorber UV-531, 0.5 parts of antioxidant 2246, and 0.5 parts of triallyl isocyanurate were weighed by weight and mixed evenly, extruded into granules at 160°C, and then extruded into a sheath layer.

[0059] Example 4

[0060] Prepare the sheath layer, the specific steps are as follows:

[0061] 95 parts of polyethylene resin, 25 parts of nitrile rubber, 30 parts of modified filler prepared in Example 1, 12 parts of 2,2,4-trimethylpentanediol isobutyl ester, 4 parts of carbon black, 1 part of zinc stearate, butyl stearate, 1 part of ethylene bisstearamide, 0.6 parts of ultraviolet absorber UV-9, 0.1 parts of light stabilizer AM-101, 0.1 parts of light stabilizer GW-540, 0.6 parts of antioxidant 1010, 0.2 parts of antioxidant 168, and 0.8 parts of benzoyl peroxide were weighed by weight and mixed evenly, extruded into granules at 170°C, and then extruded into a sheath layer.

[0062] Example 5

[0063] Prepare the sheath layer, the specific steps are as follows:

[0064] 100 parts of polyethylene resin, 30 parts of nitrile rubber, 32 parts of modified filler obtained in Example 1, 10 parts of diethylene glycol dibenzoate, 5 parts of 2,2,4-trimethylpentanediol isobutyl ester, 2 parts of phthalocyanine blue, 3 parts of phthalocyanine green, 1 part of paraffin, 1 part of butyl stearate, 1 part of ethylene bisstearamide, 0.7 parts of ultraviolet absorber UV-531, 0.3 parts of light stabilizer 744, 0.6 parts of antioxidant 1076, 0.2 parts of antioxidant DLTDP, 0.2 parts of antioxidant 168, 0.5 parts of benzoyl peroxide, and 0.5 parts of triallyl isocyanurate are weighed by weight and mixed evenly, extruded into granules at 180°C, and then extruded into a sheath layer.

[0065] Example 6

[0066] Prepare special cables for submersible pumps. The specific steps are as follows:

[0067] Copper wires are twisted together to obtain a conductor core; an EPDM rubber insulation layer and a shielding layer composed of polyethylene as a base material and carbon black are co-extruded and extrusion coated on the outside of the conductor core; then a cross-linked polyethylene explosion-proof layer is coated on the outside by extrusion coating, aramid filaments are filled between the explosion-proof layer and the shielding layer, and then an armor layer composed of steel belt armor and a sheath layer prepared in Example 3 are sequentially coated on the outside of the explosion-proof layer by a wrapping method, thereby preparing a special cable for submersible oil pumps.

[0068] Example 7

[0069] Prepare special cables for submersible pumps. The specific steps are as follows:

[0070] Copper wires are twisted together to obtain a conductor core; a polyperfluoroethylene propylene insulation layer and a shielding layer composed of polyethylene as a base material and carbon black are co-extruded and extrusion coated on the outside of the conductor core; then, a polyethylene explosion-proof layer is coated on the outside by extrusion coating, a polypropylene rope is filled between the explosion-proof layer and the shielding layer, and then an armor layer composed of steel wire armor and a sheath layer prepared in Example 4 are sequentially coated on the outside of the explosion-proof layer by a wrapping method, thereby preparing a special cable for submersible oil pumps.

[0071] Example 8

[0072] Prepare special cables for submersible pumps. The specific steps are as follows:

[0073] Copper wires are twisted together to obtain a conductor core; a polytetrafluoroethylene insulation layer and a shielding layer composed of polyethylene as a base material and carbon black are co-extruded and extrusion coated on the outside of the conductor core; then, a polyvinyl chloride explosion-proof layer is coated on the outside by extrusion coating, glass fiber is filled between the explosion-proof layer and the shielding layer, and then an armor layer composed of steel belt armor and a sheath layer prepared in Example 5 are sequentially coated on the outside of the explosion-proof layer by a wrapping method, thereby preparing a special cable for submersible oil pumps.

[0074] Comparative Example 1

[0075] Prepare the sheath layer, the specific steps are as follows:

[0076] The remaining steps remain unchanged, only the modified filler in Example 3 is replaced by the modified filler prepared in Example 2 to prepare the sheath layer.

[0077] Comparative Example 2

[0078] Prepare the sheath layer, the specific steps are as follows:

[0079] The remaining steps remain unchanged, only the modified filler in Example 3 is replaced by 21 parts of the modified filler prepared in Example 2 and 3 parts of DTFR-TPP halogen-free flame retardant produced by Suzhou Dongtuo Chemical Co., Ltd. to prepare the sheath layer.

[0080] Comparative Example 3

[0081] Prepare the sheath layer, the specific steps are as follows:

[0082] The remaining steps remain unchanged, only the modified filler in Example 3 is removed to prepare the sheath layer.

[0083] Comparative Example 4

[0084] Prepare special cables for submersible pumps. The specific steps are as follows:

[0085] The remaining steps remain unchanged, only the sheath layer of Example 6 is replaced by the sheath layer prepared in Comparative Example 1, thereby preparing a special cable for a submersible pump.

[0086] Comparative Example 5

[0087] Prepare special cables for submersible pumps. The specific steps are as follows:

[0088] The remaining steps remain unchanged, only the sheath layer of Example 6 is replaced by the sheath layer prepared in Comparative Example 2, thereby preparing a special cable for a submersible pump.

[0089] Comparative Example 6

[0090] Prepare special cables for submersible pumps. The specific steps are as follows:

[0091] The remaining steps remain unchanged, only the sheath layer of Example 6 is replaced by the sheath layer prepared in Comparative Example 3, thereby preparing a special cable for a submersible oil pump.

[0092] Performance Testing

[0093] According to the standard, the outer protective layers prepared in Examples 3-5 and Comparative Examples 1-3 were prepared into corresponding samples and the following performance tests were performed:

[0094] The limiting oxygen index test refers to GB / T2406, and the sample size is 130×6.5×3mm 3 ; Combustion performance test refers to GB / T2408-2008, sample size is 100×13×3mm 3 According to the duration of the continuous burning of the sample flame, the vertical burning grade is divided into V-0, V-1, V-2 and no grade (no grade is indicated by " / "); the wear resistance test is carried out with a universal friction and wear tester (the test load is 10N and the speed is 200r / min), and the wear resistance of the sheath layer is evaluated by the friction factor test; the test results of all items are shown in Table 1 below:

[0095] Table 1

[0096]

[0097] It can be seen from the test results in Table 1 above that the sheath layer prepared in Examples 3-5 of the present invention has efficient and safe flame retardant effect and excellent wear resistance.

[0098] The special cables for submersible pumps prepared in Examples 6-8 and Comparative Examples 4-6 were made into corresponding samples according to different test standards, and the following performance tests were carried out. The test results are shown in Table 2:

[0099] Table 2

[0100]

[0101] It can be seen from the test results that the special cables for submersible pumps prepared in Examples 6-8 have good flame retardancy and smoke suppression properties and can be used in deep wells in oil fields.

[0102] Ground shock wave overpressure test of explosion-proof cable: The cables prepared in Examples 6-8 were subjected to ground shock wave overpressure tests (shock wave 5.5 MPa); the insulation resistance and conductor conductivity of the cables prepared in Examples 6-8 before and after the test were tested in accordance with 18.2.5 of "Extruded Insulation Explosion-proof Power Cable" (Q / YXFB01-20), and the conductivity was tested with a multimeter, and the insulation resistance was tested with a megohmmeter; the test results of all items are shown in Table 3:

[0103] Table 3

[0104]

[0105] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0106] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A special cable for oilfield deep well high-pressure submersible pumps, which comprises, from inside to outside, a conductor core, an insulation layer, a shielding layer, a filler, an explosion-proof layer, an armor layer and a sheath layer, characterized in that: The sheath layer comprises the following raw materials in parts by weight: 90-100 parts of polyethylene resin, 24-32 parts of modified filler, 15-30 parts of nitrile rubber, 5-15 parts of plasticizer, 2-5 parts of pigment, 1-3 parts of lubricant, 0.5-1 parts of ultraviolet absorber, 0.5-1 parts of antioxidant, and 0.5-1 parts of cross-linking agent; Wherein, the modified filler is prepared by the following steps: S1. Add 2-amino-4,6-dichloro-S-triazine, diallyl chlorophosphate and dimethyl sulfoxide into a flask, stir and add 20wt% sodium hydroxide solution, react at 0°C for 8h, add deionized water, separate the layers, measure the pH of the aqueous phase, dry the organic phase, filter, and distill the filtrate under reduced pressure to obtain intermediate 1; the molar ratio of 2-amino-4,6-dichloro-S-triazine to diallyl chlorophosphate is 0.1mol:0.22mol; S2, add intermediate 1, 10wt% sodium carbonate solution and dimethyl sulfoxide into a flask, stir and heat to 60°C, add stearyl alcohol and dimethyl sulfoxide, react for 5h, cool, add deionized water, separate, measure the pH of the aqueous phase, take the organic phase, dry, filter, and distill the filtrate under reduced pressure to obtain intermediate 2; the usage ratio of intermediate 1 to stearyl alcohol is 45.3g:27g; S3, add intermediate 2, 10wt% sodium carbonate solution and dimethyl sulfoxide into a flask, stir and heat to 60°C, add 1,4-butanediol, react for 3h, cool, add deionized water, separate layers, measure the pH of the aqueous phase, dry the organic phase, filter, and distill the filtrate under reduced pressure to obtain intermediate 3; the usage ratio of intermediate 2 and 1,4-butanediol is 61g:8.1mL; S4, add intermediate 3, DMAP and DMF to a flask, stir and heat to 60°C, add maleic anhydride to react for 12h, filter, wash the filtrate, dry, and distill under reduced pressure to obtain intermediate 4; the amount ratio of intermediate 3, maleic anhydride, DMAP and DMF is 38.5g:5.7g:0.16g:180mL; S5. Add inorganic filler, intermediate 4 and DMF into a flask, add concentrated sulfuric acid after stirring, react at 110°C for 6 hours, cool, filter, wash, and dry the filter residue to obtain a modified filler; the dosage ratio of inorganic filler, intermediate 4, concentrated sulfuric acid and DMF is 80g:10g:0.7mL:200mL; the inorganic filler is a mixture of magnesium hydroxide, fumed silica, nano-titanium dioxide and talc in a mass ratio of 6:3:3:

4.

2. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The conductor core is formed by twisting copper wires together; the insulation layer is one or more of a polytetrafluoroethylene insulation layer, a polyperfluoroethylene propylene insulation layer, a cross-linked polyethylene insulation layer, and an EPDM rubber insulation layer.

3. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The shielding layer is composed of polyethylene as the base material and carbon black; the filling material is one or more of aramid yarn, cotton thread, hemp rope, polypropylene rope and glass fiber yarn.

4. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The explosion-proof layer is one or more of a polyvinyl chloride explosion-proof layer, a polyethylene explosion-proof layer, and a cross-linked polyethylene explosion-proof layer; the armor layer is composed of steel belts or steel wire armor.

5. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The plasticizer is one or more of diethylene glycol dibenzoate, 2,2,4-trimethylpentanediol isobutyl ester, and dioctyl phthalate; the pigment is one or more of pigment red 254, phthalocyanine red, azo orange, azo yellow, phthalocyanine blue, phthalocyanine green, and carbon black.

6. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The lubricant is one or more of paraffin wax, polyethylene wax, stearic acid, sodium stearate, magnesium stearate, zinc stearate, butyl stearate, and ethylene bis stearamide.

7. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The ultraviolet absorber is one or more of the ultraviolet absorber UV-531, ultraviolet absorber UV-9, light stabilizer AM-101, light stabilizer GW-540, and light stabilizer 744.

8. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 2246, antioxidant 1010, antioxidant 1076, antioxidant DLTDP, and antioxidant 168.

9. The cable for oilfield deep well high pressure submersible pump according to claim 1, characterized in that: The cross-linking agent is one or both of benzoyl peroxide and triallyl isocyanurate.

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